Method for treating pickling wastewater and recovering byproducts through reduced pressure and low temperature catalytic fractionation

Abstract

The invention provides a method for treating pickling wastewater and recovering byproducts through reduced pressure and low temperature catalytic fractionation, belongs to the technical field of environmental protection, and especially relates to terminal treatment of wastewater containing hydrochloric acid and metal salts and recycling of wastes. The method comprises the following steps: 1, preparing a material: filtering the pickling wastewater to remove particles with large particle sizes, and fully mixing the filtered pickling wastewater with a catalyst in a mixing device until uniformity; 2, fractioning: pumping the obtained mixed solution to a low pressure fractioning device, and separating an acid solution at a low temperature under a low pressure; 3, separating metal salts: allowing the obtained residual liquid to enter a metal salt separation device, adjusting the pH value until the metal salts precipitate, and carrying out adsorbing separation by using a rotating magnetic disc; 5, carrying out solid-liquid separation: allowing slurry to enter a solid-liquid separation device, and dehydrating; and 5, carrying out catalyst concentration: allowing the obtained metal salt removed residual liquid to enter a concentration device, carrying out low temperature and low pressure concentration, and returning the obtained concentrated catalyst to make the catalyst participate in the reaction. The reduced pressure and low temperature catalysis method is adopted to treat the pickling wastewater, so the acid solution and metal salt recovery rate is improved, the treatment cost is reduced, and the present technological gaps in low-cost, high-efficiency and zero-pollution treatment of the pickling wastewater are filled.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and relates to the terminal treatment and disposal of hydrochloric acid-containing and metal salt-containing wastewater, and the recycling of waste. Background technique [0002] In industry, strong acid solution is often used to clean the metal surface. On the one hand, it is to change the structure of the metal surface, which is beneficial to subsequent processing. When the pickling solution is used for a certain number of times, the acidity decreases and the concentration of metal ions increases, which reduces the pickling efficiency and requires replacement of the pickling solution. A large amount of waste liquid is generated during the production process. If it is not treated in time, it will cause serious pollution to the surrounding environment. The solution contains a large amount of hydrochloric acid and metal salts, which are important raw materials in the chemical indu...

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Problems solved by technology

[0009] The main purpose of the present invention is to overcome the defects of the prior art, and provide a low investment and treatment cost for pickling enterprises, which can make re

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