Method for recovering chromic acid and water from chromeplating rinse water

Abstract

The invention relates to the technical field of chromate waste water treatment, and in particular discloses a method for reclaiming chromic acid and water from chromeplating rinse water. The method comprises the following steps: rinsing chromium-plated parts from a coating bath in a first-level washing reclaiming tank, a second-level washing reclaiming tank until the last-level washing reclaiming tank in turn; refluxing the rinse water in the last-level washing reclaiming tank to the previous level reclaiming tank in turn and finally to the first-level washing reclaiming tank; overflowing the chromium-containing rinse water in the first-level washing reclaiming tank to a circulating reclaiming tank, and heating the rinse water to a temperature of 50 DEG C by a heating device; pumping the rinse water into a vacuum evaporator by a circulating pump so that the water content is evaporated and chromic acid concentrated solution is left at the bottom of the evaporator; refluxing the chromic acid concentrated solution to the circulating recovery tank, and performing circulating evaporation in the vacuum evaporator again; and pumping finally concentrated chromic acid into a chrome-plating bath for reclaiming by a chromic acid reclaiming pump. The top of the vacuum evaporator is connected with a condensate water reclaiming tank through an ejector vacuum pump, and a cooling device in the condensate water reclaiming tank condensates water vapor into liquid water which is overflowed to the last-level washing reclaiming tank from the condensate water reclaiming tank for recycling. The method can recycle the chromic acid and the water in the chromeplating rinse water on line, save the significant cost required by a chemical method control, and reclaim resources.

Description

technical field [0001] The invention relates to the technical field of chromium-containing wastewater treatment, in particular to a method for recovering chromic acid and water resources from chrome-plating rinse water. Background technique [0002] Electroplating is a process that uses electrochemical methods to decorate, protect and obtain some new properties of metal and non-metal surfaces. In the electroplating industry, the commonly used types of plating are nickel plating, copper plating, chrome plating, zinc plating, etc. In the electroplating process, in order to ensure the quality of electroplating products, make the metal coating have a smooth and good appearance and be firmly combined with the plated parts, the dirt (oil, rust, oxide scale, etc.) on the surface of the plated parts must be thoroughly removed before plating. Clean up and clean the adhesion liquid on the surface of the plated parts after plating. [0003] According to the survey, there are about 5,...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of the chemical reduction method, that is, other terminal treatment methods, is that they are all based on the principle of pollution first and then treatment. When treating chromium-containing wastewater, various chemicals such as acids, alkalis, and reducing agents need to be added. Heavy cost pressure, and due to the artificial addition of chemical ions, the quality of the treated effluent will be poor, affecting reuse, and it is easy to cause secondary pollution when treating mixed wastewater

Moreover, the end treatment treats the chrome plating rinse water as "waste", which greatly wastes a large amount of reusable chromic acid and water resources.