Getting lunar ilmenite: From soils or rocks

Lunar soils or rocks can be mined as sources of ilmenite for producing oxygen. However, separable crystals of loose ilmenite in lunar soils are rare (<2%) and small (<200 {mu}); most ilmenite in the regolith is locked together with silicate minerals as rock fragments. Since fragmentation of rock sources must be attempted to win appreciable amounts of ilmenite ({approximately}10% or more), selective collection of high-Ti basalt fragments larger than 1 cm for fragmentation and ilmenite beneficiation may be advantageous over extensive processing of fine lunar soil. Many alternative processing schemes for fragmenting rocks on the Moon have been proposed; one process which was tested early in the Apollo program successfully disaggregated lunar and terrestrial basalts by passive exposure to low-pressure alkali (K) vapor. This process is worthy of reinvestigation. 14 refs., 3 figs.