Method for recovering rare earth elements from a solid mixture containing a halophosphate and a compound of one or more rare earth elements

A technology of halophosphate and rare earth elements, which is applied in the preparation/treatment of rare earth metal compounds, rare earth metal compounds, rare earth metal oxides/hydroxides, etc., and can solve the problems of high production costs

Inactive Publication Date: 2014-09-24
RHODIA OPERATIONS SAS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Now, the emitter compounds present in these powders are expensive materials to produce and contain expensive rare elements such as rare earth elements

Method used

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  • Method for recovering rare earth elements from a solid mixture containing a halophosphate and a compound of one or more rare earth elements

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0101] This example relates to a method of the invention wherein nitric acid is used in the acid attack operation.

[0102] As a raw material mixture, luminescent body powder having the following composition expressed as oxides of various elements per 100 grams is used as a raw material:

[0103] Table 1

[0104] Eu 2 o 3

[0105] acid attack

[0106] In a stirred reactor, the phosphor powder was dispersed in water to obtain a dispersion heated to a temperature of 70° C. with a concentration of 170 g / l. The nitric acid solution was poured into the dispersion (which was stirred and heated) within 1 hour until the pH of the solution remained below 1. The mixture was then allowed to digest for 1 hour with stirring, keeping it at the same temperature and the same pH.

[0107] A solution of caustic soda having a concentration equal to 4N was then added to the mixture within 1 hour, so that the pH of the mixture rose to 2. The mixture was stirred for 1 hour.

[...

Embodiment 2

[0132] This example relates to the method according to the invention in which hydrochloric acid is used for the first acid attack of the phosphor powder. Subsequent steps of the method were performed in the same manner as in Example 1.

[0133] The table below shows the analysis of the filtered water recovered at the end of the first acid attack (Table 5) and at the end of the second acid attack (Table 6).

[0134] table 5

[0135] Al 2 o 3

[0136] Table 6

[0137] Eu 2 o 3

[0138] The total yield of rare earth elements was 84.1%.

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Abstract

The present invention relates to a method for recovering rare earth elements from a solid mixture containing a halophosphate and at least one or more rare earth element compounds, comprising the steps of: (a) attacking the mixture with an acid; (b) adding a base such that the pH is raised back to at least 1.5; (c) attacking the solid of step (b) with a solution of caustic soda or caustic potash; (d) acid attacking the solid of step (c) until a pH below 7 is obtained, thereby producing a solid phase and a liquid phase comprising at least one rare earth salt, and separating the solid phase from the liquid phase.

Description

technical field [0001] The present invention relates to a method for recovering rare earth elements from a solid mixture containing a halophosphate and one or more rare earth element compounds. Background of the invention [0002] The market for energy-saving lamps is expanding rapidly. It is known that lighting is actually a major item in energy consumption in industrialized countries, and using these lamps instead of incandescent lamps will likely reduce the level of lighting energy consumption. [0003] Government directives issued by some countries will strengthen this trend in favor of energy-saving lamps. [0004] Furthermore, the development of this type of lamps has made it necessary to manage their recovery and recycling, taking into account not only the presence of mercury in them, but also the metals included in their composition. [0005] Currently, almost all materials (glass, mercury, metal, etc.) resulting from the processing of lamps of this type are recycl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/32C01B25/37C01F17/00H01J9/52C09K11/01C01F17/206
CPCC01B25/32C01B25/37C01F17/0075C01F17/0068C09K11/7792C09K11/01H01J9/52C01F17/0043C01F17/276C01F17/271C01F17/206Y02W30/50Y02W30/82C01F17/10
Inventor J-J·布拉科尼耶A·罗拉
Owner RHODIA OPERATIONS SAS
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