Producing Metallic Antimony with Low Arsenic Content from Antimony Concentrate

Resumo

The basis of the concentrate is sodium hexahydroxoantimonate or mineral mopungite. Upon reduction of the concentrate with coke, ground antimony containing 0.34% arsenic was obtained. To reduce the arsenic content in the rough metal to 0.1% and exclude the stages of antimony refining from arsenic, reductive melting is proposed in the presence of lead compounds. Because of the smelting reduction of the antimonate concentrate in the presence of sodium plumbite or lead oxide, a rough antimony with an arsenic content of 0.07–0.1% was obtained. The process of reductive smelting of the antimonate concentrate on black antimony was carried out in an oven with silicate heaters in alundum crucibles with batches of charge of 100–150 grams. The content of impurities and the base metal in antimony was determined by chemical and atomic absorption methods. The form of arsenic in the concentrate was determined by X-ray phase analysis. The analysis was carried out on an automated diffractometer DRON-3 with CuK_α radiation, ß-filter. The concentration of arsenic in the slag phase in the form of lead diarsenate Pb₂As₂O₇ is shown. Thermal gravimetric analysis of the smelting reduction process of the antimonate concentrate was studied on the Q-1000/D derivatograph of the F. Paulik, J. Paulik and L. Erdey systems of the “MOM” company. Thermogravimetric researches of process of recovery melting of the furnace charge consisting of an antimony concentrate, lead oxide and coke as a result of which it is established that process of formation of metal antimony proceeds in the range of temperatures 445–950°C are conducted.