氯化镧从钨酸钠溶液中沉淀除氟新工艺研究  

Study on a New Process for Removing Fluoride from Sodium Tungstate Solution by Precipitation with Lanthanum Chloride

作　　者：李朝阳 杨亮[1] 张新英 龚丹丹[1] 万林生[1] LI Chao-yang;YANG Liang;ZHANG Xin-ying;GONG Dan-dan;WAN Lin-sheng(Faculty of Materials Matallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou 341000,China)

机构地区：[1]江西理工大学材料冶金化学学部,江西赣州341000

出　　处：《稀有金属与硬质合金》2023年第2期8-12,共5页Rare Metals and Cemented Carbides

基　　金：国家自然科学基金项目(51964019);江西省科技厅项目(20204BCJ23001,20212BAB204027,20212BAB214024);江西省教育厅项目(GJJ150631,GJJ190487)。

摘　　要：低品位白钨矿采用磷酸钠-氢氧化钠-氟化钙协同浸出得到的钨酸钠溶液中含有较高浓度的氟,导致冶炼废水中氟含量超出国家排放标准。基于氟化镧具有低溶解度的性质,采用在钨酸钠溶液中加入氯化镧,反应生成氟化镧沉淀将氟深度除去。考察了氯化镧添加量、溶液pH值、反应温度和反应时间等工艺条件对除氟效果的影响。实验结果表明,当钨酸钠溶液中氟浓度为0.5~2.1 g/L、氯化镧用量为理论量的1.6倍、溶液pH值为10.1、温度为40℃、反应时间为10 min时,除氟率达到98.8%,沉淀渣中钨损失为0.26%。除氟钨酸钠溶液经离子交换工序处理后能够实现废水氟含量达标排放。The sodium tungstate solution obtained from low-grade scheelite by collaborative leaching with sodium phosphate-sodium hydroxide-calcium fluoride contains a relatively high concentration of fluorine,leading to the fluorine content in the smelting wastewater exceeding the national discharge standard.Based on the low solubility of lanthanum fluoride,lanthanum chloride was added to the sodium tungstate solution and the reaction produced lanthanum fluoride precipitate to thoroughly remove fluorine.The effects of process parameters including the lanthanum chloride dosage,pH value of the solution,reaction temperature,and reaction time on the removal of fluoride were investigated.The results show that the fluorine removal rate reaches 98.8%when fluorine concentration of the sodium tungstate solution is 0.5~2.1 g/L,the dosage of lanthanum chloride is 1.6 times the theoretical amount,the pH value of the solution is 1o.1,the temperature is 60 C,and the reaction time is 30 min,with a tungsten loss of 0.26%in the precipitated slag.After the removal of fluorine,the sodium tungstate solution treated by an ion exchange process can meet the requirement of the national standard for the fluorine content in the discharging wastewater.

关 键 词：氯化镧 钨酸钠 氟化镧 沉淀除氟 

分 类 号：TF841[冶金工程—有色金属冶金]