有机添加剂在铝酸钠溶液分解中的应用研究

【作者】 阳征会；

【导师】 陈文汨；

【作者基本信息】 中南大学 ， 冶金物理化学， 2003， 硕士

【摘要】 本文研究了一定条件下温度对铝酸钠溶液分解过程二次成核和附聚的影响；表面活性剂对二次成核和附聚过程产品粒度及产率的影响；确定了分解过程中对二次成核、附聚起主导作用的温度，并将其应用于铝酸钠溶液分解过程，研究了表面活性剂对种分和碳分过程的影响。 铝酸钠溶液种子分解工艺主要包括二次成核、附聚、晶体长大、晶粒的破裂磨损等过程，选择适当的条件可以使二次成核或附聚成为主要过程。研究表明：苛性比a_k为1.375，Al₂O₃为140 g．L^-1的铝酸钠溶液：60℃加10g．L^-1的粗晶种，分解过程以二次成核为主要过程；80℃加100g．L^-1的细晶种，分解过程以附聚为主要过程。 实验结果表明：加入合适的表面活性剂，提高了氢氧化铝颗粒之间的有效碰撞次数，强化聚团程度，显著提高聚团的抗碎裂能力，增强了小粒子附聚能力，产品氢氧化铝的粒度增大。混合型表面活性剂对小粒子附聚效果优于阳离子型或非离子型表面活性剂。在种分过程中，混合-3的用量为0.2g·L^-1时，自配溶液产品中粒度大于45μm的粒子体积百分数增加9％，分解率增加近3.5％；混合-2用量为0.2g·L^-1时，使工业溶液产品粒度大于45μm的粒子体积百分数增加7％。在碳分过程中，混合-3的用量为0.1g·L^-1时，可使自配溶液产品粒度大于45μm的粒子体积百分数增加20％；混合-1量为0.1g·L^-1时，可使工业溶液产品粒度大于45μm的粒子体积百分数增加8％。 研究表明用添加剂（混合型表面活性剂）提高铝酸钠溶液分解得到的大颗粒氢氧化铝其强度不够，磨损系数偏大，不能满足工业砂状氢氧化铝生产的粒度要求。有待于更深入的探索研究。更多还原

【Abstract】 Effects of temperature on secondary nucleation and agglomeraton were studied during precipitation process of sodium aluminate solution. Effects of surfactants on particle size and productivity of aluminium hydroxide were also studied in these processes. The suitable temperature which plays main role on secondary nucleation and agglomeraton was determined. Effects of surfactants on seed precipitation and carbon dioxide decomposition of sodium aluminate were investigated.Several processes such as secondary nucleation , agglomeration, growth, rupture and attrition occur in seed precipitation process of sodium aluminate solution, Secondary nucleation or agglomeraton preferably takes place depending on precipitation condition. Results showed that secondary nucleation was main process when 100g. L-1 coarse seeds was added and the solution temperature was 60 C , whereas agglomeraton was main process when lOOg. L-1 smaller seeds was added and the solution temperature was 80C. The initial solution caustic ratio a* was 1. 375 and conceration of Al2O3 140g. L-1.Results showed that adding proper surfactants intensified agglomeraton of small particles, effective collision was increased among aluminium hydroxide particles, agglomeraton and anti-rupture ability was promoted, ability of small particles agglomeraton was intensified. The surfactants mixture was much more effective than cationic or nonionic surfactants for small particles agglomeraton. During seed precipitation, when the amount of mixture-3 was 0. 2g. L-1, the volume percent of particle with diameter larger than 45 m was increased 9% and precipitation rate was increased by 3. 5% in pure solution, and when the amount of mixture-2 was 0. 2g. L-1, the volume percent of particle with diameter larger than 45 u m was increased 7% in industry solution. During carbon dioxide decomposition, by adding 0. 1g. L-1 mixture-3 the volume percent of particle with diameter larger than 45 m increased 20%, and when the amount of mixture-1 was 0.1 g. L-1 the volume percent of particle with diameter larger than 45 u m increased 8% in industry solution.By using surfactant , large particle of aluminium hydroxide was obtained. However, they had low strength and their attrition index was high, so they do not meet the specification of sandy aluminium hydroxide, Further studies are needed.更多还原