煤矸石酸浸渣干法制备水玻璃的研究

Study on the Dry Process of Preparing Sodium Silicate Gangue Acid Leaching Slag

煤矸石酸浸渣是提取酸溶物后的固体废弃物,主要化学成分是SiO2及少量的CaSO4和TiO2。本文以煤矸石酸浸渣为原料,通过酸浸液分离时的副产品Na2SO4和酸浸渣中SiO2物质的量比确定制备水玻璃模数,采用干法制备水玻璃,为了便于实验研究,以Na2CO3替代Na2SO4,考察了制备温度、时间和冷却方式对水玻璃合成的影响,研究结果表明:按合成水玻璃模数1∶1配料,在1000℃下煅烧1 h,采用水淬骤冷方式,硅的回收率接近80%;酸渣中的硫酸钙最终转化为偏硅酸钙,进一步与偏硅酸钠形成低共熔物,会造成钠和硅的损失,而钛的存在则有利于提高钠、硅的收率,同时消除钙、铁等杂质对水玻璃合成的影响。

Gangue acid leaching residue is a kind of solid waste which is obtained after extraction of acidsoluble, the main chemical composition of which is silicon dioxide, a small amount of calcium sulfate, titanium. In this paper, coal gangue acid leaching residue was used as raw material, the mole ratio of by- product sodium sulfate and acid leaching slag sodium silicon at separated from the acid infusion was employed to determine the sodium silicate modulus, and the dry method was engaged to prepare sodium silicate. In order to facilitate the experimental studies, sodium sulfate was replaced with sodium carbonate, the effect of temperatures, times and cooling methods for the sodium silicate preparation was investigated, the results showed that： at the condition of the silicate modulus on 1： 1, calcining on 1000 % for 1 h, quenching by water quenching method, the recovery of silicon was close to 80%. The calcium sulfate in the acid residue converted to calcium metasilicate in the end, which further formed eutectic with sodium metasilicate, this would result in the loss of sodium and silicon; The presence of titanium would be helpful to improve the yield of sodium, silicon, and eliminate the effects of calcium, iron and other impurities on the synthesis of sodium silicate.