OBTAINING NIOBIUM CONCENTRATE FROM NIOBIUM-CONTAINING FLUORIDE CINDERS

Abstract

The paper presents the results of processing niobium-containing fluoride cinders to obtain niobium concentrate from them. The material composition of the cinder was studied by chemical and X-ray methods. X-ray phase analysis showed the presence of ammonium aluminium fluoride, ammonium iron fluoride, ammonium titanium fluoride, as well as niobium-containing sodium niobium fluoride. Leaching of the fluoride cinder was carried out with ammonia water at temperatures of 60 - 80°C until a precipitate was formed at pH = 9 with vigorous stirring at 300 rpm, for 90 min. Nitric acid purification of the sludge was performed with a nitric acid solution within 4 - 10 %, at 60 oC, with a S:L ratio of 1:5 and an agitation time of 120 min. 8 % HNO₃ was chosen as the optimum concentration of nitric acid. After washing the obtained cake was calcined at 500°C for 120 min. The niobium concentrate containing 57.5 % Nb₂O₅ was obtained according to the study results.