Method for recycling rare earth metal from waste fluorescent powder

Abstract

The invention provides a method for recycling rare earth metal from waste fluorescent powder. The method includes the steps that the waste fluorescent powder is subjected to acidic leaching, and a leaching agent is obtained through filtration; the leaching agent is subjected to ammonia leaching processing, and a first filter residue and first filter liquor are obtained through filtration; the first filter residue is processed with alkali liquor, the solution pH is adjusted to be higher than 12.5, and a second filter residue and second filter liquor are obtained through filtration; the second filter residue is subjected to acid hydrolysis, the solution pH is adjusted to 3.5-4.5, then non-rare-earth metal precipitator is added for precipitation, and a third filter residue and third filter liquor are obtained through filtration; the third filter liquor is subjected to ammonium hydrocarbonate precipitation, and precipitate is taken; and the precipitate is roasted, and the rare earth metal oxide is prepared. According to the method for recycling rare earth metal from waste fluorescent powder, the rare earth metal in the waste fluorescent powder is extracted in an acidic leaching manner, the leaching rate reaches up to more than 99%. Zinc, aluminum and other non-rare-earth metal are removed from the leaching agent step by step, zinc and aluminum can be recycled step by step, and resource regeneration is achieved; and the technology can save energy and reduce emission, and is low in cost, reasonable and easy to implement.

Description

technical field [0001] The invention belongs to the technical field of metal resource recycling, and in particular relates to a method for recycling rare earth metals in waste fluorescent powder. Background technique [0002] Due to the preciousness and scarcity of rare earth resources, it has become more and more necessary to recover rare earth metals from discarded items. Phosphor powders that help to display in many discarded lighting appliances, computers, televisions, mobile phones and other products contain relatively large amounts of rare earth metals, so waste phosphor powders have gradually become an important raw material choice for rare earth metal recovery. [0003] However, the zinc and aluminum impurities generally contained in phosphor powder are much higher than the content of other non-rare earth metals. Therefore, the existing processes for rare earth extraction from waste phosphor powder need to achieve effective removal of zinc and aluminum impurities dur...

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Problems solved by technology

[0004] Among them, in the method of alkali fusion-water washing and pH adjustment, hydrolysis and sedimentation, on the one hand, the amount of water used is relatively large, and on the other hand, the pH of the washing solution is difficult to control, which affects continuous operation. Too high pH of the solution promotes the dissolution and dispersion of some rare earth hydroxides. If the pH of the solution is too low, it is difficult to elute the amphoteric metal impurities in the alkali slag, which will affect the subsequent separation and purification process of rare earths; while using the precipitant precipitation method to directly remove the zinc and aluminum metal impurities with a content of more than 30% in the phosphor powder will inevitably entrain a part Rare earth metals enter the sedimentation slag, causing the rare earth metals to disperse and increase the recovery cost

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