低氮氢氧化铌的制备工艺研究

Study on Preparation Technology of Low Nitrogen Niobium Hydroxide

钽铌矿经过氢氟酸、硫酸分解后再经过仲辛醇萃取分离,得到氟铌酸溶液,向氟铌酸溶液中通入0.3MPa氨气进行中和反应,生成白色氢氧化铌沉淀,经压滤机过滤、稀氨水洗涤、0.6~0.7MPa压缩空气除去45%~50%的水分,得到含氟离子不超过5000ppm的氢氧化铌湿滤饼。由于此时的氢氧化铌烘干后,其含N在3.5%~4.5%之间,不能满足客户对氢氧化铌烘干到含Nb_(2)O_(5)在72%~78%时,N含量小于0.2%的要求。因此对氢氧化铌降N工艺进行了试验,经过综合对比,选取了合适的体积分数的化学纯盐酸作为关键试剂,采用了微波干燥设备对低氮氢氧化铌进行烘干,并取得批量生产低氮氢氧化铌的工艺参数。

The tantalum niobium ore was decomposed by hydrofluoric acid and sulfuric acid and then separated by extraction to obtain niobium solution,the white niobium hydroxide precipitates were formed by neutralizing the niobium solution with 0.3MPa ammonia gas,after filtering by filter press,washing with dilute ammonia water and removing 40%~50%of the moisture with 0.6~0.7MPa compressed air,niobium hydroxide wet filter cake containing less than 5000ppm of fluoride ion was obtained.However,after the drying of niobium hydroxide at this time,the content of N is between 3.5%and 4.5%,which cannot meet the customer's requirement that the content of N is less than 0.2%when niobium hydroxide is dried to contain Nb_(2)O_(5) in 72%~78%.Therefore,the process of niobium hydroxide reducing N was tested.After comprehensive comparison,the appropriate volume fraction of chemical pure hydrochloric acid was selected as the key reagent,Microwave drying equipment was used to dry niobium hydroxide with low nitrogen,and the process parameters for mass production of low nitrogen niobium hydroxide were obtained.