High-efficiency energy-saving hydrochloric acid pickling waste liquor triple-effect negative-pressure graphite evaporation crystallizer

Abstract

The invention discloses a high-efficiency energy-saving hydrochloric acid pickling waste liquor triple-effect negative-pressure graphite evaporation crystallizer, belonging to the field of pickling waste liquoir treatment. The evaporation crystallizer disclosed by the invention comprises an evaporation concentration unit, a feed unit, a gas condensation unit, a cooling crystallization unit, a solid-liquid separation unit, a mother liquor circulating unit and a vacuum unit. The hydrochloric acid pickling waste liquor is heated in a vacuum state, so that volatile chlorine hydride and water in the solution are evaporated together, and are condensed through the gas condensation unit to form reusable clean hydrochloric acid; and the concentration of the nonvolatile metal salt in the solution is continuously increased to form a metal salt supersaturated solution, and the metal salt supersaturated solution is cooled by the cooling crystallization unit, so that part of metal salts are precipitated in the crystalline-state hydrous crystal, thereby achieving the goal of separating the solute and solvent in the solution. The invention mainly aims to provide a high-efficiency energy-saving hydrochloric acid pickling waste liquor triple-effect negative-pressure graphite evaporation crystallizer which has the advantages of favorable antiseptic property, high recovery ratio and low treatment cost.

Description

technical field [0001] The invention relates to an evaporation and crystallization device for pickling waste liquid, more specifically, to a high-efficiency and energy-saving three-effect negative pressure graphite evaporation and crystallization device for hydrochloric acid pickling waste liquid. Background technique [0002] The pickling process is widely used in many industrial sectors in our country. The iron and steel industry and the metal products industry need to remove the oxide layer on the surface of metal materials during the production process and use hydrochloric acid for pickling. A large amount of pickling waste liquid will be generated during the pickling process. The main components of hydrochloric acid pickling waste liquid are: free acid, metal salt and water. Its content varies with pickling process, operating temperature, metal material and specifications. According to the national environmental protection regulations, waste acid is not allowed to be d...

AI Technical Summary

Problems solved by technology

The pickling waste recovery and treatment device provided in this application forms a dilute acid solution that can be returned to the workshop for reuse by heating and evaporating the waste acid solution and condensing it in a condenser. Solid crystals are precipitated by evaporating and concentrating and cooling the concentrated solution, thereby being able to Realize zero discharge of waste acid liquid, but its shortcomings are: the utilization rate of raw steam in this application is low, the waste liquid needs to be recycled multiple times to be effectively recycled, and the recycling cycle is long, and the processing equipment in it has not been improved , poor anti-corrosion performance, short service life, and low recycling rate of acid

To a certain extent, this application solves the problems of low evaporation efficiency, poor equipment corrosion resistance, and high operating costs of the existing pickling waste recovery treatment device, but its disadvantage is that the utilization rate of raw steam in this application is also low. Low, long recycling cycle, low recycling rate of acid solution, low degree of automation

The process method of this application has high efficiency, fast speed, stable production and low cost, but its disadvantages are: the treatment method of pickling waste liquid in this application does not solve the problem that the main equipment and pipes are easy to corrode, and the design and manufacture of equipment have limitations. The problem of low added value of recycled products, which makes it difficult to be promoted on a large scale

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