Method for recycling rare-earth elements from neodymium iron boron waste with high silicon content and low rare earth content

Abstract

The invention belongs to the technical field of rare earth waste resource recycling, and particularly relates to a method for recycling rare-earth elements from neodymium iron boron waste with high silicon content and low rare earth content. The method is characterized in that the neodymium iron boron waste with high silicon content and low rare earth content is mixed with neodymium iron boron waste with high rare earth content as well as fluffy powder, so that a pre-roasting process can be normally performed, and performing of a follow-up process is facilitated, and therefore, recycling for rare-earth elements with high silicon content and low rare earth content is realized. The method is suitable for a process for recycling rare earth from neodymium iron boron waste with high silicon content and low rare earth content, can effectively recycle praseodymium-neodymium oxide, dysprosium oxide, gadolinium oxide and terbium oxide, has a recovery rate of 93%, 95%, 90% and 91%, and developsa novel way for comprehensively treating and recycling rare earth elements from neodymium iron boron waste, so that wider resources are sufficiently recycled.

Description

technical field

[0001] The invention relates to the technical field of recycling rare earth waste resources, in particular to a method for recovering rare earth elements from high-silicon and low-content NdFeB waste. Background technique

[0002] In 2017, the output of NdFeB in my country exceeded 170,000 tons, and the annual NdFeB waste generated was about 65,000 tons. Due to different processing methods, many types of NdFeB wastes are produced in the process of producing NdFeB, such as ultrafine powder, oil sludge, grinding mud, chamfering mud, wire cutting material, dry powder, slag, material skin, material head , powder, scrap products, defective products, wire saw mud, multi-line mud and sweeping ash, etc. In the existing recycling process of rare earth waste resources, pre-roasting, fine grinding, oxidative roasting, excellent solvent extraction, neutralization and impurity removal, extraction separation, oxalic acid precipitation and burning processes are mainly used...

Examples

Embodiment 1

[0052] Mix high-silicon and low-content NdFeB waste (chamfering mud), high-content NdFeB waste (oil sludge) and loose agent iron slag (mass ratio 1:1:1), and pre-roast at 600 ° C for 2 hours. Obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 200 mesh; oxidize and roast the fine material at 500°C for 2 hours to obtain an oxidized material; use an extraction device to mix the oxidized material and water to adjust Slurry, heating while stirring, when it reaches 60°C, add extractant nitric acid (mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), fully stir for 1h, control pH value to 2.0, carry out dissolution extraction, keep The pH value was kept constant at 2.0, and kept for 2 hours to obtain the extracted slurry; the extracted slurry was filtered with a high-pressure filter press at 60°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and water (mass Ratio 1:0.2) washing and filtering at 50°C to ob...

Embodiment 2

[0055] Mix high-silicon and low-content NdFeB waste (wire saw mud), high-content NdFeB waste (slag) and loose agent calcium oxide (mass ratio 1:1:6), and pre-roast at 800 ° C for 3 hours. Obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 200 mesh; oxidize and roast the fine material at 800°C for 3 hours to obtain an oxidized material; use an extraction device to mix the oxidized material and water to adjust Slurry, heat while stirring, when it reaches 70°C, start to add extractant sulfuric acid (the mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), stir well for 1.5h, control the pH value to 2.0, and dissolve Extraction, keeping the pH value at 3.0, keeping the temperature for 3 hours to obtain the extraction slurry; filtering the extraction slurry with a high-pressure filter press at 80°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and Water (mass ratio 1:1) is washed and filtered at 60°C to ...

Embodiment 3

[0058] Mix high-silicon and low-content NdFeB waste (sweeping ash), high-content NdFeB waste (ultrafine powder) and loose agent calcium hydroxide (mass ratio 1:1:10), and pre-roast at 1200 ° C 5h to obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 300 mesh; oxidize and roast the fine material at 1000°C for 5 hours to obtain an oxidized material; use an extraction device to separate the oxidized material and water Mix and paste, heat while stirring, when it reaches 95°C, start to add extractant hydrochloric acid (the mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), stir well for 2 hours, control the pH value to 5.0, and dissolve Extraction, keeping the pH value at 5.0, keeping the temperature for 5 hours to obtain the extraction slurry; filtering the extraction slurry with a high-pressure filter press at 90°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and Water (mass ratio 1:2) is washed and...

technical field

[0001] The invention relates to the technical field of recycling rare earth waste resources, in particular to a method for recovering rare earth elements from high-silicon and low-content NdFeB waste. Background technique

[0002] In 2017, the output of NdFeB in my country exceeded 170,000 tons, and the annual NdFeB waste generated was about 65,000 tons. Due to different processing methods, many types of NdFeB wastes are produced in the process of producing NdFeB, such as ultrafine powder, oil sludge, grinding mud, chamfering mud, wire cutting material, dry powder, slag, material skin, material head , powder, scrap products, defective products, wire saw mud, multi-line mud and sweeping ash, etc. In the existing recycling process of rare earth waste resources, pre-roasting, fine grinding, oxidative roasting, excellent solvent extraction, neutralization and impurity removal, extraction separation, oxalic acid precipitation and burning processes are mainly used...

Examples

Embodiment 1

[0052] Mix high-silicon and low-content NdFeB waste (chamfering mud), high-content NdFeB waste (oil sludge) and loose agent iron slag (mass ratio 1:1:1), and pre-roast at 600 ° C for 2 hours. Obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 200 mesh; oxidize and roast the fine material at 500°C for 2 hours to obtain an oxidized material; use an extraction device to mix the oxidized material and water to adjust Slurry, heating while stirring, when it reaches 60°C, add extractant nitric acid (mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), fully stir for 1h, control pH value to 2.0, carry out dissolution extraction, keep The pH value was kept constant at 2.0, and kept for 2 hours to obtain the extracted slurry; the extracted slurry was filtered with a high-pressure filter press at 60°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and water (mass Ratio 1:0.2) washing and filtering at 50°C to ob...

Embodiment 2

[0055] Mix high-silicon and low-content NdFeB waste (wire saw mud), high-content NdFeB waste (slag) and loose agent calcium oxide (mass ratio 1:1:6), and pre-roast at 800 ° C for 3 hours. Obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 200 mesh; oxidize and roast the fine material at 800°C for 3 hours to obtain an oxidized material; use an extraction device to mix the oxidized material and water to adjust Slurry, heat while stirring, when it reaches 70°C, start to add extractant sulfuric acid (the mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), stir well for 1.5h, control the pH value to 2.0, and dissolve Extraction, keeping the pH value at 3.0, keeping the temperature for 3 hours to obtain the extraction slurry; filtering the extraction slurry with a high-pressure filter press at 80°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and Water (mass ratio 1:1) is washed and filtered at 60°C to ...

Embodiment 3

[0058] Mix high-silicon and low-content NdFeB waste (sweeping ash), high-content NdFeB waste (ultrafine powder) and loose agent calcium hydroxide (mass ratio 1:1:10), and pre-roast at 1200 ° C 5h to obtain a coarse material; crush and grind the coarse material to a fine material with a particle size of 300 mesh; oxidize and roast the fine material at 1000°C for 5 hours to obtain an oxidized material; use an extraction device to separate the oxidized material and water Mix and paste, heat while stirring, when it reaches 95°C, start to add extractant hydrochloric acid (the mass ratio of oxidizing material, water and extractant is 1:0.05:0.5), stir well for 2 hours, control the pH value to 5.0, and dissolve Extraction, keeping the pH value at 5.0, keeping the temperature for 5 hours to obtain the extraction slurry; filtering the extraction slurry with a high-pressure filter press at 90°C to obtain feed liquid 1 and iron slag 1; iron slag 1 and Water (mass ratio 1:2) is washed and...

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