煤矸石除杂及碱融活化制取硅酸钠的实验研究

研究利用煤矸石中的硅元素制取硅酸钠，先将煤矸石粉在750 ℃下煅烧2 h，除去有机质并破坏了煤矸石中的高岭石等矿物的晶型结构，再将煅烧过的煤矸石粉在95 ℃、液固比（mL/g）为8∶1、质量分数为40%的硫酸中酸浸5 h，煤矸石煅烧粉中的铁和铝等金属杂质离子的总去除率为86.93%；还研究了碱融活化条件对硅元素溶出率的影响，获得了适宜的碱融活化条件：m（酸浸粉）∶m（碳酸钠）=1∶1.5、碱融温度为800 ℃、碱融时间为2 h。在此条件下，硅元素溶出率大于75%，最终获得了硅酸钠溶液。

Experimental study on preparation of sodium silicate by purification of gangue and alkali melting activation

In order to utilize silicon in the coal gangue to prepare sodium silicate，the gangue powder was calcined at 750 ℃ for 2 h firstly，then the organic matters were removed and the crystal structures of the minerals，such as kaolin in the gangue were destroyed.The calcined gangue powder was leached in sulfuric acid with mass fraction of 40% and liquid to solid ratio of 8∶1 at 95 ℃ for 5 h.The total removal ratio of impurity metal ions，such as iron and aluminum was 86.93%；the influences of the alkali melting activation conditions on the dissolution ratios of silicon element were investigated，then the suitable activation conditions were obtained:the mass ratio of acid leaching powder to sodium carbonate was 1∶1.5，the alkali melting temperature was 800 ℃，and the alkali melting time was 2 h.Under these conditions silicon element dissolution ratio was more than 75% and the sodium silicate solution was obtained finally.