Study on resource treatment of pickling waste liquid in metallurgical industry

The acid pickling waste liquid from hot rolling of iron and steel generally contains 0.05-5g/l H + and 60-250g / L Fe2 +, which has been listed in the national list of hazardous wastes due to its serious corrosiveness. The direct discharge of this kind of waste liquid not only pollutes the environment seriously, but also causes great waste.

In order to avoid acid pollution of acid washing solution, the traditional method generally uses lime, calcium carbide slag or Ca (OH) 2, the product of lime digestion reaction, to neutralize. Although the pH value can meet the requirements after neutralization, it is difficult to reach the standards for other indicators, and the sludge produced is difficult to dehydrate, not easy to dry, and difficult to post-treatment. Most of the cases are piled up for treatment, occupying a large amount of land, resulting in At the same time, the method wastes a lot of acid and iron resources.

In order to protect the environment, save and make rational use of resources, scholars at home and abroad have carried out a lot of research and exploration for a long time, put forward different types of treatment and recovery methods and technologies, and achieved good application results.

1. Direct roasting

2. Recovery of iron salt

3. Membrane separation

4. Preparation of inorganic polymer flocculant