Processing method for stainless steel acid cleaning waste water and liquid

Abstract

The invention relates to a processing method of stainless steel pickling waste liquid, which is characterized in that the processing method includes the steps that: neutral salt wastewater flows into a neutral reduction cell, and mixed acid pickling waste waters flow into a neutralizing tank; reducing agent is added into the neutral reduction cell, and then the reduced wastewater liquid is put into the neutralizing tank and is mixed with the adjusted mixed acid pickling waste waters, and liquid alkali is added into the neutralizing tank; the separated clear waste liquid removes fluorin ions in a settlement tank; neutralizing liquid is added into a final neutralizing tank to cause the pH value of treatment liquid to adjust to be neutralized wastewater liquid which passes through a sand filter to be discharged. The processing method has the advantages that metal ions and fluorin ions are performed the subsection treatment, and neutralizing agent is changed into the liquid alkali from lime cream, the requirement of reaching the standard of the waste liquid emission is not only achieved, but also the mud quantity produced by a mass of lime cream is greatly reduced, heavy metal mud of a retention pond only contains heavy metal compound, the salts of calcium fluoride and calcium sulphate, etc. are separated from the inclined plate settlement tank during the fluoridation stage, thereby the treatment cost is effectively lowered.

Description

technical field [0001] The invention relates to a treatment method for sludge quality separation and volume reduction of stainless steel cold rolling pickling wastewater. Background technique [0002] During the pickling process of stainless steel, pickling wastewater will be produced. The pickling wastewater includes neutral wastewater and acidic wastewater. The neutral wastewater contains hexavalent chromium, nickel, iron, sodium and sulfate plasma. The wastewater The pH range of the medium is 3-4, and the concentration of hexavalent chromium ions is in the range of 200-600mg / L, and hexavalent chromium is an ion that needs to be pretreated. The acidic wastewater containing mixed acid contains nickel, iron, manganese, nitrate and fluoride ions, and the pH range of the wastewater is 2 to 3, among which nickel, iron, manganese and fluoride ions are the ions to be removed. [0003] At present, the wastewater treatment method adopted by stainless steel production enterprises a...

AI Technical Summary

Problems solved by technology

The above treatment method can make the Cr in the wastewater liquid 6+ 、Cr 3+ 、Ni 2+ , Mn 4+ , Fe 3+ and F - Up to standard emissions, but its disadvantage is F - Ions and Cr 3+ 、Ni 2+ , Mn 4+ , Fe 3+ It is removed in the Dengqing pond at the same time, and lime milk is used as the neutralizing agent, so that the amount of sludge produced is large, and there are chromium hydroxide, nickel hydroxide, manganese hydroxide, and hydroxide in the sludge. Iron, calcium fluoride, calcium sulfate and other components, this kind of sludge is a HW17 hazardous waste in China's national hazardous waste catalogue, and it does not have comprehensive utilization value, and the treatment cost is high

Images