采用氟化焙烧—硫酸浸出工艺从提钪后的浸出渣中回收铌,研究焙烧温度、焙烧时间、氟化氢铵用量对脱硅效果和铌富集效果的影响,以及硫酸浓度、硫酸用量、浸出温度和浸出时间对铌浸出率的影响。结果表明,焙烧温度为200℃,焙烧时间为2.5h,矿盐比为1∶1.2时,硅脱除率达到95%以上,渣中铌品位富集到2.1%左右;硫酸浓度为12mol/L,浸出时间2h,浸出温度为80℃,液固比为15∶1时,铌的浸出率达到80%。
Niobium was recovered from scandium bearing acid-leaching-residue by fluoride roasting and sulfuric acid leaching. The effects of roasting temperature, roasting time, and dosage of ammonium bifluoride on desilication and niobium enrichment were investigated. The effects of sulfuric acid concentration, dosage of sulfuric acid, leaching temperature, and leaching time on niobium leaching rate were also studied. The results show that desiliconization rate is 95% and niobium concentrate grade in slag is 2.1% under the calcination conditions including temperature of 200 ℃, roasting time of 2.5 h, and mineral salt ratio niobium is 800/6o under the leaching conditions including sulfuric acid concentration h, leaching temperature of 80 ℃, and ratio of liquid to solid of 15 : 1. of 1 : 1. 2. Leaching rate of of 12 tool/L, leaching time of 2