铝酸钠溶液深度脱硅的研究

Study on Deep Desilication in Alumina Production

应用XRD等手段考察了氧化钙、立方水合铝酸钙、六方水合铝酸钙、水合碳铝酸钙和水合硫铝酸钙等含钙脱硅剂的性质。发现脱硅活性与它们的晶体结构有关,六方晶系的好于立方晶系;脱硅活性与晶面间距成正比,晶面间距越大,密度越小,活性比表面积越大,脱硅活性越好。实验结果表明,在相同条件下,脱硅活性次序是:水合硫铝酸钙>六方水合铝酸钙>水合碳铝酸钙>立方水合铝酸钙>氧化钙。

The properties of calcic desilication additives, such as calcium oxide, cubic calcium hydroaluminate,hexagonal calcium hydroaluminate, calcium hydroacluminocarbonate and calcium hydroaluminosulfate, were studied. It was found that the efficiency of desilication has relation with the crystal structure of the additives, and the efficiency of desilication of hexagonal crystal phases was better than cubic crystal phases. The efficiency of desilication was directly proportional to the d-spacing. The greater the d-spacing was, the lower the density and the better the efficiency of desilication were. The experimental results indicated that, at the same conditions, the order of efficiency of desilication was calcium hydroaluminosulfate 〉 calcium hydroaluminate of hexagonal system 〉 calcium hydroaluminocarbonate 〉calcium hydroaluminate of cubic system 〉 calcium oxide.