电解锰阳极液中镁的去除试验研究

Removal of Magnesium From Electrolytic Manganese Anode Solution

根据热力学计算结果,确定了Mg^2+-Mn^2+-NH^+4-C2O4^2-体系中离子浓度与溶液pH之间的关系,研究了以草酸为沉淀剂从模拟阳极液中共沉淀镁、锰,以及以镁锰草酸盐沉淀物为前驱体制备镁锰氧化物材料,考察了草酸用量、溶液pH、沉淀温度、沉淀时间及陈化时间对镁、锰去除率及草酸根残余浓度的影响。结果表明:在镁、锰总物质的量与草酸用量比为1/0.8、溶液pH=2.0、沉淀温度80℃、沉淀时间0.5 h、陈化时间1 h条件下,镁、锰离子去除率分别达76.35%和81.51%,草酸根离子残余浓度为31.8 mmol/L。热重、X射线衍射(XRD)及红外光谱分析结果表明,镁锰草酸盐沉淀物在600℃条件下焙烧4 h,可获得结晶度较高的氧化物Mg6MnO8,实现镁锰资源的有效回收。

According to thermodynamic calculation results,the relationship between the ion concentration and the pH of Mg^2+-Mn^2+-NH^+4-C2O4^2- system was determined.The magnesium,manganese and magnesium-manganese oxalate precipitate in the simulated anolyte with oxalic acid as precipitant was studied.Magnesium-manganese oxide was prepared as precursors.The effects of oxalic acid dosage,solution pH,precipitation reaction temperature,reaction time and aging time on removal rates of magnesium and manganese ions and oxalate residual concentration were examined.The results show that magnesium and manganese ions are obtained under the conditions of the ratio of magnesium and manganese total amount to oxalic acid amount of 1/0.8,solution pH of 2.0,precipitation temperature of 80℃,precipitation time of 0.5 h,and aging time of 1 h,the removal rates of magnesium and manganese ions are 76.35%and 81.51%,respectively,and the residual concentration of oxalate ions is 31.8 mmol/L.The results of thermogravimetry,X-ray diffraction(XRD)and infrared spectroscopy indicate that the magnesium-manganese oxalate precipitate is calcined at 600℃for 4 h,and the oxide Mg6MnO8 with higher crystallinity is obtained.The magnesium-manganese resources is effectively recovered.