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目前世界上大部分铌矿矿山采用硫酸-氢氟酸分解法湿法冶金处理工艺,但氢氟酸的毒性高、腐蚀性强,对设备材质要求高,而且成本高,不适宜处理低品位矿石。针对我国攀西地区某低品位铌矿开展了工艺矿物学和纯硫酸体系酸化焙烧-浸出工艺研究,考察了不同焙烧时间、用酸量等对铌浸出率的影响。研究结果表明:该矿石含铌矿物主要由褐钇铌矿、复稀金矿和铌铁金红石组成,N2O5含量0.034%,嵌布粒度细,比较分散,属于低品位极难处理铌矿。铌属于难溶金属,在低温(温度低于100℃)下,采用强酸、强碱浸出,铌浸出率低于30%,无法得到有效回收。添加H2O2与水合铌矿物形成酸可溶的配合物,有效提高了铌浸出率。获得最佳的工艺参数为:在磨矿细度为-74μm占80%,硫酸化焙烧的温度为250℃,硫酸用量占原矿质量比为75%,添加H2O2用量占原矿质量比为70%,焙烧时间2 h;浸出温度90℃,液固比4∶1,酸矿比为3∶1,浸出时间2 h的条件下,铌浸出率达到81%。
At present, most of the niobium mines in the world adopt the sulfuric acid-hydrofluoric acid hydrometallurgical hydrometallurgical process, but hydrofluoric acid has high toxicity, strong corrosiveness, high equipment requirements and high costs, and is not suitable for treating low-grade ore . Aiming at the low-grade niobium ore in Panxi area of our country, the study of technology of mineralogy and acidification roasting-leaching of pure sulfuric acid system was carried out. The influence of different roasting time and acidity on the leaching rate of niobium was investigated. The results show that the ore containing niobium mainly consists of brown yttrium-niobium ore, complex rare-earth gold and niobium-iron rutile. The content of N2O5 is 0.034%. The nephelometric ore is thin and dispersive, and belongs to the low-grade extremely refractory niobium ore. Niobium is a poorly soluble metal. At low temperatures (temperatures below 100 ° C), leaching with strong acids and strong bases results in niobium leaching rates below 30% and can not be effectively recovered. The addition of H2O2 to the hydrated niobium mineral forms an acid-soluble complex, effectively increasing the niobium leaching rate. The optimum technological parameters were as follows: grinding fineness of -74μm accounted for 80%, the temperature of sulfation roasting was 250 ℃, the amount of sulfuric acid accounted for 75% of the original ore mass, the amount of H2O2 added accounted for 70% The roasting time was 2 h, the leaching temperature was 90 ℃, the ratio of liquid to solid was 4:1, the ratio of acid to ore was 3:1 and the leaching time was 2 h. The leaching rate of niobium reached 81%.