Method for recovering rare earth elements from waste red phosphor

A red phosphor, rare earth element technology, applied in rare earth metal compounds, chemical instruments and methods, inorganic chemistry, etc., can solve problems such as rare earth recycling not involved

Active Publication Date: 2012-10-24
JIANGXI HUAKE RARE EARTH NEW MATERIALS
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Problems solved by technology

The law also does not involve the recovery of rare ea...
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Abstract

The invention relates to a method for recovering rare earth elements from waste red phosphor. The method is characterized by: carrying out a calcination pretreatment on collected waste red phosphor in a calcination furnace kiln, and removing organic substances and other elements easily forming volatile gases in the red phosphor; carrying out dissolution decomposition on the calcined red phosphor in an acid (HCl, HNO3)-oxidant (H2O2)-stabilizing additive (acetic acid) composite acid system, and controlling to obtain a low acidity, such that rare earth elements such as Y and Eu or other rare earth in the red phosphor are preferentially dissolved, and completely enter the solution, and the other elements are insoluble substances, and are removed by filtration; after obtaining a rare earth acid solution, adopting an ammonia-free saponified fractionation extraction system to carry out extraction separation to obtain a high purity single rare earth chloride such as YCl3 and EuCl3 or other chlorinated rare earth enriched product solutions; and carrying out processes of precipitation and ignition to obtain a single rare earth oxide such as Y2O3 and Eu2O3 or other rare earth enriched product oxide products.

Application Domain

Rare earth metal compounds

Technology Topic

Rare-earth elementDecomposition +13

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  • Method for recovering rare earth elements from waste red phosphor

Examples

  • Experimental program(12)

Example Embodiment

[0016] Example 1
[0017] Take 1000g of discarded red phosphors for three primary color fluorescent lamps, total rare earth (TREO): 81.56%, Eu 2 O 3 /TREO: 7.25%, Y 2 O 3 /TREO: 92.73%, other rare earth <0.02%, calcined at 550℃ for 3 hours, then acid-dissolved in 2.45L composite acid system for 6 hours. The composite acid composition is: hydrochloric acid (HCl) (89%)-oxidant (H 2 O 2 )(3%)-glacial acetic acid (CH 3 COOH) (8%), amount of rare earth metal: volume of composite acid = 1:3, acid dissolution conditions are: acidity 0.5N, acid dissolution temperature 90℃, after acid dissolution, filter to remove insolubles to obtain 2.4L concentration of 338.1g/l The rare earth chloride solution, the calculated yield of rare earth dissolution is 99.5%. Dilute the rare earth chloride solution to a concentration of 120±5g/l and adjust the pH to 2.5±0.3, and enter the fractionation extraction system of 22% naphthenic acid + 18% mixed alcohol + 60% sulfonated kerosene in the organic phase saponified with NaOH After extraction and separation, after 75-stage extraction and 15-stage washing, high-purity yttrium chloride (YCl 3 ) Solution, the solution is precipitated and filtered with high-quality oxalic acid to obtain solid yttrium oxalate, and yttrium oxalate is burned to obtain high-purity yttrium oxide products. Eu 3+ Then enter the organic phase, use 4N±0.5N concentration of high-purity hydrochloric acid (HCl) to back extract the organic phase to obtain europium chloride (EuCl 3 ) Is the main component of the solution, dilute the solution to a concentration of 120±5g/l and adjust the pH to 2.5±0.3, add zinc powder to the solution to make Eu 3+ Revert to Eu 2+ , The reduced europium chloride solution enters the P507-sulfonated kerosene-HCl extraction system under the protection of argon, and after 30-stage extraction with three-outlet fractionation extraction method, high-purity Eu is obtained in the water phase 2+ Eu in solution, water phase 2+ It becomes Eu after being oxidized by hydrogen peroxide 3+ After oxalic acid precipitation, filtration, and burning of europium oxalate, high-purity europium oxide products are obtained. The other small amounts of rare earths enter the organic phase, and the organic phase is back-extracted with 4N±0.5N hydrochloric acid (HCl) to obtain the rare earth chloride enrichment solution, which is then precipitated with oxalic acid, filtered and burned to obtain the rare earth oxide enrichment product. The zinc chloride solution is obtained from the third outlet, and the zinc oxide product with higher purity is obtained by ammonium carbonate precipitation, filtration and burning.

Example Embodiment

[0018] Example 2
[0019] Take 1000g of discarded red phosphors for tri-color fluorescent lamps, total rare earth (TREO): 81.56%, EU 2 O 3 /TREO: 7.25%, Y 2 O 3 /TREO: 92.73%, other rare earth <0.02%, calcined at 850℃ for 0.5 hours, and then acid-dissolved in 2.45L composite acid system for 3 hours. The composite acid composition is: hydrochloric acid (HCl) (92%)-oxidant (H 2 O 2 )(5%)-glacial acetic acid (CH 3 COOH) (3%), amount of rare earth metal: volume of composite acid = 1:3, acid dissolution conditions: acidity 0.5N, acid dissolution temperature 110°C, after acid dissolution, filter to remove insoluble matter to obtain 2.41L with a concentration of 337.0g/l The rare earth chloride solution, the calculated yield of rare earth dissolution is 99.6%. The subsequent process steps are the same as in Example 1.

Example Embodiment

[0020] Example 3
[0021] Take 1000g of discarded red phosphors for three primary color fluorescent lamps, total rare earth (TREO): 81.56%, Eu 2 O 3 /TREO: 7.25%, Y 2 O 3 /TREO: 92.73%, other rare earth <0.02%, calcined at 550℃ for 3 hours, then acid-dissolved in 2.45L composite acid system for 6 hours. The composite acid composition is: nitric acid (HNO 3 )(89%)-oxidant(H 2 O 2 )(3%)-glacial acetic acid (CH 3 COOH) (8%), amount of rare earth metal: volume of composite acid = 1:3, acid dissolution conditions are: acidity 0.5N, acid dissolution temperature 90℃, after acid dissolution, filter to remove insolubles to obtain 2.41L concentration of 337.0g/l The calculated rare earth nitrate solution yield is 99.6%. Dilute the rare earth nitrate solution to a concentration of 120±5g/l and adjust the pH to 2.5±0.3, and enter it into a fractional extraction system of 22% naphthenic acid + 18% mixed alcohol + 60% sulfonated kerosene in the organic phase saponified with NaOH Extraction and separation, after 75-stage extraction and 15-stage washing, high-purity yttrium nitrate (Y(NO 3 ) 3 ) Solution, the solution is precipitated and filtered with high-quality oxalic acid to obtain solid yttrium oxalate, and yttrium oxalate is burned to obtain high-purity yttrium oxide products. Eu 3+ Then enter the organic phase, use 4N±0.5N concentration of high-purity hydrochloric acid (HCl) to back extract the organic phase to obtain europium chloride (EuCl 3 ) Is the main component of the solution. The subsequent process steps are the same as in Example 1.

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