晶种活化强化铝酸钠溶液的种分分解

Decomposition enhancement of seeded sodium aluminate liquor by activated seed

采用一种新方法活化氢氧化铝晶种,可以强化铝酸钠溶液的种分分解。晶种在沸腾的蒸馏水中蒸煮后得到活化,实验研究了活化晶种对铝酸钠溶液种分附聚过程以及全过程的强化分解作用及其对产品粒度分布的影响。在种分附聚实验中,对于苛碱浓度比较低的铝酸钠溶液,晶种活化0.5 h就能有效地提高溶液的分解率,而活化时间超过0.5 h对分解率的促进作用不明显;对于苛碱浓度比较高的铝酸钠溶液,晶种活化2.0 h以上才能较明显地提高溶液的分解率。在种分全过程实验中,溶液分解率的提高在10 h以后出现并逐渐增大。晶种被活化可能是因为晶种表面被有机杂质吸附封闭的活性点被活化后重新显露,活化晶种及原始晶种在溶液中种分1.0 h后的形貌初步证实了这种设想。种分附聚产品的粒度分布结果显示,只要晶种活化时间合适,产品的粒度也能明显改善。

The aluminium hydroxide seed was activated by boiling distilled water. The effects of activated seed on decomposition ratio of seeded sodium aluminate liquor and particle size distribution were investigated. The experiments were carried out both at the agglomeration stage and the whole process. In the agglomeration stage, the decomposition ratio of sodium alumihate liquor is improved apparently with the addition of the seed activated for 0.5 h at low concentration of caustic alkali, and the effect is decreased when seed is activated for more than 0.5 h. While at higher concentration of caustic alkali, the enhancement is not evident only after the seed is activated more than 2.0 h. In the whole process, the enhancement can be observed after 10 h. It is assumed that the active sites blocked by organic impurities on the surface of original seed reappear after activation and the activity of seed is increased, which is approved by the morphology of Al（OH）3 product taken from liquor. The particle size distribution of product indicates that the size distribution of particles can also be improved if the activation time is proper.