A resource recycling method for stainless steel pickling wastewater

Abstract

The invention discloses a stainless steel pickling waste water resource recycling method. The method includes the steps of firstly, conducting reduced pressure evaporation on mixed acid of hydrofluoric acid and nitric acid so that acid recycling can be achieved; secondly, separating out and recycling iron in the solution; thirdly, gathering diluted acid, nickel and chromium in a circulating mode; fourthly, recycling diluted acid through a film method; fifthly, conducting neutralization and iron recycling; sixthly, separating nickel and chromium and recycling nickel; seventhly recycling chromium. By means of the method, efficient recycling of valuable metal resources such as nitric acid, hydrofluoric acid, iron, chromium and nickel is achieved, purified water can stably reach the standard, and the method is remarkable in economic benefit.

Description

Technical field: [0001] The invention relates to a resource recovery method of hydrofluoric acid, nitric acid, iron, chromium and nickel in the production of stainless steel and steel wire rope and related surface treatment pickling wastewater, and belongs to the technical field of industrial waste treatment. Background technique: [0002] For a long time, the treatment of a large amount of pickling wastewater generated in the stainless steel production process has been a difficult problem for iron and steel enterprises. With the gradual development of the iron and steel industry, people have gradually realized the harm of pickling wastewater to the environment, especially to human beings. Stainless steel pickling wastewater contains Cr 6+ 、Cr 3+ And the acid wastewater of metal iron and nickel. Cr 3+ It is a trace element in the human body and participates in glucose and lipid metabolism, but excessive Cr 3+ It is easy to accumulate in the alveoli, cause lung cancer, an...

AI Technical Summary

Problems solved by technology

The chemical method can recover some useful substances, but the process is complex and the equipment is more; the ion exchange is an improvement from the fixed bed to the fluidized bed, but there are still problems of waste acid concentration and dilute acid treatment; the advantage of the solvent extraction method is that it consumes less energy. Equipment and materials are easy to choose, but the recovery rate of acid is low

Patent (CN201510037110) A method for recovering mixed acid from cold-rolled stainless steel pickling waste liquid discloses a method for evaporating and recovering mixed acid, which can realize the recovery of mixed acid, but the recovery rate of mixed acid in this method is not high, and the process cost is high. The key point is that valuable metals cannot be separated and recovered, and waste residues such as ferric sulfate contain sulfuric acid, which is difficult to process and utilize; patent (201510180241) discloses a treatment of stainless steel pickling waste liquid and a recovery method for iron, chromium and nickel, which can The separation of iron, chromium and nickel is achieved to a certain extent, but the mixed acid cannot be recovered, the newly added ammonia nitrogen and nitrate nitrogen in the solution will cause a great burden on the subsequent water treatment, and the amount of neutralizer used in the process of neutralizing the acid is large, High cost and other problems, the traditional method is difficult to achieve efficient recovery of valuable resources and advanced treatment of wastewater, the technology of the present invention can realize efficient recovery of acid; reduce the consumption of alkali in subsequent treatment, the amount of slag produced is small, and the separation effect of various slag is good , the loss rate of valuable metals is low, making it possible to efficiently recycle stainless steel pickling wastewater, which not only solves the problem of environmental pollution, but also obtains considerable economic benefits