A method for separating and extracting iron and nickel from iron and nickel leachate

Abstract

The invention discloses a method for separating and extracting iron and nickel from an iron and nickel leaching solution. In the method, after adjusting the pH of the waste water, oxalic acid precipitation is used to remove iron to obtain ferrous oxalate and nickel sulfate solutions. Ferrous oxalate After calcination, iron oxide is obtained; the nickel sulfate solution is further ion-exchanged to remove iron, and then nickel electrowinning is carried out to obtain a nickel plate. After the solution produced by nickel electrowinning is treated by electrodialysis, fresh water is reused; , The problem of deep separation of nickel leaching solution, the whole process constitutes a closed loop, sulfuric acid and water resources are recycled, the process operation cost is low, iron extraction production can obtain ferrous oxide with a purity >99.5%, and nickel extraction production can obtain nickel plate with a purity greater than 99.995% , high resource utilization rate, good product purity, excellent economic benefits, no waste gas, waste water and waste residue discharge in the whole process, and no secondary pollution.

Description

technical field [0001] The invention belongs to the field of advanced treatment of wastewater, in particular to a method for separating and extracting iron and nickel from iron and nickel leachate. Background technique [0002] For high-concentration iron and nickel leaching solutions, extraction, ion exchange and hydrolysis precipitation are usually used in industry to separate and extract iron and nickel. The commonly used extraction agents in the extraction method are P204 and P507. P204 and P507 have good ability to extract nickel, but they will also extract a part of iron while extracting nickel, and iron is also difficult to back-extract from the loaded organic phase with sulfuric acid. It can only be back-extracted with hydrochloric acid, and the concentration of hydrochloric acid must reach more than 4mol / L, and the acid consumption is huge; for high-concentration iron and nickel leaching solutions, when using ion exchange technology to separate iron and nickel, the ...

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Problems solved by technology

The commonly used extraction agents in the extraction method are P204 and P507. P204 and P507 have good ability to extract nickel, but they will also extract a part of iron while extracting nickel, and iron is also difficult to back-extract from the loaded organic phase with sulfuric acid. It can only be back-extracted with hydrochloric acid, and the concentration of hydrochloric acid must reach more than 4mol / L, and the acid consumption is huge; for high-concentration iron and nickel leaching solutions, when using ion exchange technology to separate iron and nickel, the first stage does not meet the standard, and multi-stage exchange columns are required. The amount of resin is large, the investment is expensive, and there are shortcomings such as competitive adsorption of iron and nickel, which cannot be separated and purified in depth; the method of hydrolysis will introduce Na into the system + Other impurities, poor product purity

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