Characterization of Lunar Ilmenite Resources.

摘要

Ilmenite will be an important lunar resource, to be used mainly for oxygen production but also as a source of iron. Ilmenite abundances in high-Ti basaltic lavas are higher (10--20%) than in high-Ti mare soils (mostly <10%). This factor alone may make crushed high-Ti basaltic lavas most attractive as a target for ilmenite extraction. Concentration of ilmenite from either a crushed basalt or regolith requires sizing to avoid polycrystalline fragments. In coarse-grained high-Ti basaltic lavas, about 60--80% of the ilmenite will consist of relatively ''clean'' single crystals if the rocks are crushed to a size of 0.2 mm. Fine-grained high-Ti basalts, with thin skeletal or hopper-shaped ilmenites, would produce essentially no free or ''clean'' ilmenite grains unless crushed to sizes of less than 0.15 mm, and only approximately 7% free ilmenite if crushed to sizes smaller than 0.05 mm. Data from the 2.8 m-thick regolith sampled by coring at the Apollo 17 site show that in even the most basalt-clast-rich and least mature stratigraphic intervals, free ilmenite grains make up less than 2% of the 0.02- to 0.2-mm size fraction and a mere 0.3% of the 0.2- to 2-mm size fraction. 23 refs., 9 figs., 1 tab.