Recycling method of industrial waste hydrochloric acid containing NaCl

Abstract

The invention provides a method for recycling low concentration industrial waste hydrochloric acid generated during acidization, wherein the waste hydrochloric acid contains a great amount of NaCl. The method comprises the following steps: pouring waste hydrochloric acid containing NaCl into a primary distilling still to carry out primary distillation to desalt, thus obtaining diluted hydrochloric acid containing no NaCl, wherein the acid content of the waste hydrochloric acid is 11-14% by mass; pouring the diluted hydrochloric acid into a secondary distillation still, adding CaCl2.2H2O to carry out secondary distillation, and using the diluted hydrochloric acid obtained from the primary distillation to absorb endvolatiles obtained from secondary distillation, thus obtaining concentrated hydrochloric acid the concentration of which is 25-30%. The hydrochloric acid can be used as acidified hydrochloric acid. The method has the positive effects of low investment and simple operation, and can utilize waste materials and save production cost; the diluted hydrochloric acid obtained from the primary distillation is used to absorb the concentrated acid obtained from secondary distillation, thus reducing the recovery cost and improving the recovery efficiency; and the concentration of obtained hydrochloric acid is 25-30%, thus the obtained hydrochloric acid can be used as acidified hydrochloric acid.

Description

technical field [0001] The invention relates to a recovery method for industrial waste hydrochloric acid produced in an acidification process, in particular to a recovery method for industrial waste hydrochloric acid containing NaCl. Background technique [0002] In the process of chemical production, waste hydrochloric acid containing a large amount of NaCl is often produced. For example, in the acidification process of dibenzoylmethane production, hydrochloric acid is usually used to react with alkaline substances to produce dibenzoylmethane. After acidification with hydrochloric acid, its concentration is reduced to 11%-14%, and it contains a large amount of NaCl, which no longer has Acidifying ability to become waste acid. The treatment method of this waste acid is to add alkali to neutralize the waste acid and then discharge it. Over the years, the vast number of scientific and technological workers have made great efforts to realize the recovery and utilization of wa...

AI Technical Summary

Problems solved by technology

Among them, the roasting method requires a large scale of equipment, large investment, high energy consumption, and will cause secondary pollution; the extraction method is complex in operation and relatively large in investment; although the evaporation method has less investment and is easy to operate, the concentration of hydrochloric acid recovered is low and cannot be obtained. Use directly