阅读说明：本技术 一种钕铁硼废料选择性分离稀土与综合回收铁的方法 (Method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste ) 是由 刘子帅 彭如振 罗仙平 周贺鹏 盛牡玲 于 2021-07-15 设计创作，主要内容包括：本发明涉及钕铁硼废料回收技术领域,特别涉及一种钕铁硼废料选择性分离稀土与综合回收铁的方法；在本发明内,将钕铁硼废料与添加剂混合焙烧,使钕铁硼废料中的稀土和铁氧化物分别转化为易溶于酸的稀土氧化物及难溶于水和酸的铁酸盐,然后采用稀酸浸出稀土,获得稀土浸出液,稀土浸出液再与草酸混合均匀搅拌,以草酸稀土的形式回收稀土；铁以铁酸盐形式存在于固相中,可作为高附加值的各类催化剂使用,从而实现稀土和铁的高效分离及回收；本发明具有稀土与铁选择性好、铁得到综合回收和资源综合利用率高的特点。(The invention relates to the technical field of neodymium iron boron waste recovery, in particular to a method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste; in the invention, neodymium iron boron waste and additives are mixed and roasted, so that rare earth and iron oxide in the neodymium iron boron waste are respectively converted into rare earth oxide which is easy to dissolve in acid and ferrite which is difficult to dissolve in water and acid, then dilute acid is adopted to leach rare earth, rare earth leachate is obtained, the rare earth leachate is uniformly mixed with oxalic acid and stirred, and rare earth is recovered in the form of rare earth oxalate; iron exists in a solid phase in a ferrite form and can be used as various catalysts with high added values, so that the high-efficiency separation and recovery of rare earth and iron are realized; the method has the characteristics of good selectivity of rare earth and iron, comprehensive recovery of iron and high comprehensive utilization rate of resources.)

1. A method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste is characterized by comprising the following steps:

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

step S2, mixing the neodymium iron boron calcine with a leaching agent, and leaching to obtain a rare earth leaching solution and ferrite;

and step S3, uniformly mixing the rare earth leachate with oxalic acid and stirring to obtain rare earth oxalate and wastewater.

2. The method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste according to claim 1, characterized by further comprising the steps of S4;

step S4: evaporating the wastewater at 60-100 ℃ for 1-4 h, and then crystallizing at 0-5 ℃ for 6-12 h to obtain oxalic acid and purified wastewater.

3. The method for selectively separating rare earth and comprehensively recovering iron from the neodymium iron boron waste material as claimed in claim 2, wherein the oxalic acid generated in the step S4 is returned to the step S3 for use.

4. The method for selectively separating rare earth and comprehensively recovering iron from the neodymium iron boron waste material as claimed in claim 2, wherein the purified wastewater generated in the step S4 is returned to the step S2 for use.

5. The method for selectively separating rare earth from neodymium iron boron waste and comprehensively recovering iron according to claim 1, characterized in that in step S1, according to the mass ratio of the additive to the neodymium iron boron waste being (1-6): 1, the additive and the neodymium iron boron waste are uniformly mixed and roasted at 600-1200 ℃ for 1-5 h to obtain neodymium iron boron calcine.

6. The method for selectively separating rare earth and comprehensively recovering iron from the neodymium iron boron waste according to claim 5, wherein the additive is at least one of titanium oxide, cobalt oxide, nickel oxide, copper oxide, strontium oxide, molybdenum oxide, barium oxide, tungsten oxide, bicarbonate and carbonate.

7. The method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste according to claim 1, wherein in step S2, according to a liquid-solid ratio of (1-6): 1, mixing the leaching agent with the neodymium iron boron calcine, leaching for 1-5 hours at the temperature of 60-90 ℃, and carrying out solid-liquid separation to obtain a rare earth leaching solution and ferrite.

8. The method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste according to claim 7, wherein the leaching agent is hydrochloric acid or nitric acid.

9. The method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste according to claim 8, wherein the concentration of the leaching agent is 0.5-1.5 mol/L.

10. The method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste according to claim 1, wherein in step S3, according to the molar ratio of oxalate to rare earth in rare earth leachate, the molar ratio is (2-6): 1, mixing oxalic acid and the rare earth leaching solution, stirring for 30-90 min at 30-60 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater.

Technical Field

The invention relates to the technical field of neodymium iron boron waste recovery, in particular to a method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste.

Background

Neodymium iron boron is an excellent rare earth permanent magnet material, and is widely applied in various fields such as computers, communication technologies, aerospace technologies, motor engineering, automobile industry, nuclear magnetic resonance imagers and the like due to the advantages of high remanence, high coercivity, high magnetic energy product and the like.

The manufacturing process of the neodymium iron boron magnet mainly comprises the steps of material preparation, ingot making by smelting/belt throwing, powder making, profiling, sintering tempering, magnetism detection, grinding, cutting, electroplating, finished product production and the like; in the process of neodymium iron boron grinding and cutting, the content of waste materials such as oil sludge, abrasive dust, sawdust and leftover materials generated by cutting and grinding is up to 30%, the content of rare earth elements such as praseodymium, neodymium and dysprosium in the waste materials is up to 20% -30%, the content of iron in the waste materials is up to 60% -70%, and the method has extremely high economic value, so that the method has great strategic significance in deeply separating and recycling rare earth and iron from neodymium iron boron waste materials.

At present, the recovery of the neodymium iron boron waste materials mainly focuses on the selective separation of rare earth and iron, and then the recovery of the rare earth with high value is carried out, but the metal iron with the highest proportion in the neodymium iron boron waste materials or the rare earth leachate containing high-concentration iron is not recovered, so the recovery of the neodymium iron boron waste materials has the problems of non-comprehensive recovery of iron, low comprehensive utilization rate of resources and the like.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide a method for selectively separating rare earth from neodymium iron boron waste and comprehensively recovering iron, which mixes and roasts the neodymium iron boron waste and additives to convert rare earth ferrite and iron oxide in the neodymium iron boron waste into rare earth oxide which is easily soluble in acid and ferrite which is difficultly soluble in water and acid, then leaches rare earth by adopting a leaching agent to obtain a rare earth leachate, and then the rare earth leachate is uniformly mixed with oxalic acid and stirred to recover rare earth in the form of rare earth oxalate; iron exists in a solid phase in a ferrite form and can be used as various catalysts with high added values, so that the high-efficiency separation and recovery of rare earth and iron are realized.

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

a method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste comprises the following steps:

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

step S2, mixing the neodymium iron boron calcine with a leaching agent, and leaching to obtain a rare earth leaching solution and ferrite;

and step S3, uniformly mixing the rare earth leachate with oxalic acid and stirring to obtain rare earth oxalate and wastewater.

As a modification of the present invention, the method further includes step S4;

step S4: evaporating the wastewater at 60-100 ℃ for 1-4 h, and then crystallizing at 0-5 ℃ for 6-12 h to obtain oxalic acid and purified wastewater.

As a further improvement of the present invention, oxalic acid generated in step S4 is returned to step S3 for use.

As a further improvement of the present invention, the purified wastewater produced in step S4 is returned to step S2 for use.

According to a further improvement of the invention, in step S1, according to the mass ratio of the additive to the neodymium iron boron waste material being (1-6): 1, the additive and the neodymium iron boron waste material are uniformly mixed, and the mixture is roasted at the temperature of 600-1200 ℃ for 1-5 h to obtain the neodymium iron boron roasted sand.

As a further improvement of the present invention, the additive is at least one of titanium oxide, cobalt oxide, nickel oxide, copper oxide, strontium oxide, molybdenum oxide, barium oxide, tungsten oxide, bicarbonate, and carbonate.

In a further improvement of the present invention, in step S2, the ratio of liquid to solid is (1-6): 1, mixing the leaching agent with the neodymium iron boron calcine, leaching for 1-5 hours at the temperature of 60-90 ℃, and carrying out solid-liquid separation to obtain a rare earth leaching solution and ferrite.

As a further improvement of the invention, the leaching agent is hydrochloric acid or nitric acid.

As a further improvement of the invention, the concentration of the leaching agent is 0.5-1.5 mol/L.

In a further improvement of the present invention, in step S3, the molar ratio of oxalate to rare earth in the rare earth leaching solution is (2-6): 1, mixing oxalic acid and the rare earth leaching solution, stirring for 30-90 min at 30-60 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater.

In the invention, neodymium iron boron waste and additives are mixed and roasted, so that rare earth and iron oxide in the neodymium iron boron waste are respectively converted into rare earth oxide which is easy to dissolve in acid and ferrite which is difficult to dissolve in water and acid, then dilute acid is adopted to leach rare earth, rare earth leachate is obtained, the rare earth leachate is uniformly mixed with oxalic acid and stirred, and rare earth is recovered in the form of rare earth oxalate; iron exists in a solid phase in a ferrite form and can be used as various catalysts with high added values, so that the high-efficiency separation and recovery of rare earth and iron are realized; the method has the characteristics of good selectivity of rare earth and iron, comprehensive recovery of iron and high comprehensive utilization rate of resources.

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 block diagram of the steps of one embodiment of the present invention;

FIG. 3 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 to 3, the method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste comprises the following steps:

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

step S2, mixing the neodymium iron boron calcine with a leaching agent, and leaching to obtain a rare earth leaching solution and ferrite;

and step S3, uniformly mixing the rare earth leachate with oxalic acid and stirring to obtain rare earth oxalate and wastewater.

In the invention, neodymium iron boron waste and additives are mixed and roasted, so that rare earth and iron oxide in the neodymium iron boron waste are respectively converted into rare earth oxide which is easy to dissolve in acid and ferrite which is difficult to dissolve in water and acid, then dilute acid is adopted to leach rare earth, rare earth leachate is obtained, the rare earth leachate is uniformly mixed with oxalic acid and stirred, and rare earth is recovered in the form of rare earth oxalate; iron exists in a solid phase in a ferrite form and can be used as various catalysts with high added values, so that the high-efficiency separation and recovery of rare earth and iron are realized; the method has the characteristics of good selectivity of rare earth and iron, comprehensive recovery of iron and high comprehensive utilization rate of resources.

In the invention, in step S1, according to the mass ratio of the additive to the neodymium iron boron waste material being (1-6): 1, the additive and the neodymium iron boron waste material are uniformly mixed, and the mixture is roasted at the temperature of 600-1200 ℃ for 1-5 hours to obtain the neodymium iron boron roasted sand, wherein the additive is at least one of titanium oxide, cobalt oxide, nickel oxide, copper oxide, strontium oxide, molybdenum oxide, barium oxide, tungsten oxide, bicarbonate and carbonate.

In step S2, the ratio of liquid to solid is (1-6): 1, mixing a leaching agent with the neodymium iron boron calcine, leaching for 1-5 hours at the temperature of 60-90 ℃, and carrying out solid-liquid separation to obtain a rare earth leaching solution and ferrite; the leaching agent is hydrochloric acid or nitric acid, and the concentration of the leaching agent is 0.5-1.5 mol/L.

In step S3, according to the molar ratio of oxalate to rare earth in the rare earth leaching solution being (2-6): 1, mixing oxalic acid and the rare earth leaching solution, stirring for 30-90 min at 30-60 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater.

The invention provides an implementation mode of a method for selectively separating rare earth and comprehensively recovering iron from neodymium iron boron waste, which specifically comprises the following steps:

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

step S2, mixing the neodymium iron boron calcine with a leaching agent, and leaching to obtain a rare earth leaching solution and ferrite;

step S3, mixing the rare earth leachate with oxalic acid uniformly and stirring to obtain rare earth oxalate and wastewater;

step S4: evaporating the wastewater at 60-100 ℃ for 1-4 h, and then crystallizing at 0-5 ℃ for 6-12 h to obtain oxalic acid and purified wastewater.

Wherein, the oxalic acid generated in the step S4 is returned to the step S3 for use, and the generated purified wastewater is returned to the step S2 for use, thereby solving the problem of wastewater recovery.

Specifically, the specific steps are as follows:

1. according to the mass ratio of the additive to the neodymium iron boron waste material of 1: 6, uniformly mixing an additive and the neodymium iron boron waste, and roasting at the temperature of 600-1200 ℃ for 1-5 hours to obtain neodymium iron boron roasted sand, wherein the additive is one of oxides, bicarbonates and carbonates of titanium, cobalt, nickel, copper, strontium, molybdenum, barium and tungsten;

2. according to the liquid-solid ratio of (1-6): 1, mixing a leaching agent and the roasted neodymium iron boron sand, leaching for 1-5 h at the temperature of 60-90 ℃, and carrying out solid-liquid separation to obtain a leaching solution and ferrite (generated correspondingly to an additive), wherein the leaching agent is one of hydrochloric acid and nitric acid, and the concentration of the leaching agent is 0.5-1.5 mol/L;

3. according to the molar ratio of oxalate to rare earth in the leaching solution of (2-6): 1, mixing oxalic acid with the leaching solution, stirring for 30-90 min at 30-60 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater;

4. evaporating the wastewater at 60-100 ℃ for 1-4 h, and then crystallizing at 0-5 ℃ for 6-12 h to obtain oxalic acid and purified wastewater, wherein the purified wastewater can be returned to the step 2 for use, and the oxalic acid is returned to the step 3 for use.

For better illustration and explanation, the present invention provides the following examples:

example one

1. According to the mass ratio of the additive to the neodymium iron boron waste material of 1: 6, uniformly mixing the additive and the neodymium iron boron waste material, and roasting at 900 ℃ for 5 hours to obtain neodymium iron boron roasted sand, wherein the additive is titanium oxide;

2. according to the liquid-solid ratio of 3: 1, mixing a leaching agent with the neodymium iron boron calcine, leaching for 5 hours at the temperature of 80 ℃, and carrying out solid-liquid separation to obtain a leaching solution and titanium ferrite, wherein the leaching agent is hydrochloric acid, and the concentration of the hydrochloric acid is 1.0 mol/L;

3. according to the molar ratio of oxalate to rare earth in the leaching solution of 3: 1, mixing oxalic acid with the leaching solution, stirring for 60min at 50 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater;

4. evaporating the waste water at 80 ℃ for 4h, and then crystallizing at 2 ℃ for 10h to obtain oxalic acid and purified waste water.

The obtained results show that the leaching rate of the rare earth is 98.56 percent, the leaching rate of the iron is 2 percent, the purity of the rare earth oxalate is 98.68 percent and the purity of the titanium ferrite is 98.89 percent.

Example two

1. According to the mass ratio of the additive to the neodymium iron boron waste material of 1: 6, uniformly mixing the additive and the neodymium iron boron waste material, and roasting at the temperature of 600 ℃ for 5 hours to obtain neodymium iron boron roasted sand, wherein the additive is copper oxide;

2. according to the liquid-solid ratio of 1: 1, mixing a leaching agent and the neodymium iron boron calcine, leaching for 5 hours at 90 ℃, and carrying out solid-liquid separation to obtain a leaching solution and copper ferrite, wherein the leaching agent is hydrochloric acid and the concentration is 0.5 mol/L;

3. according to the molar ratio of oxalate to rare earth in the leaching solution of 2: 1, mixing oxalic acid with the leaching solution, stirring for 90min at the temperature of 60 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater;

4. evaporating the waste water at 60 ℃ for 4h, and then crystallizing at 0 ℃ for 12h to obtain oxalic acid and purified waste water.

The obtained results show that the leaching rate of the rare earth is 98.98 percent, the leaching rate of the iron is 2.3 percent, the purity of the rare earth oxalate is 98.87 percent and the purity of the copper ferrite is 98.65 percent.

EXAMPLE III

1. According to the mass ratio of the additive to the neodymium iron boron waste material of 1: 6, uniformly mixing the additive and the neodymium iron boron waste material, and roasting at 1200 ℃ for 1h to obtain neodymium iron boron calcine, wherein the additive is molybdenum oxide;

2. according to the liquid-solid ratio of 6: 1, mixing a leaching agent with the neodymium iron boron calcine, leaching for 1 hour at the temperature of 60 ℃, and carrying out solid-liquid separation to obtain a leaching solution and molybdenum ferrite, wherein the leaching agent is nitric acid, and the concentration of the nitric acid is 1.5 mol/L;

3. according to the molar ratio of oxalate to rare earth in the leaching solution of 6: 1, mixing oxalic acid with the leaching solution, stirring for 30min at the temperature of 30 ℃, and carrying out solid-liquid separation to obtain rare earth oxalate and wastewater;

4. evaporating the waste water at 100 ℃ for 1h, and then crystallizing at 5 ℃ for 6h to obtain oxalic acid and purified waste water.

The obtained results show that the leaching rate of the rare earth is 99.2 percent, the leaching rate of the iron is 3.2 percent, the purity of the rare earth oxalate is 98.93 percent, and the purity of the molybdenum ferrite is 98.25 percent.

Comparison of examples one to three, as follows:

	example one	Example two	EXAMPLE III
				Leaching rate of rare earth	98.56%	98.98%	99.2%
Iron leachingRate of change	2%	2.3%	3.2%
				Purity of rare earth oxalate	98.68%	98.87%	98.93%
Purity of ferrite	98.89%	98.65%	98.25%

The invention has the following advantages:

1. the present invention adopts one additive of oxides, bicarbonate and carbonate of titanium, cobalt, nickel, copper, strontium, molybdenum, barium and tungsten to react with neodymium-iron-boron waste material to produce ferrite which is insoluble in water and dilute acid, and the rare earth is converted into rare earth oxide, and the rare earth oxide is selectively dissolved out by leaching with dilute hydrochloric acid or dilute nitric acid so as to implement the selective separation of rare earth and iron.

2. The invention adopts one additive of oxides, bicarbonate and carbonate of titanium, cobalt, nickel, copper, strontium, molybdenum, barium and tungsten to react with the neodymium-iron-boron waste material, so as to generate the ferrite of corresponding metal, the ferrite of the metal can be used as a catalyst, the iron is recovered by a product with high added value, and the comprehensive utilization rate of resources is high.

3. The technical indexes obtained by the invention are as follows: the leaching rate of rare earth is more than 98 percent, the leaching rate of iron is less than 5 percent, the purity of rare earth oxalate is more than 98 percent, and the purity of ferrite is more than 98 percent.

Therefore, the method has the characteristics of good selectivity of the rare earth and the iron, comprehensive recovery of the iron and high comprehensive utilization rate of resources.

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 therein.