铝酸钠粗液氧化铝浓度对熟料溶出过程的影响

以脱硅粉煤灰熟料为原料进行熟料溶出,控制液固比得到不同氧化铝浓度的铝酸钠粗液,通过分析上述粗液在不同溶出时间溶液成分及固相成分的变化规律,研究溶出过程发生的二次反应历程。结果表明,随着氧化铝浓度的升高、溶出时间的延长,铝酸钠溶液中的氧化铝浓度和氧化硅浓度大致呈下降趋势;固相中氧化铝和氧化钠含量呈上升趋势,熟料氧化铝溶出率和氧化钠溶出率呈逐渐下降趋势。对于原硅酸钙含量大于50%的脱硅粉煤灰熟料而言,建议将铝酸钠粗液氧化铝浓度控制在100~120g/L,熟料溶出后浆液的液固分离时间控制在180min以内。在不同初始氧化铝浓度条件下,随着溶出时间的延长,二次反应产物及反应历程随着氧化铝浓度的变化而变化。溶出固相的主要产物为水化石榴石、钠硅渣、原硅酸钙和少量方解石。

Influence of Alumina Concentration in Clinker Leaching Process

Desilication fly ash clinker was digested to obtain different concentration of sodium aluminate solution by controlling ratio of liquid to solid. Secondary reaction during clinker digestion process was analyzed by analyzing solution composition and solid phase composition in crude sodium aluminate solution under different leaching time. The results show that with increase of aluminate concentration and prolongation of leaching time, concentrations of alumina and silicon in aluminate solution decrease, contents of Al2O3 and Na2O in calcium silicate slag rise, and dissolution rates of Al2O3 and Na2O drop gradually. For calcium silicate content higher than 50% in desilication fly ash clinker, it is suggested that concentration of sodium aluminate solution be controlled at 100~120 g/L, and separation time of liquid and solid be controlled within 180 min. Reaction products and reaction process change with initial aluminate concentration with prolongation of leaching time under different initial aluminate concentration. Main products of dissolved solid phase include hydrogarnet, sodium-silicon residue, calcium silicate and a trace amount of calcite.