加盐蒸馏回收盐酸和混凝剂制备技术资源化利用盐酸酸洗废液

Resources utilization of hydrochloric pickling waste liquor by technology of salt-added distillation and coagulant preparation

为了实现钢材酸洗废液的资源化,能够同时回收盐酸和铁盐,提出了加盐蒸馏回收盐酸与蒸馏母液制备聚铁混凝剂两段组合工艺相结合的技术。实验对质量浓度为9.28%的实际盐酸废液进行了研究,考察了添加盐的种类、盐的投加量和蒸馏量等因素对再生盐酸回收效果和聚铁混凝剂溶液混凝效果的影响。研究表明,氯盐可以明显改变氯化氢、水的相对挥发度,当CaCl2投加量为1 mol/L,体积蒸馏量在30%时,为此工艺的最佳条件。在此工艺条件下,再生盐酸质量浓度约22.3%;蒸馏母液制备得到的聚铁混凝剂溶液应用实验表明,对印染废水脱色效果良好。此工艺不仅实现了酸洗废液中残酸和铁离子的资源化利用,而且达到酸洗废液的零排放。

In order to realize utilization of steel hydrochloric pickling waste liquor and recovery of hydrochloric acid and iron salts simultaneously,the combined technical process of salt-added distillation for recovery of hydrochloric acid and poly-ferric coagulant preparation with distillation residue liquor was proposed. The pickling waste liquor containing 9. 28% HCl was studied to investigate effects of the kinds of salt,dosage of salts and distillate volume on the regeneration of hydrochloric acid and coagulation performance of poly-ferric coagulant solution. The results show that chloride added can significantly alter the relative volatility of HCl-H2 O,with the optimal conditions of CaCl2 dosage of 1mol /L and distillate volume ratio of 30%. Under these conditions,the HCl mass fraction of the recycled acid was 22. 3% and application test of poly-ferric coagulant prepared from distillation residue presented good performances on color removal of dyeing wastewater. This process can realize the resources utilization of residual acid and iron in the pickling waste liquor,and reach the zero-discharge of pickling waste liquor.