拟薄水铝石工业生产中三水氧化铝含量的控制

针对中国石化催化剂长岭分公司NaAlO₂-Al₂(SO₄)₃法生产的拟薄水铝石产品中三水氧化铝含量高的问题，在拟薄水铝石反应机理研究的基础上，发现原工艺宏观上酸碱处于当量反应时，不能完全避免微观区域内pH值波动带来的NaAlO₂局部过量，是产品中三水氧化铝含量高的本质原因。三水氧化铝含量的增加会严重影响拟薄水铝石产品的孔性质和生产过程的稳定性。开发了分步连续中和的新工艺方法，从本质上消除了中和反应时微观区域内偏铝酸钠溶液过量生成三水氧化铝的可能性。工业应用结果证明，新工艺中和反应过程控制了三水氧化铝晶种的生成，在生产大孔拟薄水铝石时三水氧化铝含量的合格率达到100%、孔体积合格率98.1%、收率提高12.4百分点、年产量提高64.56%,生产成本大幅下降。

Minimizing Alumina Trihydrate Content in Pseudo-Boehmite Commercial Product

The content of alumina trihydrate mixed crystals in the pseudo-boehmite produced by NaAlO₂-Al₂(SO₄)₃ method is much higher than expected in Changling Catalyst Company, SINOPEC. Based on reaction mechanism of pseudo-boehmite synthesis， acid and alkali reaction in the process should be equivalent reaction. However, local NaAlO₂ excess can be found due to pH value fluctuation in the above local area. This is the reason of high content of alumina trihydrate in the commercial product. High alumina trihydrate content in the product can seriously impact its pore properties as well as production process stability. Base on the above results, a stepwise continuous neutralization process has been developed. This new process can eliminate the possibility of alumina trihydrate formation with using excessive sodium meta-aluminate solution in the local area during neutralization reaction. Commercial application results show that alumina trihydrate seed crystals are not formed during the process. Based on the new proposed process, the qualification ratio of alumina trihydrate content in the product can be 100%, and pore volume qualification ratio is 98.1%. In addition, product yield can increase 12.4 percentage, and annual output has increased 64.56%. Therefore, production cost has significantly reduced with applying the new proposed process.