On-line hydrochloric acid recycling method and device on steel pickling line

Abstract

The invention discloses an online hydrochloric acid cyclic utilization method on a steel acid pickling line. The method includes the following steps that firstly, acid pickling liquid on the acid pickling line is collected and filtered and is conveyed to a vapor-liquid separator; secondly, oxalic acid is added into the vapor-liquid separator through a chemical adding device; thirdly, mixed liquid is forcefully cycled between the vapor-liquid separator and an acid-resisting and high-temperature-resisting heating evaporation device, acid vapor and a super-saturated solution containing ferrous oxalate crystals are formed, and the acid vapor is conveyed to the acid pickling line; fourthly, a crystallizing tank is used for separating out ferrous oxalate and conveying the ferrous oxalate to a second filtering device; fifthly, the ferrous oxalate crystals are filtered through the second filtering device; and sixthly, the above steps are repeated. According to the online hydrochloric acid cyclic utilization method on the steel acid pickling line, low-concentration hydrochloric acid obtained after acid pickling is converted into high-concentration hydrochloric acid which can be cyclically used through the oxalic acid and is conveyed to the acid pickling line again, meanwhile, due to the reaction of the oxalic acid and ferrous chloride, the ferrous oxalate is generated and can also be used as a raw material of lithium batteries and the like, cost is saved, and profits are generated.

Description

technical field [0001] The invention relates to the technical field of steel pickling, in particular to an online hydrochloric acid recycling method and device on a steel pickling line. Background technique [0002] The hot-rolled strip and steel coil produced by the hot rolling mill is rolled and coiled. The oxide scale formed on the surface of the strip under corresponding conditions can firmly cover the surface of the strip and cover the surface of the strip. Defects. Iron oxide scale will damage the surface of the roll during cold rolling and cause defects on the surface of the strip steel. Therefore, the strip steel must be pickled to remove the scale on the surface of the raw material coil that is harmful to cold rolling before cold rolling. [0003] At present, there are a large number of cold-rolled steel strips, pickled steel strips, steel pipes, steel wires and other production lines in the country. During the deep processing of their products, the surface needs t...

AI Technical Summary

Problems solved by technology

The obtained waste acid cannot be discharged directly. In order to recycle and utilize these waste acid liquid and ferrous chloride, a relatively large investment is required to build corresponding recovery and treatment equipment

The discharge of waste acid in our country is very huge, and most of the small and medium-sized enterprises have not put into operation the waste acid regeneration device. Under the current situation, many enterprises discharge secretly. Once the direct discharge occurs, it will cause serious pollution to the environment.

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