阅读说明：本技术 一种锌化焙烧分离回收钕铁硼废料的方法 (Method for separating and recycling neodymium iron boron waste materials through zinc roasting ) 是由 彭如振 刘子帅 雷翔 马文俊 于 2021-07-15 设计创作，主要内容包括：本发明涉及稀土回收技术领域,特别涉及一种锌化焙烧分离回收钕铁硼废料的方法；在本发明内,将钕铁硼废料与锌化剂混合均匀后焙烧,使钕铁硼废料中的稀土转化为易溶于稀酸的稀土氧化物,使钕铁硼废料中的铁转化为不易溶于稀酸的铁酸锌,然后采用稀酸浸出稀土,过滤分离获得稀土浸出液和铁酸锌；获得含铁离子较低的稀土浸出液,可直接用于萃取分离生产线回收稀土；获得的副产品铁酸锌可用于吸波材料,从而使稀土和铁的高效分离；本发明具有流程简单、成本低廉、污染少、选择性高、可综合回收稀土和铁的特点。(The invention relates to the technical field of rare earth recovery, in particular to a method for recovering neodymium iron boron waste materials by zinc roasting separation; in the invention, neodymium iron boron waste materials and zinc agents are uniformly mixed and then are roasted, so that rare earth in the neodymium iron boron waste materials is converted into rare earth oxide which is easy to dissolve in dilute acid, iron in the neodymium iron boron waste materials is converted into zinc ferrite which is not easy to dissolve in dilute acid, then the rare earth is leached by the dilute acid, and the rare earth leachate and the zinc ferrite are obtained by filtering and separating; obtaining rare earth leaching solution with lower iron ions, which can be directly used for the extraction separation production line to recover rare earth; the obtained by-product zinc ferrite can be used for wave-absorbing materials, so that the rare earth and the iron are efficiently separated; the method has the characteristics of simple process, low cost, less pollution, high selectivity and capability of comprehensively recovering rare earth and iron.)

1. A method for recovering neodymium iron boron waste materials by zinc roasting separation is characterized by comprising the following steps:

step S1, uniformly mixing the neodymium iron boron waste with a zinc agent, and roasting to obtain neodymium iron boron roasted sand;

and step S2, mixing and stirring the neodymium iron boron calcine and the leaching agent, and then filtering to obtain the rare earth leaching liquid and zinc ferrite.

2. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 1, wherein in step S2, the neodymium iron boron roasted sand and a leaching agent are mixed, stirred for 60min to 180min at 40 ℃ to 80 ℃, and filtered to obtain a rare earth leaching solution and zinc ferrite.

3. The method for separating and recovering neodymium iron boron waste materials through zinc roasting according to claim 2, wherein the leaching agent is at least one of dilute hydrochloric acid, dilute nitric acid, dilute sulfuric acid and dilute acetic acid.

4. The method for separating and recovering neodymium iron boron waste materials through zinc roasting according to claim 3, wherein the concentration of the leaching agent is 0.5-3 mol/L.

5. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 1, wherein in step S1, the neodymium iron boron waste materials and the zinc agent are mixed uniformly and then directly roasted.

6. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 1, wherein in step S1, the neodymium iron boron waste materials and the zinc agent are uniformly mixed, pressed into briquettes, and then roasted.

7. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 5 or 6, wherein in the step S1, the roasting temperature is 600-1100 ℃, and the roasting time is 60-240 min.

8. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 8, wherein in step S1, the neodymium iron boron waste materials are mixed with a zinc agent according to the molar ratio of iron to zinc being (1.8-2.1): 1.

9. The method for separating and recycling neodymium iron boron waste materials through zinc roasting according to claim 8, wherein in step S1, the zincating agent is at least one of zinc oxide, zinc hydroxide and basic zinc carbonate.

Technical Field

The invention relates to the technical field of rare earth recovery, in particular to a method for recovering neodymium iron boron waste materials by zinc roasting separation.

Background

The neodymium iron boron magnetic material is widely applied to hard disk drives, fans, hybrid electric vehicles and hydroelectric turbine generators; according to different application fields, the life cycle of the neodymium iron boron magnet is different from 2-3 years of an electronic product to 20-30 years of a fan, and about 30% of waste materials are generated in the production process of the neodymium iron boron magnet; the neodymium iron boron waste contains 27% -32% of rare earth and 67% -73% of iron, so that the resource utilization of the rare earth and the iron can be realized by comprehensively recycling the neodymium iron boron waste, the environmental pollution is reduced, and the sustainable development of the rare earth magnetic material is realized.

The common wet process for recycling the neodymium iron boron waste materials comprises a hydrochloric acid optimum dissolution method, a hydrochloric acid total dissolution method, a sulfate double salt precipitation method, an oxalic acid precipitation method and the like; for example, research on rare elements recovery from high-grade cerium-rich neodymium-iron-boron waste (J)]The comprehensive utilization of Chinese resources, 2019, (2): 1-3) adopts a hydrochloric acid optimum dissolution method to recover rare earth elements in neodymium iron boron waste, firstly, the neodymium iron boron waste is crushed and then is oxidized and roasted, 31% hydrochloric acid solution is added for leaching, and then sodium chlorate is added for oxidizing ferrous ions under a certain acidity condition to enable Fe²⁺Is oxidized into Fe³⁺Adding magnesium oxide to adjust pH to 3.5, adding polymer coagulant to precipitate and separate iron. For example, the study on recovery of rare earth elements from neodymium iron boron waste by Yi Xiao Wen, Liu Min, Liwei hong, Dong Bo, Yue Ming, So hong Li, oxalate precipitation method [ J]Rare metals 2014, 38(006): 1093-. For example, the Li Jun (the "method for recovering rare earth elements from neodymium iron boron wastes", publication No. CN 102011020A) discloses a method for recovering rare earth elements from neodymium iron boron wastes, which comprises mixing and grinding neodymium iron boron wastes with water, oxidizing and roasting at 800-950 ℃, adding acid for leaching, extracting for removing iron, extracting for separating rare earth, precipitating rare earth, and calcining.

There are some disadvantages in the above-mentioned conventional wet process: the rare earth is dissolved out along with the dissolution of a large amount of iron, so that the acid consumption is high; the leachate needs iron precipitation treatment, consumes a large amount of reagents and produces waste liquid; the recycling of the leached residues is not considered, and the secondary harm to the environment caused by stockpiling is avoided, so that the development of an efficient selective leaching process has important significance for comprehensively recycling the neodymium iron boron waste.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide a method for roasting, separating and recycling neodymium iron boron waste materials by zinc, the neodymium iron boron waste materials and a zinc agent are uniformly mixed and then are roasted, so that rare earth in the neodymium iron boron waste materials is converted into rare earth oxide which is easy to dissolve in dilute acid, iron in the neodymium iron boron waste materials is converted into zinc ferrite which is not easy to dissolve in dilute acid, then the rare earth is leached by dilute acid, and a rare earth leaching solution and the zinc ferrite are obtained by filtering and separating; obtaining rare earth leaching solution with lower iron ions, which can be directly used for the extraction separation production line to recover rare earth; the obtained by-product zinc ferrite can be used for wave-absorbing material, so that the rare earth and iron can be efficiently separated.

The technical scheme for solving the technical problem is as follows:

a method for recovering neodymium iron boron waste materials by zinc roasting separation comprises the following steps:

step S1, uniformly mixing the neodymium iron boron waste with a zinc agent, and roasting to obtain neodymium iron boron roasted sand;

and step S2, mixing and stirring the neodymium iron boron calcine and the leaching agent, and then filtering to obtain the rare earth leaching liquid and zinc ferrite.

In step S2, the neodymium iron boron calcine and the leaching agent are mixed, stirred at 40-80 ℃ for 60-180 min, and filtered to obtain the rare earth leaching solution and zinc ferrite.

As a further improvement of the invention, the leaching agent is at least one of dilute hydrochloric acid, dilute nitric acid, dilute sulfuric acid and dilute acetic acid.

As a further improvement of the invention, the concentration of the leaching agent is 0.5-3 mol/L.

As a further improvement of the present invention, in step S1, the neodymium iron boron waste is mixed with the zinc agent uniformly and then directly roasted.

As a further improvement of the present invention, in step S1, the neodymium iron boron waste is mixed with the zinc agent uniformly, and then pressed into briquettes, and then baked.

As a further improvement of the invention, in step S1, the roasting temperature is 600-1100 ℃, and the roasting time is 60-240 min.

In a further improvement of the invention, in step S1, the neodymium iron boron waste is mixed with a zinc agent according to the molar ratio of iron to zinc being (1.8-2.1): 1.

As a further improvement of the present invention, in step S1, the zincating agent is at least one of zinc oxide, zinc hydroxide and basic zinc carbonate.

In the invention, neodymium iron boron waste materials and zinc agents are uniformly mixed and then are roasted, so that rare earth in the neodymium iron boron waste materials is converted into rare earth oxide which is easy to dissolve in dilute acid, iron in the neodymium iron boron waste materials is converted into zinc ferrite which is not easy to dissolve in dilute acid, then the rare earth is leached by the dilute acid, and the rare earth leachate and the zinc ferrite are obtained by filtering and separating; obtaining rare earth leaching solution with lower iron ions, which can be directly used for the extraction separation production line to recover rare earth; the obtained by-product zinc ferrite can be used for wave-absorbing materials, so that the rare earth and the iron are efficiently separated; the method has the characteristics of simple process, low cost, less pollution, high selectivity and capability of comprehensively recovering rare earth and iron.

Drawings

For ease of illustration, the present invention is described in detail by the following preferred embodiments and the accompanying drawings.

FIG. 1 is a block diagram of the steps of the present invention;

FIG. 2 is a process flow diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1 and fig. 2, the method for recovering neodymium iron boron waste by zinc roasting separation of the invention comprises the following steps:

step S1, uniformly mixing the neodymium iron boron waste with a zinc agent, and roasting to obtain neodymium iron boron roasted sand;

and step S2, mixing and stirring the neodymium iron boron calcine and the leaching agent, and then filtering to obtain the rare earth leaching liquid and zinc ferrite.

In the invention, neodymium iron boron waste materials and zinc agents are uniformly mixed and then are roasted, so that rare earth in the neodymium iron boron waste materials is converted into rare earth oxide which is easy to dissolve in dilute acid, iron in the neodymium iron boron waste materials is converted into zinc ferrite which is not easy to dissolve in dilute acid, then the rare earth is leached by the dilute acid, and the rare earth leachate and the zinc ferrite are obtained by filtering and separating; obtaining rare earth leaching solution with lower iron ions, which can be directly used for the extraction separation production line to recover rare earth; the obtained by-product zinc ferrite can be used for wave-absorbing materials, so that the rare earth and the iron are efficiently separated; the method has the characteristics of simple process, low cost, less pollution, high selectivity and capability of comprehensively recovering rare earth and iron.

In order to better separate and obtain the rare earth leachate and zinc ferrite, in step S2, mixing the neodymium iron boron calcine with a leaching agent, stirring for 60 min-180 min at 40-80 ℃, and filtering to obtain the rare earth leachate and the zinc ferrite, wherein the leaching agent is at least one of dilute hydrochloric acid, dilute nitric acid, dilute sulfuric acid and dilute acetic acid, and the concentration of the leaching agent is 0.5 mol/L-3 mol/L.

In the invention, in step S1, there are two roasting modes of the neodymium iron boron waste and the zincating agent, that is, the neodymium iron boron waste and the zincating agent are directly roasted after being uniformly mixed, and then pressed into briquettes after being uniformly mixed, and then roasted; wherein the roasting temperature is 600-1100 ℃, and the roasting time is 60-240 min.

In order to better roast, the rare earth in the neodymium iron boron waste is converted into the rare earth oxide which is easy to dissolve in dilute acid, the iron in the neodymium iron boron waste is converted into the zinc ferrite which is not easy to dissolve in dilute acid, and the neodymium iron boron waste is mixed with a zinc agent according to the molar ratio of the iron to the zinc (1.8-2.1): 1; the zinc agent is at least one of zinc oxide, zinc hydroxide and basic zinc carbonate.

Specifically, during the zinc roasting process, the rare earth in the neodymium iron boron waste is converted into rare earth oxide, the iron is converted into zinc ferrite, and the related reactions are as follows:

4Nd + 3O2 ==== 2Nd2O3	(1)
		4Fe + 3O2 ==== Fe2O3	(2)
ZnO + Fe2O3 ==== ZnFe2O4	(3)
		Zn(OH)2 + Fe2O3 ==== ZnFe2O4 + H2O	(4)
2ZnCO3·3Zn(OH)2 +5Fe2O3 ==== 5ZnFe2O4 + 3H2O + 2CO2	(5)

after the neodymium iron boron waste is roasted by zinc, the main phases in the roasted product are rare earth oxide and zinc ferrite, wherein the rare earth oxide is easy to leach out in dilute acid, and the zinc ferrite is difficult to leach out in dilute acid, so that the high-selectivity separation of rare earth and iron is realized, the obtained rare earth solution has low iron content and high purity, an iron precipitation process is not needed, the rare earth solution can be directly used for a rare earth extraction separation production line, and the obtained by-product zinc ferrite has less acid and high purity and can be used as a wave-absorbing material; the method has the advantages of simple flow, low cost and pollution reduction, and can realize the low-acid and high-selectivity leaching of the rare earth, recycle the obtained zinc ferrite and realize the comprehensive utilization of resources.

For better illustration, the invention provides several examples, as follows:

example one

Taking 5.08 g of neodymium iron boron waste (the Fe content is 44 wt%), the granularity is less than 30 mu m, adding 2.01 g of zinc oxide, mixing the two materials uniformly, preparing a columnar block with the diameter of 30mm under the pressure of 20Mpa, putting the columnar block into a corundum crucible, putting the corundum crucible into a muffle furnace for roasting, heating the muffle furnace temperature to 900 ℃ at 10 ℃/min from the room temperature, preserving the temperature for 4 hours, cooling the neodymium iron boron calcine to the room temperature along with the furnace after the heat preservation is finished, taking out the neodymium iron boron calcine for grinding, putting the ground neodymium iron boron calcine into a beaker, adding 50ml of 2mol/L HCl, heating the mixture in a water bath to 80 ℃, stirring the mixture for 2 hours at 200rpm, and filtering and separating to obtain a rare earth leaching solution and zinc ferrite, wherein the leaching results are that the rare earth leaching rate is 96.34%, the Fe rate is 1.34% and the Zn leaching rate is 2.01%.

Example two

Taking 5.05 g of neodymium iron boron waste (the Fe content is 44 wt%), the granularity is less than 30 mu m, adding 1.80 g of zinc oxide, mixing the two materials uniformly, preparing a columnar block with the diameter of 30mm under the pressure of 30Mpa, putting the columnar block into a corundum crucible, putting the corundum crucible into a muffle furnace for roasting, heating the muffle furnace temperature to 1100 ℃ at the speed of 10 ℃/min, preserving the temperature for 3 hours, cooling the neodymium iron boron calcine to the room temperature along with the furnace after the heat preservation is finished, taking out the neodymium iron boron calcine for grinding, putting the ground neodymium iron boron calcine into a beaker, adding 60ml of 1.2 mol/L HCl, heating the mixture in a water bath to 80 ℃, stirring the mixture for 2 hours at 200rpm, and filtering and separating to obtain rare earth leachate and zinc ferrite, wherein the results are that the leaching rate of the rare earth is 95.35%, the leaching rate of the Fe is 1.24% and the leaching rate of Zn is 0.56%.

EXAMPLE III

5.00 g of neodymium iron boron waste (the Fe content is 44 wt percent) is taken, and the granularity is<30 mu m, adding 2.10 g of zinc oxide, mixing the two materials uniformly, putting the mixture into a corundum crucible, and roasting the corundum crucible in a muffle furnaceHeating the temperature from room temperature to 1100 ℃ at a speed of 10 ℃/min, preserving the heat for 4 hours, cooling the neodymium iron boron calcine to the room temperature along with the furnace after the heat preservation is finished, taking out the neodymium iron boron calcine for grinding, placing the ground neodymium iron boron calcine into a beaker, adding 3mol/L H₂SO₄Heating the mixture in a water bath to 60 ℃, stirring the mixture for 2 hours at 200rpm, filtering and separating the mixture to obtain rare earth leaching solution and zinc ferrite, wherein the leaching rate of the rare earth is 95.2 percent, the leaching rate of the Fe is 0.73 percent, and the leaching rate of the Zn is 0.35 percent.

The results of examples one to three are compared as follows:

	example one	Example two	EXAMPLE III
				Leaching rate of rare earth	96.34%	95.35%	95.2%
Iron leaching rate	1.34%	1.24%	0.73%
				Leaching rate of zinc	2.01%	0.56%	0.35%

In the first to third embodiments, the leaching rate of rare earth is more than 95%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.