锰渣的理化特性及煅烧特性

Physicochemical and calcination characteristics of manganese residue

分析＂两矿一步法＂电解Mn O2酸浸中和压滤渣（简称锰渣）的理化特性,采用热重-差热分析法（TG-DTA）和X线衍射分析（XRD）确定不同温度下物相转变行为以及锰渣中锰的浸出随煅烧温度的变化。研究结果表明：锰渣为第Ⅱ类一般工业固体废物,以石英、水化硫酸钙、针铁矿和铁、铝矾矿相为主,矿相颗粒细、结晶度低。随着煅烧温度的升高,硫酸钙、针铁矿,以及铁、铝矾逐步脱水、分解,形成无水石膏、赤铁矿等,超过900℃时锰渣明显熔融、烧结,部分金属与硅反应形成玻璃态硅酸盐;锰渣中总锰质量分数约5%,约3%以Mn SO4的形式存在。锰渣锰的浸出毒性根据煅烧温度分为3类,即低温可浸出（〈300℃,锰离子质量浓度为0.6～1.0 g/L）,中温易浸出（400～700℃,锰离子质量浓度为2～3 g/L）;高温难浸出（〉800℃,锰离子质量浓度为〈0.01 g/L）。

The physicochemical characteristics of manganese residue from two ore one-step process were analyzed. The thermal phase transition behavior was detected by using TG-DTA and XRD. And manganese leaching toxicity was determined. The results show that manganese residues which belongs to general industrial solid waste in small particles contain quartz, hydrated calcium sulfate, goethite, jarosite and hydrobasaluminite. The calcium sulfate, goethite, jarosite and hydrobasaluminite are dehydrated at high temperature and decomposed to form anhydrite and hematite. Manganese residues sinter and melt obviously and silicate glass appears through reaction between some metals and silicon when the temperature is over 900 ℃. There is about 5% of Mn present in the residue and 3% of it is MnSO4. Manganese leaching toxicity appeared in three stages according to calcination temperature, that is, low-temperature stage （below 300 ℃, mass concentration of manganese ion is 0.6-1.0 g/L）, middle-temperature stage （between 400 ℃ to 700 ℃, mass concentration of manganese ion is 2-3 g/L）, and high-temperature stage （above 800 ℃, mass concentration of manganese ion is less than 0.01 g/L）.