| Sodium, Potassium, Phosphorus It is my understanding that oxidized Na, K and P remain in the molten silicate melt. This is strange because they take less energy to de-oxidize than silicon. Hypothetically, they boil out of the melt since their m.p.s are well below the 1300-1600 C. temp. of magma electrolysis and reoxidize and settle back into the melt. Perhaps helium 4 from volatiles mining can be used to flush the particles of Na2O, K2O and P2O5 out with oxygen and then be filtered out of the gas stream. Separating these oxides and converting them to useful salts is another matter entirely. Any good chemist should be able to devise a way to do it without too many reagents unavailable on the Moon. KREEP Data lacking I have found no studies of K, REE or P extraction from lunar KREEP or KREEPy basalts. Perhaps a KREEP simulant is needed. Herein, I can only hypothesize. KREEP defined KREEP is not a single mineral or rock. My understanding is that it consists of K-feldspar and REEs in a phosphate mineral [apatite-Ca5(PO4)3(F,Cl)3 or whitlockite-Ca9(Mg,Fe)(PO4)7(F,Cl)] matrix. Some basalts are rich in KREEP. Sometimes KREEPy regolith or KREEPy basalt is referred too. Extraction Monazite sands are leached in H2SO4, the soluble REE sulfates filtered off, crystallized, carbonchlorinated and the REE chlorides are subjected to sequential fused salt electrolysis with different REEs coming out of the melt at different voltages. Perhaps lunar KREEP can be processed in a similar way. Chlorine would be required and the phosphate minerals contain some. HCl will form during the reaction with H2SO4 and these can be separated by distillation. Perhaps KREEP can simply be fried with solar heat to drive off phosphorus, essential for n-type solar panel material. Perhaps magma electrolysis of KREEPy basalt will allow K and P to boil out and these can be prevented from reoxidizing and settling back into the melt with a helium 4 gas flushing system. Rare Earth Elements that dissolve into silicon could be concentrated into rod ends by zone refining. The rod ends would be cut off, ground and treated with Cl gas to form SiCl4 that is volatile leaving chlorides of REEs that would then be subjected to fused salt electrolysis. This is all hypothetical. |
| Na-K-P-KREEP |
| David A. Dietzler, 2007 |
 |
 |
| see: Rare Earth Metals Find Interesting New Uses Despite Lack of Engineering Data. By Roman Lundin and John R. Wilson http://www.arris-intl.com/customer/Papers/remetalspaper.html |
 |