基于化学沉淀法去除电解锰渣中锰和氨氮的实验

Experimental Study on Removal of Manganese and Ammonia Nitrogen from Electrolytic Manganese Residue by Chemical Precipitation Method

为了实现电解锰渣中锰、氨氮的有效去除,研究基于化学沉淀法,选取磷酸氢二纳和氯化镁为主要化学稳定剂,氢氧化钙作为外掺剂,设计不同配比实验方案,分析不同化学稳定剂掺入质量分数、锰渣含水率和氢氧化钙掺入质量分数对锰渣浸出毒性的影响。研究表明:随着稳定剂掺入质量分数的增加,锰渣中锰和氨氮的浸出质量浓度降低;锰渣含水率的改变会改变锰的浸出质量浓度,但对氨氮浸出质量浓度影响不大;氢氧化钙掺入质量分数的增加使得电解锰渣稳定后锰的浸出质量浓度降低,但氨氮的去除效率下降。因此,研究最终提出采用磷化物-碱系化学稳定电解锰渣技术的稳定剂配比为3%磷酸氢二纳、3%氯化镁以及外掺2%氢氧化钙,同时控制电解锰渣含水率为24%,锰和氨氮的去除效果最优。研究结果对锰渣的无害化、资源化利用具有参考意义。

In order to achieve effective removal of manganese and ammonia nitrogen in electrolytic manganese residue(EMR),a study was conducted based on chemical precipitation method.Sodium hydrogen phosphate and magnesium chloride were selected as the main chemical stabilizers,and calcium hydroxide was used as an admixture.Different mix ratio experimental schemes were designed to analyze the effects of different chemical stabilizer dosages,water content of manganese residue,and calcium hydroxide dosages on the leaching toxicity of EMR.The study found that with the increase of stabilizer dosage,the leaching concentration of manganese and ammonia nitrogen in EMR decreases;The change in moisture content of EMR will alter the leaching concentration of manganese,but has little effect on the leaching concentration of ammonia nitrogen;Increasing the calcium hydroxide addition reduces the leaching concentration of manganese in EMR,but decreases the removal efficiency of ammonia nitrogen.Therefore,the stabilizer ratio using the phosphate-alkali stabilized EMR technology is ultimately proposed,which is 3%sodium hydrogen phosphate,3%magnesium chloride,and 2%calcium hydroxide added externally.At the same time,controlling the water content of EMR to 24%results in the best removal efficiency of manganese/ammonia nitrogen.The findings are significant for the harmless and resourceful utilization of EMR.