钢厂酸性废水循环浸出软锰矿工艺条件研究

Technical Conditions for Leaching of Pyrolusite with Acidic Wastewater from Steel Mill

以钢厂酸性废水为还原剂,研究了钢厂酸性废水还原浸出软锰矿工艺,以达到综合利用软锰矿和钢厂酸性废水的目的。结果表明,在FeCl2与MnO_(2)物质的量比2.2、浸出温度90℃、浸出时间3 h、液固比11∶1、初始酸性废水浓度2.5 mol/L条件下,软锰矿中Mn、Fe、Al的浸出率分别达到97.14%、95.37%和41.33%。采用废铁屑还原浸出液中Fe^(3+),在反应温度80℃、反应时间50 min、废铁屑加入量为理论量的1.1倍时,Fe^(3+)还原率达到99.85%。Fe^(3+)还原为Fe^(2+)后,含Fe^(2+)还原液返回浸出,浸出结果稳定,其中,软锰矿中Mn、Fe、Al平均浸出率分别达到96.75%、95.31%、41.18%。

An experiment study was carried out on a processing technique of reduction leaching of pyrolusite with acidic wastewater from steel mills as the reductant,for comprehensive utilization of pyrolusite and acidic wastewater of steel mills.The results show that 3 hours of leaching at 90℃,with FeCl2 and MnO_(2) in a mass ratio of 2.2,liquid-solid ratio of 11∶1 and the acid wastewater at an initial concentration of 2.5 mol/L,can result in the leaching rates of Mn,Fe and Al from the pyrolusite at 97.14%,95.37%and 41.33%,respectively.And then,Fe^(3+)in the leachate is reduced with scrap iron at an amount of 1.1 times the theoretical amount at a temperature of 80℃for 50 min,leading to the reduction rate of Fe^(3+)up to 99.85%.After Fe^(3+)is reduced to Fe^(2+),the Fe^(2+)-containing reducing solution is returned for leaching again,presenting stable leaching results.It is shown that the average leaching rates of Mn,Fe and Al from pyrolusite are 96.75%,95.31%and 41.18%,respectively.