重庆市秀山县电解锰渣场地下水处理工艺研究

A Study on Leachate Treatment Technology of Electrolytic Manganese Slag Field in Xiushan County of Chongqing

我国是全球最大的电解金属锰生产、消费和出口国,2017年我国电解金属锰产量高达150万t[1],占全球电解锰总产量的98.5%。电解锰渣是电解金属锰生产工艺过程中锰矿石经酸解、中和、压滤、除杂后产生的酸浸渣、硫化渣和阳极渣的混合体,是电解锰行业的重点污染物。电解锰渣每年产生量约为2000万t,历年累积存量巨大。目前,企业尚未找到妥善处理电解锰渣的方法,一般将电解锰渣运输到堆场筑坝堆放。长期堆放的电解锰渣在雨水冲刷等自然因素的影响下,通过地表径流及渗滤作用严重污染填埋场地周边土壤、地表水及地下水。电解锰渣堆场地下水成分复杂、浓度高、变化大,其主要污染物是氨氮及总锰重金属离子。经研究采用由“高效沉淀+循环氨氮吹脱”组合的工艺对电解锰渣场具有良好的处理能力,能够达到《污水综合排放标准》一级标准的排放要求,对电解锰渣场渗滤液处理及渣场周边环境保护具有重大意义。

China is the world’s largest producer,consumer and exporter of electrolytic manganese metal.In 2017,the output of electrolytic manganese metal reached 1.5 million tons,accounting for 98.5%of the global electrolytic manganese output.Electrolytic manganese slag is a mixture of acid leaching slag,sulfide slag and anode slag produced by manganese carbonate ore after acid hydrolysis,including neutralization,pressure filtration and impurity removal during the production process of electrolytic manganese metal.It is a key pollutant in the electrolytic manganese industry.The amount of electrolytic manganese slag produced amounts to 7~11 tons of manganese.Our annual output is about 20 million tons.At present,the enterprise has not found a proper method to dispose of the electrolytic manganese slag.Generally,the electrolytic manganese slag is transported to the storage yard for dam construction.Under the influence of natural factors such as rain erosion,the electrolytic manganese slag is stacked for a long time seriously pollutes the soil,surface water and groundwater around the landfill site through surface runoff and infiltration.The electrolytic manganese slag dump site has a complex composition,high concentration and large changes in the water.The main pollutants are ammonia nitrogen and total manganese heavy metal ions.After research,the combined process of“high-efficiency precipitation+circulating ammonia nitrogen removal”has a good processing capacity for the electrolytic manganese slag field.It can meet the discharge requirements of the first-level standard of the“Integrated Wastewater Discharge Standard”.Environmental protection around the slag yard is of great significance.