以真空铝热炼钙还原渣为原料溶出氧化铝的研究

Study on extracting alumina from calcium smelting reduction slags

以铝粉为还原剂真空热还原炼钙后的还原渣的主要物相为12CaO·7Al2O3,其氧化铝含量超过40%。以碳酸钠溶液为溶出液,对该炼钙还原渣中氧化铝的溶出进行了研究。通过XRD和SEM分析得出了还原渣和溶出渣的主要物相。研究结果表明,溶出过程中炼钙还原渣中大部分的12CaO·7Al2O3可被分解,渣中80%以上的氧化铝可被溶出进入溶液,溶出后渣的主要物相为CaCO3,还原渣中的3CaOAl2O3较难溶出,这是造成溶出过程中氧化铝损失的主要原因。

The main phase of calcium reduction slags by vacuum reduction using aluminum powder as reductants is 12CaO·7Al2O3 and the content of alu- mina is over 40%. The process of extracting alumina from the reduction slag by leaching with sodium carbonate solution is studied. XRD and SEM are used to study the phases of reduction slags and leaching residues. The results show that the 12CaO·7Al2O3 in the reduction slag can be decomposed and more than 80% alumina can be leached. The main phase of leaching residue is CaCO3. The alumina in the form of 3CaOAl2O3 is difficult to leaching, that is the main way of loss of alumina in leaching process.