Method and device for on-line regeneration of sulfuric acid pickling waste liquid

Abstract

The invention discloses a method and a device for on-line regeneration of sulfuric acid pickling waste liquid. The method mainly comprises the following steps: 1) adding a certain amount of concentrated sulfuric acid into the pickled low-concentration waste acid liquid to adjust the waste acid liquid to the required acid concentration; 2) adding cooling liquid into the solution to sharply cool the acid pickling liquid obtained in the step 1) so as to quickly reduce the temperature of the acid pickling liquid to between 5 DEG C below zero and 15 DEG C below zero and separate out ferrous sulphate; and 3) performing solid-liquid separation for the solution obtained in the step 2) through solid-liquid separation equipment, conveying the produced regenerative acid after heat exchange and temperature increment to a pickling system to be recycled. The device is provided with the pickling system to prepare waste acid and concentrated acid into acid liquid with the required concentration, then the acid liquid is conveyed to a heat exchange system connected with the pickling system to exchange heat and reduce temperature, a crystallizing system is connected with the heat exchange system to separate out crystals in the acid liquid, the crystals and the acid liquid are separated through a separation system, and the acid liquid is conveyed to the heat exchange system to be recycled. The device has the advantages of short process, less equipment investment, low power consumption and low operating expense, has no three-waste emission, and greatly reduces environment pollution.

Description

technical field [0001] The invention belongs to the field of environmental protection, and relates to iron and steel pickling, in particular to an on-line regeneration device for sulfuric acid pickling waste liquid in iron and steel enterprises. Background technique [0002] Since iron and steel enterprises widely use sulfuric acid as the steel pickling medium, the resulting waste liquid is often discharged into rivers after general neutralization treatment, which is one of the more serious pollution sources of water areas and is also a waste of resources. [0003] With the improvement of people's awareness of environmental protection and the development of circular economy, if these waste acids can be effectively recycled and reused to produce useful chemical products, it will not only reduce environmental pollution, but also reduce the waste of resources, which is in line with the concept of energy saving and emission reduction. Conducive to the national economy and people...

AI Technical Summary

Problems solved by technology

[0002] Since iron and steel enterprises widely use sulfuric acid as steel pickling medium nowadays, the resulting waste liquid is mostly discharged into rivers after general neutralization treatment, and this is one of the more serious pollution sources of water areas, and it is also a waste of resources

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