Method for recycling rare earth from waste nickel-metal hydride battery

Abstract

The invention provides a method for recycling rare earth from a waste nickel-metal hydride battery. The method is carried out by the following steps in sequence: crushing the battery, dissolving battery core powder, removing impurities, extracting for a plurality of grades and reversely extracting for a plurality of grades. The step of extracting comprises the step of adding an extracting agent organic solution into a rare earth raw solution without the impurities; the extracting agent organic solution comprises an alkyl methyl amine mixed organic matter, organophosphorus esters, sulfonated kerosene and liquid organic alcohols with more than six carbon atoms; the grades for extracting are at least three grades and the grades for reversely extracting are at least three grades. The recycling method provided by the invention utilizes the special extracting agent organic solution and the extraction and separation efficiency on the rare earth is high and commonly can be up to more than 99%; with the adoption of the recycling method, any sodium ion is not introduced and a sodium removing procedure and the sodium removing cost are saved; an organic extracting agent can be recycled and reutilized so as to further reduce the cost; the organic extracting agent does not need to be saponified so that the saponification cost is saved.

Description

technical field [0001] The invention relates to a method for recovering valuable substances from waste batteries, in particular to a method for recovering rare earths from waste nickel-hydrogen batteries. Background technique [0002] In today's energy shortage, new energy batteries have been widely used as a solution. But for the recycling of waste batteries, domestic technology is still relatively rough, and many precious elements have not been carefully separated, such as rare earths in nickel-metal hydride batteries. [0003] In the traditional method of recovering rare earths from nickel-metal hydride batteries, the method of adding anhydrous sodium sulfate to precipitate to obtain rare earth sulfate double salts is often used to recover rare earths. Although this method is simple to operate, there are three defects: 1. The precipitation method is affected by the solubility product. When the rare earth concentration in the solution is lower than 0.2~0.3g / L, the precipi...

AI Technical Summary

Problems solved by technology

Although this method is simple to operate, there are three defects: 1. The precipitation method is affected by the solubility product. When the rare earth concentration in the solution is lower than 0.2~0.3g / L, the precipitation reaction will become very difficult. It shows that the rare earth precipitation is not complete, and the general recovery rate is difficult to be higher than 95%; 2. In order to improve the precipitation efficiency, the addition of sodium sulfate needs to be added in excess, which will bring more sodium ions into the solution, and it is necessary to increase the sodium removal in the follow-up Process and cost; 3. The thermal stability of the precipitate rare earth sulfate double salt is high, it is not easy to carry out further finishing, and the added value of the rare earth sulfate double salt itself is low

[0004] However, most of the existing methods for extracting and separating light rare earths from sulfate systems are single rare earth extraction and separation methods. In a few mixed rare earth extraction and separation methods, it is also necessary to add alkali metal salt additives such as sodium, which will cause battery damage. The increase of sodium discharge cost in the later stage of refining recovered products