从粉煤灰生产Al_2O_3废液中提取高模数硅酸钠的应用研究  

A Method and Precess for Improving the Modulus of Sodium Metasilicate

作　　者：李丽芳 汪林 张炜铭[1,2] LI Li-fang;WANG Lin;ZHANG Wei-ming(Jiangsu NJU Environmental Technology Co.,Ltd.The state environmental protection organic chemical wastewater treatment and reuse engineering technology center,Nanjing 210046,China;School of environment Nanjing University,Nanjing 210093,China)

机构地区：[1]江苏南大环保科技有限公司国家环境保护有机化工废水处理与资源化工程技术中心,江苏南京210046 [2]南京大学环境学院,江苏南京210093

出　　处：《环境科技》2018年第5期25-28,共4页Environmental Science and Technology

摘　　要：采用萃取法从粉煤灰生产Al_2O_3废液中提取高模数硅酸钠。由于直接萃取需要消耗大量的萃取剂,且上层中SiO_2的含量高,因此粉煤灰生产Al_2O_3废液不宜进行直接萃取。浓缩预处理之后萃取剂的用量大幅度下降,显著降低运行成本。浓缩处理后,硅酸钠的模数为1.03～1.04,下层硅酸钠中Na_2O的质量分数为12.55%～17.9%,SiO_2的质量分数为13.06%～18.46%。上层中SiO_2的质量分数均在0.5%以下,上层碱度的质量分数为34.9%～45.3%,上层萃取剂的质量分数维持在80%～85%之间。经二级萃取之后,硅酸钠的模数由废液的0.55～0.63提升至2.0～2.3之间,下层硅酸钠中的Na_2O的质量分数为14.8%～17.4%,SiO_2的质量分数为29.5%～36.9%。上层碱度的回收率在42%～50.2%之间。The extraction of high modulus sodium silicate from Al2O3 waste water from fly ash was studied in this paper. As direct extraction required a large amount of extractant, and the content of SiO2 in the upper layer was high, it is not suitable to extract the waste water directly. After the pretreatment of concentration, the amount of the extractant was greatly reduced, and the operating costs wass remarkably declined.The modulus of sodium silicate was 1.03 - 1.04, the content of Na2O in the lower sodium silicate was 12.55% - 17.9%, and the content of SiO2 was 13.06% - 18.46%. The content of SiO2 in the upper layer was less than 0.5%, the content of the upper alkalinity achieved 34.9% - 45.3%, and that of the upper extractant was between 80% 85%. After the secondary extraction, the modulus of sodium silicate was increased from 0.55 - 0.63 to 2.0 - 2.3, the content of Na2O in the lower sodium silicate was 14.8% - 17.4%, and the content of SiO2 attained 29.5% - 36.9%. The recoveries of the upper alkalinity were 42% - 50.2%.

关 键 词：粉煤灰 硅酸钠 模数 萃取法 

分 类 号：X7[环境科学与工程—环境工程]