Study on Direct Reduction Melting Separation-Leaching Process of Disposal Rare Earth Composite Iron Ore

摘要

In this paper the direct reduction melting separation-leaching process is investigated on recovering rare earth from rare earth Bayan Obo complex iron ore (REBOCIO). The REBOCIO was reduced and melting separated to produce iron nugget and rare-earth-rich slag at 1400°C for 12 or 15 min. The RE_2O_3 is enriched into Ce_(4.667)(SiO_4)O or Ca_3Ce_2[(Si,P)_3O_4]_3F, which closely depend on chemical components, especially basic. The optimal acid-leaching parameters of rare earth elements from the rare earth slag are suggested as the hydrochloric acid concentration, the ratio of solid to liquid, leaching temperature, and the leaching time are 1 mol/L, 1:14, 50°C and 120 min, respectively. The rare earth elements leaching efficiency are more than 95%. Adding of calcium CaCO_3 and sodium Na_2CO_3 in direct reduction process have great influence on leaching efficiency of thorium.