醚类添加剂B35对铝酸钠溶液晶种分解过程的影响

Effect of ethers additive B35 on seeded precipitation of sodium aluminate solution

研究醚类添加剂B35对铝酸钠溶液晶种分解过程的影响,采用红外光谱仪分析溶液的结构,采用微电泳仪测定Al(OH)3颗粒表面的Zeta电位。结果表明:加入适量醚类添加剂可强化分解过程,当添加剂B35用量为500 mg/L时,相对空白样可提高分解率4%;醚类添加剂B35对分解过程的强化不是由铝酸钠溶液结构的改变引起的;添加剂B35可使Al(OH)3晶种表面Zeta电位明显升高,说明Al(OH)3对该表面活性剂发生特性吸附,导致铝酸钠溶液在Al(OH)3颗粒表面的润湿角减小,其固液界面张力降低,从而使分解过程得以强化;此外,醚类添加剂B35使产品Al(OH)3平均粒径增大10μm左右,而粗颗粒在溶液中的平衡溶解度较小,分解过程推动力较大,也应是强化分解过程的原因之一。

The effect of ethers additive B35 on the seeded precipitation of sodium aluminate solution was investigated,the structure of the sodium aluminate solution was analyzed by FTIR,the zeta potential of the solid surface of Al（OH）3 particles was measured by micro-electrophoresis.The results show that proper dosage of ethers additive can improve the seeded precipitation process of sodium aluminate solution.The precipitation rate can be raised by 4% when the B35 dosage is 500 mg/L.The change of the solution structure is due to the enhancement of seeded precipitation process by adding the additive rather than the effect of the additive itself.Zeta potential of solid surface of Al（OH）3 particles increases significantly when adding B35,the characteristic adsorption occurs between Al（OH）3 particles and the additive.This characteristic adsorption decreases the wet angle of the Al（OH）3 surface,reduces the solid-liquid interfacial tension force and ultimately intensifies the seeded precipitation process of sodium aluminate solution.In addition,there is another reason for enhancing precipitation that the equilibrium solubility of coarse particles is relatively smaller than that of the fine particles in sodium aluminate solution,and thus increases the driving force of precipitation process,and the average particle size of products increases by about 10 μm through adding ethers B35.