Method for recovering and treating chromium from waste chromium electrodeposition solution

Abstract

The process of recovering chromium from waste electric deposition solution includes adding concentrated sulfuric acid and hydrazine hydrate in certain amount into waste electric deposition solution at 28-32 deg.c to reduce six-valent chromium into trivalent chromium; depositing trivalent chromium with concentrated ammonia water; filtering and washing the precipitate; adding sulfuric acid to dissolve the precipitate, evaporation and stoving to obtain Cr2(SO4)3 crystal. The process has chromium recovering rate over 95 %, and has mild condition, fast speed and no harmful gas produced.

Description

technical field

[0001] The invention relates to a method for recovering and treating chromium in electrodeposited chromium waste liquid. Background technique

[0002] The direct discharge of electrodeposited chromium waste liquid will cause very serious impact on the environment. The treatment of chromium waste liquid is a work that cannot be ignored. At present, the treatment methods for chromium waste liquid mainly include: biological treatment, chemical treatment, chromium sludge stabilization treatment, etc. The vast majority of these methods are to convert the chromium in the waste liquid into chromium sludge and deposit it, so as to reduce the chromium content in the waste liquid and achieve the purpose of waste liquid treatment. Obviously, these methods will face the difficult problem of the further treatment of chromium sludge again. And use hydrazine hydrate to remove the Cr in the electrodeposited chromium waste liquid (VI) Reduced Cr (III) And made into Cr 2...