碳酸钠对铝酸钠溶液深度脱硅的影响

在氧化铝的生产过程中,随着循环母液里碳酸钠的积累使物料流量增加,溶液的粘度增大,并影响分解过程A l(OH)3的结晶及生长。试验采用氧化钙为脱硅剂,研究了碳酸钠对铝酸钠溶液深度脱硅条件和结果的影响,确定出较佳反应条件:在脱硅温度90℃、时间110m in、搅拌速度867 r/m in,碳酸钠用量30g/L时,精制液的硅量指数达到3642。硅渣的XRD光谱分析表明,碳酸钠浓度在0~30g/L之间时,促进铝酸钠溶液脱硅;碳酸钠浓度高于30g/L时,抑制溶液脱硅。

Effect of Sodium Carbonate on Deep Desiliconization of Sodium Aluminate Solution

During the course of producing aluminum oxide,as accumulation of sodium carbonate in circulation mother liquor,the flow rate increases and also the solution viscosity,which has influences on crystallization and growth of Al(OH)3.The experiment was performed by using calcium oxide as desiliconization reagents to study the effects of sodium carbonate on the condition and result of deep desiliconization of sodium aluminate solution.Finally,the optimal reaction condition of temperature as 90℃,time as 110min,stirring speed as 867r/min and dosage of sodium carbonate as 30g/L was determined and the silicon index of refine liquor reached 3642.Meanwhile,Silicon residue of deep desiliconization was analyzed by XRD and found when the sodium carbonate concentration is 0～30g/L,it can promote disiliconization but when the concentration is more than 30g/L,it inhibits.