CO2 ELECTROLYSIS

CO2 electrolysis is advancing. It could be superior to shifting CO and CO2 to CH4 and H2O by combining with H2 over a nickel or ruthenium catalyst then decomposing to carbon and H2 over hot bricks at about 900 C. and electrolysis of the H20 to recover H2 and oxygen and then incompletely burning the carbon with oxygen to get CO for the LUNAR FORGE.




Less complex. How would we get carbon off the hot bricks? Ultrasonics? CO2 electrolysis involves less machinery, fewer devices, certainly less man power.




Two things: 1) Zubrin said in The Case for Mars in 1994 that CO2 electrolysis takes 5x as much energy as H2O electrolysis, but the technology could advance, become more efficient. 2) Zirconium is necessary and yttrium to make yittria-stablilized ziroconia. There is 311 ppm Zr and 84.2 ppm Y is regolith, average. CO2 electrolysis devices are basically solid oxide fuel cells, SOFCs, run in reverse. Yep, stored CO and O could be used for night span power as they react with about half as much energy/mass as carbon and oxygen. Maybe we could use the CO2 electrolysis cells for energy storage also??? With the big underground vaults of LOX and liquid CO???
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TOP BLOWN SOLAR HEATED STEEL FURNACE
On the Moon, we would inject pure oxygen to convert cast iron to steel. The vessels might be made more cubical with interlocking ceramic bricks and a refractory lining. If cooling is needed we could use N or CO2 (very stable up to high temps) gas cooling and space radiators shielded with foil or run them at night. Where would we get heat at night to run the process? By day we could heat the iron up with solar energy then inject oxygen to burn off excess carbon in the cast iron and make steel. Electric heat at night from nuclear batteries and hot sodium from power towers ( to warm up the oxygen)? CO2 generated would be recycled. Can't waste carbon.
Heat Treatment: Slow cooling anneals steel. Rapid cooling hardens steel.

Good webpages:

http://anvilfire.com/FAQs/heat_faq_index.htm

also see: http://www.dfoggknives.com/hardening.htm
"Common table salt works and is a fairly good all round medium. Special heat treating salts are also sold. The only time the type of salt is critical is if the bath is to be used for hardening (yes, they get that hot) OR if there is a "use no chlorides" requirement for the application."

"According to Grant Sarver's "guru page" post in 9/1998; All sorts of salts are used in salt pots. For temperatures up to 1000 F sodium nitrate can be used. Barium chloride is used for high temperatures like 2500 F. For temperatures to 3000 F magnesium fluoride can be used. Most heat treat salt pots are heated simply by passing and electric current through them controlled by a thermostat. Heat treating suppliers have an assortment of salts for this purpose. "

Salt baths can be used to harden, temper or anneal steel.
Heat Treating Salts

Salt
Formula
Melts
Max
Action

Sodium Chloride

Common salt
NaCl
1473 F

801 C
2574 F

1413 C
Boils

Potassium Chloride
KCl
1418 F

770 C
2822 F

1550 C
Sublimates

Potassium Nitrate (Saltpeter)
KNO3
663 F

334 C
752 F

400 C
Decomposes

Barium Chloride

TOXIC
BaCl2
1765 F

963 C
2840 F

1560 C
Boils

Magnesium Fluoride
MgFl2
1263 C
2227 C
?
The melting point for common salt is high enough for annealing and hardening carbon steels. Potassium Nitrate is easier to melt but has a narrow working range. Organics mixed with nitrates can be dangerous. Small amounts of sulfur can result in explosive mixtures but saltpeter is still commonly used for various metal working processes.

Heat treating suppliers sell various salt mixtures. Some are considered "neutral" and some carburizing.
On the Moon, we don't much oil, so salt baths will be the way to heat and cool steel for heat treament. We have magnesium, small amounts of sodium and potassium (but if we can get them there is about 0.290% Na and 0.113% K or 2900 tons Na per million tons-250 acres-of regolith) and next to no barium. Where do we get chlorine and fluorine? There's only about 174 ppm F and 25.6 ppm Cl. It is contained in calcium appatite Ca5(PO4)3(F,Cl)3 and we might get it by leaching with H2SO4 to form CaSO4, HF, HCl and H3PO4 acids that can be distilled apart. Or, electrophoresis might be used.

The other thing we might do is just import some lithium chloride and lithium fluoride. LiF is 27% Li and 73% F by mass and LiCl is 16.5% Li and 83.5% Cl by mass. Barium chloride, BaCl2 is heavy at atomic mass 137.327 so it is 71/(71+137) or 34% chlorine.

We can electrolyze the LiF and LiCl to get the chlorine and use it for making salt baths for heat treating steel and use the salts over and over again. Lithium hydroxide is used to make CO2 absorbers, alloy aluminum and treat manic-depression (now called bi-polar disorder).

What if come up with some super alloy steel on the Moon made with REEs from KREEP minerals? Or some mixture of REEs and other elements? Or find a nickel and platinum rich asteroid impact crater? And chromium in crater central peaks? And it has to be heat treated at high temperatures in MgF2? On Earth it might be so expensive and even dangerous to make it isn't considered worth it, but on the Moon?????? Lunasite. A new form of steel. An export? Who knows? We could use some super turbine blade steels couldn't we now? Or reactor pressure vessel steels?
                                                                     Barium, Strontium, etc.

Say we do want barium chloride for salt bath heat treating. Most sulfates are soluble in water except for BaSO4, SrSO4(strontium sulfate) and PbSO4 (lead sulfate). CaSO4 is only slighty soluble in water and acids, about 2 gr per liter, so little will get in the sulfates of Al and Mg that are highly soluble (AlSO4 about 700-800 grams per liter!!!) and traces of Na, Mn and Cr and some stuff only present in ppm not worth worrying about, or we'll find ways to purify stuff for high quality. I'm optmistic. So the BaSO4 (also called Barite in mineral form) will stay with the silica and anhydrite. But SrSO4 is soluble in H2SO4 so it will leach out.

We can separate CaSO4 (dried in the leach tanks so it won't be gypsum) from the silica electrostatically at 7800 V+. The silica doesn't repel until 8892 to 14820 V + or -

BaSO4 repels at 5772 V + or - So we could repel it out of there, but we would be working with low concentrations and lots of gangue material. If we repel the CaSO4 at 7800 V+ it will also repel the BaSO4, so that's where it will go.
BaSO4 m.p. 1580 C. CaSO4 1450 C. CaO 2850 C. BaO 1972 If we roast the stuff the sulfates will break down into oxides and perhaps we could melt the BaO out. Both react with water to form hydroxides [Ca(OH)2 is slaked lime] but BaO is soluble in ethyl alcohol! So we could wash it out with ethanol! The CaO is not soluble in EtOH. Ba m.p. 727 C b.p. 1897 C

As for the silica, we could turn it into glass, mix it with CaO, Al2O3, MgO and a little Na2O (about 1%) according to G. Landiss to make a lower m.p. more workable glass and since we don't have boron for Pyrex we can just us pure silica which is even tougher than Pyrex though tougher to work with. We could also turn the silica into silicon either by 1) FFC 2) direct electrolysis 3) reduction with carbon SiO2 + C = Si + CO2 To make silicon carbide, a good abrasive we use SiO2 + 3C = SiC + 2CO. Need an arc furnace or a real hot solar furnace at 3000 F. or C. I don't remember.

Then we can zone refine the silicon to purify it in the low gravity and free vacuum of the Moon. This will concentrate impurities in the rod or sheet ends. Then we can cut the ends off, grind them up and do whatever we can to get the impurities which might have value. What will remain in the silicon? Who knows. Europium Sulfate in insoluble in water and probably some other uncommon element besides more common lead, barium and strontium. Calcium, Barium, Strontium and Radium are all in column II of the periodic table. Lead is in column IV with tin, germanium and silicon, and silicon doesn't even form a sulfate probably because the chemical bond angles don't line up. It does form a disulfide (SiS2). Anyhow, Barium is right next to Lanthanum, the first element in the REE series (called lanthanides). Those are only present in ppm but more concentrated in KREEP. So maybe many sulfates of REEs are insoluble and will be present in silicon rod ends after zone refining. We shall see. KREEP also contains K and P but also Al2O3, SiO2, and other common silicate mineral components. Monazite sand (Ce, La, Di)SO4 is repelled at 6,532 V + or - KREEP is not a solid rock. The better term is KREEPy regolith that has lots in it. So perhaps we can repel it out like Monazite sand.

Finally: If we are going to grind stuff up we will need rod mills and ball mills-that means we need HARD STEEL. And 3 phase A.C. For motors. So we need solar thermal turbogenerators besides silicon photovoltaics. Centrifugal grinders for really smashing up tiny fused particles of metal and other stuff have been suggested by Dr. Willian Agosto. See Mark Prado's website P.E.R.M.A.N.E.N.T. STEEL AGAIN. If we want to grind up tiny particles of iron and titanium dioxide from CARBOTEK's hydrogen reduction fluidized bed so we can just yank the iron away from the TiO2 with magnets, we need find grinders. STEEL. Otherwise we give up on titanium and rutile (TiO2) ceramics or use acid leaching. I say milling is better. Avoid acids if we can.

And from Linus Pauling's General Chemistry page 688 we find:

"The amount of tempering can be estimated by the interference colors of the thin film of oxide formed on a polished surface of the steel during reheating: a straw color (230 C.) for razors, yellow ( 250 C.) for pocket knives, brown (260 C.) for scissors and chisels, purple ( 270 C.) for butcher knives, blue ( 290 C.) for watch springs and blue-black (320 C.) for saws."

Interesting stuff. I don't think our workers will be tempering steel products out in the vacuum, so yes and oxide film will form that they can keep an eye on.

Hardening can be done in a rapidly cooled salt bath, or by taking the steel part and dipping it in another salt bath just at the melting point of the salt. Annealing might be done in plain regolith because it is a good insulator and will allow slow cooling. A MMM article once described vermiculites from regolith. Just run steam through it. Vermiculites are used to anneal steel because they insulate and slow the cooling.

Ad Luna
                LUBES
We must have lubricants for machinery. All oil will be recycled. H2O, CO2, N, salts, can be transformed by plants and animals into chemically complex living tissue. Thermal depolymerization can turn guts and other scrap into OIL. We can crack it is small refinery shops in underground bases, get the right stuff for lubes. Increasing the weight of thinner fractions of oil like the gasoline and kerosene can be done in reflux condensors with catalysts. You can saturate with hydrogen too. Organic chemistry time! All I know about is lunar regolith stuff as a result of years of study and thought and basic chemistry, but so what? Oil refining is high art these days. So besides ethyl alcohol (EtOH) we can get other organic solvents for trace mineral extraction, but lubricants are the LIFE's BLOOD of machinery. We might synthesize silicones too with ample silicon in the labs.

If we import Chlorine in the form of LiCl and Flourine in the form of LiFl what do we do with the lithium? Alloy aluminum for rocketships? Nope. Titanium actually has a higher strength to weight ratio that aluminum does it not? Make the rocketships out of titanium and use the lithium FOR LITHIUM GREASE. Some of our carbon can be used for graphite dry lubricant also, but not under vacuum conditions.

We can mine hundreds of square kilometers for solar wind implanted H, C and N (BTW, the compound HCN is hydrogen cyanide, NaCN sodium cyanide and KCN potassium cyanide, I forgot what use they have for steel....case hardening I think)

The ice may be rich in CH4 and NH3

Think: One ton of carbon can make 50 tons of 2% carbon steel and 500 tons of 0.2% carbon steel and 5000 tons of 0.02% carbon steel. The beauty of steel is we don't need a lot of carbon to make a lot of steel!!! That should be POINT NUMBER ONE.

Alloying Elements

From the January 2001 Scientific American article by John D. Verhoeven "The Mystery of Damascus Blades" about some of the finest steel blades made in the ancient world, hence the naming of the lunar forge as the Damascus Project with no implication of this author having had any revelations while on the road...we find that as little as 0.003% Vandium in high purity steels yields "good banding" and that molybdenum and to a slighter extent chromium, manganese and niobium do the same. They promote carbide formation and banding but copper and nickel do not. Only 0.02% of V, Mo, Cr, Mn and Nb "become microsegregated into the interdendritic regions...leading to the microsegregation of cemetite particles." Whatever that means, it must be good. I'm either faithful or gullible.

Anyhow, my first Moon Miner's Manifesto article published in August 2002 contains this clue:
So, after H2SO4 leaching, we could take the dried sulfates, calcine them to oxides, possibly in a solar "zapper" that concentrates a beam of solar energy on a falling ribbon of particles (we'd have to crush and grind those sulfates) with superior yields than a simple solar furnace that just heats up a whole batch of stuff, grind them fine again, seive, grind, and take the stuff and heat it up in a chamber, perhaps a fluidized bed, with CO gas to make carbonyls of V ( 114 ppm), Cr, and Mn, boil them off in vacuum or wash them out with EtOH made by fermenting some corn, or use a magnet-Vanadium Hexacarbonyl is paramagnetic. Vanandium, good for tool steels. We could decompose them in thick walled chambers for safety (Cr(CO)6 explodes at 210 C. Other ways surely exist. Forming carbonyls with hot CO gas seems most logical.
Where do we get CO gas? From traces in regolith, perhaps polar ice and perhaps volcanic gas chambers.  There are many low volcanic domes on the Moon, especially in the Marius region.