Comprehensive Utilization Technology of Low-Grade Clay-Type Lithium Resources

Abstract

The invention relates to the technical field of lithium recovery, and in particular to a comprehensive utilization process of low-grade clay-type lithium resources, comprising the following steps: S1. grinding raw ore into fine particles, and then sequentially performing constant temperature roasting, constant temperature acid leaching, filtering and washing to obtain leaching residue and leaching solution; S2. adding ammonium sulfate to the leaching solution, filtering to obtain a crude ammonium aluminum sulfate product and a crystallization tail liquid; S3. adding new acid and water to the crystallization tail liquid, and then using it for constant temperature acid leaching again; S4. repeating steps S1-S3 for many times to obtain a lithium-rich crystallization tail liquid; S5. concentrating the lithium-rich crystallization tail liquid, adding NaOH to remove impurities, and then evaporating and concentrating, cooling, crystallizing and filtering to obtain sodium sulfate crystals; S6. precipitating lithium carbonate on the lithium-rich crystallization tail liquid; the aluminum in the leaching solution of the invention is efficiently separated, and an ammonium aluminum sulfate product is prepared; the lithium resources are effectively enriched, and finally a green and efficient comprehensive utilization process of clay-type lithium ore with almost no tail and no wastewater discharge is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium recovery, and in particular to a comprehensive utilization process of low-grade clay-type lithium resources. Background Art

[0002] my country has abundant sedimentary clay lithium ore resources and huge development potential. Through ore property analysis, the sedimentary clay lithium is a lithium-rich kaolinite clay rock, the main valuable components of which are lithium and aluminum. 2 The average grade of O is 0.34%, Al 2 O 3 The content is 38.40%. The mineral components in the sample are mainly kaolinite, and the minor ones are halloysite, lithophore, and diaspore. Kaolinite has a finer particle size (micrometer level), and lithophore has an even finer particle size (micrometer level to nanometer level). Lithophore is mainly distributed in the aggregate of kaolinite mineral grains in the form of fine clusters, and is interwoven with other fine-grained layered silicate minerals such as clinochlore and halloysite. It is difficult to dissociate, and it is difficult to enrich potassium chlorite with conventional physical beneficiation. If chemical beneficiation (metallurgy) is used directly, due to the Li in the original ore, 2 O grade is low and does not reach the boundary grade of carp resources. At present, there are very few reports on the utilization of this type of sedimentary clay carp ore.

[0003] Patent publication number CN114891998 performs a high-temperature roasting of clay-type lithium ore, adds additives, performs a second low-temperature roasting, and then uses acid circulation leaching to recover lithium elements in the clay-type lithium. However, the two-stage roasting and acid leaching process intersects with the first-stage roasting and acid leaching process, which is complex and costly.

[0004] The patent with publication number CN101633980A achieves leaching of rare earths by high-temperature sulfuric acid roasting of rare earth ore. However, high-temperature sulfuric acid roasting has high requirements on equipment and is difficult to treat exhaust gas.

[0005] The patent with publication number CN114892024 uses sulfuric acid roasting water to leach lithium from clay lithium. Compared with the blank roasting-acid leaching process, the roasting conditions are more stringent and the environmental impact is greater.

[0006] The patent with publication number CN115198109 uses a mixture of sulfuric acid and phosphoric acid to leach lithium from clay lithium. Although the leaching rate can reach 90%, the acidity of the leaching solution is high, and the anion composition is complex compared to that of a single acid leaching solution, resulting in great difficulty in recovering the lithium element in the leaching solution. Summary of the invention

[0007] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a process for comprehensive utilization of low-grade clay lithium ore elements. The process comprises the following steps: roasting and acid leaching the clay lithium ore, obtaining an aluminum sulfate product through a crystallization method, and circulating the leaching of the crystal tail liquid to finally obtain a lithium-rich solution. After concentration, the solution is subjected to step-by-step precipitation to remove impurities and precipitate lithium to obtain a lithium carbonate product. Meanwhile, the leached residue can be used as a building raw material, thereby realizing the green and efficient comprehensive utilization of valuable elements such as clay-type lithium and aluminum.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] A low-grade clay-type lithium resource comprehensive utilization process comprises the following steps:

[0010] S1. grinding the raw ore of the low-grade clay-type lithium resource into fine particles, and then performing constant temperature roasting, constant temperature acid leaching, filtering and washing in sequence to obtain leaching residue and leaching solution;

[0011] S2. ammonium sulfate is added to the leaching solution, and after crystallization, the crude product of ammonium aluminum sulfate and the crystallization tail liquid are obtained by filtration;

[0012] S3. After adding new acid and water to the crystallization tail liquid, it is used again for the constant temperature acid leaching;

[0013] S4. Repeat steps S1-S3 multiple times, and after the last step S2, obtain a lithium-rich crystalline tail liquid;

[0014] S5. After the lithium-rich crystal tail liquid is concentrated, NaOH is added to remove impurities, and then concentrated by evaporation, cooled, crystallized, and filtered to obtain sodium sulfate crystals;

[0015] S6. Adding carbonate or introducing carbon dioxide into the lithium-rich crystal tail liquid to obtain lithium carbonate precipitate.

[0016] Furthermore, among the low-grade clay-type lithium resources, Li 2 O grade is 0.34%, Al 2 O 3 The grade is 38.40%.

[0017] Furthermore, in step S1, the particle size of the fine particles is -0.15 mm, accounting for 20-100%.

[0018] Furthermore, in step S1, the constant temperature calcination is carried out at a temperature of 400-800° C. and a time of 60-240 min.

[0019] Furthermore, in step S1, the acid used in the constant temperature acid leaching includes hydrochloric acid or sulfuric acid, the volume concentration of the acid solution is 2-100%, the liquid-solid ratio of the acid solution to the fine particles is (4-10):1, the acid leaching time is 20-120min, and the acid leaching temperature is 60-150°C.

[0020] Furthermore, in step S2, the amount of ammonium sulfate added is controlled as follows: after addition, the ammonium-aluminum molar ratio in the leaching solution is 1:1, the terminal temperature of the crystallization is 16°C, the solution is stirred at a speed of 200 r / min during the crystallization process, and the crystallization time is 60 min.

[0021] Furthermore, in step S5, the impurity removal step is: firstly adjusting the pH value of the lithium-rich crystal tail liquid to 7-10, filtering after the reaction, then adjusting the pH value to 12-14, and filtering again after the reaction.

[0022] The first step is to remove aluminum and iron ions from the lithium-rich crystallization tail liquid, and the second step is to remove magnesium ions.

[0023] Furthermore, in step S6, the carbonate includes ammonium carbonate or sodium carbonate.

[0024] Furthermore, in step S6, the amount of carbonate added and the amount of carbon dioxide introduced are controlled such that after addition, Li + and CO 3 2- The molar ratio is 2:1.

[0025] The present invention also provides an application of the leached residue obtained by a comprehensive utilization process of low-grade clay-type lithium resources in cement production.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention undergoes roasting - acid leaching - crystallization separation of aluminum - cyclic enrichment of lithium - concentration and impurity removal - lithium precipitation, mainly leaching valuable elements such as lithium and aluminum, the leaching residue yield is 62.00%, and the slag leaching rate is: Li 2 O, 90.15%, Al 2 O 3 , 73.34%; the crude ammonium aluminum sulfate crystals obtained contain Al 2 O 3 12.86%, the recovery rate of the original ore is 62.18%; after 5 cycles, the concentration is 90%, and the impurities and precipitated lithium are removed to obtain the primary lithium carbonate product containing Li 2 CO 3 87.56%, and the recovery rate of original ore is 61.63%.

[0028] 2. Leaching slag Li obtained by the present invention 2O content is 0.054%, Al 2 O 3 The content is 16.51%, SiO 2 The content of MgO is 60.38% and the content of MgO is 0.15%. The slag has a high silica content and is used as a building raw material for producing cement.

[0029] 3. It is very difficult to enrich lithium in low-grade clay-type lithium ore. The direct leaching has low grade and low utilization value of lithium element. The aluminum in the leachate of the present invention is efficiently separated, and the aluminum ammonium sulfate product is prepared; through the circulation process, lithium enrichment in the leachate is achieved, which is convenient for efficient separation of lithium in the leachate, and finally a green and efficient comprehensive utilization process of clay-type lithium ore with almost no tail and no wastewater discharge is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0032] The clay-type lithium resources treated in the following examples and comparative examples are lithium-rich kaolinite clay rocks, the main valuable components of which are valuable elements such as lithium and aluminum. 2 The average grade of O is 0.34%, Al 2 O 3 The content is 38.40%. The mineral components in the sample are mainly kaolinite, and the minor ones are halloysite, chlorite and diaspore.

[0033] Example 1

[0034] A process for utilizing low-grade clay-type lithium resources: 600 g of the raw ore of the low-grade clay-type lithium resources is ground to a particle size of -0.15 mm, accounting for 100%, and constant temperature roasting, constant temperature acid leaching, filtering and washing are performed in sequence to obtain leaching residue and leaching solution.

[0035] The calcination temperature is 600°C, the calcination time is 120 min, the acid leaching agent is 8% sulfuric acid by volume, the acid leaching liquid-solid ratio is 10:1, the acid leaching temperature is 90°C, the time is 90 min, and stirring is carried out continuously during the acid leaching process.

[0036] 327 g of leached residue was obtained, with a leached residue yield of 54.50%. 2 O 3 The content of Li is 5.21%, 2 The content of O is 0.079%, Al 2 O 3 The leaching rate was 92.61%, Li2 The O leaching rate was 87.34%.

[0037] Example 2

[0038] A process for utilizing low-grade clay-type lithium resources: 600 g of the raw ore of the low-grade clay-type lithium resources is ground to a particle size of -0.15 mm, accounting for 100%, and constant temperature roasting, constant temperature acid leaching, filtering and washing are performed in sequence to obtain leaching residue and leaching solution.

[0039] The calcination temperature is 450°C, the calcination time is 120 min, the acid leaching agent is hydrochloric acid with a volume fraction of 15%, the acid leaching liquid-solid ratio is 10:1, the acid leaching temperature is 90°C, the time is 90 min, and stirring is carried out continuously during the acid leaching process.

[0040] 459.9 g of leached residue was obtained, with a leached residue yield of 76.65%. 2 O 3 The content of Li is 28.76%, 2 The content of O is 0.078%, Al 2 O 3 The leaching rate was 42.59%, Li 2 The O leaching rate was 82.19%.

[0041] Example 3

[0042] A process for utilizing low-grade clay-type lithium resources: 600 g of the raw ore of the low-grade clay-type lithium resources is ground to a particle size of -0.15 mm, accounting for 100%, and constant temperature roasting, constant temperature acid leaching, filtering and washing are performed in sequence to obtain leaching residue and leaching solution.

[0043] The roasting temperature is 450°C, the roasting time is 120 minutes, the acid leaching agent is 8% sulfuric acid by volume, the acid leaching liquid-solid ratio is 6:1, the acid leaching temperature is 90°C, the time is 90 minutes, and stirring is carried out continuously during the acid leaching process.

[0044] 372 g of leached residue was obtained, with a leached residue yield of 62.00%. 2 O 3 The content of Li is 16.51%, 2 The content of O is 0.054%, Al 2 O 3 The leaching rate was 73.34%, Li 2 The O leaching rate is 90.15%. The leaching solution contains Al 3+ 653.50×10 -3 M / L, containing Li + 24.18×10 -3 M / L.

[0045] Example 4

[0046] A process for utilizing low-grade clay-type lithium resources: adding ammonium sulfate to the leaching solution obtained in Example 3, filtering after crystallization to obtain a crude ammonium aluminum sulfate product and a crystal tail liquid.

[0047] Among them, the amount of ammonium sulfate added is: after addition, the ammonium-aluminum molar ratio in the leaching solution is 1:1, the solution is stirred at a speed of 200 r / min during the crystallization process, the terminal temperature of crystallization is 16° C., and the crystallization time is 60 min.

[0048] Obtained 1114g of crude product of ammonium aluminum sulfate. 2 O 3 The content of Li is 12.86%, 2 The content of O is 0.0048%, which is equivalent to the original Al 2 O 3 The recovery rate of Li 2 The O recovery rate was 2.62%.

[0049] Example 5

[0050] A process for utilizing low-grade clay-type lithium resources: 600 g of the raw ore of the low-grade clay-type lithium resources is ground to a particle size of -0.15 mm, accounting for 100%, and constant temperature roasting, constant temperature acid leaching, filtering and washing are performed in sequence to obtain leaching residue and leaching solution, ammonium sulfate is added to the leaching solution, and a crystal tail liquid is obtained after crystallization, and new acid and water are added to the crystal tail liquid to make the volume fraction of sulfuric acid in the crystal tail liquid 8%, and the crystal tail liquid is returned to the leaching operation, the raw ore roasting residue is leached, and the filtering, washing and crystallization steps are repeated to obtain the first cycle crystal tail liquid.

[0051] Among them, the operations and parameters of constant temperature roasting, constant temperature acid leaching, filtration and washing are the same as those in Example 3, and the crystallization operation and parameters of ammonium aluminum sulfate are the same as those in Example 4.

[0052] The first cycle of crystallization tail liquid contains Al 3+ 123.70×10 -3 M / L、Li content + 59.43×10 -3 M / L.

[0053] Example 6

[0054] The first cycle crystallization tail liquid obtained in Example 5 was supplemented with fresh acid and water to make the volume fraction of sulfuric acid in the crystallization tail liquid 8%, and then returned to the leaching operation to leach the original ore roasting slag for recycling. After recycling for a total of 5 times, a lithium-rich crystallization tail liquid was obtained. The lithium-rich crystallization tail liquid contained Al 3+ 124.5×10-3 M / L、Li content + 141.04×10 -3 M / L.

[0055] Among them, the operations and parameters of constant temperature roasting, constant temperature acid leaching, filtration and washing are the same as those in Example 3, and the crystallization operation and parameters of ammonium aluminum sulfate are the same as those in Example 4.

[0056] After the lithium-rich crystal tail liquid is evaporated and concentrated by 90%, NaOH is added to remove impurities, and then evaporated and concentrated, cooled, crystallized, and filtered to obtain sodium sulfate crystals;

[0057] The specific steps of impurity removal are: first adjust the pH value of the lithium-rich crystal tail liquid to 10, stir at 90°C for 30 minutes, filter to remove impurities, then adjust the pH value to 12, stir at 40°C for 30 minutes, and then filter to remove impurities. During crystallization, the impurity-removed solution is first evaporated and concentrated by 50%, stirred at a speed of 200r / min, the crystallization end temperature is 16°C, and the crystallization time is 60min.

[0058] Prepare 400 g / L sodium carbonate solution at 90°C, add sodium carbonate to the lithium-rich crystal tail liquid, and make the tail liquid Li + and CO 3 2- The molar ratio was 2:1, and the mixture was stirred at 90°C for 30 min to obtain a primary lithium carbonate product. 2 CO 3 The content is 87.56%, and the recovery rate of the original ore is 61.63%.

[0059] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A comprehensive utilization process of low-grade clay-type lithium resources, It is characterized in that The following steps are involved: S1. grinding the raw ore of the low-grade clay-type lithium resource into fine particles, and then performing constant temperature roasting, constant temperature acid leaching, filtering and washing in sequence to obtain leaching residue and leaching solution; S2. ammonium sulfate is added to the leaching solution, and after crystallization, the crude product of ammonium aluminum sulfate and the crystallization tail liquid are obtained by filtration; S3. After adding new acid and water to the crystallization tail liquid, it is used again for the constant temperature acid leaching; S4. Repeat steps S1-S3 multiple times, and after the last step S2, obtain a lithium-rich crystalline tail liquid; S5. After the lithium-rich crystal tail liquid is concentrated, NaOH is added to remove impurities, and then concentrated by evaporation, cooled, crystallized, and filtered to obtain sodium sulfate crystals; S6. Adding carbonate or introducing carbon dioxide into the lithium-rich crystal tail liquid to obtain lithium carbonate precipitate.

2. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that Among the low-grade clay-type lithium resources, Li 2 O grade is 0.34%, Al 2 O 3 The grade is 38.40%.

3. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S1, the particle size of the fine particles is -0.15 mm, accounting for 20-100%.

4. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S1, the constant temperature calcination is carried out at a temperature of 400-800°C and a time of 60-240 minutes.

5. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S1, the acid used in the constant temperature acid leaching includes hydrochloric acid or sulfuric acid, the volume concentration of the acid solution is 2-100%, the liquid-solid ratio of the acid solution to the fine particles is (4-10):1, the acid leaching time is 20-120min, and the acid leaching temperature is 60-150°C.

6. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S2, the amount of ammonium sulfate added is controlled to make the ammonium-aluminum molar ratio in the leaching solution 1:1 after addition, the terminal temperature of the crystallization is 16° C., and the crystallization time is 60 min.

7. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S5, the impurity removal step is: first adjust the pH value of the lithium-rich crystal tail liquid to 7-10, filter after reaction, then adjust the pH value to 12-14, and filter again after reaction.

8. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S6, the carbonate includes ammonium carbonate or sodium carbonate.

9. A low-grade clay-type lithium resource comprehensive utilization process according to claim 1, It is characterized in that In step S6, the amount of carbonate added and the amount of carbon dioxide introduced are controlled to: after addition, the Li + and CO 3 2- The molar ratio is 2:

1.

10. Application of the leached residue obtained by the comprehensive utilization process of low-grade clay-type lithium resources according to claim 1 in cement production.

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