2种回转窑工艺还原低品位软锰矿的效果评价

Effect of Products from Two Rotary Kiln Processes on Reduction of Low Grade Pyrolusite Ore

用XRD、SEM和化学分析等方法对2种回转窑工艺还原低品位软锰矿的产物进行表征,同时结合硫酸浸出试验,考察锰、铁和铝的浸出差异。结果表明：改进回转窑工艺的产品中锰的还原率可达到93%以上,原回转窑工艺锰的还原率为50%~90%。常温常压时在较佳浸出条件下,酸矿比0.55∶1、液固比5∶1、时间40 min、搅拌速度300 r/min,改进回转窑工艺使锰的浸出率达94.1%,高于原回转窑工艺的产品,而铁、铝的浸出率则相对较低,分别是33.6%和26.3%。将回转窑中的燃烧室和还原室分离有利于提高锰的还原率,改进回转窑工艺产品中锰、铁、铝的存在形态,而颗粒表面粗糙、带小孔有裂纹的形貌具有较大比表面积,有利于提高锰的浸出率。

The products of two rotary kiln processes on the reduction of low grade pyrolusite ore were characterized by XRD, SEM and chemical analysis. Leaching difference of manganese, iron and aluminum were investigated by sulfuric acid leaching experiment. The results show that manganese reduction rate of improved rotary kiln processes can reach above 93%, but the original one is 50% -90%. Under ordinary temperatures and pressures, the optimum leaching conditions read as follows, sulphuric acid： pyrolusite ore = 0.55： 1, liquid-solid ratio 5： 1, stirring speed 300 r/min, leaching time 40 min. Finally, leaching rate of manganese reached of improved rotary kiln processes is 94.1%, which is higher than that of the original rotary kiln process. But the lower leaching rate of iron, aluminum is 33.6%, 26.3% respectively. The separation of combustion chamber and the reduction chamber in rotary kiln are helpful to improve reduction percent of manganese. Both speciation of manganese, iron, aluminum and the rough surface with small hole giving larger specific surface area contribute to the higher leaching rate of manganese, lower leaching rate of manganese iron, aluminum.