Reducing Roasting of the Niobium–REM Ores of the Chuktukon Deposit with the Production of Phosphorus Cast Iron and Niobium–REM Slag

Abstract

The results of studying the reducing roasting of the high-iron (65% Fe2O3) niobium–rare earth ore of the Chuktukon deposit with the production of high-phosphorous cast iron and niobium–rare earth slag are discussed. The optimum reducing roasting conditions are found, and fairly complete separation of the roasting product into metal and slag phases is shown to be achieved at 1400°C. Under these conditions, 88% of phosphorus passes into cast iron, and 95% of niobium and 85% of manganese are concentrated in a rare-earth slag. The yield of phosphorous cast iron (up to 3.5% P) is about 45% and that of slag is 25% of the ore mass. The main slag phases are glass and, crystals with perovskite, loparite and spinel structures. Niobium and rare earth metals are concentrated in the first three phases, and the spinel phase is represented by an MnAl2O4–MgAl2O4 solid solution. After the preliminary removal of iron and phosphorus from the ore in the form of a metallic product, the material flows in the hydrometallurgical stage of processing are found to be reduced fourfold. Moreover, the entire process can become environmentally friendly with high technical and economic indicators.