Hydrogen-mineral reactions and their application to the removal of iron from spodumene

Abstract

Pegmatitic deposits contain three distinctly different types of spodumene: 1.(1) Phenocrystic spodumene in unzoned pegmatites. This type is high-iron spodumene, with Fe2O3 = 0.6 − 0.9%.2.(2) Zonal spodumene. Large laths in central zones; it contains 0.01–0.03% Fe2O3.3.(3) Spodumene plus quartz aggregates pseudomorphous after petalite; Fe2O3 = 0.007 − 0.03%. Only Type 1 generally occurs in deposits sufficiently large and uniform to be economically exploitable. Two processes are presently available for iron removal. Both require initial inversion of the (a) spodumene to its β-dimorph: 1.(1) The chlorine process in which the isomorphous iron is converted to bon chloride and2.(2) The hydrogen process in which the Fe3+ ion is reduced to metallic iron.Hydrogen-mineral reactions, such as hydrogen-carbonate reactions, are potential sources of lime, methane and iron. They also are important for the benefication of such ceramic materials as spodumene and feldspar.