CN111041198B

CN111041198B - Method for leaching rare earth in rare earth-containing porcelain clay ore raw ore

Info

Publication number: CN111041198B
Application number: CN201811198937.9A
Authority: CN
Inventors: 赵龙胜; 冯宗玉; 黄小卫; 尹海峰; 范波; 彭新林; 崔大立; 齐少雷; 胡权霞
Original assignee: Grirem Advanced Materials Co Ltd
Current assignee: Grirem Advanced Materials Co Ltd
Priority date: 2018-10-15
Filing date: 2018-10-15
Publication date: 2021-09-17
Anticipated expiration: 2038-10-15
Also published as: CN111041198A

Abstract

The invention provides a method for leaching rare earth in rare earth-containing porcelain clay raw ore, which comprises leaching associated rare earth in the rare earth-containing porcelain clay raw ore by adopting a magnesium salt solution, sequentially adding magnesium salt solid into primary slurry and secondary slurry for stirring and leaching, washing high alumina sand by adopting clear water, wherein the leaching rate of the rare earth is up to more than 90%, and the leaching rate of aluminum is lower than 0.2%, then performing non-saponification and non-equilibrium coupling centrifugal extraction and centrifugal back extraction on the rare earth-containing solution, and then circularly returning raffinate to stir and leach the rare earth-containing porcelain clay raw ore, so that the leaching rate of aluminum is further reduced, and the quality of a final high alumina porcelain clay product is improved.

Description

Method for leaching rare earth in rare earth-containing porcelain clay ore raw ore

Technical Field

The invention relates to the field of comprehensive utilization of rare earth-containing porcelain clay ore raw ore, in particular to a method for leaching rare earth in rare earth-containing porcelain clay ore raw ore.

Background

China china clay has abundant resources, and the total reserve of the preserved ore reaches 14.3 hundred million tons, which occupies the 7 th position in the world. According to different types of ore deposits, the porcelain clay ore can be divided into a weathering shell type ore deposit, a hot liquid etching modification ore deposit and a deposition ore deposit, wherein the weathering shell type ore deposit is the most important, ionic rare earth is often associated, and the grade of the rare earth is 0.02-0.05%. World china clay consumption is mainly focused in the fields of paper making, ceramics, paints, plastics and the like. About 80% of china clay products are applied to middle and low-end industries such as ceramics, while paper making and coating level china clay products with high whiteness mostly depend on import, and the import amount is about 600 more than ten thousand tons every year.

China has the main porcelain clay mining areas with the names of Guangdong Mao, Fujian Longyan, Jiangxi Guixi, Jiangsu Wu county and Hunan myna carinling. At present, the porcelain clay product is usually produced by adopting a dry separation process and a wet separation process in industrial production. The dry separation process includes crushing raw ore to 25mm, feeding into cage crusher to reduce the grain size to about 6mm, reducing the water content in porcelain clay to about 10% with hot air inside the cage crusher, and final further milling with air blowing Raymond mill with centrifugal separator and cyclone dust collector to obtain porcelain clay product. The process is simple and economic, can save the dehydration and drying processes of products, reduces the loss of ash powder, but is difficult to obtain high-purity high-quality porcelain clay products which are commonly used as low-price fillers in rubber, plastics and paper making industries. The wet separation process is that after being crushed, the raw ore is mixed with water, etc. and slurried in a slurry pounding machine, large-grain sandstone is removed, the obtained ore slurry is first desanded by a rake type washing box, a floating trough classifier or a swirler, and then the ore slurry is divided into two coarse and fine fractions by a continuous centrifuge, a hydrocyclone or a vibrating fine screen (325 meshes). Leaching iron oxide from fine-fraction products of a classifier, adding alum into the obtained ore pulp to coagulate clay minerals, and finally dehydrating by adopting a high-speed centrifuge, a rotary vacuum filter or a filter press to obtain the porcelain clay product. The wet separation process can be used for producing high-quality porcelain clay products, which is incomparable with the dry separation process.

At present, a recovery process for leaching rare earth by using a leaching agent aiming at associated rare earth resources in raw ores of porcelain clay ores containing rare earth is not available, and related processes mainly aim at the rare earth recovery and utilization of ionic rare earth ores or products containing ionic rare earth and particularly adopt a method combining a wet separation process and an ammonium sulfate leaching process. Chinese patent CN85102529 proposes a process for extracting rare earth from ion type rare earth ore and comprehensive utilization, namely leaching rare earth by ammonium sulfate in a mechanical classifier (leaching rate of rare earth is higher than 90%), and obtaining porcelain clay products through procedures of screening, hydraulic cyclone classification and the like. Chinese patent CN200810019986.1 proposes a method for synchronously recovering kaolin and rare earth from ion-adsorption type rare earth ore, namely, sulfuric acid, ammonium bisulfate or ammonium sulfate is added as a leaching agent in the process of slurry stirring to ensure that the rare earth in the ore and the leaching agent fully carry out ion exchange reaction, and then filter cakes containing kaolin and filtrate containing rare earth are obtained through wet-method ore dressing and filtration, wherein the leaching rate of the rare earth is 88-90%. Chinese patent CN201210021455.2 proposes a method for extracting rare earth from kaolin product containing ionic rare earth, which comprises mixing kaolin product with ammonium sulfate solution to make slurry, stirring in an ore leaching pool to make the rare earth in the kaolin product fully react with ammonium sulfate, and finally filtering with a plate-and-frame filter press to obtain filter cake containing kaolin product and filtrate containing rare earth sulfate. Chinese patent CN201510587600.7 proposes a comprehensive treatment process method of ion adsorption type rare earth ore, namely, ammonium sulfate or ammonium carbonate is adopted to stir and leach rare earth ore with 60-mesh sieve, and the extraction rate of rare earth is 85-96%; and extracting kaolin in the obtained rare earth tailings by adopting gravity separation-magnetic separation.

As mentioned above, the process of leaching rare earth by using leaching agent such as ammonium sulfate in the prior art is mainly directed to ion type rare earth ore or products containing ion type rare earth, no similar research specially aiming at recycling of associated rare earth resources in raw ore containing rare earth china clay ore exists at present, and the recycling of associated rare earth resources in raw ore containing rare earth china clay ore has not yet realized industrial production, mainly because: with the wet separation process, about 8 tons of water are consumed for producing 1 ton of china clay product, and about 0.3 ton of china clay tailings are produced at the same time. After the porcelain clay minerals are sorted, the quality of the porcelain clay products can be influenced by residual ammonium salt in the obtained porcelain clay products; meanwhile, most of water is converted into wastewater, and serious ammonia nitrogen wastewater pollution is caused if the traditional ammonium sulfate or sodium chloride leaching process is adopted to treat the porcelain clay ore. In addition, if the porcelain clay tailings are not effectively treated in time, not only a large amount of land is occupied, but also the residual ammonia nitrogen threatens the surrounding ecological environment of a mining area for a long time, so that serious environmental protection hidden troubles are caused. If a sulfuric acid leaching process is adopted, a large amount of aluminum in the porcelain clay ore is leached, so that the quality of the final porcelain clay product is seriously influenced.

The ionic rare earth ore is a typical rare earth mineral, the existing industrial production mainly adopts an ammonium sulfate in-situ leaching process to recover rare earth resources, and the porcelain clayThe raw ore is mainly recovered by physical ore dressing (cyclone classification) to obtain products of different size fractions (including china clay products), and is applied to the industries of ceramics, building materials, paper making and the like. Compared with the recovery of rare earth resources in ionic rare earth ores, the recovery of associated rare earth resources in crude ores of porcelain clay ores containing rare earth mainly has the following difficulties: (1) the leaching process of the rare earth in the ionic rare earth ore does not need to consider chemical components in tailings after leaching, only needs to ensure high leaching rate of the rare earth, and the leaching process of the associated rare earth in the raw ore of the porcelain clay ore containing the rare earth must simultaneously consider the quality of porcelain clay products and the leaching rate of the rare earth. If the existing ammonium sulfate leaching process is adopted to treat the raw porcelain clay ore, a large amount of Al in the raw porcelain clay ore containing rare earth is leached into the leaching solution, so that the quality of the final porcelain clay product is reduced (the Al in the TC-1 product specified in GB/T14563-₂O₃The content of the rare earth is higher than 33%), and the difficulty of recovering and extracting the rare earth in subsequent leachate is increased. (2) The recovery of associated rare earth resources in the raw ores of the porcelain clay ores containing rare earth has technical and economic feasibility, and the recovery process is organically combined with the existing porcelain clay ore dressing process. Because the existing porcelain clay ore dressing process consumes a great amount of water, if a single-stage leaching technology is simply adopted, the higher leaching rate of rare earth is realized, the dosage of a leaching agent is very large, and the recovery cost of associated rare earth is multiplied, so that the rare earth ore dressing process has to be purposefully leached by combining the different grades of rare earth in different size-fraction products of the porcelain clay ore containing rare earth, the high leaching rate of the rare earth is ensured, and the consumption of the leaching agent is greatly reduced, thereby reducing the production cost.

Therefore, there is a need to develop a new technology for recovering associated rare earth and high alumina china clay products from rare earth-containing china clay ores, which can not affect the quality of the final high alumina china clay products, but also realize the efficient clean recycling of the associated rare earth, so as to promote the green development of china clay industry in the new era.

Disclosure of Invention

Aiming at the problems that the process of leaching and recycling associated rare earth resources in rare earth-containing porcelain clay ore by using an inorganic salt leaching agent is not specially researched at present, and the problems of ammonia nitrogen pollution, low rare earth yield, low quality of high alumina porcelain clay products and the like existing in the process of leaching by using ammonium sulfate in ionic rare earth ore are solved.

In order to achieve the above purpose, the main content of the invention is as follows:

the invention provides a method for leaching rare earth in rare earth-containing porcelain clay ore raw ore, which comprises the following steps:

step S1, adopting a magnesium-containing salt solution to stir and leach the rare earth-containing porcelain clay ore raw ore, and then washing sand to obtain river sand and primary slurry;

step S2, adding the magnesium salt solid into the primary slurry for agitation leaching, and then performing cyclone classification treatment to obtain potash sand and secondary slurry;

step S3, adding the magnesium salt solid into the secondary slurry for stirring and leaching, and then carrying out liquid-solid separation treatment to obtain high-aluminum sand and leaching solution containing rare earth;

step S4, washing the high-alumina sand by using clear water, and performing liquid-solid separation to obtain a rare earth-containing washing liquid and a high-alumina porcelain clay product;

the magnesium salt solution and the magnesium salt solid contain one or more of magnesium sulfate, magnesium chloride and magnesium nitrate.

The magnesium-containing salt solution is adopted to stir and leach the rare earth-containing porcelain clay ore raw ore, the leaching rate of Al is obviously reduced compared with that of the leaching by adopting ammonium sulfate, and the Al content in the obtained leaching solution is reduced, so that the rare earth can be efficiently extracted and recovered, and the quality of the final porcelain clay product cannot be reduced. Meanwhile, aiming at the characteristic that the grade of rare earth in each grade product in the raw ore of the porcelain clay ore containing the rare earth is improved along with the increase of the grade, the method combines the existing ore dressing process of the raw ore of the porcelain clay ore, adopts a mode of adding magnesium salt solid step by step, gradually improves the concentration of a leaching agent, pertinently carries out multi-grade rare earth leaching, and can obviously improve the leaching rate of the rare earth and reduce the leaching rate of impurities by regulating and controlling the acidity of leaching solutions at all levels, and meanwhile, the consumption of the leaching agent is greatly reduced, and the production cost is reduced.

Further, the pH value of the magnesium-containing salt solution in the step S1 is 1.0-7.0, preferably 2.0-5.0.

Further, in the magnesium-containing salt solution of step S1, the concentration of cations other than hydrogen ions is 0.01 to 0.20mol/L, preferably 0.05 to 0.15 mol/L.

Further, the volume mass ratio of the magnesium-containing salt solution to the rare earth-containing porcelain clay ore raw ore in the step S1 is 0.1-10L/kg, preferably 0.5-2L/kg.

Further, Mg in the magnesium salt solid in the steps S2 and S3²⁺The ratio of the amount of the substances to the mass of the rare earth-containing porcelain clay ore raw ore is 0.01-0.10 mol/kg, and preferably 0.02-0.06 mol/kg.

Further, the leaching time in the steps S1-S3 is 0.1-10 hours, preferably 0.5-5 hours.

Further, the river sand of the step S1 has a particle size range of +40 meshes, the potassium sand of the step S2 has a particle size range of-40 to +200 meshes, and the high-alumina sand of the step S3 has a particle size range of-200 meshes.

Further, the volume-mass ratio of the clean water to the high-alumina sand in the step S4 is 0.05-3L/kg, preferably 0.2-1L/kg.

Further, the washing time in step S4 is 0.1 to 10 hours, preferably 0.5 to 5 hours.

Further, after the rare earth-containing leachate and the rare earth-containing washing solution are combined into a rare earth-containing solution, the rare earth can be recovered by adopting a non-equilibrium extraction enrichment method, wherein the method comprises the following steps:

step S5, carrying out non-saponification and non-equilibrium centrifugal extraction on the rare earth-containing solution by using an organic extractant to obtain a rare earth-loaded organic phase and raffinate;

and step S6, carrying out centrifugal back extraction on the loaded organic phase by adopting inorganic acid to obtain the rare earth enrichment liquid.

And step S7, circularly returning the raffinate to the step S1 to stir and leach the rare earth-containing porcelain clay ore.

Adopting non-saponification and non-equilibrium centrifugal extractionThe process treats the rare earth-containing solution, and Al is not substantially extracted into the raffinate. Due to Al³⁺A certain distribution ratio exists between the water phase and the solid phase of the porcelain clay ore containing the rare earth (the principle is similar to that of ion exchange resin), the raffinate containing the Al is circularly returned to be stirred and leached, the leaching rate of the Al can be further reduced, and the quality of the final porcelain clay product is improved. At the same time, Al³⁺The rare earth leaching agent can also be used as a leaching agent, and the leaching rate of the rare earth can also be improved to a certain extent.

Further, the organic extracting agent is P507, P204 or P227, and the concentration of the P507, P204 or P227 is preferably 0.5-1.5 mol/L.

Further, in the non-saponification and non-equilibrium coupling centrifugal extraction step, the volume flow ratio of the organic extractant to the rare earth-containing solution is controlled to be 1: 2-1: 80, preferably 1: 10-1: 50; the contact time is 5-60 s, preferably 8-15 s;

in the centrifugal back extraction step, the volume flow ratio of the rare earth-loaded organic phase to the inorganic acid is controlled to be 20: 1-80: 1, preferably 20: 1-50: 1, and the contact time is controlled to be 60-600 s, preferably 100-200 s.

The method adopts magnesium salt solution to leach associated rare earth in the rare earth-containing porcelain clay raw ore, also sequentially adds magnesium salt solid into primary slurry and secondary slurry for agitation leaching, and adopts clear water to wash high alumina sand, the leaching rate of rare earth reaches over 90 percent, the leaching rate of aluminum is lower than 0.2 percent, then adopts non-saponification and non-equilibrium coupling centrifugal extraction and centrifugal back extraction on the rare earth-containing solution, and then circularly returns raffinate to agitate and leach the rare earth-containing porcelain clay raw ore, thereby further reducing the leaching rate of aluminum, and further improving the quality of the final high alumina porcelain clay product.

Compared with the prior art, the invention has the following advantages:

(1) the method has no special requirement on the rare earth-containing porcelain clay ore raw ore, is in seamless connection with the existing porcelain clay production process, is suitable for recovering associated rare earth in various different grades of rare earth-containing porcelain clay ore raw ore, and enlarges the supply source of the rare earth-containing porcelain clay ore raw ore and the universality of process industrialization.

(2) The invention specially aims at the rare earth-containing porcelain clay ore raw ore and adopts magnesium-containing salt solution for leaching, and leaching parameters are strictly controlled, so that the leaching rate of ionic phase rare earth is up to more than 90%, the leaching rate of aluminum is obviously reduced (less than 0.2%), ammonia nitrogen wastewater pollution can be eliminated, and high-valued utilization of the rare earth-containing porcelain clay ore raw ore is realized.

(3) According to the method, the leaching agent containing magnesium salt with different concentrations is adopted for stirring and leaching according to the different grades of the associated rare earth in the raw ore of the rare earth-containing porcelain clay ore with different grain grades, so that the accurate extraction of the associated rare earth in the rare earth-containing porcelain clay ore can be realized, and the production efficiency is improved.

(4) In the process for leaching the rare earth in the rare earth-containing porcelain clay raw ore, after the magnesium-containing salt solution is adopted to stir and leach the rare earth-containing porcelain clay raw ore, the magnesium salt solid is further added into the primary slurry and the secondary slurry in sequence to carry out multistage stirring and leaching, and meanwhile, the acidity of each stage of leaching solution is regulated and controlled, so that the leaching rate of the rare earth can be obviously improved, the leaching rate of impurities is reduced, the consumption of a leaching agent is greatly reduced, and the production cost is reduced.

(5) The obtained high-alumina sand is washed by clear water, most of the residual mineral leaching agent can be eluted, ammonia nitrogen wastewater pollution is avoided, the washing water meets the underground water quality standard, and the environmental protection pressure of porcelain clay production enterprises is greatly reduced.

(6) Non-saponification and non-equilibrium centrifugal extraction are adopted, reasonable extraction parameters are controlled, the extraction process is in a non-equilibrium and weakly acidic state, all rare earth can be extracted into an organic phase by keeping the extraction equilibrium acidity at the pH value of 1-2, impurities such as aluminum and the like are not extracted basically, high-efficiency separation of rare earth and non-rare earth impurities such as aluminum and the like is realized, the problem of loss of a large amount of rare earth in the existing precipitation enrichment technology and impurity removal process can be avoided, the process flow can be simplified greatly, the rare earth recovery rate is improved, the operation is simple, the cost is low, the discharge of ammonia nitrogen wastewater and oxalic acid wastewater can be avoided, and the method is friendly to the ecological environment.

(7) Non-saponification and non-equilibrium centrifugal extraction are adopted, the impurity aluminium is not extracted basically, the obtained raffinate contains aluminium, and the aluminium is circularly returned to mineral leaching due to Al³⁺A certain distribution ratio exists between the water phase and the porcelain clay ore solid phase containing the rare earth (the principle is similar to that of ion exchange resin), which is beneficial to further reducing the leaching rate of aluminum, and meanwhile, because the aluminum ions can be used as a leaching agent, the leaching rate of the rare earth can be improved to a certain extent, and the quality of the final high-alumina porcelain clay product is further improved.

The invention will be further described with reference to the figures and examples. The description is intended to be illustrative of the invention and is not to be construed as limiting the invention.

Drawings

FIG. 1 is a process flow chart of the present invention for leaching rare earth from raw ore of rare earth-containing porcelain clay ore

Detailed Description

The scheme and the technical effect of the invention are further illustrated by the following specific examples.

Example 1

The leaching object is the rare earth-containing porcelain clay ore raw ore, the mass is 1kg, and the rare earth grade is 0.05%. The specific process comprises the following steps: step S1, stirring and leaching the rare earth-containing porcelain clay ore raw ore by using a magnesium-containing salt solution with the pH value of 2.0 and the cation concentration of 0.01mol/L, wherein the volume-mass ratio of the magnesium-containing salt solution to the rare earth-containing porcelain clay ore raw ore is 10.0L/kg, the leaching time is 10 hours, and the river sand and primary slurry are obtained after sand washing treatment after leaching; step S2, mixing Mg²⁺Adding magnesium salt solid with the mass ratio of the amount of the substance to the raw ore of 0.01 into the primary slurry for agitation leaching for 10h, and performing cyclone classification treatment after leaching to obtain potash sand and secondary slurry; step S3, mixing Mg²⁺Adding magnesium salt solid with the mass ratio of the amount of the substance to the raw ore of 0.01 into the secondary slurry for stirring and leaching, wherein the leaching time is 10 hours, and performing liquid-solid separation treatment after leaching to obtain high-aluminum sand and leaching solution containing rare earth; and step S4, washing the high-alumina sand by using clean water, wherein the volume-mass ratio of the clean water to the high-alumina sand is 0.05L/kg, the washing time is 10h, and the rare earth-containing washing liquid and the high-alumina porcelain clay product are obtained after liquid-solid separation. The leaching rate of rare earth is 94.3 percent, and the leaching rate of Al is 0.11 percent.

Examples 2 to 14

The steps of the embodiments 2-14 are the same as those of the embodiment 1, the process conditions shown in the table 1 are adopted to leach the rare earth in the rare earth-containing porcelain clay ore raw ore, and the leaching effect is shown in the table 2.

Table 1:

table 2:

comparative example 1

The leaching object is the same as the example 1, and is the rare earth-containing porcelain clay ore raw ore, the mass is 1kg, and the rare earth grade is 0.05%. The specific process comprises the following steps: stirring and leaching the rare earth-containing porcelain clay ore raw ore by adopting 0.06mol/L ammonium sulfate leaching agent, wherein the pH value of the leaching agent is 2.0, the volume-mass ratio of the leaching agent to the rare earth-containing porcelain clay ore raw ore is 5L/kg, and the leaching time is 10 h. And after leaching, carrying out liquid-solid separation treatment to obtain the porcelain clay ore after leaching the rare earth and a leaching solution containing the rare earth. And finally, washing the rare earth leached porcelain clay ore by using clean water, wherein the volume mass ratio of the clean water to the rare earth leached porcelain clay ore is 3L/kg, the washing time is 10h, and obtaining rare earth-containing washing liquor and a porcelain clay product after liquid-solid separation. The leaching rate of rare earth is 93.1 percent, and the leaching rate of Al is as high as 0.29 percent.

Comparative example 2

The leaching object is the same as the example 1, and is the rare earth-containing porcelain clay ore raw ore, the mass is 1kg, and the rare earth grade is 0.05%. The specific process comprises the following steps: stirring and leaching the rare earth-containing porcelain clay ore raw ore by adopting 0.15mol/L ammonium sulfate leaching agent, wherein the pH value of the leaching agent is 2.0, the volume-mass ratio of the leaching agent to the rare earth-containing porcelain clay ore raw ore is 4L/kg, and the leaching time is 10 h. And after leaching, carrying out liquid-solid separation treatment to obtain the porcelain clay ore after leaching the rare earth and a leaching solution containing the rare earth. And finally, washing the rare earth leached porcelain clay ore by using clean water, wherein the volume mass ratio of the clean water to the rare earth leached porcelain clay ore is 3L/kg, the washing time is 10h, and obtaining rare earth-containing washing liquor and a porcelain clay product after liquid-solid separation. The leaching rate of rare earth is 94.3 percent, and the leaching rate of Al is as high as 0.33 percent.

Example 15

The leaching object is the same as the example 4, and is the rare earth-containing porcelain clay ore raw ore, the mass is 1kg, and the rare earth grade is 0.05%. The specific process comprises the following steps: in the multi-stage leaching of steps S1-S4, the rare earth leaching rate is 94.9%, and the Al leaching rate is 0.09% according to example 4. Then, after the leaching solution containing the rare earth and the washing solution containing the rare earth are combined into solution containing the rare earth, the rare earth is recovered by adopting a non-equilibrium extraction enrichment method, which comprises the following steps: step S5, adopting an organic extractant P507 with the concentration of 0.5mol/L to carry out non-saponification and non-equilibrium centrifugal extraction on the rare earth-containing solution, wherein the volume flow ratio (O/A) is 1:15, the contact time is 10S, and a rare earth-loaded organic phase and raffinate are obtained; step S6, carrying out centrifugal back extraction on the rare earth-loaded organic phase by adopting inorganic acid with the concentration of 5mol/L, wherein the volume flow ratio (O/A) is 40:1, and the contact time is 150S, so as to obtain rare earth enrichment liquid; and step S7, recycling the obtained raffinate to step S1, and performing multistage leaching according to the conditions of the example 4, wherein the leaching rate of the rare earth is 95.1 percent, and the leaching rate of the Al is 0.06 percent.

Examples 16 to 19

The leaching object is the same as the example 4, and is the rare earth-containing porcelain clay ore raw ore, the mass is 1kg, and the rare earth grade is 0.05%. The specific process comprises the following steps: the multistage leaching in steps S1-S4 was performed according to example 4, with the rare earth leaching rate of 94.9% and the Al leaching rate of 0.09%, as shown in Table 3. And then combining the rare earth-containing leachate and the rare earth-containing washing liquor into a rare earth-containing solution, recovering rare earth by adopting a non-equilibrium extraction enrichment method, adopting the process conditions shown in the table 4 in the steps S5-S6, circularly returning the raffinate obtained in the step S7 to the step S1, and carrying out multistage leaching according to the conditions of the example 4, wherein the leaching rate of rare earth and the leaching rate of Al are shown in the table 4.

TABLE 3

TABLE 4

According to the embodiment of the invention, compared with the prior art, the method has the advantages that firstly, the rare earth-containing porcelain clay ore is leached by the magnesium-containing salt solution, then, the magnesium salt solid is sequentially added into the primary slurry and the secondary slurry for multistage leaching, the leaching rate of the ionic phase rare earth is up to more than 90 percent by strictly controlling the leaching parameters, the leaching rate of aluminum is obviously reduced (less than 0.2 percent), the ammonia nitrogen wastewater pollution can be eliminated, the consumption of the leaching agent is greatly reduced, and the high-value utilization of the rare earth-containing porcelain clay ore is realized. Adopting non-saponification and non-equilibrium centrifugal extraction, controlling reasonable extraction parameters to make the extraction process in non-equilibrium and weakly acidic state, keeping the extraction equilibrium acidity at pH value of 1-2, extracting all rare earth into organic phase, and basically not extracting impurities such as aluminium, etc. so as to implement high-effective separation of rare earth and aluminium, etc. non-rare earth impurities, and making the obtained raffinate containing aluminium be circularly returned into mineral leaching, because Al is used as material³⁺A certain distribution ratio exists between the water phase and the solid phase of the porcelain clay ore containing the rare earth, which is beneficial to further reducing the leaching rate of aluminum (as low as 0.06 percent), and simultaneously, the leaching rate of the rare earth can be improved to a certain extent because aluminum ions can be used as a leaching agent.

The present invention is capable of other embodiments and its several details are capable of modifications in various obvious respects, all without departing from the invention and its spirit, and all such modifications and changes are deemed to be within the scope of the appended claims.

Claims

1. A method for leaching rare earth in rare earth-containing porcelain clay ore raw ore is characterized by comprising the following steps:

the magnesium salt solution and the magnesium salt solid contain one or more of magnesium sulfate, magnesium chloride and magnesium nitrate;

after the leaching solution containing the rare earth and the washing solution containing the rare earth are combined into the solution containing the rare earth, the rare earth is recovered by adopting a non-equilibrium extraction enrichment method, and the method comprises the following steps:

step S6, carrying out centrifugal back extraction on the rare earth-loaded organic phase by using inorganic acid to obtain a rare earth enrichment solution;

2. The method of claim 1, wherein the pH value of the magnesium-containing salt solution in step S1 is 1.0-7.0.

3. The method according to claim 1, wherein the concentration of cations other than hydrogen ions in the magnesium-containing salt solution in step S1 is 0.01 to 0.20 mol/L.

4. The method according to claim 1, wherein the volume mass ratio of the magnesium-containing salt solution to the rare earth-containing porcelain clay ore raw ore in step S1 is 0.1-10L/kg.

5. The method of claim 1, wherein the Mg in the magnesium salt solid of steps S2 and S3²⁺The ratio of the amount of the substances to the mass of the rare earth-containing porcelain clay ore raw ore is 0.01-0.10 mol/kg.

6. The method as claimed in claim 1, wherein the leaching time of the steps S1-S3 is 0.1-10 h.

7. The method as claimed in claim 1, wherein the river sand of step S1 has a grain size range of +40 mesh, the potassium sand of step S2 has a grain size range of-40 to +200 mesh, and the high alumina sand of step S3 has a grain size range of-200 mesh.

8. The method according to claim 1, wherein the volume-to-mass ratio of the clear water to the high-alumina sand in step S4 is 0.05-3L/kg.

9. The method as claimed in claim 1, wherein the washing time of step S4 is 0.1-10 h.

10. The method of claim 1, wherein the organic extractant is P507, P204 or P227, and the concentration is 0.5-1.5 mol/L.

11. The method of claim 1,

in the step of non-saponification and non-equilibrium coupling centrifugal extraction, controlling the volume flow ratio of the organic extractant to the rare earth-containing solution to be 1: 2-1: 80; the contact time is 5-60 s;

in the centrifugal back extraction step, the volume flow ratio of the rare earth-loaded organic phase to the inorganic acid is controlled to be 20: 1-80: 1, and the contact time is controlled to be 60-600 s.