Method for separation and purification of fluorescent grade yttrium oxide and europium oxide from waste phosphor powder

Abstract

The invention relates to a method for separation and purification of fluorescent grade yttrium oxide and europium oxide from waste phosphor powder, comprising the steps of: first conducting impurity removal so as to obtain mischmetal containing Y2O3 and Eu2O3, then dissolving the mischmetal with an acid solution for preparing a rare earth feed liquid, and carrying out extraction with an extraction system after alkaline solvent saponification, thus obtaining the raffinate, washing liquid and strip liquor; adding an oxalic acid solution and conducting filtration, then subjecting the obtained filter residue to calcination, thus obtaining the fluorescent grade yttrium oxide, and yttrium-rich rare earth and europium oxide. The invention has the advantages that, reagents are of wide source, lowprice and easy availability, and the simple process of the method can greatly shorten the extraction process of naphthenic acid. In the invention, three deposition impurity-removal treatments before extraction can remove most impurities and leave only a small amount of aluminium and silicon, so that an emulsification phenomenon in the naphthenic acid extraction system cannot be caused, thus providing a good solution to the problem that naphthenic acid extraction is susceptible to high valent metal ions and results in emulsification.

Description

technical field [0001] The invention relates to the fields of environmental protection and comprehensive recycling of resources, in particular to a method for separating and purifying fluorescent-grade yttrium oxide and europium oxide from waste fluorescent powder. Background technique [0002] Rare earth trichromatic phosphors are mainly used in electronic products such as fluorescent energy-saving lamps and color displays, and are high value-added fine chemicals. The three primary color phosphor systems all contain four rare earth elements, Eu, Y, Ce, and Tb, and the rare earths account for about 20% of the total phosphor. Therefore, it is necessary to study the recycling of rare earth trichromatic phosphors, which can not only reduce environmental pollution, but also recycle rare earth materials such as europium, yttrium, cerium, and terbium. [0003] Japan is at the forefront of research on the separation and recovery of rare earth phosphors from discarded electronic pr...

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Problems solved by technology

However, the cost of recycling rare earth phosphors by the above methods is high, the process is complicated, and it is easy to cause secondary pollution to the environment

[0004] In recent years, researchers have tried to use supercritical technology to extract rare earths from waste phosphors, or use centrifugation and flotation separation techniques to separate and recycle rare earth phosphors, and have achieved good research results. However, there is still a long way to go before the industrial application stage. small gap

However, the research work on the recycling of trichromatic phosphors in my country has not yet attracted people's attention, and the collection system is not perfect, so there are few relevant literature reports at present.

[0005] CN101307391A discloses a method for recovering rare earths in waste fluorescent lamps. This method uses KOH or NaOH to melt fluorescent powder to obtain water insolubles and alkaline filtrates. The water insolubles are extracted and precipitated after adding acid to obtain Y, Mixed rare earth precipitates of Eu, Ce, Tb; precipitation of alkaline filtrate to obtain aluminum hydroxide precipitation and manganese carbonate, burning aluminum hydroxide to obtain alumina; this method does not involve the separation of rare earths, and what is obtained is a mixture of rare earths, which is of practical value not tall

The process of this method is complex and requires a large amount of zinc powder and three kinds of extractants, and the economic value is not high

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