Recovery method for cadmium and nickel in waste cadmium and nickel battery

Abstract

The invention provides a recovery method for cadmium and nickel in a waste cadmium and nickel battery. The method comprises the following steps: impregnating a waste cadmium and nickel battery material in an HCl solution, adjusting the pH value of the obtained metal ion mixed liquid to 4-7, and filtering the solution to obtain a pre-treated liquid; mixing the pre-treated liquid with citric acid toreact to obtain a reaction liquid, adjusting the pH value to 8-11, and filtering the mixture to obtain cadmium hydroxide and a filtrate; mixing the filtrate with calcium nitrate, adjusting the pH value to 9-12, and carrying out a reaction to obtain a precipitate; and carrying out a reaction on the precipitate and the HCl solution, filtering the mixture, and adjusting the pH value of the obtainedfiltrate to 7-12 to obtain nickel hydroxide. The recovery method is simple in recovery equipment adopted and simple to operate. Nickel and cadmium are recovered by means of different pH values, so that the method is simple, and the recovery rate and the purity are relatively high. Materials used in the recovery method are conventional reagents which are low in cost. In the recovery process, toxicreagents such as sulfides are unavailable, so that no secondary pollution is generated.

Description

technical field [0001] The invention relates to the technical field of cadmium-nickel separation by hydrometallurgy, in particular to a method for recovering cadmium-nickel from waste nickel-cadmium batteries. Background technique [0002] Due to the excellent performance and wide application of cadmium-nickel batteries, waste cadmium-nickel batteries contain a large amount of toxic heavy metals cadmium and nickel, which will cause great harm if they enter the environment without treatment. Long-term consumption of cadmium-lead-contaminated vegetables, rice, and groundwater can cause renal tubular damage, rickets, and itai disease. Short-term excessive intake of cadmium can cause toxic pulmonary edema, dyspnea, and acute kidney failure. Excessive intake of nickel can lead to serious diseases such as lung cancer, leukemia, asthma, and urinary stones. The combination of nickel with chloride ions, sulfide ions, and carbonyl groups is more toxic, which can cause central circulat...

AI Technical Summary

Problems solved by technology

Among them, the methods used in hydrometallurgy are: (1) Ammonium salt leaching method: first roast nickel-cadmium battery waste, and then use ammonium nitrate solution to separate and recycle the ammonium nitrate solution. This method has low cost and no secondary pollution, but its recovery Rate is only 20-30%

(2) Fluidized bed electrolysis method: metal copper particles are used as the cathode to reduce metal ions at the cathode, but due to the difficulty in manufacturing granular cathodes, it has not yet been put into industrial application

The recovery rate of this method can reach more than 99%, but it is expensive and not suitable for industrial application

(4) Sulfide precipitation method: Dissolve the cadmium-nickel battery waste with acid, feed hydrogen sulfide to precipitate cadmium sulfide, and the filtrate is concentrated and cooled to make the nickel ions form NiSO 4 ·6H 2 O crystals are precipitated, the separation rate of this method is high and the cost is low, but H 2 S smell foul, pollute the atmosphere

[0004] Technologies such as pyrometallurgy, biometallurgy and mechanical recycling have the problems of complex equipment, high cost, and low purity of recovered metals

Existing wet recycling of waste batteries often involves complex processes and high reagent consumption