Category Archives: Geology

What’s the Deal with LiBeB?

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If you look the chart of elemental abundances in the cosmos below, you’ll notice that beyond hydrogen and helium atomic numbers, there is a steep log-scale drop in the abundances of lithium, beryllium and boron, or just ‘LiBeB’. This is followed immediately by a sharp exponential rise in the abundance of carbon, nitrogen and oxygen, etc. Beyond oxygen there is a general downward trend in elemental abundances. Well, except for iron, Fe. It is a special case related to the demise of stars. The zig-zag in the curve is explained by the Oddo-Harkins rule which postulates that even numbered atomic numbers are more abundant. I’ll leave this to the reader to explore.

Maybe 15 years back I decided to understand why each of the LiBeB elements are so scarce. And, if they are so bloody scarce, then how do they end up concentrated in ore bodies on earth? As a first-order approximation, you’d think that the explosion of stars and the resulting rapid dispersal of matter into the surrounding space would argue against the LiBeB concentrations on a planetary body like earth.

So, here is the question: Given that the cosmic abundances of lithium, beryllium and boron (LiBeB) are dramatically smaller than the succeeding light elements, how is it that “concentrated” ore bodies containing these elements exist on Earth?

Source: Wikipedia. “Oddo–Harkins rule.” Notice that the vertical axis is a log scale.

As I look at it now, the answer is bloody obvious. But when I asked the question 15 years ago, my understanding of hydrothermal activity and fluid movement through the earth’s crust was pretty slim nonexistent. But hey, my focus in college was not astronomy or geology.

The graphic below shows how elements can be grouped according to a few particular categories. It is an absolute tragedy that the Platinum Group Metals (yellow shading) are in such the low abundance. These elements are uniquely valuable in chemical and industrial applications.

Source: Abundance of elements in Earth’s crust Wikipedia – Online Store (tiesalesm.live)

An even more fundamental question is, how is it that the cosmic abundances of lithium, beryllium, and boron are so low? Answer: they can’t survive the temperature and pressure conditions in the core of a star. They are fuels and therefore too delicate.

So LiBeB nuclei are produced during cataclysmic stellar explosions by some kind of spallation process, scattering fragments of larger nuclei into space. Another theory claims that cosmic radiation is responsible for the spallation of larger nuclei leading to LiBeB fragments. Subsequent generations of star formation resulting from an accumulation of hydrogen, helium, and heavier elements can lead to a star system with a protoplanetary disc where mass is brought into closer proximity. Mutual gravitational attraction between dust, chunks and aggregations of solid phase matter not already drawn into the star begin over time to aggregate and form planetary bodies. Some of the larger bodies are heated to liquid phase by collisions. Smaller mass objects may remain in the solid phase. Planet or moon sized bodies can collide to produce another planetary body or just debris. A fluid body of sufficient mass will spontaneously alter its shape in the direction of spherical such that all of the mass is as close to the center of gravity as possible. A spherical planet is one in which all of the mass is as close to the center of gravity with minimum potential energy as possible. A flat, disk-shaped body does not. It is hard to say just exactly how a flat planet-sized body would form with only gravity to drive it.

A cooling but still partially molten planetary body will begin to sort its large-scale composition by density and melting point. High melting point materials near a cooler surface will form solid crystalline bodies within the magma and then settle and possibly stratify according to density, then re-melt and disperse and convect to repeat the process. With cooling, the magma becomes increasingly viscous which would be expected to slow down mixing within the magma body. Over a long period, the planetary surface will continue to cool by loss of radiant energy and eventually the surface will crust over. Planetary bodies will accumulate mass by gravitational attraction as they sweep through space in their orbits, adding whatever chemical diversity that may be falling inwards to the surface. It seems reasonable to suppose that infalling dusts, rocks and asteroids are not uniform in their total compositions and may result in a non-uniform, spotty distribution of elements on the planet.

Solidification

Well before the surface cools to the point where a gas such as water can condense to form bodies of liquid water, water vapor in the atmosphere can convect to produce clouds at altitude, releasing latent heat and further adding to the heat transfer from the planet. Eventually, liquid water on the surface of a cooling planet can carry heat energy upward by conduction from the surface and atmospheric convection upwards, releasing the latent heat of condensation as clouds form in the upper atmosphere where it is colder. Heat transferred to the atmosphere will radiate infrared energy in all directions including space. The planet has developed weather.

Source. GIA. Formation of minerals from magma. Minerals with the highest melting point begin to crystallize first, depleting the molten phase of those components. This is fractional crystallization described in Bowen’s Reaction Series.

Solidification processes in a magma begin to spontaneously partition or nucleate into particular combinations of elements. Some groups elements like silicates combine with metals into molecules (covalent bonds and ion pairs). For a period of time on any given crystalline surface, the temperature will support equilibration to and from the magma wherein ionic species will attach to the crystalline surface from the magma. With sufficient temperature, ions can detach from the surface and diffuse into the magma. This process will continue as the temperature drops freezing the magma and suppressing diffusion.

Bowen’s Reaction Series summarizes trends in the order of melting/freezing of various classes of minerals with temperature in magma. From location to location, the composition of magma is variable where some may be silicate rich and others silicate poor. That melting/freezing points of minerals vary with composition shouldn’t surprise my chemist friends.

Graphic: Shamelessly and laboriously redrawn by Sam Hill.

Reaction selectivity is driven by the sign and magnitude of Gibbs energy in a particular transformation and the ability of the combination process to be reversed at the local temperature. The formation of crystals or their dissolution in hydrothermal fluids or magma is taken to be a type of reaction. Many of the species present at magma temperatures will be ion pairs.

A few covalent species like the highly stable Si-O bonds in silicates are found in great abundance. The O of Si-O may or may not be connected to other silicon atoms such as … -O-Si-O-Si-O-Si-O-Si-O- … for examples. There is no upper limit to the number of O-Si groups possible in minerals, though their assembly can go many directions. Quartz is a 3-dimensional network homopolymer. All 4 of the oxygens on silicon are connected to adjacent silicon atoms via the oxygen linkages. Quartz is a mineral comprised of all covalent bonds. Quartz has a much higher softening temperature than manufactured glass.

Silicon readily forms tetrahedral connections with oxygen as in silicate (SiO4)4- units. Si-Si bonds are not found in nature.

In a hydrothermal fluid solution or in magma, ionic species randomly diffuse, collide or swap partners. Charged species like iron (2+) cations can collide but will bounce apart owing to their like positive charges. But at a sufficiently low temperature, a sulfide (2-) anion can collide with the oppositely charged iron (2+) cation and remain connected as iron sulfide. The two ions are now chemically bonded and in doing so, heat is released and dispersed into the surroundings leading to a localized increase in temperature. Heat spontaneously flows from high temperature material to lower temperature material. The localized heated surrounding crystallizing minerals can keep dispersing the energy outwards, but as it encounters more mass which also absorbs heat energy, the resulting temperature rise diminishes rapidly as the energy is diluted over more mass.

Chemical transformations have two broad drivers- kinetic and thermodynamic. Kinetically driven transformations favor the pathways that are the fastest Thermodynamic transformations are equilibrium-controlled meaning that transformations that are reversable will favor the end state having the lower Gibbs energy. The Gibbs energy (ΔG) combines the heat of reaction (enthalpy, H) minus the entropy (S) times the absolute temperature (T). The entropy accounts for whatever heat energy may be gained/lost from/to the environment. When a bond forming reaction occurs, heat is released and moves into the environment.

Mineral nucleation starts with a microscopic “seed crystal or compatible surface” that will provide a template to further crystal growth by like molecules. Some combinations of elements will begin to polymerize forming high melting point, low solubility molecules comprising silicates and aluminates.

The concentration of the Li or Be or B into what would later become economic ore bodies is driven by the flow of ground water. Subsurface hot water flow in the crust is referred to as hydrothermal flow and from it is where concentration of the LiBeB begins. An ore body is a mass or formation of rock that is enriched in some particular element or group of elements. Usually, these elements are part of chemical compounds rather than pure elements. Gold would be an exception.

Definition- Minerals and Rocks

Mineral– A solid substance with a well-defined chemical composition and characteristic crystal structure.

Rock– A solid, naturally occurring aggregation of minerals.

Water, and especially hot water under pressure, will chemically alter the rock it is in contact with. While it is in contact, some fraction of the altered rock will dissolve and some components may be entrained as suspended solids in the fluid. This will extract and partition part of the altered rock into a solution with a range of possible compositions depending on solubility, pH, temperature and pressure. In this way, elements get partitioned into solution phase and away from the solid phase.

Source: Wikipedia. This diagram shows felsic magma as the heat and mineral source. Felsic magma is enriched in the lighter elements like silicon, oxygen, aluminum, sodium and potassium. Because of the enhanced presence of silicates and aluminates, the magma or lava tends to be more viscous.

Hydrothermal solutions can sit in place for a very long time, eventually saturating with mineral components. If there is cooling in place, the saturated solution can precipitate to form a solid body of mineral filling the local spaces. The deeper the fluid, the warmer it will be and likely the slower it will cool. However, if the surrounding rock is porous or develops fractures or faults, the hydrothermal fluid will flow to the zone of lower pressure. If the flow is into a cooler zone, there may be precipitation of the least soluble components leading to solid mineral formation. Precipitation can also occur from a drop in pressure.

Solubility vs Temperature vs Pressure Example with Quartz

The effect of temperature and pressure on precipitation of silicate can be seen with the beautiful pressure/temperature/solubility relationship shown below. For instance, we can see that for temperatures at or below 150 oC, there is very little change in solubility of silicate with increasing pressure. On the higher side of the temperature scale at 350 oC, we see that there is a considerable solubility change with increasing pressure. At high pressure, say 700 MPa, the solubility of silicate is most sensitive to changing temperature.

Source: For educational purposes only. Williams, Randolph; Fagereng, Åke Fagereng, The Role of Quartz Cementation in the Seismic Cycle: A Critical Review, March 2022 Reviews of Geophysics 60(1), DOI:10.1029/2021RG000768

The research article above cites the solubility of SiO2 in mg/kg water, or ppm. I am using the term silicate indicating hydrated and charged SiO2, the SiO4 tetrahedral form, which is known to dissolve in water. It is common in some of the geological literature to refer to the neutral oxide form of a mineral or metal.

SiO2 is often observed in its amorphous or crystalline topological polymer (or network polymer) form as a quartz vein, pegmatite or crystalline mineral component of a felsic igneous rock. Quartz found in a vein is there because a fault or fracture was available for filling with a hydrothermal fluid. As the curve above infers, saturation and precipitation can be abrupt with a sudden drop in pressure during a fault movement or sudden opening of a fracture network. Quartz veins are often accompanied by metallic gold in the upper oxidized zones (gossan) of the formation. In the context of mining, these veins are sometimes called quartz reefs.

Back to LiBeB

Although LiBeB elements are scarce, there are hydrothermal processes in the crust that can concentrate them in economic quantities.

An excursion into ore geology shows that selective hydrothermal extraction and transport are critical to the formation of a great many types of ore bodies. In fact, all three elements of LiBeB are moved by hydrothermal fluid transport on Earth at some point.

Lithium

Lithium metal is quite reactive and not found on Earth in the neutral metallic state. It is a single-electron donating Group 1 element and the lightest atomic weight metal of all the elements. Lithium has a large standard reduction potential of -3.05 Volts and is an excellent donor of electrons and a poor acceptor of electrons.

Lithium metal reacts with three major components of air: water, to form LiOH + H2; Oxygen to form Li2O + Li2O2 + H2; and nitrogen gas to form NLi3, lithium nitride. While other air-reactive metals can be stored under a hydrocarbon like kerosene for protection, lithium will float in these liquids and may be mixed with a heavy hydrocarbon or grease to keep it covered.

Lithium deposits can be split into two general domains- brines/muds/leachates, and hard rock deposits. Spodumene is the common hard rock source of lithium found in a few places around the world. Spodumene is lithium aluminum inosilicate and has a few variants such as Hiddenite, Kunzite, and Triphane coming from trace elements present in the surrounding rock.

The Silicate Zoo section is a bonus feature and may be skipped.

Bonus: A Step into the Zoo of Silicates

Spodumene is an inosilicate. Silicates as a group make up 90 % of the Earth’s crust. The basic unit is the tetrahedral [SiO4]4- silicate with 4 oxygen corners of the tetrahedron. These are known as ortho- or nesosilicates. The 4 minus charges are balanced by 4 plus charges provided by one or several metal cations at a time. Orthosilicates are the simplest variants of silicates.

A basic silicate ion, (SiO4)-4 with cations omitted. Graphics by Arnold Ziffel.

The corner oxygen ions of silicate can be attached to the silicon of another silicate. These are called the sorosilicates and have the formula [Si2O7]6−.

A sorosilicate ion, (Si2O7)-6 with cations omitted. Two silicates sharing an oxygen. Graphics by Arnold Ziffel.

Silicate units can also form rings called cyclosilicates. The rings consist of silicate tetrahedrons with alternating linkages of silicon-oxygen atoms. The general formula is [SinO3n]2n−.

A cyclosilicate, (Si3O9)-6 with cations omitted. Commonly called ‘D3’ when pendant oxygen atoms are replaced by CH3. Graphics by Arnold Ziffel.

There are several varieties of inosilicates. As a group they link silicate units into interlocking chains. There can be a single chain (pyroxenes such as spodumene) or two (amphiboles such as asbestos). The single chain inosilicates have the formula [SinO3n]2n−. The double chain inosilicates have the formula [Si4nO11n]6n−.

Monomeric silicates can polymerize along 1, 2 or 3 dimensions and by 1 or 2 connections to other tetrahedral silicates through the sharing of oxygen atoms. Graphic: Libretexts.

Phyllosilicates are sheet structures of silicate and have the general formula [Si2nO5n]2n−. This group includes micas and clays.

The tectosilicates are 3-dimensional frameworks and have the general formula [AlxSiyO(2x+2y)]x−. Note that aluminum may be present. This tectosilicate group includes quartz, feldspars and zeolites.

If you look at all of the general formulas, note that the negative charges must be balanced with positive ions (cations) of some kind. They are typically metal cations that vary in positive charge and ionic radius, although they can be capped off with hydrogen. A metal cation with its positive charge and ionic radius can be most easily replaced by a different metal with the same charge and similar ionic radius. Different charges and ionic radii are possible replacements but cause distortions in the lattice structure.

Minerals can form such that a silicate [SiO4]4- unit can be replaced by one or more aluminate (AlO4)-4 units and the metal counterions can be substituted by other metals of the same charge and similar ionic radius.

Back to Lithium

A growing fraction of lithium exploration and production involves lithium brines. Subsurface brines enriched in lithium (up to 0.14 %) can be pumped to the surface and exposed to sunlight in large evaporation ponds. Brines are saline solutions comprised of numerous soluble ionic substances. The lithium component must be isolated to a specified level of purity prior to sale. The most common product leaving a lithium mining operation is the insoluble lithium carbonate.

The process of concentrating a mineral from the ore is called beneficiation. An ore is comprised of the target mineral and gangue or mine waste from previous activity. The idea is to use economical physical and chemical methods to remove the gangue from the target mineral.

The largest collection of lithium brine reservoirs, known as salars, is in the Lithium Triangle in Latin America. The countries in the Triangle are Chili, Bolivia and Argentina. This area holds more than 75 % of the world’s lithium resources under their salt flats.

The salar brine is pumped into an evaporation pond and allowed to concentrate in the sunlight for a year +/-, then it is filtered and sent to another evaporation pond for further concentration. What happens next depends on which of the several possible processes is being used. The type of processing that is used depends on few things: The composition of the ore and interfering substances present; the company may have in-house technology they can adapt; there may be patent constraints in force; the process economics will apply considerable effects on equipment size and required annual throughput.

Source: Google maps. The Yanacocha gold mine owned by Newmont. The curved features are evaporation ponds taking advantage of evaporation and subsequent concentration of the brine by solar energy. This process is fractional crystallization, precipitating the least soluble ion-pairs in the presence of more soluble ion-pairs. An ion pair is defined as XmYn, where X is a cation of variable charge and Y is an anion where m and n are numbers such that m times the cationic charge plus n times the anionic charge add to zero net charge.

Economic ore is that resource which can be beneficiated and further refined and sold at a profit. So, the amount of ore that constitutes an economic deposit can shrink or grow with the market price of the product.

A recent development in lithium resources is the Rhyolite Ridge Lithium-Boron Mining Project near the ghost town of Rhyolite, Nevada, and southwest of Tonopah. The mine will be a large scale open pit operation operated by the Australian mining company ioneer. The mining will be carried out in the conventional drill-and-blast, and load-and-haul method. In the beginning the mining fleet will use automated haul trucks.

Even though nature has provided a concentrated lithium ore body, people still have to go to considerable lengths to produce economical lithium product, all the while gambling on the market price in the future.

Beryllium

Beryllium, Be, atomic number 4, has some very useful properties that make it a valuable metal. It is also quite scarce. The world’s richest beryllium deposit is located near Spor Mountain in Utah. The mine is operated by Materion Brush Inc., formerly known as Brush Wellman. The mine is operated by Materion Inc., formerly known as Brush Wellman. The beryllium rich tuff is located by trenching and drilling. Tuff is compacted volcanic ash that has been cemented into porous rock by contact with water flows. The area also contains fluorspar and uranium, separately, in combination with beryllium. Bertrandite (Be4Si2O7(OH)2) and beryl (Be3Al2Si6O18) are the chief beryllium-bearing minerals and fluorspar is a common accessory mineral.

Source: US Geological Survey. A sample of beryllium tuff after mineralization.

Spor Mountain is located in South Western Utah in basin & range country that extends across Nevada to California.

The above map is from the US Geological Survey and shows 3 extinct calderas in the immediate Spor Mountain vicinity represented in blue. It is interesting that tuff, made from pyroclastic flows and ash where particulates are later cemented together, is the rock in which beryllium is found in the area AND there are 3- count ’em 3 -calderas right nearby. Coincidence?

Source: Google Maps. The red circle shows the location of Spor Mountain beryllium mines in Utah. Closer examination of the mines shows that the mines and roads are bare of vehicles. Nearby, a parking lot with large haul trucks can be seen, but the overall location leaves the impression that excavation of the ore has paused.

Beryllium is a rare element on earth showing up in veins, pegmatites and tuff. In the cosmos its existence is thought to be due to cosmic ray spallation.

“The beryllium tuff is a favorable host for beryllium ore because 1) it is adjacent to faults and rhyolite vents where mineralizing fluids could enter the tuff, 2) it is a porous, reactive conduit for mineralizing fluids, including both hydrothermal and ground waters, and 3) it contains carbonate clasts, which reacted with fluorine-rich fluids to precipitate fluorite and beryllium.” Source: USGS, 1998

Source: USGS, 1998. A rare showing of Be ore at the surface. The white band runn9ng diagonally across the image is the ore body. Most Be mining at Spor Mountain is open pit mining.

Boron

We’ll defer to the Wikipedia to provide background information on the element boron. The main source of economic boron is borax. Borax is a type of evaporite originating from hydrothermal fluids that have flowed to the surface where subsequently the water carrier evaporated to afford dissolved and suspended solid borax, a hydrated borate. Boron the pure element is not found, it only appears as set of various borates. There are monoborates, nesoborates, inoborates, phylloborates and tektoborates. The prefixes below are applicable to silicates and other oxides as well. The older Nickel-Strunz categorization system has been used to describe the classification of complex borate anions found in minerals.

  • neso-: insular (from Greek νῆσος nêsos, “island”)
  • soro-: grouped (from Greek σωρός sōrós, “heap, pile, mound”)
  • cyclo-: rings of (from Greek κύκλος kúklos, “circle”)
  • ino-: chained (from Greek ίνα ína, “fibre”, [from Ancient Greek ἴς])
  • phyllo-: sheets of (from Greek φῠ́λλον phúllon, “leaf”)
  • tekto-: three-dimensional framework (from Greek τεκτονικός tektōnikós, “of building”)
Hydrolysis of Borax to boric acid. Graphics by Arnold Ziffel.

The structures of borax and hydrated borax above have been reduced to their minimum hydration. In reality these are idealized structures not reflecting the agglomeration into larger hydrogen bonded structures. Neutral sp2 boron atoms have an empty, low-lying p-orbital which can bond to the O of O-H groups whether from water or other borates.

The actual composition of any oxy-borate including borax will depend on its thermal history and its chemical environment. Attempting to dehydrate a borate may indeed remove water, but in doing so may open up a p-orbital on boron that would allow an exchange of oxygen species, whether another borate, boric acid or just another water molecule. This is not worrisome when producing boric acid, but when one of the OH groups of boric acid is replaced with a carbon atom, then dimerization and trimerization may occur even at low temperature under vacuum to form boronic anhydrides.

When ordering an organoboronic acid, look at the specs very carefully. Sometimes the water spec may be quite broad due to adventitious dehydration. Using azeotropic removal of water will work by toluene azeotropic distillation, but you may not recognize the 1H-NMR spectrum of the toluene solution because this dehydration method may produce the dimers, trimers and oligomers from the original organoborate. In my experience, the anhydrides work very well in the Suzuki coupling.

A trial sample of an organoborate must represent what can actually be made at scale. A lab sample will have an analysis of what a skilled chemist can do under optimal conditions. If the customer wants bulk boronic acid matching the qualifying lab sample, then you may be sunk if you cannot reproduce the sample specs in the plant. Been der, done dat.

When submitting an organoboronic acid to a customer for approval, avoid sending the very best material from the R&D lab. They will spec on that sample and expect to see the same thing from a production run.

In the organic synthesis area that I have been witness to, boron showed up in our lives mostly for purposes of aryl coupling chemistry with an aryl halide, an organoboronic ester and a palladium catalyst. The nomenclature gets confusing with boron species. Borax is a borate because of the B-O-B and B-OH bonds. But KBF4, potassium tetrafluoroborate, has a boron-based anion with 4 fluorides. The -ate suffix does not always mean that oxygen is in the formula. Many anionic boron species have a net negative charge because a group like OH or F brought the negative charge to make a tetrahedral boron. Quaternary borates are often used as a weakly coordinating conjugate anions where non-interference by the anion is needed.

Source: Data table from Wikipedia. Graph by Arnold Ziffel.

Lithium, beryllium and boron are all three transported by meteoric and hydrothermal water flows. When hot, pressurized water penetrates a fault or fracture system, the fluid can interact with whatever rock it is in contact with. Over long periods of time the fluid can corrode the wall minerals of the fault.

In this scenario, water can do several things to the rock. At the atomic level, the outermost layers of a crystal lattice in the mineral may be subject to aqueous hydrolysis making metal hydroxides, MOH, and liberating the anionic X– species from the latticework. Or, the water may just pull unaltered polar species into solution where they can swap ionic partners and either remain in solution or precipitate onto the surface features of the rock. If the hydrothermal fluids are in motion upwards to cooler regions above, precipitation may occur as the fluid naturally cools and depressurizing. Over time, layers of different insoluble material can stack onto the previous layers. This can go on until the void in the rock is filled and can no longer pass fluids through the fractured formation.

Conclusion

Despite the cosmic scarcity of each of the LiBeB elements, these elements may be found on or near the surface of the Earth concentrated as minerals in an ore body. Transport and placement of enriched individual LiBeB ores derives from multiple instances of differential solubility from the source rock to the ore body. Minerals that have more water solubility than adjacent minerals will tend to be transported in aqueous flows. The transported mineral gets concentrated in this way, but so do the minerals left behind. Aqueous flows at the surface can drop out their dissolved minerals as the surface water evaporates. As the surface water concentrates and cools, a sorting process is underway driven by solubility properties.

The original salt ion pair, M+X–, may be extracted into in water and dissociated to produce M+ and X– ions in solution. Other ionic substances like N+ and Y– can switch partners in a double displacement reaction and produce MY and NX. If it turns out that NX has poorer solubility than MY, then the mixture of M+X– and N+Y– will produce a precipitate of NX, leaving much or most of M+Y– in the water. Minerals deposited from evaporation are called evaporites.

Which is more desirable from the manufacturing perspective, the precipitate or the concentrated solution? Not being a mining engineer or an economic geologist, I can only speak as a person from the fine chemical industry. The precipitation of the desired product from a complex mixture seems a bit more desirable in that it is both an isolation and purification process. Often the solids can be washed and dried in a filter dryer and bang, you have your product.

Precipitating out an undesired solid component from a mixture, pure or not, while leaving the desired product in solution with solvent and other side components from the reaction is a bit less desirable. This version is at least another step away. If the product is a solid, perhaps a scheme can be found for precipitating it as well.

A Swerve into the Weeds of Asteroid Mining

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Notice: As an organic chemist and not a geochemist I will be using descriptions and vocabulary that may not ordinarily be used in geology. While a geochemist might easily write a lovely article that could bring tears to the eyes of the most sour geochemist, I will stumble forward with just my trailer park chemistry background- organometallic, organic, inorganic, physical and quantum chemistry.

When you step back and view mining technology as a whole, it becomes apparent that two of the largest scale inputs in mineral refining are water and electrical energy. On Earth diesel is also required in large quantities.

A good question for those who propose mining asteroids is this: Have you solved the water and electric power requirements for unit operations? Let’s say it is solved for one mineral. How will the value be mined, transported and gently lowered to the Earth’s surface without breaking into flaming pieces on re-entry or forming a crater in a city? Is there an element or mineral that is so valuable as to justify the costs and risks to be met for a space mining mission? Is it rhodium? Gold? Diamonds? Or what?

Do the people behind the fanciful images and hype believe that they only have to dock with the asteroid and grab valuable minerals from the surface? There is a good chance that the target ore will need exploration, excavation, and possibly some kind of blasting. The target elements may well be dispersed within the host rock. This will require comminution in preparation for further processing. The ore will likely need ore dressing which is the job of removing undesired rock from the valuable ore. This lowers the quantity of ore to be processed.

The rocky bodies in the solar system have surfaces of regolith. Regolith is an unconsolidated jumble of loose rock and dust presumably overlying a solid body. Given that the regolith may well be consist of rocks and dust accreted from a distant source, merely assaying the regolith might not reveal the minerals that could be there in abundance just below the regolith. There is no way around it- core samples will be needed to properly assess the economic geology.

PGM Mining on Earth

A look at the large-scale Platinum Group Metal (PGM) production activity in South Africa is instructive. The Bushveld Igneous Complex (BIC) near Limpopo and North-West provinces contains some of the richest PGM deposits in the world. The BIC is found in the Kaapvaal craton. The BIC also extends into Zimbabwe.

The Bushveld complex is located on a ‘craton‘ which is a section of continental crust that has been stable for 400 million years or so. Over that time period some portion of crust has not been subjected to subduction or rifting as an effect of continental drift. A craton is relatively untouched by continental drift over some lengthy time interval and as a consequence the crustal rocks found in a craton may be quite old. Here, ‘old’ means rock that has not been metamorphosed recently, vented out of a volcano or eroded and stratified in a sedimentary formation within several hundred MA.

The Bushveld complex is found in the Kaapvaal craton of South Africa, extending into Zimbabwe. A consequence of this location on a very stable parcel of continental crust is that vertical transposition of rock formations, i.e., subduction activity, has not led to metamorphism or folding of strata. This stability has allowed a relatively undisturbed magma chamber to form and cool, producing layered cumulates.

The formation of cumulates is a partitioning process within the magma chamber that produces solid minerals that can float or sink within the magma. Cumulates with higher density than the magma will tend to sink, building a layer, and lower density minerals will float to the top of the chamber and form an upper layer. In this way, minerals can self-purify and stratify by fractional crystallization.

While fractional crystallization can result in enhanced purity of specific minerals, the melt from which the crystals precipitate is also changing in composition. Magma is a viscous fluid and its components can undergo anion/cation exchange to produce new minerals upon further cooling. Anions include silicate, aluminate, sulfide, hydroxide, chloride, oxide, and a whole basket of metal oxyanions like titanate, tungstate, molybdate, chromate, etc. Cations include most every metal, sometimes including the noble metals. Every metal has a set of positive oxidation states that may be subject to reduction or oxidation to afford a different oxidation state or charge.

While both anions and cations present in magma have a particular charge, their individual size is important as well. Size and charge matter most when crystals are assembling. When, for instance, a calcium-containing mineral is crystallizing, the crystal lattice is subject to collisions with the whole gamut of species in the magma. If the temperature and pressure are appropriate, calcium (+2) cations nestle into a vacancy in the lattice. This is controlled by the concentration, temperature and Gibbs energy of the placement of the cation. However, if a different cation of +2 charge and similar ionic radius happens by, that different +2 cation may find itself occupying calcium’s place in the lattice. An example would be where the Ca+2 cation was replaced by Mg+2 or Fe+2.

Mineral crystal formation is a type of equilibrium wherein lattice anions and cations at the surface of the crystal are in equilibrium with anions and cations in the melt. The rate of crystallization or dissolution is driven by several things. Substitution of a Ca+2 ion in a lattice with Mg+2 or Fe+2 ions retains the charge balance in the lattice. But if a too large or too small +2 cation attempts to sit in place of Ca+2, a mismatch occurs which may be energetically favorable, but as a result may be much more prone to removal by equilibration. The interloping cation could be of such a size that its heat of formation is small and therefore subject to replacement by equilibration. Or not. The resulting mineral could be comprised of Ca+2 cations and M+2 cations in a non-stoichiometric ratio. Or a new mineral comprising a stoichiometric ratio of both cations.

The anions in a mineral substance can be quite varied and several may exist in a mineral at the same time as in the case of anions silicate and aluminate.

The Stillwater Igneous Complex in Montana, USA; the Sudbury Basin in Canada; and the Norilsk-Talnakh deposits north of the arctic circle on the Siberian Craton.

The Stillwater Igneous Complex in south central Montana, USA. Source: Google Maps.
Image from Google Maps. Elevator shafts for the Sibanye-Stillwater K3 Shaft, South Africa.
Image from Google Maps. The Sibanye-Stillwater K3 shaft, South Africa.

Russia is the leading producer of palladium with 40 % of the global market. Norilsk Is also known as a center of non-ferrous metallurgy as well as noble metals. Norilsk Nickel, also known as Nornickel, is a mining and smelting company. Platinum Group Metals (PGM) have been recovered as a side stream of nickel and copper mining by Norilsk Nickel.

Open pit mile near Norilsk, Russia. Norilsk was originally started as a gulag in the far north of Siberia and eventually became a mining community.

The aerospace proponents of asteroid mining should spend some time at an actual mine. Breaking rock and hauling it around is simple on Earth but consider doing this in a vacuum at near-zero gravity. Look at all of the methods of conveyance and processing in operation at a mine that works only in a gravitational field. Blasting, front-end loaders, haul trucks, conveyor belts, crushers, ball and rod mills, flotation and settling tanks, lixiviation in sulfuric acid and several shifts of staff to operate and maintain it. Don’t forget the analytical lab and chemist or the maintenance group.

Proponents will always say that with the right technology, asteroid mining could work. But in the airgap between could and will is the nagging question of why? Maybe asteroid mining is best left to our descendants in the 22nd century.

A human trip to an asteroid, which is always in orbital motion and probably rotating, to mine and return with paydirt for the investors will always be high cost. Bodies outside of the Earth-Moon system will be nearby only for a short time, depending on the orbital period of the asteroid. While our Earth is measurably overheating, the biosphere is disintegrating and political turmoil is rampant on Earth, perhaps we should focus closer to home?

Humanity must stay focused on critical housekeeping activity here on planet A. Monetizing the outer worlds can wait.

I do believe that eventually somebody will design mining technology to solve the unique problems of mining smaller asteroid bodies with negligeable gravity. Energy dense power sources will be needed to move commercial scale machines and ore. The big problem will be the economics. What mineral is so valuable as to justify the trillion-dollar expense of finding an asteroid with suitable quantities of mineral, up front R&D costs, and beneficiation and isolation of the mineral?

Minerals dispersed in the regolith matrix will need comminution, extraction by lixiviation, floatation, isolation and packaging. Now, we can get it back to earth orbit but then what? Do we just deorbit in the usual way?

Bringing home the paydirt

Let’s say they return 1000 kg (contained) of rhodium valued at todays price of $5400/toz (toz = troy ounce). 1000 Kg contained of rhodium = 32150.7 troy ounces, so 32150.7 toz x $5400/toz = $173,613, 780. However, just the rumor of 1000 kg of new rhodium about to come on the market will drive rhodium prices down. So, $174 million sounds like a lot of money and in a sense it is. But in aerospace and heavy industry, millions are quickly consumed.

Rhodium was chosen for its general scarcity and high price. There is no reason to suppose that rhodium will be more abundant on a given asteroid than on earth so numerous asteroids may need exploration by geologists. Core samples might be needed for the economic geologists to sketch out the size and value of an ore body.

There will be a threshold price of rhodium that must me exceeded before rocket launching and asteroid digging begins. This is how mining works on earth. Until then, the celestial rhodium discovery will just keep orbiting the sun into the future.

The North American craton. Source: Wikipedia.

An aspect of PGMs is that the very few mines that produce them do so in a unique geological feature on a craton. The mechanism for PGM mineralization in districts like the Bushveld Igneous Complex in South Africa took place in a magma chamber where over time the magma began to cool. Magma gets its minerals from the mantle far below and from the walls of the magma chamber. In subduction zones the subducting crust is pushed downwards causing rising temperatures.

Subducting oceanic crust is loaded with water in several forms. Many minerals are ‘hydrated’ meaning that one or more water molecules are strongly attached to the mineral. These might be called coordinated water. The oxygens are strongly attracted to a cationic feature of the mineral. Interstitial water molecules may be occupying voids in the mineral lattice. Discrete water is only weakly attached and may diffuse elsewhere. Interstitial and discrete water may evaporate readily if exposed to air or heat. At the elevated pressures and temperatures of magma at depth, the three kinds of water are hot enough to flash to steam if the pressure was released. However, as the magma rises to the surface to cooler surroundings and lower pressures, eventually the water will flash to the gas phase moving magma in the direction of lower pressure. Just below the surface the dissolved gases including CO2, steam and SO2 will expand as a gas and push magma to the surface causing a volcanic eruption.

As the magma cools, the substances with the highest melting point begin to crystallize. If the crystals that have a higher density than the magma, they will settle lower in the magma chamber and form a distinct layer. While this layer is building, other minerals will follow in a similar process. The layers of precipitated minerals are called cumulates.

The process of minerals selectively crystallizing and precipitating to the upper or lower zones of the magma chamber. The overall process is called fractional crystallization and layers called cumulates can form. In the photo below are several layers of dark chromite cumulate.

From the Bushveld Igneous Complex. Exposure of cumulate layering of dark chromite. Mining involves following the cumulate layers.

Now that I have expressed my doubts about asteroid mining, I must ask ‘Am I being a Luddite’? Maybe a little bit, but even the doubts of a Luddite can be on the mark now and then. Asteroid mining will be an adventure for a few astronauts, profitable for aerospace contractors and an entertainment spectacle for the public; however, resources seem better used on Earth for remediation of the biosphere, diplomatic solutions for the conflict of the week, lower hydrocarbon consumption and better education, especially in the area of civics.

The whole purpose of mentioning PGM geology and mining in a post titled Asteroid Mining is that we on Earth are fortunate to have concentrated mineral deposits that exist only because of unique geological processes. These processes only work in Earth’s gravitational field. The upwelling of lower density hot hydrothermal fluids. The formation of evaporites rich in borax. Lithium brines.

Take my uranium, please

The formation of cumulates in lava chambers relies on differential density driven by gravity. The ability of rain and snow runoff to mobilize gold sulfides will produce lode gold and placer deposits. The ability of oxygenated meteoric water to oxidize insoluble U4+ to soluble U6+ in sandstone formations to form concentrated roll front deposits. The ability of oxygen to switch uranium oxidation states from U4+ to produce a soluble form (U6+) that can migrate and concentrate leading to the partitioning of U6+/U4+ species. Underground formations of uranium can be dissolved in a solution of sodium bicarbonate by injection and pregnant solutions of the uranium carbonate can be brought to the surface as a solution. This solution is run through a column of ion exchange resin beads which exchange chloride ions for the uranium complex. Once loaded, the beads are washed with a special solution to remove the uranium (6+) concentrate.

Oxidation and isolation of U6+ from U4+. Graphics by Arnold Ziffel.

Our ability to mine and isolate minerals is uniquely enabled by planet earth. The ability of nature to dissolve, mobilize and concentrate minerals into ore bodies from highly dispersed placement in source rock has been positive for humanity. A great many elements are found in a dispersed condition in the continental crust. For some, there are natural processes for concentration. For others, they form secondary minerals that end up mined with the primary ore. A few like gallium, indium and bismuth are valuable but are only available as a side stream from the primary ore. Copper is an excellent example of a primary metal whose ore includes many other metals like zinc and bismuth. Copper can be electro-refined to 99.99 % purity. The slimes left behind after the electrolysis and dusts caught in ventilation systems can be enriched in useful metals and are often collected for processing.

The purpose of citing the large-scale processes in use on the home planet is not to suggest that asteroid mining must start out at large-scale. It would likely start out as a small-scale surface or underground operation with a small crew or with robotics. Only a few select minerals would be economically suitable for recovery. Platinum Group Metals are mentioned above because of their high intrinsic value and ability to exist as the native metal. If luck is with the astro-miners, the motherlode might be easily visible so later the gangue material can be chipped off. The process of trimming ore to retain the value and discard the gangue was called ore dressing. Being quite dense, the volume of PGM metal ore may be low, but the density and mass is quite high.

If a given asteroid has never been part of a larger system with magma and sufficient gravity to force stratification by density, the cumulate model may not apply. A given asteroid having never been exposed to bulk water and consequently never been subject to hydrothermal flows and weathering may not have minerals that here on Earth are known to be formed with water or partitioned as a result of hydrothermal flows. Lake and ocean sedimentary units are almost surely absent as are processes requiring aqueous migration through porous rock as in the case of uranium roll fronts.

Asteroid mining will be a totally new activity and most all of the natural geological processes on earth will have been absent. Many geological processes on earth produce economic ore bodies. These will be largely absent on an airless, dry asteroid.

One thing to consider: Most of the rock accessible at the Earth’s surface is not economic ore. The surface of the Earth brimming with carbonates, silicates and aluminates bound to a variety of ‘ordinary’ metals like calcium, magnesium, iron, sodium, potassium and a handful of other common metals. While there are important and valuable uses for these common metals, they are predominantly found dispersed in surface rock comprised of many individual minerals, or that an ore body is too small for economic recovery.

The fraction of the desired mineral in the ore can be highly variable. Depending on the market, some parts of the ore body may be economical to mine while other parts may not. This is why cores are drilled to locate the 3-dimensional extent of the ore body, estimate the potential value and minimize the expense of digging and processing uneconomical ore.

It seems reasonable to suppose that, just as much of the surface of the earth is covered with rocks made from mineral constituents of low economic value like crushed roadbed rock or sand and cement for concrete use, why should we assume that a given asteroid would be any better endowed with value than Earth’s surface? Asteroid mining will necessarily be preceded by expensive exploration. Obviously, right? But it means that considerable money and time will be spent up front finding an asteroid that is sufficiently ‘pregnant’ with valuable metal ore. Finding investors to fund exploration and mining development today is based on economic geology surveys and signed off by certified experts.

A mine is a hole in the ground with a liar standing at the top. –Attributed to Mark Twain

On Earth many mineral deposits have been located historically by surface exposures that are part of a larger ore body. The economics of isolating any one mineral or metal in the presence of the others will depend heavily on the % concentration of the target mineral, the processing methods available and the market price of the final product. A market downturn can last months, years or represent new long-term realities in demand for the product.

Update: Huo Yao (Fire-Drug)- Predecessor to Gunpowder.

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[Note: This is an updated version of an earlier post.]

Recently I spent some time tracing the very early history of gunpowder or Huo Yao (China, ca 850 AD). It turns out that the earliest clear description of a gunpowder-like composition was described in a document produced during the Tang Dynasty. A document titled “Classified Essentials of the Mysterious Tao of the True Origins of Things” contained a list of particularly dangerous elixirs. A comprehensive history of Chinese science can be found in “Science and Civilisation in China, Volume 5: Chemistry and Chemical Technology, Part 4, Spagyrical Discovery and Invention: Apparatus, Theories and Gifts” by Joseph Needham. Within this list of hazardous compositions, a warning was offered citing the dangers of mixing and heating together realgar, salt peter, sulfur, and honey.  The document tells of alchemists mixing this combination and heating it, resulting in a deflagration leading to burnt beards, faces, and hands as well as the loss of the structure to fire. This mixture has been translated as “fire-drug”.

There are earlier references to admixtures that could produce a violent effect, but the compositions are not disclosed. The information in the 850 AD document clearly describes the components of classic gunpowder- a nitrate oxidizer, sulfur or sulfide for low ignition temperature, and a carbohydrate reducing agent- honey. What is notable about gunpowder is that is a self-contained redox system containing two sides of the fire triangle– fuel and oxidizer in intimate contact. All that is needed for an exothermic reaction is initiation with some kind of energy stimulus.

A couple of thoughts on the realgar present in the mix. First, alchemists were commonly in the apothecary trade and made their living preparing medicaments, not so much searching for the philosopher’s stone. It is not unreasonable to suppose that the composition was intended for some medicinal effect. Realgar is red tetraarsenic tetrasulfide (As4S4), possibly with some amount of yellow Orpiment (As2S3), and may have been a common apothecary ingredient of the time. Crystalline realgar is a ruby-like, eye-catching substance and it is not surprising that it captured the fancy of alchemists.

Source: Wikipedia. Crystalline realgar, As4S4.
Source: Wikipedia. Crystalline orpiment, As2S3.

Second, realgar and orpiment are found in hydrothermal deposits as are copper, gold, silver, and mercury sulfides (metal sulfides as a group were referred to then by the obsolete term sulphuret). Back when roasting ore was widely practiced (and legal), it was common for miners in American lode gold districts to heap sulphuretted ores onto a wood pile and set it alight directly or air oxidize it in a reverberatory furnace. This process would actually ignite the sulphureted ore and in the case of gold and mercury, release the native metal. The point is that sulphuretted arsenic would be expected to contribute to the combustion process as a reducer of nitrate or just as a spectator fuel.

My understanding of sulfur’s role in gunpowder is that of a low-melting, combustible substance which, when ignited, maintains intimate thermal contact with the solid nitrate and carbon elements, transferring heat to trigger and sustain the deflagration or explosive redox reaction.

In medieval times, before blasting with gunpowder was available, it was common in hard rock mining to fracture rock by creating a large fire adjacent to a rock face to get it hot, then water was splashed on it in an attempt to fracture the hot rock by thermal shock. [In my lonely voice squeaking out from under my rock along the riverbank, I would offer that this activity might have presented the opportunity to discover that some (sulphuretted) minerals were combustible. Alternatively, building a ring of sulfuretted rock around a campfire may have led to the same discovery.]

Lateral O&G drilling

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Most people have heard of fracking in the context of oil and gas (O&G) drilling and maybe a few of them know that this can be done in horizontal drilling at a distance from the surface well hole. Explosives or hydraulic pressure is used to fracture a section of rock formation surround the drill hole and then frac sand is forced into the fractures to prop them open. Sometimes the sand is referred to as a proppant. This increases the permeability of the formation and, hopefully, increases the productivity of the well.

The first directional drilling was performed in 1930 from shore at Huntington Beach, CA, into an offshore deposit of oilsands.

The fracking controversy stems from evidence that fracturing can lead to O&G migration into ground water and then into drinking water. This essay does not address this matter.

Within the O&G drilling world is the question of how far laterally a hole can be drilled and to what extent it pays. According to one source, in 1997 the lateral distance stood at about 500 ft to completion. At present it stands at 3 miles with 4 miles becoming more common. Greater length requires an upgrade in drilling equipment to handle the extra power demands.

Today there are steerable down-hole mud motors that can rotate the drill bit independent of the drill string. Mud is pumped downhole at high pressure to rotate a rotor connected to the bit. The rotor fits in a stator near the end of the drill string. A steerable feature is able to bend ~3 to 4 degrees.

Source: Drilling Knowledge blog. A very informative site.

In the literature there is mention of the issues in vertical drilling through a steeply inclined fault. As the bit penetrates a steep fault surface it could slip and lead to damage of the drill string and casing. Better to penetrate a fault perpendicular to the fault plane with directional drilling.

There are many good reasons for a driller to use directional drilling.

  • A borehole that has gone off-course can be redirected to the desired direction from the same borehole.
  • From a single drilling site multiple boreholes can be drilled, each going to a different part of the formation.
  • During a well blow-out or fire, a new borehole can be drilled from a distance to intercept the blown-out borehole and pump material into it to control the blow-out.
  • A drilling site can be situated away from a settlement or body of water and still get to the oil reservoir by directional drilling.
  • Directional drilling can be performed in an existing well where equipment or debris is blocking the original bore hole.
  • Drilling through a salt dome is problematic for several reasons. A soft formation like a salt dome can result in bit balling where the tricone bit packs with debris and the wheels quit turning. Wellbore erosion, salt creep, and excessive mud losses can occur as well.
Source of graphic: The Art of Directional drilling.

Salt domes form from plastic deformation of an underlying low density and ductile salt layer (90 to 99 % halite) into a fault or fracture where it is subject to movement by lateral forces of the surrounding sediment layers. These lateral forces push the salt formation in the direction of weakest forces which is generally upwards. Irregular features in the salt dome can lead to collection of oil and gas pockets. Lateral drilling can be used to access the reservoirs, bypassing the salt formation.

Cells Count on Earth

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Wow. A study was published calculating the number of living cells currently present on Earth and the number that have ever lived. The paper, titled “The geologic history of primary productivity,” was published in Current Biology, October 11, 2023. Sadly, the full article rests behind a paywall. But the abstract is open access so I will reproduce it here.

The lead author, Peter Crockford, is a geologist at Carleton University.

Abstract: The rate of primary productivity is a keystone variable in driving biogeochemical cycles today and has been throughout Earth’s past. 1 For example, it plays a critical role in determining nutrient stoichiometry in the oceans,2 the amount of global biomass,3 and the composition of Earth’s atmosphere.4 Modern estimates suggest that terrestrial and marine realms contribute near-equal amounts to global gross primary productivity (GPP).5 However, this productivity balance has shifted significantly in both recent times 6 and through deep time.7 ,8 Combining the marine and terrestrial components, modern GPP fixes ≈250 billion tonnes of carbon per year (Gt C year−1).5 ,9 ,10 ,11 A grand challenge in the study of the history of life on Earth has been to constrain the trajectory that connects present-day productivity to the origin of life. Here, we address this gap by piecing together estimates of primary productivity from the origin of life to the present day. We estimate that ∼1011–1012 Gt C has cumulatively been fixed through GPP (≈100 times greater than Earth’s entire carbon stock). We further estimate that 1039–1040 cells have occupied the Earth to date, that more autotrophs than heterotrophs have ever existed, and that cyanobacteria likely account for a larger proportion than any other group in terms of the number of cells. We discuss implications for evolutionary trajectories and highlight the early Proterozoic, which encompasses the Great Oxidation Event (GOE), as the time where most uncertainty exists regarding the quantitative census presented here.

Source: Peter W. Crockford 6, 7 , Yinon M. Bar On, Luce M. Ward, Ron Milo, Itay Halevy, Current Biology, October 11, 2023, DOI: https://doi.org/10.1016/j.cub.2023.09.040.

An article by Elizabeth Pennisi was published in Science which is a decent summary of the paper. The Science review reports that the number of cells alive today amounts to 1030 cells with most of them cyanobacteria. The total number of cells to ever have lived is estimated to be between 1039 and 1040. The article goes further and says that the resources on Earth cannot support more than 1041 cells.

Economic Foams and Lithium

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While cockeyed optimists are working toward a new age of electric vehicles in the glare of an admiring public, I find myself standing off to the side mired in skepticism. What are the long-term consequences of large-scale electrification of transportation?

The industrial revolution as we in the west see it began as early as 1760 and continues through today. Outwardly it bears some resemblance to an expanding foam. A foam consists of a large number of conjoined bubbles, each representing some economic activity in the form of a product or service. A business or product hits the market and commonly grows along a sigmoidal curve. Over time across the world the mass of growing bubbles expand collectively as the population grows and technology advances. Bubbles initiate, grow and sometimes collapse or merge as consolidation and new generations of technology come along and obsolescence takes its toll.

The generation of great wealth often builds from the initiation of a bubble. The invention of the steam engine, the Bessemer process for the production of steel, the introduction of kerosene replacing whale oil, the Haber process for the production of ammonia and explosives, and thousands of other fundamental innovations to the industrial economy played part in the growing the present mass of economic bubbles worldwide.

After years of simmering on the back burner, electric automobile demand has finally taken off with help from Tesla’s electric cars. Today, electric vehicles are part of a bubble that is still in the early days of growth. The early speculators in the field stand the best chance of winning big market share. A major contribution to this development is the recent availability of cheap, energy dense lithium-ion batteries.

Of all of the metals in the periodic table, lithium is the lightest and has the greatest standard Li+/Li reduction potential at -3.045 volts. The large electrode potential and the high specific energy capacity of Lithium (3.86 Ah/gram) makes lithium an ideal anode material. Recall from basic high school electricity that DC power = volts x amps. Higher voltage and/or higher amperage gives higher power (energy per second). Of all the metals, lithium has the highest reduction potential (volts).

Rechargeable lithium batteries have high mass and volume energy density which is a distinct advantage for powering portable devices including vehicles. Progress in the development of lithium-ion batteries was worth a Nobel Prize in 2019 for John B. Goodenough, M. Stanley Whittingham and Akira Yoshino.

All of this happy talk of a lithium-powered rechargeable future should be cause for celebration, right? New deposits of lithium are being discovered and exploited worldwide. But cobalt? Not so much. Alternatives to LiCoO2 batteries are being explored enthusiastically with some emphasis on alternatives to cobalt. But, the clock is ticking. The more infrastructure and sales being built around cobalt-containing batteries, the harder it will become for alternatives to come into use.

One of the consequences of increasing demand for lithium in the energy marketplace is the effect on the price and availability of industrial lithium chemicals. In particular, organolithium products. The chemical industry is already seeing sharp price increases for these materials. For those in the organic chemicals domain like pharmaceuticals and organic specialty chemicals, common alkyllithium products like methyllithium and butyllithium are driven by lithium prices and are already seeing steep price increases.

Is it just background inflation or is burgeoning lithium demand driving it? Both I’d say. Potentially worse is the effect on manufacturers of organolithium products. Will they stay in the organolithium business, at least in the US, or switch to energy-related products? It is my guess that there will always be suppliers for organolithium demand in chemical processing.

A concern with increasing lithium demand has to do with recycling of lithium and perhaps cobalt. Hopefully there are people working on this with an eye to scale up soon. A rechargeable battery contains a dog’s lunch of chemical substances, not all of which may be economically recoverable to specification for reuse. In general, chemical processes can be devised to recover and purify components. But, the costs of achieving the desired specification may price it out of the market. With lithium recovery, in general the lithium in a recovery process must be taken to the point where it is an actual raw material for battery use and meets the specifications. Mines often produce lithium carbonate or lithium hydroxide as their output. Li2CO3 is convenient because it precipitates from aqueous mixtures. It must also be price competitive with “virgin” lithium raw materials as well.

Lithium ranks 33rd in terrestrial abundance and less than that in cosmic abundance. Unlike some other elements like iron, lithium nuclei formed are rapidly destroyed in stars throughout their life cycle. Lithium nuclei are just too delicate to survive stellar interiors. The big bang is thought to have produced a small amount of primordial lithium-7. Most lithium seems to form during spallation reactions when galactic cosmic rays collide with interstellar carbon, nitrogen and oxygen (CNO) nuclei and are split apart from high energy collisions yielding lithium, beryllium and boron- LiBeB. All three elements of LiBeB are cosmically scarce as shown on the chart below.

Solar system abundances relative to silicon at 106. Source: Wikipedia, https://en.wikipedia.org/wiki/Cosmological_lithium_problem#:~:text=all%20heavier%20elements.-,Lithium%20synthesis%20in%20the%20Big%20Bang,more%20than%201000%20times%20smaller.

Lithium is found chiefly in two forms geologically. One is in granite pegmatite formations such as the pyroxene mineral spodumene, or lithium aluminum inosilicate, LiAl(SiO3)2. This lithium mineral is obtained through hard rock mining in a few locations globally, chiefly Australia.

Source: “A Preliminary Deposit Model for Lithium Brines,” Dwight Bradley, LeeAnn Munk, Hillary Jochens, Scott Hynek, and Keith Labay, US Geological Survey, Open-File Report 2013–1006, https://pubs.usgs.gov/of/2013/1006/OF13-1006.pdf

Chemical Definition: Salt; an ionic compound; A salt consists of the positive ion (cation) of a base and the negative ion (anion) of an acid. The word “salt” is a large category of substances, but for maximum confusion it also refers to a specific compound, NaCl or common table salt. In this post the word refers to the category of ionic compounds.

The other source category is lithium-enriched brines. The US Geological Survey has proposed a geological model for brine or salt deposition. According to Bradley, et al.,

“All producing lithium brine deposits share a number of first-order characteristics: (1) arid climate; (2) closed basin containing a laya or salar; (3) tectonically driven subsidence; (4) associated igneous or geothermal activity; (5) suitable lithium source-rocks; 6) one or more adequate aquifers; and (7) sufficient time to concentrate a brine.”

Lithium and other soluble metal species are extracted from underground source rock by hot, high pressure hydrothermal fluids and eventually end up in subsurface, in underwater brine pools or on the surface as a salt lake or a salt flat or salar. These deposits commonly accumulate in isolated locations that have prevented drainage. An excellent summary of salt deposits can be found here.

Source: Wikipedia, https://en.wikipedia.org/wiki/Brine_mining

Critical to any kind of mineral mining is the definition of an economic deposit. The size of an economic deposit varies with the market value of the mineral, meaning that as the value per ton of ore increases, the extent of the economic deposit may increase to include less concentrated ore. If you want to invest in a mine, it is good to understand this. A good opportunity may vanish if the market price of the mineral or metal drops below the profit objectives. Hopefully this happens before investment dollars are spent digging dirt.

Lithium mining seems to be a reasonably safe investment given the anticipated demand growth unless страшный товарищ путины invasion of Ukraine lets the nuclear genie out of the bottle.

Just for fun, there is an old joke about the definition of a mine-

Mine; noun, a hole in the ground with a liar standing at the top.

M 7.8 Quake in Central Turkey

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The US Geological Survey (USGS) has technical information on the Feb.6, 2023, magnitude 7.8 earthquake in southern Turkey. The event happened at 1:17:35 UTC and the epicenter located at 37.174°N 37.032°E at 17.9 km depth. The strike slip quake occurred in a seismically active region near the triple-junction of the Anatolia, Arabia, and Africa plates. As of this writing the exact location isn’t clear but the USGS suspects it happened either along the Eastern Anatolian Fault zone or the Dead Sea transform fault zone.

Image from Wikipedia. Dead Sea transform.
Image from Wikipedia. East Anatolian fault.

According to USGS, the East Anatolian fault accommodates the westward motion of Turkey towards the Aegean Sea and the Dead Sea Transform accommodates the northward motion of the Arabian plate.

The quake was reportedly felt as far away as Istanbul, Tbilisi and Cairo.

Yellow Gold and Black Gold in the Ground

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Some years back I visited the large CC&V open pit gold mine by Cripple Creek, Colorado. Standing at the bottom of the pit we could see haul trucks busily transferring ore to a staging site. Suspecting that it might be overburden, I asked what they were doing. Our guide, a geologist, said that this ore would be staged as unrefined until the price of gold rose to a certain higher value. The whole ore body had been mapped 3-dimensionally so at any given location and level where they blast, they have a rough idea of how much gold is present. At the time, ~10 years back, the geologist said that each large haul truck was typically carrying about $10,000 worth of gold. I don’t know how accurate that is, but there you have it.

The Cripple Creek gold load was discovered about 1893 and occurs in the throat of an extinct volcano. The ore contains gold and calaverite, AuTe2, a gold telluride mineral. The gold and AuTe2 is so finely dispersed that most people who work at the mine have never actually seen the gold. The recovery method they use is cyanide extraction. Unfortunately, tellurium interferes with this extraction process and unavoidably some of the gold as the telluride is left in the tailings. The ore is said to contain about 1 gram of recoverable gold per ton.

What prompted this essay was a moment of clarity I had reading a notice from the Energy Information Administration, EIA. It is common to hear about oil reserves. One might suppose that this refers to the total proven reserves in the ground. But this article referred to “economically recoverable oil resources”. When oil reserves are expressed in this way, the recoverable oil then becomes a function of the current oil prices. If oil prices are low, then the reserves are considered smaller than when oil prices are high. It seems so obvious but I never gave it a thought before. As with gold, the lesson is to pay attention to the type of reserves being discussed.

Antimony is in Short Supply

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Antimony, Sb, is an obscure metalloid that rarely gets much notice outside of a few highly specialized areas of technology. The element is most often found in the mineral Stibnite, Sb2S3. Antimony is a pnictogen found in Group 5 between arsenic and bismuth in the p-block of the periodic table. Crustal abundance is 0.2 to 0.5 ppm according to Wikipedia, making it several times more abundant than silver. It has many interesting properties and uses which will be left to the reader to discover. Interestingly, there is a rare allotrope of antimony that is explosive when scratched. Luckily, this is unusual.

In a May 6, 2021, article in Forbes, writer David Blackmon cites the many uses of antimony and where it occurs in greatest natural abundance. As it turns out, the US is not one of those locations where it is found in great abundance. China has the largest abundance of antimony- greater than half of the known reserves in the world, with Russia coming in second. At present, the US imports 100 % of this key strategic material. Blackmon writes-

“Antimony is a strategic critical mineral that is used in all manner of military applications, including the manufacture of armor piercing bullets, night vision goggles, infrared sensors, precision optics, laser sighting, explosive formulations, hardened lead for bullets and shrapnel, ammunition primers, tracer ammunition, nuclear weapons and production, tritium production, flares, military clothing, and communication equipment. It is the key element in the creation of tungsten steel and the hardening of lead bullets, two of its most crucial applications during WWII.“

According to Blackmon, China currently supplies 80 % of the world’s antimony and also imports ore from other nations for refining. Here is the kicker- China may soon run short of the element. Running short of antimony doesn’t just mean that prices will rise in short supply. It could also mean that China may stop exporting much of its refined antimony in favor of internal consumption to produce goods up the value chain. China tried to do this with rare earth elements already. A country rich in strategic minerals and a sophisticated manufacturing base is a country that can wield significant power over the rest of the world. In the US, antimony is considered critical to economic and national security.

The US has had only one mining district that produced significant antimony. That would be the Stibnite mine in the Stibnite Mining District near Yellow Pine, Idaho. Mining activity stopped in the mid-1990s. The district, like most of Idaho, sits atop the granite Idaho Batholith. Volcanic activity in the past forced hot water through cracks and fissures in the rock, dissolving soluble minerals, moving mineral rich hydrothermal fluids that, when cooled, precipitated as mineral veins in the granite. Antimony minerals are often associated with another Group 5 element, arsenic, in the form of minerals like realgar and orpiment.

The Stibnite mine began as a gold mine in 1938 during the Idaho gold rush. Throughout WWII, the stibnite mine produced 40 % of the antimony and tungsten needed by the US. Tungsten, or wolfram, appears as the tungstate salt with a metal cation like iron, calcium or manganese paired with a WO4 oxoanion. The hydrothermal fluid partitions minerals in a rock formation into concentrated zones through selective solubility. This process is responsible for the formation of veins in solid rock.

Oh look. I’ve driven off into the weeds again rambling on about minerals.

Fear and Loathing with Frac Fluids

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There is considerable handwringing over hydraulic fracturing fluids and their potential effects on “the environment”. I use quotes in ironic fashion because I see very little parsing of the issue into relevant components. The chemical insult to the environment is highly dependent on both the substances and the extent of dispersion. But I state the obvious.

There are surface effects at the drill site and there are subsurface effects. A spill on the surface is going to be relatively small due to the limited size of the available tankage on site. I drive by these sites almost daily and can see with my own eyes the scale of the project. A surface spill of materials will be limited in scope.

The subsurface effects are complex, however, and the magnitude of consequences will depend on both the extent of the fluid penetration into aquifers and the nature of the materials in the fluid. Much criticism has been dealt, rightfully I think, over the secrecy claims on the composition of these fluids. The default reply from drillers has rested on trade secrecy. To be sure, the matter of government forcing a company to reveal its art is a serious matter. But the distribution of chemical substances into the environment requires some oversight. Especially when substances are injected into locations where they cannt be readily remediated. The remediation of an aquifer is a serious undertaking which may or may not be effective.

If you want to see what is potentially in frac fluids, go to Google Patents and search “hydraulic fracturing fluid”. A great many patents will be found. This will give the length and breadth of the compositions patented. Of this large list only a few are used in current practice. The potential carrier fluids vary from water to LPG (!). Water is a common component, but brine is said to be preferred. Additives include hydrochloric acid and surfactants. The MSDS documents may be a good source of info. Consider that a substantial threat to ground water may be that it is rendered non-potable rather than outright  toxic.