利用秸秆电厂灰渣制备Na₂SiO₃的工艺初探

Preliminary Study of Na₂SiO₃ Production from the Ash of Power Plant Firing Agro-Residue

摘要: 生物质发电产业已得到迅速发展，是消纳秸秆最大的行业，推动了秸秆露天禁烧及大气污染控制工作，目前迫切需要研发秸秆灰渣的高值化技术。秸秆灰渣经水浸提取钾素、酸浸提取磷素之后，大部分未燃尽炭也会随钾磷去除，剩余的成分主要是二氧化硅及硅酸盐，二氧化硅含量一般在50%以上。本文以氢氧化钠为提取剂提取秸秆灰渣中的SiO₂，对比了焙烧法、水热法、常压液相法，初步获得秸秆电厂灰渣制备Na₂SiO₃溶液的工艺参数，灰渣原料中的SiO₂溶出率达到74%。制备的Na₂SiO₃溶液可继续用于硅气凝胶、硅溶胶等硅基材料的生产，本文具有重要意义。

Abstract: The industry of biomass power generation has been developed rapidly, contributes a lot to agro-residue treatment, and promotes the works of burning-forbidding in open air and air pollution control. Currently, high-value reutilization of the ash of power plant firing agro-residue is needed urgently. After potassium extraction by water leaching and phosphorus extraction by acid leaching, most of unburnt carbon can also be removed; the ash would be mainly composed of SiO₂ and silicate, and can be reused to produce Na2SiO3 through the reaction with NaOH. This study compared the processes of calcination, hydrotherm and atmospheric liquid, and established the optimal process of Na₂SiO₃ production from the ash. The dissolution rate (DR) of SiO₂ in the ash could reached at 74%, and the attained Na₂SiO₃ solution can be used further to produce silica-based materials such as silica aerogel, silica sol, and etc. This study is helpful for the biomass power industry.