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Liquid alkali low-temperature roasting decomposition process of caustic soda liquid of mixed rare earth concentrates

A technology of mixing rare earths and low-temperature roasting, which is applied in the field of rare earth metallurgy, can solve the problems of non-continuous production, and achieve the effects of saving washing water, saving equipment, and great flexibility

Inactive Publication Date: 2010-09-08
BAOTOU RES INST OF RARE EARTHS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the existing rare earth concentrate alkali decomposition process requires pickling to remove calcium and cannot be continuously produced, and to realize the recovery of valuable elements such as rare earth, thorium, fluorine and other resources to provide a mixed rare earth concentrate liquid Alkali low-temperature roasting decomposition process, the invention can make the alkali decomposition process realize continuous industrial production

Method used

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  • Liquid alkali low-temperature roasting decomposition process of caustic soda liquid of mixed rare earth concentrates
  • Liquid alkali low-temperature roasting decomposition process of caustic soda liquid of mixed rare earth concentrates

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Take 500g of sodium hydroxide to make a 70wt% solution, add 500g of mixed rare earth concentrate (REO 58.2wt%, CaO 5.65wt%), after mixing, enter and exit continuously in the rotary kiln, and the residence time in the kiln is 1.5 to 2.0 hours. The inlet temperature is 180°C, the kiln temperature is 190°C, and the outlet temperature is 230°C. The roasted ore after roasting automatically enters the collecting hopper at the outlet of the rotary kiln. Then wash with water until neutral, hydrochloric acid is preferentially dissolved, and the pH of the solution is controlled to be 4-5 to obtain a rare earth chloride solution and thorium enrichment. Analyze the content of rare earth and thorium in rare earth chloride solution and thorium enrichment. The rare earth hydrochloric acid leaching rate is 93.8%, the total rare earth yield is 96.2%, and the thorium content in the rare earth chloride solution is less than 0.01%.

Embodiment 2

[0026] Take 500g of sodium hydroxide to make a 70wt% solution, add 500g of mixed rare earth concentrate (REO 56.5wt%, CaO 5.74wt%), and mix it in and out of the rotary kiln continuously. The residence time in the kiln is 1.5 to 2.0 hours. The inlet temperature is 180°C, the kiln temperature is 190°C, and the outlet temperature is 230°C. The roasted ore after roasting automatically enters the collecting hopper at the outlet of the rotary kiln. Then wash with water until neutral, hydrochloric acid is preferentially dissolved, and the pH of the solution is controlled to be 4-5 to obtain a rare earth chloride solution and thorium enrichment. Analyze the content of rare earth and thorium in rare earth chloride solution and thorium enrichment. The rare earth hydrochloric acid leaching rate is 97.1%, the total rare earth yield is 99%, and the thorium content in the rare earth chloride solution is less than 0.01%.

Embodiment 3

[0028] Take 500g of sodium hydroxide to make a 70wt% solution, add 500g of mixed rare earth ore (REO 56.5wt%, CaO 5.74wt%), and mix it in and out of the rotary kiln continuously. The residence time in the kiln is 1.5 to 2.0 hours. The temperature is 210°C, the kiln temperature is 350°C, and the outlet temperature is 340°C. The roasted ore after roasting automatically enters the collecting hopper at the outlet of the rotary kiln. Then wash with water until neutral, hydrochloric acid is preferentially dissolved, and the pH of the solution is controlled to be 4.5-5 to obtain a rare earth chloride solution and thorium enrichment. Analyze the content of rare earth and thorium in rare earth chloride and thorium enrichment. The rare earth hydrochloric acid leaching rate is 98.4%, the total rare earth yield is 99%, and the thorium content in the rare earth chloride solution is less than 0.01%.

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Abstract

The invention relates to a liquid alkali low-temperature roasting decomposition process of caustic soda liquid of mixed rare earth concentrates, which comprises the following steps of: (1) mixing mixed rare earth concentrates and sodium hydroxide in the weight ratio of 1:0.5 to 1.5; (2) roasting the mixed rare earth ore at the roasting temperature of between 150 and 550 DEG C for 0.5 to 4 hours; (3) washing roasted ore water obtained by roasting until the water is neutral; (4) dissolving washed alkali cakes in hydrochloric acid, and controlling the pH value to be between 4 and 5 to prepare rare earth chloride solution; (5) after washing thorium enrichment dissolved by the hydrochloric acid, performing sealing pile-up or extracting thorium and rare earth through further dissolution. The mixed rare earth concentrates are processed by adopting the low-temperature roasting decomposition process, so that the continuous production of the alkali-decomposing mixed rare earth ore can be realized, no waste gas or ammonia nitrogen waste water is generated in the process, and the pollution-free production and comprehensive utilization of resources are realized.

Description

Technical field: [0001] The invention relates to a low-temperature roasting and decomposition process of mixed rare earth concentrate liquid alkali, which belongs to the field of rare earth metallurgy. Background technique: [0002] Baotou is endowed with unique rare earth resources, accounting for 81% of the country's rare earth reserves, and Baotou rare earth concentrates account for more than 60% of my country's smelted rare earth concentrates. The process of extracting mixed rare earths from Baotou rare earth concentrate is mainly concentrated sulfuric acid roasting process. However, this process has the following environmental protection defects that are difficult to solve: (1) The roasting tail gas is an acidic gas containing a large amount of sulfur and fluorine, which is treated by water spraying and absorption, but the exhaust tail gas is difficult to meet the relevant national emission standards. At the same time, because the spray liquid is a mixed acid of sulfur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/02C22B59/00
Inventor 许延辉李良才孟志军刘海娇崔建国张旭霞王英杰胡卫红
Owner BAOTOU RES INST OF RARE EARTHS
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