氟化法制备高纯硫酸锰中氟含量的控制

采用氟化法除钙镁与控制结晶法除氟相结合的方式制备了高纯硫酸锰，有效控制硫酸锰中氟含量的同时实现了氟的循环利用。具体工艺如下: 首先依次加入适量的MnF2、双氧水、锰粉、硫化铵去除溶液中的钙、镁、铁以及重金属杂质; 再调节脱水泊美度将晶体中的氟杂质控制在标准范围内; 最后通过母液直接净化结晶和母液与原液1∶2混合这2种方式实现氟的循环利用。实验结果表明: 氟化锰最佳加入量13 g/L，反应温度为室温，反应时间2 h，除铁最佳pH值5.5，硫化铵最佳加入量1 mg/L，脱水泊美度51,母液与原液1∶2混合后，只需加入9 g/L的氟化锰就能将钙镁杂质含量降至50 μg/g以内。

Control of Fluorine Content in High Purity Manganese Sulfate Prepared By Fluorination

High-purity manganese sulfate was prepared by a combined process consisting of removing calcium and magnesium by fluorination and removing fluorine by controlling crystallization, which effectively controlled the fluorine content in manganese sulfate and actualized recycling of fluorine. The practical processing technique is as follows: firstly, an appropriate amount of MnF2, hydrogen peroxide, manganese powder and ammonium sulfide are added in turn to remove calcium, magnesium, iron and heavy metallic impurities in the solution; secondly, the dehydration pomedox is adjusted to control the fluorine impurities in the crystal within the standard range; finally, the fluorine can be recycled by two ways, including direct purification of mother liquor, or mixing mother liquor and stock liquor at a ratio of 1∶2. The experimental results show that a reaction firstly run at the room temperature for 2 h, with an optimal addition of 13 g/L of manganese fluoride, an optimal pH value of 2.5 for iron removal, an optimal addition of 1 mg/L of ammonium sulfide; hydration pomedox is then selected around 51; finally, the mother liquid was mixed with the stock liquor at a ratio of 1∶2, by adding 9 g/L of magnanese fluoride. Under this conditions, the calcium and magnesium impurities can be reduced to below 50 μg/g.