组合法废稀盐酸浓缩工艺

Concentrating dilute hydrochloric acid by combined method

进行了加盐解吸-气体吸收-加盐精馏组合法提浓稀盐酸的实验研究。分别研究了盐浓度、吸收剂流量、塔釜加料量对该过程的影响。小试实验装置中采用解吸釜与吸收塔相连,分别以20%盐酸作为解吸液和吸收液。结果表明:解吸液中加盐浓度为0.3g/mL MgCl2时,高浓度HCl解吸气经吸收液吸收可获得浓度为32.80%的浓盐酸;将解吸釜内解吸至6.5%盐酸釜残液继续进行间歇加盐精馏,其中首先从塔顶采出的20%稀盐酸可作为解吸液或吸收液循环使用。该方法适用于间歇法小规模稀盐酸提浓处理。

In this work,the combination of salt desorption,gas absorption and salt-added distillation was used to conduct experimental research of concentrating dilute hydrochloric acid.The influence of salt concentration,absorbent flow rate,still capacity on the process was investigated.For the lab experiment,the desorption still was connected directly with the absorption tower,and hydrochloric acid（20%） was used as both desorption solution and absorbent.It was shown that when 0.3 g/mL MgCl2 was added in the desorption solution,hydrochloric acid enriched gas from the solution could be absorbed by the absorbent,whose concentration then increased to 32.80%.After that,salt-added distillation was carried out to deal with the residue hydrochloric acid（6.5%）in the desorption still.Hydrochloric acid（20%）,which was recycled in the experiment as both desorption solution and absorbent,could be wihdrawn from the top of the distillation tower.The method mentioned in this work is suitable for small scale batch operation of concentrating dilute hydrochloric acid.