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Separation and recovery method of valuable components in rare earth praseodymium neodymium molten salt electrolysis waste

A technology of molten salt electrolysis and recovery method, applied in the direction of improving process efficiency, can solve the problems of long process flow and high processing cost, and achieve the effects of simple process, high yield and short process flow

Active Publication Date: 2017-04-12
YIYANG HONGYUAN RARE EARTH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this process avoids the pollution of the waste gas produced by the process to the environment, the result of calcification and roasting leads to the introduction of calcium element into the system. The content of CaO in the acid solution solution exceeds 10g / L, and the method of extraction has to be used to remove Rare earth decalcification, long process, high processing cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A method for separating valuable components in rare earth praseodymium and neodymium molten salt electrolysis waste, which comprises the following steps:

[0025] ⑴Raw material treatment: use the waste produced by the molten salt electrolysis method to produce rare earth praseodymium and neodymium metals as raw materials, and crush the raw materials to obtain powder;

[0026] This embodiment takes the rare earth molten salt electrolysis waste of a rare earth factory in Hunan as an example to further illustrate the present invention. The analysis results of the total amount of rare earth and the main impurity content of the electrolyte waste are shown in Table 1 (unit: ﹪):

[0027] Table 1 Analysis results of electrolytic waste

[0028] TREO Fe 2 o 3

[0029] In order to facilitate the leaching of soluble oxides in the slurry, especially non-rare earth impurities, in step (1) of the present invention, the particle size of the powder is above 325 mesh.

[...

Embodiment 2

[0055] In order to facilitate the leaching of the acid-soluble impurities and oxide slag in the slurry into the solution, in the step (3) of the separation method of the valuable components in the rare earth praseodymium-neodymium molten salt electrolysis waste, after stopping adding acid, the slurry is heated up to 60 ℃ ~ 80 ℃, and then continue to stir the reaction for 2h ~ 4h.

[0056] In order to facilitate the leaching of the acid-soluble impurities and oxide slag in the slurry into the solution, in the step (3) of the recovery method of valuable components in the rare earth praseodymium-neodymium molten salt electrolysis waste, after stopping adding acid, the slurry is heated up to 60 ℃ ~ 80 ℃, and then continue to stir the reaction for 2h ~ 4h.

[0057] In this embodiment, after the addition of acid was stopped, the temperature of the slurry was raised to 60° C., and the stirring reaction was continued for 2 hours. The pH value hardly changed, and the filter residue con...

Embodiment 3

[0068] In this example, take 1 kg of powder into a beaker, add 2 kg of pure water and mix evenly, add 2 mol / L hydrochloric acid while stirring at room temperature, stop adding acid until the final pH value remains at 1.0-1.5, and the temperature of the slurry rises to 60 °C, continue to stir for 2 h, the pH value hardly changes; filter to obtain the filter residue and filtrate.

[0069] The filter residue was washed with water until neutral, and dried at 70°C to obtain 534.9 g of praseodymium and neodymium fluoride. The composition analysis results are shown in Table 6 (unit: ﹪):

[0070] Table 6: Analytical results of praseodymium and neodymium fluoride in embodiment 3

[0071] TREO Fe 2 o 3

SiO 2

CaO Al 2 o 3

82.50 0.06 0.05 0.07 0.05

[0072] Obtain 3.21L of filtrate containing praseodymium neodymium chloride, the concentration (TREO) is 110.5g / L, after heating the filtrate to 75°C, add saturated oxalic acid solution to carry o...

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Abstract

The invention discloses a separating and recovering method for separating valuable components in rare earth praseodymium-neodymium fused salt electrolysis waste into a liquid phase (praseodymium-neodymium chloride) and a solid phase (praseodymium-neodymium fluoride) by adopting leaching by low-concentration hydrochloric acid. The method is characterized by comprising steps of raw materials processing, beating and leaching to obtain filter residues containing praseodymium-neodymium fluoride and filtrate containing praseodymium-neodymium chloride; the filter residues containing praseodymium-neodymium fluoride are washed to neutral and dried at the temperature of 60-80 DEG C to obtain praseodymium-neodymium fluoride; the filtrate containing praseodymium-neodymium chloride is subjected to crystallization and precipitation with an oxalic acid method to obtain praseodymium-neodymium oxalate, and the obtained praseodymium-neodymium oxalate is burnt at the temperature of 950 DEGC and degraded to obtain praseodymium-neodymium oxide. By means of the characteristic that rare earth fluoride does not react with hydrochloric acid, the low-concentration hydrochloric acid is used for leaching soluble impurities and oxides, a rare earth fluoride structure is not required to be damaged with high-temperature strong acid or strong base, and the valuable components are recycled; compared with the traditional concentrated sulfuric acid roasting method or strong base roasting method, the method omits a roasting process, a follow-up feed liquid is not required to be subjected to an extraction process, so that the method has the characteristics of simple process, short process flow, low cost, high yield and environment-friendliness, and the fluorine element is recycled efficiently.

Description

technical field [0001] The present invention relates to a method for separating and recovering valuable components in rare earth waste residue, in particular to a method for separating and recovering valuable components in rare earth praseodymium-neodymium molten salt electrolysis waste, in particular to a method using low-concentration hydrochloric acid leaching A separation and recovery method for separating valuable components in rare earth praseodymium neodymium molten salt electrolysis waste into liquid phase (praseodymium neodymium chloride) and solid phase (praseodymium neodymium fluoride). Background technique [0002] Due to their special electronic structure, rare earth elements have the characteristics of 4f orbitals that are not filled with electrons and lanthanide contraction, and have optical, electrical, magnetic and thermal effects that many other elements do not have. They are called "treasures of new materials". Widely used in permanent magnet, metallurgy, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00
CPCY02P10/20
Inventor 肖勇陈月华许鸽鸣朱焱任萍崔小震
Owner YIYANG HONGYUAN RARE EARTH
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