WO2022188248A1 - Method for recovering rare earth from eudialyte - Google Patents

Abstract

The present invention relates to the technical field of eudialyte beneficiation. Disclosed is a method for recovering rare earth from eudialyte, comprising the following steps: S1, crushing and screening raw ore to obtain ore to be separated and first tailings; S2, performing color sorting on the ore to be separated to obtain a color sorted concentrate and second tailings; S3, grinding the color sorted concentrate to obtain ore pulp; S4, performing magnetic separation on the ore pulp to obtain a rare earth-containing eudialyte concentrate, and third tailings; and S5, performing leaching on the rare earth-containing eudialyte concentrate to obtain a rare earth leaching solution and a leaching residue. In the present invention, the color sorting and magnetic separation combined process is applied to eudialyte beneficiation, so that the sorting of low-grade rare earth-containing eudialyte ore is realized, providing a technical premise for conversion of eudialyte into ore having an economic value. Moreover, in the present invention, the leaching rate can reach 97.3%, the total loss rate of rare earth of three discarded tailings in the whole process flow is lower than 40%, and the effects of high beneficiation efficiency, small amount of magnetic separation ore, low energy consumption and environmental friendliness are achieved.

Description

Method for recovering rare earth from heterosexual stone technical field

The invention relates to the technical field of beneficiation of heteromorphic stones, in particular to a method for recovering rare earths from heteromorphic rocks.

Background technique

Anisotropic stone (NaCa) ₄ Zr[Si ₃ O ₉ ] ₂ (OH·Cl) ₂ , the common single crystal is plate or rhombohedral, the hardness is 5-5.5, the specific gravity is 2.9-3.0, and it is often special cherry red. Some are pink, reddish-brown and yellow. Heteromorphic stones often coexist with nepheline, nepheline, amphibolite, cerium-niobium perovskite, brown silicate perovskite, and sphene. Heteromorphic stone is a kind of rock-forming mineral, which is produced in Fengcheng, Liaoning and Saima, Liaoning, China. It is produced in large quantities in rocks and has a huge amount of minerals. It is a promising mineral resource.

The economic and industrial value of a single heterosexual stone is not high, and it is generally used as ornamental stone or stone raw material. In recent years, more and more rare earth elements have been found in the minerals of the heterosexual stone, and the content can reach 10% or more. In addition, the heterosexual stone has a huge amount of ore, so the economic value of the heterosexual stone has been paid more and more attention.

Theresa Stark's group tested magnetic separation and direct selective flotation in Norway

The applicability of the anisotropic stone beneficiation, the results show that: magnetic separation is suitable for the anisotropic stone beneficiation process, the higher the magnetic field strength, the higher the recovery rate, but the concentrate grade of about 0.76% is not enough for further metallurgical process steps; Oxalic acid and sodium hexametaphosphate as inhibitors, and mono/diphosphate as collectors, the method of direct selective flotation at pH value below 4 is suitable for raw ores and magnetic separation of pre-enrichment concentrates .

However, there is no mature anisotropy beneficiation process in the current state of the art. At the same time, the cost of beneficiation of anisotropic stones by conventional beneficiation process is also much higher than the value of the minerals themselves. Therefore, there is an urgent need for a beneficiation process that is simple to operate, low-cost and environmentally friendly while improving the beneficiation efficiency, so as to recover rare earth elements in anisotropic stones.

Color sorting technology is a technology that uses the color difference on the surface of objects to classify and enrich objects of different colors. The color of heterosexual stones is bright, often showing red, pink, brown and other colors, which are quite different from common gangue minerals, which provides a prerequisite for the color selection of heterosexual stones. At the same time, because the color separation technology only distinguishes minerals of different colors, the equipment power is low, the processing speed is high, and it does not involve the process of changing the surface properties of minerals. Therefore, compared with processes such as gravity separation, magnetic separation and flotation, it can reduce the The processing cost, coupled with the mature equipment manufacturing process, provides the possibility of its application in the anisotropic stone beneficiation process.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for recovering rare earths from heteromorphic stones, so as to at least achieve the effects of simple operation, low cost and environmental friendliness while improving the beneficiation efficiency.

The object of the present invention is to be achieved through the following technical solutions: the method for reclaiming rare earth from anisotropic stone, comprising the following steps:

S1. Crushing and screening the raw ore to obtain the ore to be separated and the first tailings;

S2. Color separation is carried out on the ore to be separated to obtain color separation concentrate and second tailings;

S3. Grinding the color separation concentrate to obtain pulp;

S4. Magnetic separation is performed on the ore slurry to obtain rare earth-containing anisotropic stone concentrate and third tailings;

S5. Leach the rare earth-containing anisotropic stone concentrate to obtain rare earth leaching solution and leaching slag.

It should be understood that the method of the present invention is not only applicable to anisotropic ore with low rare earth grade (ie, rare earth grade of 0.4% to 0.6%); if the rare earth grade is higher, the method described in the present invention can obtain better Effect. Moreover, the final product of the method of the present invention is a rare earth leaching solution, and the recovery of other elements is not considered for the time being.

In certain embodiments, the first, second, and third tailings are discarded as final tailings, and the leach slag may be discarded.

In certain embodiments, in S1, the crushing and screening comprises the steps of:

1) coarsely crushing raw ore to obtain coarsely crushed ore;

2) screening the coarsely crushed ore for the first time to obtain fine ore with particle size≤10mm and coarse ore with particle size>10mm;

3) Screening the fine ore again to obtain the ore to be separated with a particle size of 1-10 mm and the first tailings with a particle size of less than 1 mm.

In certain embodiments, S1 further includes the steps of finely crushing the coarse ore to obtain finely divided ore, and returning the finely divided ore to the first screening operation.

In certain embodiments, in S1, the particle size of the raw ore is ≤60 mm.

In certain embodiments, in S2, the color sorting comprises the following steps:

1) first color separation is carried out to the ore to be separated, to obtain color separation concentrate and color separation tailings;

2) Perform color separation on the color separation tailings again to obtain the color separation ore and the second tailings, and return the color separation ore to the first color separation operation.

In certain embodiments, in S3, in the slurry, the weight percentage of minerals with a particle size of less than or equal to 74 μm is 60% to 70%.

In certain embodiments, in S4, the number of times of the magnetic separation is 1, and the magnetic field strength of each magnetic separation is 1-1.5T.

In certain embodiments, in S5, a leaching agent is used for the leaching, and the leaching agent includes one or both of sulfuric acid, hydrochloric acid and nitric acid.

In certain embodiments, in S5, the leaching conditions are: diluting the leaching agent to 10-15 vol%, the reaction temperature being 50-80°C, and the reaction time being 110-130 min.

In certain embodiments, in S5, the mass volume ratio of the rare earth-containing anisotropic stone concentrate to the diluted leaching agent is 1:8-10.

It is worth noting that the present invention applies the combined process of color separation and magnetic separation to the beneficiation of anisotropic stone, realizes the separation of low-grade rare earth-containing anisotropic stone ores, and provides anisotropic stone for the transformation of rock drilling ore into a mineral with economic value. technical prerequisites. Specifically, the present invention firstly uses the color separation to pre-enrichment the anisotropic stone based on the color difference between the anisotropic stone and other minerals, and then uses the magnetic separation to obtain the rare earth-containing anisotropic stone concentrate, and finally the The rare earth-containing anisotropic stone concentrate is leached to obtain a rare earth leaching solution, and the leaching rate can reach 97.3%. At the same time, the total loss rate of rare earth in the three tailings in the whole process is lower than 40%, achieving high beneficiation efficiency and magnetic separation of ore volume. Small, low energy consumption and environmentally friendly effects,

Wherein, the technical problem that the present invention mainly solves is as follows:

1. Low-cost and high-efficiency pre-concentration of heteromorphic stone: Because the heteromorphic stone is medium in hardness and brittle in texture, it is a fragile mineral, and the crushing cost of crushing it to a particle size of ≤10mm is low. At the same time, the color separation of the minerals to be separated obtained by crushing and further screening can select most of the anisotropic stone minerals, which greatly reduces the ore input of the magnetic separation.

2. Separation of rare earth by strong magnetic separation: using the characteristics of weak magnetic properties of rare earth elements, the color separation concentrate is ground and then subjected to strong magnetic separation, and the anisotropic stone concentrate containing rare earth can be selected to realize rare earth At the same time, since the slurry entering the magnetic separation is dominated by heteromorphic stone minerals, and rare earth elements are present in the heteromorphic stone in the same phase, the requirements for the degree of monomer dissociation of the minerals are not high, and the grinding Fineness control The weight percentage of minerals with a particle size of ≤74 μm can be 60% to 70%, and an excessively high grinding fineness is not required.

3. Throwing tailings many times to improve the mineral processing capacity: Since the rare earth content in the heteromorphic stone is far lower than the rare earth content in the rare earth minerals, in order to remove the gangue minerals in the minerals as much as possible, the present invention has 3 gangue throw points, namely:

1) Throwing of the first tailings: the crystals of the anisotropic stones are relatively large, generally in the range visible to the naked eye. The rare earth grade is lower than the original ore grade and can be directly discarded as the final tailings;

2) Disposal of the second tailings: The second tailings obtained by color separation basically do not contain anisotropic minerals, while rare earth elements are mainly present in the anisotropic stones, so the second tailings after color separation can Directly discarded as final tailings;

3) Throwing of the third tailings: the color separation concentrate entering the grinding is basically dominated by anisotropic stones. After simple grinding, the anisotropic stones have been dissociated from the gangue minerals, and then the strong magnetic separation is used. Rare earth minerals can be selected, so the third tailings after strong magnetic separation basically do not have rare earth-containing heterolithic minerals, which can be directly discarded as final tailings.

4. Simple and efficient rare earth leaching process: the rare earth leaching process adopted in the present invention is a single acid leaching process, and the process is simple and effective. After the magnetic separation, the gangue minerals are further removed, so that the minerals entering the leaching operation are basically only rare earth minerals containing anisotropic stones, and a single acid leaching process can achieve a good leaching effect without the interference of excess gangue minerals. .

It should be understood that in the prior art method for recovering rare earths from heteromorphic stones, complex flotation reagents are required to selectively flotate the pre-enriched concentrate obtained by magnetic separation, so that rare earths with a grade of approximately 2% concentrate, which undoubtedly brings a series of problems such as the inability to reuse the flotation backwater, waste of resources and environmental pollution. In the present invention, only a single acid leaching process is used to achieve a good recovery effect, thereby avoiding the above-mentioned problems. This is because: the present invention first removes a large number of fine-grained low-grade rare earths through crushing and screening. A tailings; gangue minerals with different colors and rare earth-containing heterolithic minerals are separated by color separation, so as to avoid the magnetic separation of ore pulp (mainly composed of rare earth-containing heterolithic minerals) due to excessive gangue minerals Then the gangue minerals are separated from the rare earth-containing heterolithic minerals by grinding and magnetic separation, so as to further remove the gangue minerals and avoid a large number of impurity ions (such as Ca ²⁺ , Mg ²⁺ , etc. in the gangue minerals). The unfavorable effect of the leaching of ) on the subsequent leaching is obtained, and the rare earth-containing anisotropic stone concentrate entering the leaching operation is obtained; on this basis, through the action of acid leaching, the rare earth elements are leached in the sulfuric acid solution, and the rare earth leaching solution can be obtained. . In this regard, the prior art obviously does not give any technical inspiration, so the prior art has no reference effect for the present invention.

The beneficial effects of the present invention are:

1. A method for recovering rare earths from heterolithic stones of the present invention realizes the pre-enrichment of heteromorphic rock minerals through the color separation, and has tailings throwing in the screening, color separation and magnetic separation operations. In addition, the amount of ore entering the leaching process is greatly reduced and the throughput of the entire process is maximized.

2. A method for recovering rare earths from anisotropic stones of the present invention efficiently recovers rare earth elements in anisotropic stones through the combination of the color separation and magnetic separation, providing a low-cost, high-efficiency beneficiation method, Finally, rare earth concentrates that can be directly smelted are obtained.

3. A method for recovering rare earths from anomalous stone of the present invention is aimed at low-grade rare earth-containing anomaly stone ore, whose rare earth grade is basically close to the industrial grade of rare earth, and it is difficult to create good industrial value by conventional processes. It greatly reduces the cost of beneficiation and leaching, and provides technical support for the development of heteromorphic stone resources.

4. A method for recovering rare earth from heteromorphic stone of the present invention fills the gap in the field of heteromorphic stone beneficiation technology. With the existing beneficiation means, it is difficult to formulate heteromorphic stone with industrial application value considering mineral value and beneficiation cost. The present invention combines color separation and traditional beneficiation technology to develop a brand-new beneficiation method.

Description of drawings

Fig. 1 is the flow chart of a kind of method of reclaiming rare earth from heteromorphic stone of the present invention;

FIG. 2 is a flow chart of the color sorting exploratory test in Test Example 1 of the present invention.

Detailed ways

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

It should be noted that, in the following examples, control examples and test examples, the raw ore was taken from a rare earth mine in a foreign country, and the minerals were simply crushed in the mining area. The grade of rare earth is 0.53%; among them, the anisotropy stone can be seen in the ore, and the grade of rare earth reaches 0.5% of the industrial grade of rare earth selection; the gangue minerals of the ore mainly include sodalite, plagioclase, neolite, etc., and a small amount of monazite rare earth in the minerals There is an associated relationship between minerals and heterosexual stones, and rare earths in minerals and heterosexual stones are occurrence or associated relationship.

Example 1

A method for recovering rare earth from heteromorphic stone, as shown in Figure 1, specifically includes the following steps:

S1. Coarsely crush the raw ore to obtain coarsely crushed ore;

S2. Screen the coarsely crushed ore for the first time to obtain fine ore with particle size ≤ 10mm and coarse ore with particle size > 10mm;

S3. Finely crush the coarse ore to obtain finely crushed ore, and return the finely crushed ore to the first screening operation until the particle size of all ore is ≤10mm;

S4. Screen the fine ore again to obtain the ore to be separated with a particle size of 1-10 mm and the first tailings with a particle size of less than 1 mm, and discard the first tailings;

S5. Perform the first color separation of the ore to be separated to obtain the color separation concentrate and the color separation tailings;

S6. Perform color separation on the color separation tailings again to obtain the color separation ore and the second tailings, return the color separation ore to the first color separation operation, and discard the second tailings;

S7. The color separation concentrate is ground to a weight percentage of 65% of minerals with a particle size of ≤74 μm to obtain pulp;

S8. Perform 1 magnetic separation on the pulp, and the magnetic field intensity of each magnetic separation is 1.2T to obtain rare earth-containing anisotropic stone concentrate (ie, the final concentrate), and the third tailings, and discard the third tailings;

S9. Put 20 g of rare earth-containing anisotropic stone concentrate into 200 mL of a sulfuric acid solution with a concentration of 10 vol%, and stir and leaching for 120 minutes at a constant temperature of 50 °C to obtain rare earth leaching solution and leaching slag, and discard the leaching slag.

Example 2

A method for recovering rare earth from heteromorphic stone, as shown in Figure 1, specifically includes the following steps:

S1. Coarsely crush the raw ore to obtain coarsely crushed ore;

S2. Screen the coarsely crushed ore for the first time to obtain fine ore with particle size ≤ 10mm and coarse ore with particle size > 10mm;

S3. Finely crush the coarse ore to obtain finely crushed ore, and return the finely crushed ore to the first screening operation until the particle size of all ore is ≤10mm;

S4. Screen the fine ore again to obtain the ore to be separated with a particle size of 1-10 mm and the first tailings with a particle size of less than 1 mm, and discard the first tailings;

S5. Perform the first color separation of the ore to be separated to obtain the color separation concentrate and the color separation tailings;

S6. Perform color separation on the color separation tailings again to obtain the color separation ore and the second tailings, return the color separation ore to the first color separation operation, and discard the second tailings;

S7. The color separation concentrate is ground until the weight percentage of minerals with a particle size of ≤74 μm is 60% to obtain pulp;

S8. 1 magnetic separation is carried out to the ore slurry, and the magnetic field intensity of each magnetic separation is 1T to obtain rare earth-containing anisotropic stone concentrate (i.e. final concentrate), and the third tailings, and the third tailings are thrown away;

S9. Put 20 g of rare earth-containing anisotropic stone concentrate into 160 mL of a sulfuric acid solution with a concentration of 12 vol%, and stir and leaching for 110 minutes at a constant temperature of 80 °C to obtain rare earth leaching solution and leaching slag, and discard the leaching slag.

Example 3

A method for recovering rare earth from heteromorphic stone, as shown in Figure 1, specifically includes the following steps:

S1. Coarsely crush the raw ore to obtain coarsely crushed ore;

S2. Screen the coarsely crushed ore for the first time to obtain fine ore with particle size ≤ 10mm and coarse ore with particle size > 10mm;

S3. Finely crush the coarse ore to obtain finely crushed ore, and return the finely crushed ore to the first screening operation until the particle size of all ore is ≤10mm;

S4. Screen the fine ore again to obtain the ore to be separated with a particle size of 1-10 mm and the first tailings with a particle size of less than 1 mm, and discard the first tailings;

S5. Perform the first color separation of the ore to be separated to obtain the color separation concentrate and the color separation tailings;

S6. Perform color separation on the color separation tailings again to obtain the color separation ore and the second tailings, return the color separation ore to the first color separation operation, and discard the second tailings;

S7. The color separation concentrate is ground until the weight percentage of minerals with a particle size of ≤74 μm is 70%, and the pulp is obtained;

S8. Perform 1 magnetic separation on the pulp, and the magnetic field intensity of each magnetic separation is 1.5T to obtain rare earth-containing anisotropic stone concentrate (ie, the final concentrate), and the third tailings, and discard the third tailings;

S9. Put 20 g of rare earth-containing anisotropic stone concentrate into 180 mL of a sulfuric acid solution with a concentration of 15 vol%, and stir and leaching for 130 minutes at a constant temperature of 70° C. to obtain rare earth leaching solution and leaching slag, and discard the leaching slag.

Comparative Example 1

The indexes of Example 1 of the present invention are used to compare with Comparative Example 1, wherein the difference between Comparative Example 1 and Example 1 is: ① does not contain S5 to S8; ② in S9, the ore to be separated is directly leached; other conditions such as remaining The selection of the medicament, the dosage of the medicament and the technological process adopted are the same as those in the embodiment 1 of the present invention.

Comparative Example 2

The indexes of Example 1 of the present invention are used to compare with Comparative Example 2, wherein the difference between Comparative Example 2 and Example 1 is: ① does not contain S7-S8; ② in S9, the color separation concentrate is directly leached; other conditions For example, the selection of the remaining medicament, the dosage of the medicament and the technological process adopted are the same as those in Example 1 of the present invention.

Comparative Example 3

The indexes of Example 1 of the present invention are used to compare with Comparative Example 3, wherein the difference between Comparative Example 3 and Example 1 is: ① does not contain S5 to S6; ② in S7, the ore to be separated is directly ground; other conditions such as The selection of the remaining medicament, the dosage of the medicament and the technological process adopted are the same as those in Example 1 of the present invention.

Comparative Example 4

The indexes of Example 1 of the present invention are used to compare with Comparative Example 4, wherein the difference between Comparative Example 4 and Example 1 is: 1. S5-S6 are not included; 2. In S7, the ore to be separated is directly ground; 3. In S8, The pulp is subjected to three closed-circuit magnetic separations of one coarse, one fine and one sweep; other conditions such as the selection of the remaining medicament, the dosage of the medicament and the adopted technological process are the same as those in Example 1 of the present invention.

Comparative Example 5

The indexes of Example 1 of the present invention are used to compare with Comparative Example 5, wherein the difference between Comparative Example 5 and Example 1 is that it does not contain S4, and the ore is not subjected to secondary screening, so that all ores with particle size ≤ 10mm enter Color sorting; other conditions such as the selection of the remaining medicament, the dosage of the medicament and the technological process adopted are the same as those in Example 1 of the present invention. Specifically include the following steps:

S1. Coarsely crush the raw ore to obtain coarsely crushed ore;

S2. Screen the coarsely crushed ore for the first time to obtain fine ore with particle size ≤ 10mm and coarse ore with particle size > 10mm;

S3. Finely crush the coarse ore to obtain finely crushed ore, and return the finely crushed ore to the first screening operation until the particle size of all ore is less than or equal to 10mm;

S4. Perform the first color separation on all ores with particle size ≤10mm to obtain color separation concentrate and color separation tailings;

S5. Perform color separation on the color separation tailings again to obtain the color separation ore and the first tailings, return the color separation ore to the first color separation operation, and discard the first tailings;

S6. Grind the color separation concentrate to a weight percentage of 65% of minerals with a particle size of ≤74 μm to obtain pulp;

S7. Perform magnetic separation on the pulp, the magnetic field strength is 1.2T, to obtain rare earth-containing anisotropic stone concentrate (ie final concentrate), and second tailings, and discard the second tailings;

S8. Put 20 g of rare earth-containing anisotropic stone concentrate into 200 mL of a sulfuric acid solution with a concentration of 10 vol%, and stir and leaching for 120 minutes at a constant temperature of 50°C to obtain rare earth leaching solution and leaching slag, and discard the leaching slag.

Test Example 1

The color selection exploration test of heterosexual stone, as shown in Figure 2, includes the following steps:

S1. Use a jaw crusher to crush the raw ore to a particle size of ≤10 mm to obtain crushed ore;

S2. sieve the crushed ore to obtain fine-grained ore with a particle size of <1 mm, a first coarse-grained ore with a particle size of 3 to 10 mm, and a second coarse-grained ore with a particle size of 1 to 3 mm;

S3. Color separation is performed on the first coarse-grained ore to obtain the first concentrate and the first tailings; the second coarse-grained ore is subjected to color separation to obtain the second concentrate and the second tailings;

S4. Test the first concentrate, the second concentrate, the first tailings, the second tailings and the fine-grained ore respectively, and obtain the grades of rare earth elements in each product. The results are shown in the following table:

product name	Yield(%)	REO grade (%)	REO recovery rate (%)
first concentrate	14.69	0.92	25.99
Second concentrate	13.98	1.41	37.91
first tailings	34.92	0.22	14.77
Second tailings	22.1	0.32	13.60
fine-grained ore	14.31	0.29	7.98
raw ore	100	0.52	100

It can be seen from the above table that the rare earth enrichment phenomenon is the most obvious in the second coarse-grained ore; although the enrichment phenomenon in the first coarse-grained ore is slightly lower than that of the second coarse-grained ore, there is also obvious enrichment; In the fine-grained ore, the grade of rare earth is lower than that of the original ore, and the tail can be thrown directly. It can be seen from the test results that pink minerals can be effectively sorted through the color separation process; from the test results, it can be seen that the rare earth in the color separation concentrate has been enriched, that is, the color separation process can be used to separate the heterosexual stones. Effective pre-enrichment, the recovery rate of rare earth after the combination of the first concentrate and the second concentrate is 63.90%, and the grade of the concentrate is also greatly improved. The color concentrate can be further enriched to improve the grade of the concentrate. .

Test Example 2

1. In order to verify the effect of the method of the present invention in the beneficiation stage, the final concentrates (that is, the concentrates entering the leaching operation) obtained in Examples 1-3 and Comparative Examples 1-5 and the yield, REO grade and REO recovery were determined. The results are shown in the following table:

2. In order to verify the effect of the method of the present invention in the leaching stage, the experiments of Examples 1-? The rare earth concentration in the rare earth leaching solution obtained in Comparative Examples 1 to 4, the REO grade in the leaching slag and the REO leaching rate were measured. The results are shown in the following table:

group	Rare Earth Concentration in Rare Earth Leachate (g/L)	REO grade in leaching residue (%)	REO leaching rate (%)
Example 1	2.23	0.18	97.30
Comparative Example 1	0.55	0.15	91.33
Comparative Example 2	1.02	0.16	94.08
Comparative Example 3	1.01	0.2	92.87
Comparative Example 4	1.04	0.21	93.24
Comparative Example 5	1.52	0.19	95.36
Example 2	2.39	0.17	97.57
Example 3	2.24	0.17	97.40

Combining the test results of part 1 and part 2, it can be seen that:

1) It can be seen from Examples 1 to 3 that after the beneficiation operation, the rare earth grade in the final concentrate increased to 4.36 to 4.80 times that of the original ore, and the recovery rate reached 54.68% to 66.57%; % of the tailings, 48.42%-48.85% of the tailings are thrown out in the color separation stage. Timely throwing the tails can greatly improve the processing capacity of the ore. The amount of ore into grinding only accounts for about 35% of the original ore. It greatly reduces the energy consumption in production; 19.46% of the tailings are thrown away in the magnetic separation stage, and the ore entering the leaching operation only accounts for about 15% of the original ore, which reduces the difficulty of leaching and the dosage of chemicals; the final leaching of rare earths The recovery rate is as high as 97.30% to 97.57%, the rare earth concentration in the leaching solution reaches 2.23 to 2.39 g/t, and at least 60% of the rare earth elements in the original ore are recovered.

2) Compared with Comparative Example 1, the grade of rare earth in the final concentrate in Comparative Example 2 increased by 0.49% compared to the original ore, and the REO leaching rate increased by 2.75%; in Comparative Example 3, the grade of the final concentrate increased by 0.42% %, the REO leaching rate increased by 1.54%; the final concentrate grade in Example 1 increased by 1.67%, and the REO leaching rate increased by 5.97%. It can be seen that, compared with Comparative Example 1, the improvement effect of the beneficiation process of Example 1 on rare earth recovery is obviously better than that of Comparative Examples 2 to 3, and even higher than the sum of the improvement effects of Comparative Examples 2 to 3, which shows that this The combined effect of color separation and magnetic separation in the invention is significantly improved compared to the effect of using the two alone, that is, there is a synergistic effect of color separation and magnetic separation in the beneficiation process of the invention.

3) Compared with Comparative Example 2, the recovery rate of the final concentrate in Comparative Example 3 is reduced by 20.78%, and the recovery rate of the final concentrate in Comparative Example 4 is reduced by 26.66%, which shows that the color separation can more effectively recover rare earth-containing ore The main reason is that although rare earth elements have certain magnetic properties, because there are many gangue minerals with low ore grade, after grinding, the interference of gangue minerals is large; , reducing the amount of gangue in the grinding ore, improving the environment of the pulp, making the magnetic separation effect better than the effect of direct magnetic separation. From this, it can be seen that the step of performing color separation before magnetic separation in the present invention can improve the recovery effect.

4) Compared with Comparative Example 4, the grade of rare earth in the final concentrate in Example 1 increased by 1.17% compared to the original ore, and the leaching rate of REO increased by 4.06%, which shows that although the effects of color separation and magnetic separation are both The gangue minerals and the rare earth-containing heterolithic minerals are separated, but the effect of separating the gangue minerals with different colors from the rare earth-containing heterolithic minerals achieved by color separation cannot be replaced by multiple magnetic separations.

5) Compared with Comparative Example 5, the grade of rare earth in the final concentrate in Example 1 increased by 0.65% compared to the original ore, and the REO leaching rate increased by 1.94%. From this, it can be seen that in the present invention, the step of re-screening the fine ore with particle size ≤ 10 mm can improve the recovery effect.

To sum up, the method of the present invention for recovering rare earth from anomalous rare earth stone achieves the effects of high beneficiation efficiency, small amount of leached ore, low energy consumption, low pharmaceutical cost and environmental friendliness.

The foregoing are only preferred embodiments of the present invention, and it should be understood that the present invention is not limited to the forms disclosed herein, and should not be construed as an exclusion of other embodiments, but may be used in various other combinations, modifications, and environments, and Modifications can be made within the scope of the concepts described herein, from the above teachings or from skill or knowledge in the relevant field. However, modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all fall within the protection scope of the appended claims of the present invention.

Claims (10)

1. The method for recovering rare earth from heterosexual stone is characterized in that, comprises the following steps:

   S1. Crushing and screening the raw ore to obtain the ore to be separated and the first tailings;

   S2. Color separation is carried out on the ore to be separated to obtain color separation concentrate and second tailings;

   S3. Grinding the color separation concentrate to obtain pulp;

   S4. Magnetic separation is performed on the ore slurry to obtain rare earth-containing anisotropic stone concentrate and third tailings;

   S5. Leach the rare earth-containing anisotropic stone concentrate to obtain rare earth leaching solution and leaching slag.
2. The method for recovering rare earths from anisotropic stones according to claim 1, wherein in S1, the crushing and screening comprise the following steps:

   1) coarsely crushing the raw ore to obtain coarsely crushed ore;

   2) screening the coarsely crushed ore for the first time to obtain fine ore with particle size≤10mm and coarse ore with particle size>10mm;

   3) Screening the fine ore again to obtain the ore to be separated with a particle size of 1-10 mm and the first tailings with a particle size of less than 1 mm.
3. The method for recovering rare earths from anisotropic stones according to claim 2, wherein in S1, the method further comprises finely crushing the coarse ore to obtain finely divided ore, and returning the finely divided ore to the first screening job steps.
4. The method for recovering rare earths from anisotropic stones according to any one of claims 1 to 3, characterized in that, in S1, the particle size of the raw ore is ≤60 mm.
5. The method for recovering rare earths from anisotropic stones according to claim 1, wherein in S2, the color sorting comprises the following steps:

   1) first color separation is carried out to the ore to be separated, to obtain color separation concentrate and color separation tailings;

   2) Perform color separation on the color separation tailings again to obtain the color separation ore and the second tailings, and return the color separation ore to the first color separation operation.
6. The method for recovering rare earths from anisotropic stones according to claim 1, wherein in S3, the weight percentage of minerals with particle size ≤74 μm in the slurry is 60% to 70%.
7. The method for recovering rare earths from anisotropic stones according to claim 1, wherein in S4, the number of times of the magnetic separation is 1, and the magnetic field intensity of the magnetic separation is 1-1.5T.
8. The method for recovering rare earths from heteromorphic stones according to claim 1, wherein in S5, the leaching adopts a leaching agent, and the leaching agent comprises one or both of sulfuric acid, hydrochloric acid and nitric acid.
9. The method for recovering rare earth from heteromorphic stones according to claim 8, wherein in S5, the leaching conditions are: diluting the leaching agent to 10vol%～15vol%, and the reaction temperature is 50～80℃ , the reaction time is 110 ~ 130min.
10. The method for recovering rare earth from anisotropic stone according to claim 9, wherein in S5, the mass volume ratio of the rare earth-containing anisotropic stone concentrate to the diluted leaching agent is 1:8～10.

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