活性白土副产石膏渣中铁、铝的硫酸浸出

Sulfuric acid leaching of iron and aluminum from by-productgypsum residues of activated clay

为了纯化活性白土副产石膏渣中的石膏及综合回收铁、铝元素,探究了硫酸对石膏渣中铁、铝的浸出效果,主要考察了酸浸温度、酸浸时间、硫酸浓度、液固比等过程因素对铁、铝浸出效果的影响,并通过热力学分析、浸出动力学阐述了铁、铝的浸出机制。研究结果表明,当酸浸条件在温度25℃、时间120 min、硫酸浓度6 mol/L、液固比7 mL/g时,铁、铝的浸出率分别达到70.48%、79.29%;结合相关热力学计算推测升高温度促进硫酸钙的大量生成,其很可能沉淀于原料矿物表面从而阻碍了铁、铝的进一步溶出;浸出过程主要受固体产物层扩散模型影响;酸浸后固体渣中SO 3质量分数提高至54.00%,相关质量符合水泥行业标准要求。研究结果表明,使用硫酸对活性白土副产石膏渣进行浸出获得了较好的铁、铝浸出效果,同时实现了石膏的纯化,这为活性白土副产石膏渣的资源化利用提供了参考。

In order to purify by-product gypsum residues of activated clay and comprehensively recover iron and aluminum elements,the leaching effect of sulfuric acid on iron and aluminum in gypsum residues was explored.The effects of process factors such as acid leaching temperature,acid leaching time,sulfuric acid concentration,liquid solid ratio on the leaching effect of iron and aluminum were mainly investigated.The leaching mechanism of iron and aluminum was elaborated through thermodynamic analysis and leaching kinetics.The results show that when the acid leaching temperature is at 25℃,the leaching time is 120 min,sulfuric acid concentration is 6 mol/L and liquid solid ratio is 7 mL/g,the leaching rates of iron and aluminum reached 70.48%and 79.29%,respectively.Combined with the relevant thermodynamic calculations,it is speculated that the increase in temperature promoted the mass formation of calcium sulfate,which is likely to precipitate on the surface of raw material and hinder the further leaching of iron and aluminion.The leaching process is mainly affected by the layer diffusion model of solid products.After acid leaching,the quality score of SO 3 in the solid residues increases to 54.00%,and the relevant quality in line with cement industry standards.The results showed that the leaching effect of iron and aluminum was obtained by leaching by-product gypsum residue of activated clay by using sulfuric acid,and the purification of gypsum was realized,which provided a reference for the resource utilization of by-product gypsum residue of activated clay.