QUANTITATIVE MINERALOGICAL CHARACTERIZATION OF LUNAR HIGH-TI MARE BASALTS AND SOILS FOR OXYGEN PRODUCTION

Efficient lunar resource utilization requires accurate and quantitativ e evaluation of mineral and glass abundances, distribution, and extrac tion feasibility, especially for ilmenite. With this in mind, true mod al analyses were performed on high-Ti mare basalts and soils with X ra y/backscattered electron signal digital-imaging techniques, and these data indicate that (1) ilmenite concentrations are similar for basalts and immature-submature soils with similar TiO2 content; (2) ilmenite liberation of crushed mare basalts and immature-submature mare soils a re comparable (i.e., both contain similar amounts of free ilmenite); a nd (3) because of impact melting and agglutination of primary minerals , mature mare soils contain less ilmenite (both free and attached). Mo dal analyses of magnetic separates of high-Ti mare basalts and soils s how that (1) ilmenite was concentrated by a factor of greater than or equal to 3.3 and (2) soil ilmenite was concentrated to factors of 1.7- 2.3. The lower soil ilmenite separation efficiency is attributed to Fe -o-bearing agglutinitic glass and amorphous rinds adhered to soil part icles. Mass yields of magnetically generated feedstocks were generally less than 5 wt % in most cases. Calculation of oxygen yield (as relea sed by hydrogen gas reduction of ilmenite) show that (1) beneficiated basalt will provide the most oxygen (8-10%), because of higher ilmenit e concentration; (2) reduction of raw immature-submature mare soils an d basalts will produce similar amounts of lunar liquid oxygen (LLOX) ( 2.1-3.1%); and (3) raw Fe-rich pyroclastic soil, 74220, will provide m ore oxygen (5.4%) than beneficiated high-Ti mare soils and half that o f beneficiated high-Ti mare basalts. High-Ti mare soils are attractive resources for lunar liquid oxygen (LLOX) production because of their unconsolidated nature, high ilmenite abundance, and widespread occurre nce. Energy-intensive excavation and comminution likely prohibits the basalt mining during early lunar occupation. Orange soils are importan t resources for LLOX and various volatile elements, but slower reactio n kinetics and glass sintering pose potential difficulties for large-s cale operations.