磁尾矿的硼盐混合焙烧抑氟-酸浸提取稀土和制备KBF_4的研究

Anti-Fluorination Activation with Boron Salts-Hydrochloric Acid Leaching for Magnetic Tailings and Preparation of KBF_4

磁尾矿是包头白云鄂博矿经磁选后产生的尾矿,含有大量的稀土和氟资源,对其开发利用具有重大的环境和经济价值。利用F-B强的配位能力采用硼化物焙烧抑氟-盐酸浸出法,以硼砂为抑氟剂,650℃焙烧1.0 h后,稀土矿中RE-F的结合能力被高温下活泼的B弱化,焙烧混合矿继续在80℃条件下4.0 mol·L-1HCl中浸出3.0 h,氟浸出率为96.52%,稀土最大浸出率为76.68%。同样采用P204对浸出液进行萃取,稀土进入有机相,实现了氟、稀土的两相分离,萃余液中添加K+并调节pH,沉淀得氟硼酸钾,产物杂质单一,基本实现了氟的资源化和稀土与氟的分离。

Magnetic tailings is the gangue obtained after magnetic separation of Baotou BaiyunObo ore with a large number of rare earth and fluorine resources. The development and utilization of magnetic tailings has tremendous environmental and economic value. The anti-fluorination activation-hydrochloric acid leaching with borides using strong coordination ability of F-B for magnetic tailings was studied in the article. Using borax as an anti-fluorine agent, roasting at 650 ℃ for 1.0 h, the bonding capacity of RE-F in rare earth ore could be weakened by active B at high temperature. Then the roasted mixed ore leached with 4.0 mol·L-1 HC1 at 80 ℃ for 1.0 h, and the RE leaching rate of 76.68% and F leaching rate of 96.52% were obtained. The leaching solution was extracted by P204, and the RE was extracted into the organic phase, realizing was prepared from raffinate by adding K＋ and adjusting the the separation of RE/F. Potassium fluoroborate pH, and the product almost had no impurity. The re- covery for F resources and separation of RE/F were realized basically.