稀土转型硫酸镁废水草酸法除钙实验研究  

Treatment of Magnesium Sulfate Wastewater from Rare Earth Transformation with Oxalic Acid Precipitation Method

作　　者：侯少春 马莹[1] 张文娟[1] 赵永志[1] 丁艳蓉 赵拓 郝一凡 HOU Shao-chun;MA Ying;ZHANG Wen-juan;ZHAO Yong-zhi;DING Yan-rong;ZHAO Tuo;HAO Yi-fan(State Key Laboratory Baiyunobo Rare Earth Resources Research and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China)

机构地区：[1]包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室

出　　处：《稀土》2019年第5期100-105,共6页Chinese Rare Earths

基　　金：中国北方稀土(集团)高科技股份有限公司项目(2014H1840)

摘　　要：研究了用草酸沉淀法去除稀土转型硫酸镁废水中少量的钙离子,考察了草酸加入量、溶液p H值和反应时间对除钙效果的影响,对得到的沉淀草酸钙进行了X射线衍射分析和扫描电镜形貌观察,并采用浓硫酸对草酸进行了回收实验。结果表明,草酸沉淀除钙法随草酸加入量的增大Ca O去除率增加,当草酸加入量为理论量的1.2倍时,Ca O去除率较高,达到89.53%;废水p H值较低时,Ca O去除率较低,用MgO调节废水p H为5~6,Ca O去除率较高;反应时间为90 min时,Ca O去除率在89%以上,出水Ca O含量低于0.1 g/L;当浓硫酸的加入量为理论量的4倍时,草酸钙的转化率达到了95%以上,可作为浓硫酸法回收草酸适宜的工艺条件。Using oxalic acid precipitation method to remove the small amount of calcium in magnesium sulfate wastewater of rare earth transformation was studied.The influences of the oxalic acid addition amount,pH value and reaction time on CaO removal efficiency were investigated,and the precipitate of calcium oxalate was studied by X ray diffraction analysis and scanning electron microscope observation.Also the recovery of oxalic acid was carried out by using sulfuric acid.The results showed that CaO removal efficiency had increased with the increase of quantity of oxalic acid.When the quantity of oxalic acid was 1.2 times of the theoretical amount,the CaO removal rate reached higher than 89.53%;the CaO removal rate was lower when the pH value was lower.However,when pH value was adjusted to 5~6 with MgO,the CaO removal rate was higher;when reaction time was 90 min,the CaO removal rate reached a higher value of 89%and the CaO content of the magnesium sulfate wastewater of rare earth transformation was lower than 0.1 g/L.The conversion rate of calcium oxalate was more than 95 percent when the amount of concentrated sulphuric acid was four times the theoretical quantity.It is suitable for recycling of oxalic acid by the method of concentrated sulphuric acid.

关 键 词：硫酸镁废水 草酸沉淀法 除钙率 P H值 

分 类 号：X703[环境科学与工程—环境工程]