Desilication of sodium aluminate solution by Friedel's salt (FS: 3CaO•Al2O3•CaCl2•10H2O)
Desilication of sodium aluminate solution by Friedel's salt (FS: 3CaO•Al2O3•CaCl2•10H2O)
复制标题
弗里德尔盐对铝酸钠溶液的脱硅（FS：3CaO·A12O3·CaCl2·10H2O）
DOI：
10.1016/j.hydromet.2009.08.010
复制
发表时间：
2009-11-01
期刊：
影响因子：
4.7
通讯作者：
Demopoulos, George P.
中科院分区：
文献类型：
--
作者：
Ma, Jiayu;Li, Zhibao;Demopoulos, George P.
为了防止结垢或氧化铝质量问题，控制拜耳液中的二氧化硅水平至关重要。从铝酸盐溶液中除去硅酸盐的常规方法需要引入氧化钙或氢氧化钙。本文首次证明了Friedel盐（FS：3CaO中心点Al_2O_3中心点CaCl_2中心点10 H（2）O）能去除铝酸钠溶液中高达95%的硅。FS是属于层状双氢氧化物（LDHs）的矿物阴离子交换剂，其通过在50-90 ° C的温度范围内将氯化钙添加到铝酸钠中来制备。采用XRD、SEM、粒度分析仪、TG-DSC等手段对其进行了表征。在50 ℃下制备的FS具有较高的脱硅能力，优于氧化钙，详细考察了温度、铝酸钠溶液组成、初始二氧化硅浓度（4-10 g/L）和FS投加量等影响脱硅过程的实验参数，并对FS和CaO的脱硅效果进行了比较。脱硅产物（DSP）主要为钙铝硅酸盐，经XRD鉴定为菱沸石和硅铝钙石，用FS阴离子交换后铝酸钠溶液中的最终氯离子浓度接近0.015 g/L。FS脱硅速率为一级反应，速率常数为2.582 × 10（6）min（-1）。在80-110 ℃的温度范围内，表观活化能估计为57.7 kJ mol（-1）。(C)2009 Elsevier B. V.保留所有权利。
Controlling silica level in Bayer liquor is critical in order to prevent scaling or alumina quality issues. The conventional method of removing silicates from aluminate solutions requires the introduction of calcium oxide or calcium hydroxide. In this work, Friedel's salt (FS: 3CaO center dot Al2O3 center dot CaCl2 center dot 10H(2)O) is proved for the first time to remove up to 95% silica from sodium aluminate solution. FS is a mineral anion exchanger belonging to the layered double hydroxides (LDHs) which was prepared by adding calcium chloride to sodium aluminate over the temperature range of 50-90 degrees C. It was characterized by XRD, SEM, Particle Size Analyzer and TG-DSC. FS prepared at 50 degrees C has a relatively high desilication capacity, better than calcium oxide.Experimental parameters affecting the desilication process, such as temperature, sodium aluminate liquor composition, initial silica concentration (4-10 g/L) and FS dosage were investigated in detail and a comparison of desilication between FS and CaO was carried out. The desilication products (DSP) were mainly calcium aluminium silicates, identified by XRD to be Chabazite and Wadalite and the final chloride concentration in the sodium aluminate solution after anion exchange with FS was similar to 0.015 g/L The rate of desilication by FS was first order with a rate constant 2.582 x 10(6) min(-1). The apparent activation energy was estimated to be 57.7 kJ mol(-1) over the temperature range of 80-110 degrees C. (C) 2009 Elsevier B.V. All rights reserved.