Short-process method for recovering rare earth from ionic rare earth ore leaching solution

Abstract

The invention relates to the field of rare earth smelting, in particular to a short-process method for recovering rare earth from ionic rare earth ore leachate. According to the method, a rare earth leaching solution is obtained through an ore leaching process, then suspended solids in the rare earth leaching solution are removed through sand filtration treatment, and a rare earth sand filtrate is obtained; and finally, carrying out reverse osmosis on the rare earth sand filtrate to obtain a rare earth concentrated solution and purified water, and directly separating rare earth elements after the rare earth concentrated solution is fed into a smelting plant. Compared with a traditional process, the method has the advantages that the impurity removal and precipitation process of leaching mother liquor in a mine, the precipitation process of rare earth and the acid dissolution process in a smelting plant are reduced, the rare earth recovery process is effectively shortened, effective recovery of rare earth ions is achieved through two-stage reverse osmosis, the rare earth recovery process is greatly reduced, the rare earth recovery rate is increased, and the method is suitable for industrial production. And the cost of rare earth precipitation is saved.

Description

Technical Field

[0001] The invention relates to the field of rare earth smelting, and in particular to a short-process method for recovering rare earth from ionic rare earth ore leaching solution. Background Art

[0002] Ionic rare earth ores are known for their comprehensive rare earth element distribution and significant resource value, and are one of the world's important resources. Their mining and recovery technologies have evolved from pool leaching, heap leaching to in-situ leaching technology. At present, in-situ leaching technology is mainly used. First, rare earth elements are leached in situ to obtain leaching mother liquor. Subsequently, after standing, impurity removal, precipitation and filtration, the rare earth-containing precipitate is sent to the rare earth smelter. In the smelter, these precipitates are dissolved and further separated from the rare earth elements. This process has a long process flow. In addition, after mining, the mines will discharge tail water containing rare earth elements for a long time due to the presence of residues such as leaching agents. Since the rare earth content in these tail waters is low and difficult to recover, rare earth elements are eventually discharged directly into natural water bodies, causing metal ion pollution and loss of rare earth resources. Therefore, developing a process for efficiently recovering rare earths from leachate and a technology for recovering rare earths from tail water has become a major challenge facing the rare earth industry.

[0003] According to statistics, during the impurity removal and precipitation process, mines consume 5.5 to 6.5 tons of precipitants for every ton of rare earth oxide produced. In rare earth smelters, the dissolution process of each ton of rare earths consumes another 3 to 4 tons of hydrochloric acid or sulfuric acid. In addition, there is also energy consumption such as heating and corresponding carbon dioxide emissions. Therefore, it is particularly urgent to develop a low-cost, high-efficiency, short-process rare earth recovery method. Summary of the invention

[0004] In view of the above technical problems, the present application has developed a short-process method for recovering rare earths from ionic rare earth ore leachate, which omits the traditional steps of precipitation and impurity removal, rare earth precipitation, and dissolution in a smelter. Through this method, not only can clean purified water be directly obtained, but also a short process, low cost and high efficiency of rare earth recovery are achieved.

[0005] The present application embodiment provides a short process method for recovering rare earth from ionic rare earth ore leachate, comprising:

[0006] S1. Obtaining rare earth leaching solution through leaching process, wherein the rare earth leaching solution is ionic rare earth ore leaching mother liquor or low-concentration rare earth tail water;

[0007] S2, sand filtration treatment, removing suspended matter in the rare earth leaching solution to obtain rare earth sand filtrate;

[0008] S3. The rare earth sand filtrate is subjected to reverse osmosis, and the obtained rare earth concentrated liquid is sent to a smelter for rare earth element separation, and the obtained purified water is discharged or reused.

[0009] Preferably, in step S1, the rare earth ion concentration in the ionic rare earth ore leaching mother liquor is 0.11 g / L to 0.25 g / L, and the pH is 2 to 4.

[0010] Preferably, in step S1, the rare earth ion concentration in the low-concentration rare earth tail water is 0.001 g / L to 0.01 g / L.

[0011] Preferably, in step S2, rare earth sand filtrate is obtained after removing ≥ 75% of suspended matter in the rare earth leachate by sand filtration.

[0012] Preferably, in step S2, the sand filtration is followed by PP cotton filtration.

[0013] Preferably, in step S2, the sand filter adopts 1m 3 A fiberglass container is used to put 0.5mm to 3mm quartz sand into it.

[0014] Preferably, in step S2, the PP cotton filter is 0.5m 3 Glass fiber reinforced plastic container with built-in PP cotton.

[0015] Preferably, in step S3, the rare earth sand filtrate is subjected to reverse osmosis to obtain a rare earth concentrate having a rare earth ion concentration greater than 1.0 g / L and purified water.

[0016] Preferably, in step S3, the turbidity of the discharged purified water is less than 10 NTU, and the purified water can be directly discharged or fully reused.

[0017] Preferably, in step S3, the reverse osmosis includes primary reverse osmosis and secondary reverse osmosis, the primary reverse osmosis membrane surface pressure is 0.8 MPa to 1.3 MPa, and the secondary reverse osmosis membrane surface pressure is 1.5 MPa to 1.8 MPa.

[0018] Preferably, the water production rate of the first-stage reverse osmosis is 45% to 60%; the rare earth ion concentration in the second-stage reverse osmosis concentrate (rare earth concentrate) is greater than 1 g / L, and the water production rate is 70% to 90%.

[0019] Preferably, the concentrated water flow rate in the secondary reverse osmosis is 0.2m 3 / h~0.5m 3 / h, return flow 0m 3 / h~0.5m 3 / h, concentrated water production 43% ~ 47%, fresh water production 53% ~ 57%, membrane pressure 1.2Mpa ~ 1.25Mpa.

[0020] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0021] 1. In the technical effect of the present invention, a simple and effective process is adopted to remove suspended matter from the leaching solution, and then the rare earth ions in the mother liquor or tail water are recovered by reverse osmosis, and the obtained rare earth-containing concentrated solution is directly sent to the rare earth smelter for rare earth element separation. Compared with the traditional process, the impurity removal and precipitation process of the leaching mother liquor in the mine, the precipitation process of the rare earth and the acid dissolution process in the smelter are reduced, and the rare earth recovery process is effectively shortened. In addition, the present invention realizes the effective recovery of rare earth ions through two-stage reverse osmosis, greatly reduces the rare earth recovery process, improves the rare earth recovery rate, and saves the cost of rare earth precipitation.

[0022] 2. More than 90% of purified water can be obtained through reverse osmosis, all of which can be reused in rare earth mine production or discharged. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation of the present invention or the technical solution in the prior art, the drawings required for describing the specific implementation or the prior art will be briefly introduced below. Obviously, the drawings described below are only one implementation of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 The process flow chart of the traditional ionic rare earth recovery method is as follows;

[0025] Figure 2 This is a process flow chart of the short process method for ionic rare earth recovery in this application. DETAILED DESCRIPTION

[0026] The embodiment of the present application provides a short process method for recovering rare earths from ionic rare earth ore leachate, and obtains rare earth concentrate with high rare earth concentration by sand filtration-reverse osmosis for rare earth leaching mother liquor or tail water, and directly sends it to the smelter, and does not need to be dissolved in the smelter, and directly enters the rare earth element separation process. Therefore, the present invention can replace the traditional process of leaching mother liquor-removing suspended matter-precipitation and impurity removal-precipitation of rare earth-filtration-drying-sending to smelter-acid dissolution-rare earth separation widely used in the industry (such as Figure 1 As shown), a short process of leaching mother liquor - removing suspended solids - reverse osmosis recovery - smelting separation is realized (as shown Figure 2 shown).

[0027] In order to better understand the above technical solution, the above technical solution is described in detail below with specific implementation methods.

[0028] Example 1: This example is a short process method for recovering rare earth from ionic rare earth ore leachate, and the specific steps are as follows:

[0029] S1. The ionic rare earth leaching mother liquor of a rare earth mine 1 was used. After testing, the specific composition of the ionic rare earth leaching mother liquor was as shown in Table 1, with a pH of 3.0 and a turbidity of 87 NTU.

[0030] Table 1 Multi-element analysis of ionic rare earth leaching mother liquor from a rare earth mine

[0031]

[0032] S2, take 1m 3 Ionic rare earth leaching mother liquor, first use 1m 3 The glass fiber reinforced plastic container is used as a sand filter. 0.5mm~3mm quartz sand is loaded into it to filter the ionic rare earth leaching mother liquor. Then a 0.5m 3 The PP cotton filtration was carried out in a glass fiber reinforced plastic container. The composition of the rare earth sand filtrate obtained after PP cotton filtration is shown in Table 2, with a pH of 3.0 and a turbidity of 17 NTU.

[0033] Table 2 Multi-element analysis of rare earth sand filtrate

[0034]

[0035] S3. The rare earth sand filtrate in S2 is introduced into a primary reverse osmosis system for treatment to obtain a primary reverse osmosis concentrate and fresh water (purified water). In the primary reverse osmosis process, the experimental data of different process parameters and products are shown in Table 3.

[0036] Table 3 Primary reverse osmosis test data table

[0037]

[0038]

[0039] Then the primary reverse osmosis concentrate was introduced into the secondary reverse osmosis system for treatment. The results are shown in Table 4, and rare earth concentrate and purified water were obtained.

[0040] Table 4 Secondary reverse osmosis test results

[0041]

[0042]

[0043] As can be seen from Table 4, after secondary reverse osmosis, the concentration of rare earth ions in the rare earth concentrate obtained ranges from 1.6g / L to 3.0g / L, which can be directly sent to the smelter for rare earth element separation. Compared with the ionic rare earth leaching mother liquor, the rare earth ions are enriched by 13 to 25 times, reducing the total amount of ionic rare earth leaching mother liquor by 92% to 96%. This part of the purified water produced during the concentration process can be fully reused in industrial production or directly discharged.

[0044] Example 2: This example is a short process method for recovering rare earth from ionic rare earth ore leachate, and the specific steps are as follows:

[0045] S1. Take the rare earth tail water from a rare earth mine 2. After testing, its specific composition is shown in Table 5, with a pH of 3.4 and a turbidity of 78 NTU.

[0046] Table 5 Multi-element analysis of rare earth tailings water from rare earth mine 2

[0047]

[0048] S2, take 1m 3 The rare earth tail water is firstly 1m 3 The glass fiber reinforced plastic container is used as a sand filter. 0.5mm~3mm quartz sand is loaded into it to filter the rare earth tail water. Then a 0.5m 3 The PP cotton filtration was carried out in a glass fiber reinforced plastic container. The water quality of the rare earth sand filtrate obtained after PP cotton filtration is shown in Table 6, with a pH of 3.4 and a turbidity of 45 NTU.

[0049] Table 6 Multi-element analysis of rare earth sand filtrate

[0050]

[0051] S3. The rare earth sand filtrate directly enters the primary reverse osmosis system for treatment to obtain primary reverse osmosis concentrate and fresh water (purified water). In the primary reverse osmosis process, the experimental data of different process parameters and products are shown in Table 7.

[0052] Table 7 Primary reverse osmosis test data table

[0053]

[0054]

[0055] It can be seen from Table 7 that the rare earth ion concentration in the primary reverse osmosis concentrate ranges from 0.15 g / L to 0.19 g / L.

[0056] Then the primary reverse osmosis concentrate enters the secondary reverse osmosis system for treatment. The results are shown in Table 8, and rare earth concentrate and purified water are obtained.

[0057] Table 8 Secondary reverse osmosis test results

[0058]

[0059]

[0060] As can be seen from Table 8, after secondary reverse osmosis, the concentration of rare earth ions ranges from 2.13g / L to 2.88g / L, which can be directly sent to the smelter for rare earth element separation. Compared with rare earth tail water, rare earth ions are enriched by 53 to 72 times, reducing the total amount of rare earth tail water by more than 95%. This part of the purified water produced during the concentration process can be fully reused in industrial production or directly discharged.

[0061] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0062] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A short-process method for recovering rare earth from ionic rare earth ore leachate, characterized in that: include: S1. Obtaining rare earth leaching solution through leaching process, wherein the rare earth leaching solution is ionic rare earth ore leaching mother liquor or low-concentration rare earth tail water; S2, sand filtration treatment, removing suspended matter in the rare earth leaching solution to obtain rare earth sand filtrate; S3. The rare earth sand filtrate is subjected to reverse osmosis, and the obtained rare earth concentrated liquid is sent to a smelter for rare earth element separation, and the obtained purified water is discharged or reused.

2. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S1, the rare earth ion concentration in the ionic rare earth ore leaching mother liquor is 0.11 g / L to 0.25 g / L, and the pH is 2 to 4.

3. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S1, the rare earth ion concentration in the low-concentration rare earth tail water is 0.001 g / L to 0.01 g / L.

4. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S2, rare earth sand filtrate is obtained by removing ≥75% of suspended matter in the rare earth leaching solution through sand filtration.

5. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S2, the filtrate is filtered with PP cotton after sand filtration, and the sand filtration uses 0.5mm-3mm quartz sand.

6. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S3, the rare earth sand filtrate is subjected to reverse osmosis to obtain a rare earth concentrate having a rare earth ion concentration greater than 1.0 g / L and purified water.

7. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S3, the turbidity of the discharged purified water is less than 10 NTU, and can be directly discharged or fully reused.

8. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 1, characterized in that: In step S3, the reverse osmosis includes primary reverse osmosis and secondary reverse osmosis, the primary reverse osmosis membrane surface pressure is 0.8MPa-1.3MPa, and the secondary reverse osmosis membrane surface pressure is 1.5MPa-1.8MPa.

9. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 8, characterized in that: The water production rate of the first-stage reverse osmosis is 45% to 60%; the rare earth ion concentration in the second-stage reverse osmosis concentrated liquid is greater than 1g / L, and the water production rate is 70% to 90%.

10. A short-process method for recovering rare earth from ionic rare earth ore leachate according to claim 9, characterized in that: Secondary reverse osmosis concentrated water flow rate 0.2m 3 / h~0.5m 3 / h, return flow 0m 3 / h~0.5m 3 / h, concentrated water production 43% ~ 47%, fresh water production 53% ~ 57%, membrane pressure 1.2Mpa ~ 1.25Mpa.

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