加料方式对氟化沉淀法脱除硫酸锰溶液中钙镁杂质的影响  

Effect of feeding methods on removal of calcium and magnesium from manganese sulfate solution by fluorination precipitation method

作　　者：李云[1] 李玉虎 徐志峰[1] 王瑞祥[1] 贺欣豪 陈金龙 LI Yun;LI Yuhu;XU Zhifeng;WANG Ruixiang;HE Xinhao;CHEN Jinlong(Department of Materials and Metallurgy 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：《中南大学学报（自然科学版）》2021年第9期3103-3110,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51864019);江西省“双千”人才项目(jxsq2018106051);江西省自然科学基金资助项目(20181BAB206019);江西省教育厅科学技术研究项目(GJJ170508);江西理工大学清江拔尖人才项目(JXUSTQJBJ2018005)。

摘　　要：考察加料方式对氟化沉淀法脱除硫酸锰溶液中钙、镁杂质的影响,查明在正加、反加和并加条件下氟化锰用量对钙镁脱除率、沉淀渣过滤速度及沉降性能的影响规律。研究结果表明:增加锰离子质量浓度不利于钙镁离子的脱除,即使在锰离子质量浓度饱和状态下,采用氟化锰仍可将钙和镁完全脱除。理论上,当Mn^(2+)质量浓度达到140 g/L时,采用氟化沉淀法可将溶液中的钙和镁质量分数分别降至9.65×10^(−7)和7.46×10^(−9),均远低于电池级高纯硫酸锰对钙、镁杂质的要求(质量分数低于5×10^(−5));加料方式对氟化沉淀法除钙、镁有较显著的影响,当氟化锰用量超过40.9 g/L,采用并加时,钙、镁脱除率高于正加和反加条件的脱除率,而当氟化锰用量低于40.9 g/L时,正加和反加条件除杂效果更好。与此同时,并流加料条件下氟的引入量更高,其氟化锰的利用率更高。在3种加料方式下,正向加料所得料浆的过滤速度较高,且随着氟化锰用量增加,其过滤性能进一步改善,但其沉降性能较差。加入晶种有助于改善氟化沉淀物的沉降性能,特别是当晶种质量浓度超过2.5 g/L时,沉降性能显著改善。The influence of feeding methods on the removal of Ca2+and Mg^(2+) in MnSO_(4) solution was investigated by using fluorination precipitation method.Effects of the dosage of MnF_(2) on removal rate of Ca^(2+) and Mg^(2+),filtration rate of the precipitated residue and sedimentation performance under the conditions of positive addition,reverse addition and combined addition were clarified.The results show that increasing the mass concentration of Mn2+is not conducive to the removal of Ca2+and Mg2+.However,when the mass concentration of Mn2+reaches saturation,this method can still remove Ca^(2+) and Mg^(2+) completely.Theoretically,when the mass concentration of Mn2+reaches 140 g/L,the mass fraction of Ca^(2+) and Mg^(2+) in MnSO_(4) solution can be reduced to 9.65×10^(-7) and 7.46×10^(-9),respectively,both of which are far lower than the requirements of 5×10^(-5) for Ca^(2+)and Mg^(2+) impurities in high purity MnSO_(4) solution.In addition,feeding methods has significant effect on the removal of Ca^(2+) and Mg^(2+) by fluorination precipitation method.When the dosage of MnF2 exceeds 40.9 g/L,the removal rate of Ca^(2+) and Mg^(2+) in the combined addition method is better than that of positive and reverse addition conditions.However,when the dosage of MnF_(2) is less than 40.9 g/L,the impurities removal rate in the conditions of positive and reverse addition is higher.Meanwhile,the amount of F-introduced and the utilization rate of MnF_(2) are higher under the combined addition condition.Among the three feeding methods,the filtration rate of the slurry obtained by positive addition is fastest,and with the increase of dosage of MnF_(2),its filtration performance is further improved,but its sedimentation performance is poor.The addition of seed crystal is helpful to improve sedimentation performance of fluoride precipitate,and especially when the mass concentration of seed crystal exceeds 2.5 g/L,sedimentation performance is improved significantly.

关 键 词：氟化沉淀 加料方式 过滤速度 脱除率 

分 类 号：TQ137.12[化学工程—无机化工]