失效磷酸基化学抛光液的再生

采用氟铝酸钠沉淀法去除失效磷酸基化学抛光液中的铝杂质,并对溶液再生利用的工艺条件进行了研究.实验结果表明,在氢氧化钠和氢氟酸加入量与理论值的比均为1.2(即n(氢氧化钠):n(Al~(3+)):2:1、n(氢氟酸):n(Al~(3+))=28:5)的条件下,采用二步法过滤后,抛光液中磷酸质量分数大于50%,磷酸回收率为79.5%,Al~(3+)去除率为97.1%,剩余Al~(3+)质量分数为0.05%.滤渣经处理后成为新的有价物质,滤液在补加磷酸和其他有效成分后可再生循环使用.

Regeneration of Spent Phosphoric Acid-Based Chemical Polishing Solution

Aluminium in spent phosphoric acid-based chemical polishing solution was removed by precipitation process with sodium fluoaluminate and the process conditions for regeneration of the solution were studied. When the dosages of NaOH and HF are all 1. 2 times the stoichiometric ratio (That is n(NaOH) : n(Al~(3+)) =2 : 1, n(HF) :n(Al~(3+) ) =28 : 5), the two-step filtration is used, and the mass fraction of phosphoric acid in the polishing solution is more than 50% , the recovery rate of phosphoric acid is 79.5% , the removal rate of aluminum is 97.1% , and the mass fraction of remained aluminum is 0.05% . The filter residue can become a kind of valuable material after treating, and the filtrate can be regenerated and recycled after adding phosphoric acid and other effective constituents .