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Method for dissolving out rare-earth by treating waste neodymium-iron-boron materials

A neodymium iron boron and rare earth technology, applied in the direction of improving process efficiency, can solve the problems of fast oxidative roasting, large acid consumption, high energy consumption, improve rare earth extraction rate, high rare earth leaching rate, and easy environmental treatment Effect

Active Publication Date: 2014-01-29
CENT SOUTH UNIV
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Problems solved by technology

Oxidation-acid soluble method oxidizes waste materials into oxides, and then controls acidity to leach rare earths in oxides and limit iron dissolution; oxidation includes high-temperature oxidation roasting method [1] and normal temperature (acidic) air oxidation method [2], The oxidation roasting speed is fast and the efficiency is high, while the air oxidation speed is slow and occupies a large space
[0005] Obviously, the hydrochloric acid full dissolution method consumes a lot of acid, the sulfuric acid dissolution-double salt method consumes more chemical materials, and the oxidation-acid optimal dissolution method has a long process and high energy consumption. In view of the above problems, the present invention proposes a chemical material consumption An efficient, economical, and short-process method for treating NdFeB waste with less energy consumption

Method used

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  • Method for dissolving out rare-earth by treating waste neodymium-iron-boron materials

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Effect test

Embodiment 1

[0035] Use 2.2mol / L sodium chloride solution to slurry the powdery material at a liquid-to-solid mass ratio of 4:1, then heat and stir to dissolve the rare earth. According to the total leaching time, it is divided into three stages of leaching operation; each stage of leaching time is 20 minutes; the temperature of the first, second and third stage is controlled at 85-90°C, 80-85°C and 70-80°C respectively; each stage of leaching is drummed into the industrial Oxygen and hydrochloric acid are added from the first and second sections respectively, and the solution potential in the leaching tank is controlled at +400~+600mV, pH2.5~3.5; pH3.5~4.5. After the dissolution process is completed and the solid-liquid separation is completed, the main metal element content (g / L) in the filtrate is: rare earth 65.7; Fe4.6.

[0036] After treatment, the leaching rates (%) of rare earth and iron in waste NdFeB materials are: 88.7; 3.1.

Embodiment 2

[0038] Use 0.8mol / L sodium chloride solution to slurry the powdery material at a liquid-to-solid mass ratio of 8:1, then heat and stir to dissolve the rare earth. According to the total leaching time, it is divided into four stages of leaching operations; each stage of leaching time is 10 minutes; the temperature of the first, second, third, and fourth stages is controlled at 75-80°C, 70-75°C, 70-75°C and 50-70°C; Industrial oxygen is blown into each stage of leaching; hydrochloric acid is added from the first, second and third stages respectively to control the solution potential +500~+700mV and pH2.5~3.5 in the leaching tank; the fourth stage is the post-leaching stage, The leaching end point is the solution potential +700~+800mV, pH3.5~4.5. After the dissolution process is completed and the solid-liquid separation is completed, the main metal element content (g / L) in the filtrate is: rare earth 35.0; Fe2.7.

[0039] After treatment, the leaching rates (%) of rare earth and...

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Abstract

The invention discloses a method for dissolving out rare-earth by treating waste neodymium-iron-boron materials. The method comprises the following steps of: crushing materials into powder, wetting and dispersing by using an electrolyte solution, and carrying out size mixing; then controlling electric potential between +400 mV and +800 mV by adding an oxidizing agent, and controlling pH between 2.5 and 4.5 by adding inorganic acid; leaching for 30-80 minutes under the condition that the temperature is 50-90 DEG C; after the leaching is completed, carrying out solid-liquid separation and filter residue washing; purifying, enriching and separating the rare-earth from leach liquor with solid leaching residues separated, wherein filter residues are taken as raw materials used for producing iron products after being washed. The method disclosed by the invention improves the extraction rate of the rare-earth and is convenient for extracting the rare-earth subsequently by adopting multiple methods by adopting subacid oxidizing leaching, reduces the usage amount of acid, alkali and other chemicals, does not adopt the high-temperature oxidation method and reduces the energy consumption.

Description

technical field [0001] The invention relates to a method for separating and extracting valuable substances from recycled resources, and belongs to the field of resource recycling. Specifically, it relates to a method for dissolving rare earths from waste neodymium-iron-boron materials. Background technique [0002] NdFeB permanent magnet material, known as the "magnet king", has excellent magnetic properties and is widely used in many fields. NdFeB materials contain rare earth metals such as metal neodymium or praseodymium neodymium alloy, and metal dysprosium, which is the largest market area for rare earth applications in modern materials; my country's current annual output of NdFeB permanent magnet materials has exceeded 100,000 tons, and the use of rare earth metals exceeds 30,000 tons. In the production process of NdFeB magnets, NdFeB waste (including turning blocks and oil-immersed waste, etc.) is produced, which is about 20% of the weight of raw materials. At presen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B59/00
CPCY02P10/20
Inventor 胡启阳李新海王志兴郭华军彭文杰
Owner CENT SOUTH UNIV
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