含碱硅酸钠溶液的回收和利用工艺研究

Study on recovery and utilization process of alkali containing sodium silicate solution

添加石灰作为脱硅剂,对含硅酸钠的碱浸脱硅液进行脱硅处理后回收。将脱硅后的碱液对高硅铝土矿进行循环脱硅,考察钙硅物质的量比、苛碱浓度、初始硅浓度及脱硅时间对脱硅率的影响,并在较佳溶液脱硅条件下验证循环脱硅效果。脱硅结果表明,在碱性条件下[ρ(Na_(2)O)≈100 g/L],将石灰按钙硅物质的量比为1.2进行添加,反应2 h后溶液中二氧化硅质量浓度从约为7 g/L降至约为1 g/L。循环脱硅的结果表明,碱液经5次循环后,铝土矿中的n(Al)/n(Si)均大于7。这不仅为氧化铝工业生产提供了理论指导,也为碱液循环利用提供了一种有效途径。

Adding lime as desilication agent,the desilication solution of alkali leaching containing sodium silicate was recovered after desilication treatment.The desilication solution was recycled to desilicate high silica bauxite.The effect of calcium/silica ratio,caustic soda concentration,initial silica concentration and desilication time on desilication ratio were investigated,and the effect of recycling desilication was verified under the optimal desilication condition.The results of desilication showed that under alkaline condition [ρ (Na_(2)O)≈100 g/L],the concentration of silica in the solution decreased from about 7 g/L to about 1 g/L after adding lime with calcium silicon ratio of 1.2 for 2 h.The results of cyclic desilication showed that the n(Al)/n(Si) of bauxite was greater than 7 after 5 cycles of alkali liquor.This not only provided theoretical guidance for alumina in-dustrial production,but also provided an effective way for caustic solution recycling.