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A method for recovering rare earth elements by utilizing low-purity silicon and rare earth-containing oxide materials

A technology of rare earth oxides and rare earth elements, which is applied in the preparation/processing of rare earth metal oxyhalides, rare earth metal compounds, and rare earth metal fluorides, etc., and can solve problems such as the limitation of recycling and utilization of silicon cutting waste.

Active Publication Date: 2022-05-27
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods limit the recycling of silicon cutting waste due to the insufficiency of their respective processes. Therefore, how to develop more effective methods for recycling silicon cutting waste is of great significance

Method used

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  • A method for recovering rare earth elements by utilizing low-purity silicon and rare earth-containing oxide materials

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] like figure 1 As shown, the specific steps of the method for recovering rare earth elements by utilizing low-purity silicon and rare earth-containing oxide materials are as follows:

[0026] Step 1. Combine industrial silicon (purity 99.3%), oxide slag containing lanthanum oxide (La 2 O 3 , CaO, SiO 2 , MgO, Al 2 O 3 The content of slag is 33.52wt.%, 16.76wt.%, 23.8wt.%, 11.17wt.% and 14.75wt.%, respectively) and slag-forming agent (the amount of CaO added is 11.73wt.% of the total slag) to reduce together For smelting, the mass ratio of industrial silicon to total slag is 0.6:1, the smelting temperature is 1823K, and the smelting time is 2 hours. After separation of the slag and gold, a Si-La alloy and waste slag with a La content of 15.9wt.% are obtained;

[0027]Step 2. Separate and purify the Si-La alloy obtained in step 1 in a directional crystallization furnace heated by electromagnetic induction to obtain high-purity bulk silicon with a purity of 99.99% (the...

Embodiment 2

[0029] like figure 1 As shown, the specific steps of the method for recovering rare earth elements by utilizing low-purity silicon and rare earth-containing oxide materials are as follows:

[0030] Step 1. Combine industrial silicon (industrial silicon, purity 99.3%), oxide slag containing lanthanum oxide (La 2 O 3 , CaO, SiO 2 , MgO, Al 2 O 3 The content of slag is 33.52wt.%, 16.76wt.%, 23.8wt.%, 11.17wt.% and 14.75wt.%, respectively) and slag-forming agent (the amount of CaO added is 11.73wt.% of the total slag) to reduce together Smelting, the mass ratio of industrial silicon to total slag is 0.2:1, the smelting temperature is 1973K, and the smelting time is 3 hours. After the slag and gold are separated, a Si-La alloy and waste slag with a La content of 55.2 wt.% are obtained;

[0031] Step 2. Separate and purify the Si-La alloy obtained in step 1 in a directional crystallization furnace heated by electromagnetic induction to obtain high-purity LaSi with a purity of 9...

Embodiment 3

[0033] like figure 1 As shown, the specific steps of the method for recovering rare earth elements by utilizing low-purity silicon and rare earth-containing oxide materials are as follows:

[0034] Step 1. Silicon cutting waste (Si content 86.9wt.%, in which the content of main impurities C, O and Al are 0.83mass%, 3.85mass% and 0.87mass%, respectively), oxide slag containing neodymium oxide (Nd 2 O 3 , CaO, SiO 2 , MgO, Al 2 O 3 The contents of slag-forming agents (CaO and SiO) were 2 , the addition amount is 17.8wt.% and 13.8wt.% of the total slag, respectively) for reduction smelting, the mass ratio of silicon cutting waste to the total slag is 0.8:1, the smelting temperature is 1823K, and the smelting time is 3 hours. After slag gold separation, Si-Nd alloy and waste slag with Nd content of 11.3wt.% were obtained;

[0035] Step 2. Grind the Si-Nd alloy obtained in step 1 into powder with a particle size of less than 74 microns, and pickle it with HCl. The pickling co...

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Abstract

The invention relates to a method for recovering rare earth elements by using low-purity silicon and rare earth oxide materials, and belongs to the technical field of solid waste resource recycling and material preparation. Reduce and smelt low-purity silicon, rare earth-containing oxide materials and slagging agents together, and separate slag and gold to obtain Si-RE alloy and waste slag respectively; grind the obtained Si-RE alloy into powder and use HCl-containing leaching solution After pickling, high-purity silicon powder and RE-containing acidic filtrate are obtained; alkali or fluoride is added to the obtained RE-containing acidic filtrate to obtain hydrate precipitation of rare earth oxychlorides or rare earth fluoride precipitation; or the obtained rare earth-containing acidic filtrate The rare earth chlorides are obtained after distillation; the obtained precipitates are calcined to obtain high-purity rare earth oxychlorides, or dried to obtain rare earth fluorides. The present invention is a technology with no waste gas generation, low cost, environmental friendliness and high efficiency.

Description

technical field [0001] The invention relates to a method for recovering rare earth elements by utilizing low-purity silicon and rare earth oxide-containing materials, and belongs to the technical field of solid waste resource recycling and material preparation. Background technique [0002] As one of the important strategic resources for the development of high-tech materials, rare earths are increasingly used in high-tech and daily necessities due to their unique optical, electrical, magnetic, catalytic and other excellent physical and chemical properties, such as fuel cells, permanent Magnets, high temperature superconductors, rare earth catalysts, turbines and thermoelectric materials, etc. Due to the increasing scarcity of rare earth resources that can be mined in the world, it is of great significance to study the recovery and utilization of rare earth secondary resources. At present, the recovery rate of rare earth resources is only 1% to 10%, so there are a large num...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/04C22B9/04C22B9/00C22B59/00C01B33/037C01F17/259C01F17/265C01F17/271C01F17/10
CPCC22B7/04C22B7/001C22B59/00C22B9/04C22B9/006C22B9/003C22B7/007C01B33/037C01F17/259C01F17/265C01F17/271C01F17/10Y02P10/20Y02P10/25
Inventor 雷云雷敏鹏马文会何勇李鹏张陈康健
Owner KUNMING UNIV OF SCI & TECH
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