摘要
电解锰行业发展面临的困境之一是锰渣的处理处置方法.为探索绿色低碳的锰渣无害化处理技术,选取中国5家典型电解锰企业新、旧电解锰渣,通过其理化特性及浸出毒性分析,研究堆存条件、时间及工艺参数等因素对不同企业锰渣特性的影响.结果显示:不同企业的新、旧锰渣平均质量含水率相差最大时均达19％以上,浸出液pH值最高分别相差0.95、1.45,不同企业新鲜锰渣的SiO2和Al2O3平均质量分数最大相差分别为43.18％、146.25％,且可溶性盐质量分数均超过10％,未达到填埋入场标准.锰渣中石膏和石英的质量分数随堆存条件和时间发生不同的变化.企业C在堆存过程中石膏和石英的质量分数在增加,而企业E锰渣中烧石膏质量分数在增加,石英质量分数在减少.历史锰渣浸出液中Mn2+和氨氮(NH4+-N)的质量浓度较高,分别超过GB/T 8978-1996 一级排放标准限值的65.92～935.00倍和2.56～63.80倍,表明长期堆存的锰渣仍存在较大的环境污染风险.不同地区企业的锰渣应通过无害化处理与资源化利用来降低其环境污染风险,须根据化学成分、理化性质不同选择合适的资源化方式.
Abstract
More than half of the manganese producers in China are located in the southwest region,and the annual generation of tens of millions of tons of electrolytic manganese slag,mostly disposed of by damming and stockpiling,poses a great threat to the environment.In this paper,characterization and leaching toxicity experiments are conducted on the electrolytic manganese slag from southwest China.The basic physical properties such as water content,pH of leachate,soluble salt content and particle size are first determined from the collected electrolytic manganese slag,and then X-ray fluorescence spectrometry(XRF),X-ray powder diffractometer(XRD),scanning electron microscopy(SEM)and inductively coupled plasma mass spectrometry(ICP-MS)are used to analyze the chemical composition,phase composition,microscopic morphology and leaching toxicity of manganese slag.The research results show that the maximum difference between the average mass water content of new and old manganese slag of different enterprises is more than 19％,and the highest difference of leachate pH is 0.95 and 1.45 respectively.In addition,the soluble salt content of fresh manganese slag can reach up to 15.15％,and the index of soluble salt content needs to be paid attention to in the environmentally friendly treatment.The main chemical components in manganese slag were SO3,SiO2,CaO,Fe2O3 and Al2O3,with average mass fractions of 20.55％,13.69％,16.06％,14.88％and 4.93％in all samples,respectively.In addition,the main mineral phases in the manganese slag were gypsum,quartz,mica,microplagioclase,chlorite,burnt gypsum and pyrite,etc.The characteristic peaks of gypsum and quartz in the old and new manganese slags of enterprise C and enterprise E show opposite trends during the stockpiling process influenced by the stockpiling conditions,and the characteristic peaks of gypsum and quartz in the manganese slag of enterprise C are enhanced during the stockpiling process,but enterprise E is weakened.Besides,the leaching toxicity characteristics of manganese slag show that the leaching concentrations of Mn2+and NH4+-N both decrease continuously during the process of stockpiling,but the concentrations of Mn2+and NH4+-N in the leaching solution of historical manganese slag still exceed the limits of GB/T 8978-1996 primary emission standards by 65.92-935.00 times and 2.56-63.80 times,and the long-term stockpiling still has a large risk of environmental pollution in long-term storage.The purpose of this study is to provide data support for the treatment and disposal of electrolytic manganese slag in China.
基金项目
贵州省科技计划项目(黔科合重大专项[2022]002)
NETL
NSTL
维普
万方数据