Study On Innovation Process And Mechanisms Of Fe And RE-Nb Separation For Refractory RE-Nb Associated Ore

This topic was founded by "Study on the separation technology of beneficiation-metallurgy from the poor&fine rare earth and niobium associated rare-metal ores"(serial number:2012EG115006),"Study on the metallurgical physical and chemical basis of separation and extraction of rare earth and niobium from the complex rare metal"(serial number:51304055) and "Study on the metallurgical physical and chemical basis of separation and extraction from the complex rare metal"(serial number:S2013040015625).The paper systematic researched the physicochemical properties of RE-Nb associated ore and features of process mineralogy, taking a RE-Nb associated ore which located in Inner Mongolia as the research object. As for the characteristic that the gangue mineral content is higher, the paper tries to treat it with the method of magnetic separation preconcentration and apply the method of reduction roasting and magnetic separation to restore roasting behavior and the research on separation technology of Fe, RE and Nb. The paper also revealed the mechanism separation of Fe, RE and Nb with the application of proper compound additives to strengthen the technological process of reducing roasting separation of Fe, RE and Nb, combing with thermodynamic calculation, optical microscope, XRD and scanning electron microscope analysis etc.The process mineralogy analysis on the RE-Nb associated ore and the RE-Nb-Fe associated rough concentration show that the relationship of embedded iron, rare earth and niobium minerals are complexed. It is difficult to separate and concentrate.Fe, RE-Nb separation and recovery from RE-Nb-Fe associated rough concentrate was studied by reduction roasting-magnetic separation. The results show that metallic iron powder with total iron grade of89.32%, RE-Nb enrichment with REO grade of5.36%and Nb2O5content of4.62%are obtained when the sodium sulfate dosage is15%, the temperature is1100℃and time is120min, and the grinding fineness is85.4%ores less than0.074mm and the magnetic field intensity is800mT, then the iron recovery is91.47%, the REO recovery is96.09%and the Nb2O5recovery is95.82%.The iron oxide is easier reduced than rare earth oxide and niobium oxide by carbon. When iron oxide is reduced by carbon, the solid reaction occurs at low temperature resulting in the formation of FeOSi02and FeOAl2O3, which are reduced to metallic iron when temperature exceeds1167.0K. FeO is found to at lower temperature than1167.0K when sodium sulfate was added during the reduction. The results of XRD and microstructure analyzes of the reducing roasting product have proved that the iron particles were fine and can not aggregation and growth without additive. When added sodium sulfate and active carbon powder, the tiny metallic iron crystal would aggregation and growth then become the laminated shape, closely structure, and the distribution of iron, rare earth and niobium were different. It is advantageous separates the metal powdered iron in the magnetic separation.