METHOD OF PROCESSING LOPARITE CONCENTRATE Russian patent published in 2000 - IPC

FIELD: hydrometallurgical processing of ore concentrates. SUBSTANCE: method consists in grinding concentrate into particles having size of no more than 0.075 mm together with classification, breaking down loparite concentrate by concentrated inorganic acid at atmospheric pressure followed by separation of ingredients to be extracted. For breaking down the concentrate, use is made of nitric acid at concentration of 650 to 700 g/l; process is performed at temperature of 115 to 118 C at continuously moving the pulp through row of reactor volumes connected in series. Hydrate cake of oxides of refractory metals is washed off by water to obtain pure hydrate cake to be used for subsequent processing and combined nitrate solution of rare-earth elements with admixtures and activity; then it is neutralized with soda and decontaminated settling all admixtures, thorium and mesothorium inclusive, by means of ammonium and barium sulfate, after which pure nitrate nitrate solution of rare-earth elements which is then used for subsequent processing and iron-thorium cake are obtained through filtration. Iron-thorium cake with all admixtures is subjected to processing and burial. Decontamination is effected by means of ammonium sulfate and barium nitrate at temperature of 70 to 80 C and pH=4.5-5 for 6 to 8 h. EFFECT: facilitated process; enhanced economical efficiency; high degree of extraction of tantalum and niobium. 2 cl, 1 tbl, 1 ex