METHOD OF EXTRACTING LITHIUM FROM SPODUMENE AND MEANWHILE RECOVERING LOW IRON AND LOW SULFUR SILICON ALUMINUM MICRO-POWDER, HIGH PURITY GYPSUM, TANTALUM NIOBIUM CONCENTRATE AND LITHIUM RICH IRON MATERIAL

Abstract

The present invention relates to the technical field of comprehensive recovery and utilization of mineral resources, in particular to a method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material. The method of the present invention comprises: mixing and leaching the lithium extraction acid clinker of spodumene with water; filtering the leached pulp to obtain the filtrate 1 and the filter residue 1; neutralizing the filtrate 1; filtering the neutralized pulp to obtain the filtrate 2 and high purity gypsum, extracting lithium from the filtrate 2 to obtain lithium salt; neutralizing and mixing the filter residue 1 to obtain the coarse and fine particles by classification; carrying out weak magnetic separation of fine particles to obtain lithium rich iron material and non-magnetic material; and carrying out strong magnetic separation, strong magnetic material gravity separation and tantalum niobium crude concentrate pickling on the non-magnetic material to obtain tantalum niobium concentrate. The present invention solves the major problem that the slag plaguing the lithium salt industry is difficult to deal with; and the present invention also gives priority to the separation of gypsum, which can simplify the subsequent treatment of lithium slag and provide high-quality low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material.

Claims

1. A method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, wherein the method comprises the following steps: a: Mix and leach the lithium extraction acid clinker of spodumene with water to obtain the leached pulp; b: Filter the leached pulp in step a, wash the filter residue with water, and combine the washing liquid with the filtrate to obtain the filtrate 1 and the filter residue 1; c: Neutralize the filtrate 1 in step b to obtain the neutralized pulp; d: Filter the neutralized pulp in step c, wash the filter residue with water, combine the washing liquid with the filtrate to obtain the filtrate 2 and high purity gypsum, and extract lithium from the filtrate 2 to obtain lithium salt; e: Neutralize and mix the filter residue 1 in step b to obtain coarse and fine particles by classification; f: Grind the coarse particles in step e and return to step e; g: Carry out weak magnetic separation of fine particles in step e to obtain lithium rich iron material 1 and the non-magnetic material; h: Carry out strong magnetic separation of the non-magnetic material 1 in step g to obtain low iron and low sulfur silicon aluminum micro-powder and the weak magnetic material; i: Carry out the weak magnetic material by gravity separation in step h to obtain lithium rich iron material 2 and tantalum niobium crude concentrate; j: Pickle the tantalum niobium crude concentrate in step i to obtain tantalum niobium concentrate.

2. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step a, the concentration of the leached pulp is 30-60%.

3. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step a, the lithium extraction acid clinker is obtained from spodumene concentrate through high temperature phase transition, meanwhile react with concentrated sulfuric acid.

4. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step c, alkali 1 is added to the filtrate 1 to regulate pH to 6-7.

5. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 4, wherein: the alkali 1 is any one or more of calcium carbonate, calcium hydroxide and calcium oxide.

6. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step c, the concentration of the neutralized pulp is 5-20%.

7. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step d, the filtration adopts at least one of a plate-and-frame filter press, a belt filter and a centrifuge.

8. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step e, the neutralizing and mixing is to add alkali 2 to the filter residue 1 for pulping and regulate the pH to 6.5-7.5, and the pulp concentration is 30-40%.

9. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 8, wherein: the alkaline substance in the alkali 2 is at least one of calcium carbonate, calcium hydroxide and calcium oxide.

10. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step e, the classification is at least one of hydrocyclone, mechanical vibrating screen and spiral classifier.

11. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step f, the grinding is at least one of ball mill grinding, vertical mill grinding and tower mill grinding.

12. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step f, the grinding is ball mill grinding; and the ball mill medium of the ball mill grinding is a steel ball, a steel forging, a steel bar, a zirconia ball, an alumina ball or a ceramic ball.

13. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step f, the pulp concentration of the grinding is 40-60%.

14. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: the magnetic field intensity of the weak magnetic separation is 0.05-0.5 T; and the magnetic field intensity of the strong magnetic separation is 1.0-1.7 T.

15. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step g, the pulp concentration of the weak magnetic separation of fine particles is 20-30%.

16. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step h, the pulp concentration of the strong magnetic separation of non-magnetic material 1 is 15-25%.

17. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step i, the pulp concentration of the gravity separation is 10-30%.

18. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step i, the gravity separation adopts at least one of a table concentrator, a spiral chute, a blanket machine, a centrifuge and a reciprocating separator.

19. The method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material according to claim 1, wherein: in step j, the pickling adopts the acid with a concentration of 5-40%, and the acid is at least one of sulfuric acid, hydrochloric acid and oxalic acid.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0046] FIG. 1 is the process flow diagram of the method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material of the present invention;

[0047] FIG. 2 is the process flow diagram of the traditional method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material.

DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following solutions are combined to further elaborate the present invention. Obviously, the embodiments described are only partial embodiments of the present invention and not all embodiments. Based on the embodiments of the present invention, any other embodiments obtained by a person skilled in the art without any creative work will fall within the protection scope of the present invention.

[0049] A method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, including the following steps: [0050] a: Mix and leach the lithium extraction acid clinker of spodumene with water to obtain the leached pulp; [0051] b: Filter the leached pulp in step a, wash the filter residue with water, and combine the washing liquid with the filtrate to obtain the filtrate 1 and the filter residue 1; [0052] c: Neutralize the filtrate 1 in step b to obtain the neutralized pulp; [0053] d: Filter the neutralized pulp in step c, wash the filter residue with water, combine the washing liquid with the filtrate to obtain the filtrate 2 and high purity gypsum, and extract lithium from the filtrate 2 to obtain lithium salt; [0054] e: Neutralize and mix the filter residue 1 in step b to obtain coarse and fine particles by classification; [0055] f: Grind the coarse particles in step e and return to step e; [0056] g: Carry out weak magnetic separation of fine particles in step e to obtain lithium rich iron material and the non-magnetic material; [0057] h: Carry out strong magnetic separation of the non-magnetic material 1 in step g to obtain silicon aluminum micro-powder and the strong magnetic material; [0058] i: Carry out the weak magnetic material by gravity separation in step h to obtain lithium rich iron material 2 and tantalum niobium crude concentrate; [0059] j: Pickle the tantalum niobium crude concentrate in step i to obtain tantalum niobium concentrate.

[0060] In some embodiments, in step a, the concentration of the leached pulp is 30-60%.

[0061] In some embodiments, in step a, the lithium extraction acid clinker is obtained from spodumene concentrate through high temperature phase transition, meanwhile react with concentrated sulfuric acid.

[0062] In some embodiments, in step c, alkali 1 is added to the filtrate 1 to regulate pH to 6-7.

[0063] In some embodiments, the alkali 1 is any one or more of calcium carbonate, calcium hydroxide and calcium oxide.

[0064] In some embodiments, in step c, the concentration of the neutralized pulp is 5-20%.

[0065] In some embodiments, in step d, the filtration adopts at least one of a plate-and-frame filter press, a belt filter and a centrifuge.

[0066] In some embodiments, in step d, the lithium extraction is to obtain lithium salt products after the filtrate 2 is treated by deep impurity removal and lithium deposition in sequence.

[0067] In some embodiments, in step e, the neutralizing and mixing is to add alkali 2 to the filter residue 1 for pulping and regulate the pH to 6.5-7.5.

[0068] In some embodiments, the alkaline substance in the alkali 2 is at least one of calcium carbonate, calcium hydroxide and calcium oxide.

[0069] In some embodiments, in step e, the classification is at least one of hydrocyclone, mechanical vibrating screen and spiral classifier.

[0070] In some embodiments, in step f, the grinding is at least one of ball mill grinding, vertical mill grinding and tower mill grinding.

[0071] In some embodiments, in step f, the grinding is ball mill grinding.

[0072] In some embodiments, the ball mill medium of the ball mill grinding is a steel ball, a steel forging, a steel bar, a zirconium ball, an alumina ball or a ceramic ball.

[0073] In some embodiments, in step f, the pulp concentration of the grinding is 40-60%.

[0074] In some embodiments, the magnetic field intensity of the weak magnetic separation is 0.05-0.3 T; and the magnetic field intensity of the strong magnetic separation is 1.0-1.7 T.

[0075] In some embodiments, in step g, the pulp concentration of the weak magnetic separation of fine particles is 20-30%.

[0076] In some embodiments, in step h, the pulp concentration of the strong magnetic separation of non-magnetic material 1 is 15-25%.

[0077] In some embodiments, in step i, the pulp concentration of the gravity separation is 10-30%.

[0078] In some embodiments, in step i, the gravity separation adopts at least one of a table concentrator, a spiral chute, a blanket machine, a centrifuge and a reciprocating separator.

[0079] In one of the embodiments of the present invention, in step j, the pickling adopts the acid with a concentration of 5-40%, and the acid is at least one of sulfuric acid, hydrochloric acid and oxalic acid.

[0080] In order to further demonstrate the effect of the method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material provided in the present invention in improving the recovery and utilization of spodumene ore resources, the following embodiments and comparative examples are provided:

Embodiment 1

[0081] The embodiment provides a method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, and the specific steps are as follows: [0082] 1) Add water to the acid clinker, mix and leach it to obtain the pulp A with a solid concentration of 30%, and filter the pulp A to obtain the filter residue and the filtrate; wherein, the acid clinker is obtained from spodumene concentrate through high-temperature phase transition, meanwhile react with concentrated sulfuric acid, and the statistics of the chemical component analysis results of spodumene concentrate are shown in Table 1.

TABLE-US-00001 TABLE 1 Chemical components and contents of spodumene concentrate Chemical Li.sub.2O Nb.sub.2O.sub.5 Ta.sub.2O.sub.5 BeO SiO.sub.2 Fe.sub.2O.sub.3 Al.sub.2O.sub.3 P.sub.2O.sub.5 component (%) (ppm) (ppm) (%) (%) (%) (%) (%) Content 6.13 85 62 0.188 63.86 1.34 23.81 0.46 Chemical MnO K.sub.2O Na.sub.2O CaO Rb.sub.2O Cs.sub.2O Ga Sn component (%) (%) (%) (%) (%) (%) (%) (%) Content 0.79 0.42 0.70 1.50 0.055 0.00624 0.0121 0.0646

[0083] Note: In view of the low tantalum niobium content in spodumene concentrate, the test results of different batches of spodumene concentrate have a certain fluctuation range, and the test results of the same spodumene concentrate samples based on GB/T 15076.1-2017 and GB/T 15076.2-2019 also have fluctuations, which is a normal phenomenon. The results of Nb.sub.2O.sub.5 and Ta.sub.2O.sub.5 in Table 1 are the average values of the same sample after three parallel measurements. [0084] 2) Add calcium carbonate to the filtrate obtained in step 1) for neutralization to obtain the pulp B, with a concentration of 10% and a pH of 6.5; [0085] 3) Filter the pulp B obtained in step 2) to obtain high purity gypsum and lithium rich solution, the lithium rich solution is directly used for lithium extraction. Wherein, the particle size of the obtained high purity gypsum is 1-74 m; [0086] 4) Add water to the filter residue obtained in step 1) for pulping, with a pulp concentration of 25%, and meanwhile add calcium carbonate to regulate the pH to 7.0; [0087] 5) Separation on the pulp obtained in step 4) with a hydrocyclone to obtain coarse-grained and fine-grained products by hydrocyclone, and ensure that the content of 325 mesh in the fine-grained product is greater than 90%; [0088] 6) Carry out weak magnetic separation on the fine-grained pulp obtained in step 5) with a magnetic field intensity of 0.2 T and a pulp concentration of 30% to obtain lithium rich iron material and non-magnetic product; [0089] 7) Add the coarse-grained product in step 5) to the mill for grinding, wherein the grinding medium is a steel ball, the grinding concentration is 60%, the content of the product with grinding fineness of 325 mesh is greater than 80%, and the ores discharged by the mill return to step 5) for further grading; [0090] 8) Carry out strong magnetic separation on the non-magnetic product obtained in step 6) with a magnetic field intensity of 1.5 T and a pulp concentration of 25% to obtain the weak magnetic product and low iron and low sulfur silicon aluminum micro-powder; [0091] 9) Carry out gravity separation on the weak magnetic product obtained in step 8) with a table concentrator, with a pulp concentration of 20%, to obtain tantalum niobium crude concentrate and lithium rich iron material; [0092] 10) Add 20% sulfuric acid solution to the tantalum niobium crude concentrate obtained in step 9), stir and leach it at the room temperature for 2 hours, and obtain tantalum niobium concentrate after solid-liquid separation; [0093] 11) Filter, dry and bag the high purity gypsum obtained in step 3), the silicon aluminum micro-powder obtained in step 8) and the tantalum niobium concentrate obtained in step 9) and step 10) to obtain high purity gypsum, silicon aluminum micro-powder, tantalum niobium concentrate and lithium rich iron material in turn.

Embodiment 2

[0094] The embodiment provides a method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, and the specific steps are as follows: [0095] 1) Add water to the acid clinker, mix and leach it to obtain the pulp A with a concentration of 45%, and filter the pulp A to obtain the filter residue and the filtrate; [0096] 2) Add calcium oxide (lime) to the filtrate obtained in step 1) to obtain the pulp B, with a pH of 6.5 and a concentration of 5%; [0097] 3) Filter the pulp B obtained in step 2) to obtain high purity gypsum and lithium rich solution, which is directly used for lithium extraction; [0098] 4) Add water to the filter residue obtained in step 1) for pulping, with a pulp concentration of 25%, and meanwhile add calcium oxide (lime) to regulate the pH to 6.5; [0099] 5) Separation on the pulp obtained in step 4) to obtain coarse-grained and fine-grained products by spiral classifier, and ensure that the content of 325 mesh in the obtained fine-grained product is greater than 90%; [0100] 6) Carry out weak magnetic separation on the fine-grained product obtained in step 5) with a magnetic field intensity of 0.3 T and a pulp concentration of 20% to obtain lithium rich iron material and non-magnetic product; [0101] 7) Add the coarse-grained product in step 5) to the mill for grinding, wherein the grinding medium is a ceramic ball, the grinding concentration is 50%, the content of the product with grinding fineness of 325 mesh is greater than 70%, and the ores discharged by the mill return to step 5) for further grading; [0102] 8) Carry out strong magnetic separation on the non-magnetic product in step 6) with a magnetic field intensity of 1.6 T and a pulp concentration of 20% to obtain and the weak magnetic product and low iron and low sulfur silicon aluminum micro-powder; [0103] 9) Carry out gravity separation on the weak magnetic product in step 8) by the combined process of a blanket machine and a table concentrator, with a pulp concentration of 15%, to obtain tantalum niobium crude concentrate and lithium rich iron material; [0104] 10) Add 10% sulfuric acid solution to the tantalum niobium crude concentrate in step 9), stir and leach it at the room temperature for 4 hours, and obtain tantalum niobium concentrate after solid-liquid separation; [0105] 11) Filter, dry and bag the high purity gypsum obtained in step 3), the low iron and low sulfur silicon aluminum micro-powder obtained in step 8) and the products obtained in step 9) and step 10) to obtain high purity gypsum, low iron and low sulfur silicon aluminum micro-powder, tantalum niobium concentrate and lithium rich iron material in turn.

Embodiment 3

[0106] The embodiment provides a method of extracting lithium from spodumene and meanwhile recovering low iron and low sulfur silicon aluminum micro-powder, high purity gypsum, tantalum niobium concentrate and lithium rich iron material, and the specific steps are as follows: [0107] 1) Add water to the acid clinker, mix and leach it to obtain the pulp A with a concentration of 55%, and filter the pulp A to obtain the filter residue and the filtrate; [0108] 2) Add calcium hydroxide to the filtrate obtained in step 1) to obtain the pulp B, with a pH and a concentration of 4.5%; [0109] 3) Filter the pulp B obtained in step 2) to obtain high purity gypsum and lithium rich solution, which is directly used for lithium extraction; [0110] 4) Add water to the filter residue obtained in step 1) for pulping, with a pulp concentration of 25%, and meanwhile add calcium hydroxide to regulate the pH to 7.0; [0111] 5) Separation on the pulp obtained in step 4) to obtain coarse-grained and fine-grained products by spiral classifier, and ensure that the content of 325 mesh in the obtained fine-grained product is greater than 90%; [0112] 6) Carry out weak magnetic separation on the fine-grained product obtained in step 5) with a magnetic field intensity of 0.2 T and a pulp concentration of 28% to obtain lithium rich iron material and non-magnetic product; [0113] 7) Add the coarse-grained product in step 5) to the mill for grinding, wherein the grinding medium is a ceramic ball, the grinding concentration is 50%, the content of the product with grinding fineness of 325 mesh is greater than 75%, and the ores discharged by the mill return to step 5) for further grading; [0114] 8) Carry out strong magnetic separation on the non-magnetic product in step 6) with a magnetic field intensity of 1.7 T and a pulp concentration of 20% to obtain and the weak magnetic product and low iron and low sulfur silicon aluminum micro-powder; [0115] 9) Carry out gravity separation on the weak magnetic product in step 8) by the combined process of a reciprocating gravity separator and a table concentrator, with a pulp concentration of 15%, to obtain tantalum niobium crude concentrate and lithium rich iron material; [0116] 10) Add 15% sulfuric acid solution to the tantalum niobium crude concentrate in step 9), stir and leach it at the room temperature for 6 hours, and obtain tantalum niobium concentrate after solid-liquid separation; [0117] 11) Filter, dry and bag the high purity gypsum obtained in step 3), the low iron and low sulfur silicon aluminum micro-powder obtained in step 8) and the products obtained in step 9) and step 10) to obtain high purity gypsum, low iron and low sulfur silicon aluminum micro-powder, tantalum niobium concentrate and lithium rich iron material in turn.

Comparative Example 1

[0118] Based on FIG. 2, the comparative example provides a traditional high value utilization process of the lithium slag from the spodumene lithium extractor, and the specific steps are as follows: [0119] 1) Add water to the acid clinker and mix and leach it to obtain the pulp A with a concentration of 30%; [0120] 2) Add calcium carbonate to the pulp obtained in step 1) to obtain the pulp B, with a pH of 7.0 and a concentration of 35%; [0121] 3) Filter the pulp B obtained in step 2) to obtain filter residue and lithium rich solution, the lithium rich solution is directly used for lithium extraction; [0122] 4) Add water to the filter residue in step 3) for pulping, and then carry out flotation desulfurization; wherein, the flotation pulp concentration is 33%, in roughing selection, the dosage of Na.sub.2SiO.sub.3 is 3000 g/t, and the dosage of gypsum collector is 200 g/t; in scavenging I, the dosage of Na.sub.2SiO.sub.3 is 1500 g/t and the dosage of gypsum collector is 150 g/t; in scavenging II, the dosage of Na.sub.2SiO.sub.3 is 500 g/t and the dosage of gypsum collector is 100 g/t; and in scavenging III, the dosage of Na.sub.2SiO.sub.3 is 500 g/t and the dosage of gypsum collector is 100 g/t; [0123] Dehydrate and dry the gypsum concentrate obtained from flotation to obtain gypsum concentrate; [0124] 5) Separation on pulp obtained in step 4) with a hydrocyclone to obtain coarse-grained and fine-grained products by spiral classifier, and ensure that the content of 325 mesh in the fine-grained lithium slag is greater than 90%; [0125] 6) Add the coarse-grained product in step 5) to the mill for grinding, wherein the grinding medium is a steel ball, the grinding concentration is 60%, the content of the product with grinding fineness of 325 mesh is greater than 80%, and the ores discharged by the mill return to step 5) for further grading; [0126] 7) Carry out weak magnetic separation on the fine-grained pulp obtained in step 5) with a magnetic field intensity of 0.2 T and a pulp concentration of 30% to obtain lithium rich iron material and non-magnetic product; [0127] 8) Carry out strong magnetic separation on the non-magnetic product obtained in step 7) with a magnetic field intensity of 1.5 T and a pulp concentration of 30% to obtain the weak magnetic product and silicon aluminum micro-powder; [0128] 9) Carry out gravity separation on the weak magnetic product in step 8) with a table concentrator, with a pulp concentration of 20%, to obtain tantalum niobium concentrate and lithium rich iron material; [0129] 10) Filter, dry and bag the gypsum obtained in step 4), the silicon aluminum micro-powder obtained in step 8) and the tantalum niobium concentrate and lithium rich iron material obtained in step 9) to obtain gypsum, silicon aluminum micro-powder, tantalum niobium concentrate and lithium rich iron material in turn.

Comparative Example 2

[0130] The comparative example provides a traditional high value utilization process of the lithium slag from the spodumene lithium extractor, and the specific steps are as follows: [0131] 1) Add water to the acid clinker and mix and leach it to obtain the pulp A with a concentration of 45%; [0132] 2) Add calcium carbonate to the pulp A obtained in step 1) to obtain the pulp B, with a concentration of 35% and a pH of 6.5; [0133] 3) Filter the pulp B obtained in step 2) to obtain filter residue and lithium rich solution, the lithium rich solution is directly used for lithium extraction; [0134] 4) Add water to the filter residue in step 3) for pulping, and then carry out flotation desulfurization; wherein, the flotation pulp concentration is 30%, in roughing selection, the dosage of Na.sub.2SiO.sub.3 is 4000 g/t, and the dosage of gypsum collector is 200 g/t; in scavenging I, the dosage of Na.sub.2SiO.sub.3 is 2000 g/t and the dosage of gypsum collector is 100 g/t; in scavenging II, the dosage of Na.sub.2SiO.sub.3 is 1000 g/t and the dosage of gypsum collector is 50 g/t; and in scavenging III, the dosage of Na.sub.2SiO.sub.3 is 500 g/t and the dosage of gypsum collector is 25 g/t; [0135] Dehydrate and dry the gypsum concentrate obtained from flotation to obtain gypsum concentrate; [0136] 5) Separation on the pulp obtained in step 4) with a spiral grader to obtain coarse-grained and fine-grained products by spiral classifier, and ensure that the content of 325 mesh of the lithium slag in the fine-grained product is greater than 90%; [0137] 6) Add the coarse-grained product in step 5) to the mill for grinding, wherein the grinding medium is a steel ball, the grinding concentration is 60%, the content of the product with grinding fineness of 325 mesh is greater than 80%, and the ores discharged by the mill return to step 5) for further grading; [0138] 7) Carry out weak magnetic separation on the fine-grained pulp obtained in step 5) with a magnetic field intensity of 0.25 T and a pulp concentration of 30% to obtain the strong magnetic product (lithium rich iron material) and the non-magnetic product; [0139] 8) Carry out strong magnetic separation on the non-magnetic product obtained in step 7) with a magnetic field intensity of 1.6 T and a pulp concentration of 30% to obtain the weak magnetic product and silicon aluminum micro-powder; [0140] 9) Carry out gravity separation on the weak magnetic product in step 8) by the combined process of a blanket machine and a table concentrator, with a pulp concentration of 20%, to obtain tantalum niobium concentrate and lithium rich iron material; [0141] 10) Filter, dry and bag the gypsum obtained in step 4), the silicon aluminum micro-powder obtained in step 8) and the tantalum niobium concentrate and lithium rich iron material obtained in step 9) to obtain gypsum, silicon aluminum micro-powder, tantalum niobium concentrate and lithium rich iron material in turn.

Performance Test:

[0142] Based on the lithium measurement method in Methods for Chemical Analysis of Lithium, Rubidium and Cesium Ores (GB/T 17413.1-2010), the content of lithium (calculated by Li.sub.2O) in the silicon aluminum micro-powder and lithium rich iron material obtained in the embodiments 1-2 and the comparative examples 1-2 is determined; [0143] Based on Methods for Chemical Analysis of Tantalum and NiobiumPart 1: Determination of Tantalum Content in NiobiumInductively Coupled Plasma Atomic Emission Spectrometry (GB/T 15076.1-2017), the content of tantalum (calculated by Ta.sub.2O.sub.5) in the tantalum niobium concentrate in the embodiments 1-2 and the comparative examples 1-2 is determined; [0144] Based on Methods for Chemical Analysis of Tantalum and NiobiumPart 2: Determination of Niobium Content in TantalumInductively Coupled Plasma Atomic Emission Spectrometry and Stratography Gravimetry (GB/T 15076.2-2019), the content of niobium (calculated by Nb.sub.2O.sub.5) in the tantalum niobium concentrate in the embodiments 1-2 and the comparative examples 1-2 is determined; [0145] Based on Methods for Chemical Analysis of Gypsum (GB/T 5484-2012), the contents of CaO, SO.sub.3, Fe.sub.2O.sub.3, Al.sub.2O.sub.3 and SiO.sub.2 indexes in the gypsum product in the embodiments 1-2 and the comparative examples 1-2 are determined; [0146] Based on Methods for Chemical Analysis of Silicate RocksPart 31: Determination of 12 Components Including Silicon Dioxide Etc.Lithium Metaborate FusionInductively Coupled Plasma Atomic Emission Spectrometry (GB/T 14506.31-2019), the contents of SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.2O.sub.3, SO.sub.3, CaO, K.sub.2O, Na.sub.2O, TiO.sub.2, Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, Li.sub.2O, P.sub.2O.sub.5 and B.sub.2O.sub.3 indexes in the silicon aluminum micro-powder in the embodiments 1-2 and the comparative examples 1-2 are determined. [0147] The statistics of the test results of the index contents of the silicon aluminum micro-powder product in the embodiments 1-2 and the comparative examples 1-2 are shown in Table 2.

TABLE-US-00002 TABLE 2 Components and contents of silicon aluminum micro-powder product SiO.sub.2 Al.sub.2O.sub.3 Fe.sub.2O.sub.3 SO.sub.3 CaO K.sub.2O Na.sub.2O Component (%) (%) (%) (%) (%) (%) (%) Embodiment 1 66.49 24.31 0.38 0.18 0.29 0.43 0.34 Embodiment 2 65.76 23.97 0.40 0.13 0.32 0.52 0.26 Embodiment 3 63.96 24.15 0.42 0.20 0.26 0.45 0.30 Comparative 64.88 24.52 0.67 0.58 0.31 0.66 0.47 example 1 Comparative 65.71 24.13 0.69 0.61 0.35 0.62 0.39 example 2 TiO.sub.2 Ta.sub.2O.sub.5 Nb.sub.2O.sub.5 Li.sub.2O P.sub.2O.sub.5 B.sub.2O.sub.3 Component (%) (ppm) (ppm) (%) (%) (%) Embodiment 1 0.042 38 25 0.31 0.31 0.14 Embodiment 2 0.064 35 28 0.30 0.30 0.11 Embodiment 3 0.039 40 27 0.33 0.35 0.16 Comparative 0.032 36 29 0.46 0.34 0.094 example 1 Comparative 0.045 31 26 0.44 0.37 0.12 example 2

[0148] Note: In view of the low tantalum and niobium content in silicon aluminum micro-powder product, the test results of different batches of silicon aluminum micro-powder product have a certain fluctuation range, and the test results of the same silicon aluminum micro-powder product based on GB/T 15076.1-2017 and GB/T 15076.2-2019 also have fluctuations, which is a normal phenomenon. The results of Nb.sub.2O.sub.5 and Ta.sub.2O.sub.5 in Table 2 are the average values of the same sample after three parallel measurements.

[0149] The statistics of the index content test results of the tantalum niobium concentrate product and the recovery rate results of the tantalum niobium concentrate product in the embodiments 1-2 and the comparative examples 1-2 are shown in Table 3.

TABLE-US-00003 TABLE 3 Components and contents of tantalum Recovery rate of tantalum niobium concentrate product niobium concentrate Component Ta.sub.2O.sub.5 (%) Nb.sub.2O.sub.5 (%) Ta.sub.2O.sub.5 (%) Nb.sub.2O.sub.5 (%) Embodiment 1 17.39 13.38 54.17 50.14 Embodiment 2 16.15 12.58 56.42 52.59 Embodiment 3 16.84 12.49 54.67 51.08 Comparative 15.04 9.29 50.90 49.58 example 1 Comparative 14.58 8.93 50.12 48.32 example 2

[0150] The statistics of the test results of the gypsum product components and contents in the embodiments 1-2 and the comparative examples 1-2 are shown in Table 4.

TABLE-US-00004 TABLE 4 Components and contents of gypsum product Component CaO SO.sub.3 Fe.sub.2O.sub.3 Al.sub.2O.sub.3 SiO.sub.2 (%) (%) (%) (%) (%) Embodiment 1 31.12 43.51 0.37 2.18 0.90 Embodiment 2 32.54 42.98 0.35 2.32 0.85 Embodiment 3 30.89 42.88 0.41 2.09 0.92 Comparative example 1 13.99 19.34 0.58 12.81 35.71 Comparative example 2 14.84 20.97 0.56 12.27 34.29

[0151] The statistics of the test results of the lithium rich iron material product components and contents in the embodiments 1-2 and the comparative examples 1-2 are shown in Table 5.

TABLE-US-00005 TABLE 5 Components and contents of lithium rich iron material product component SiO.sub.2 Al.sub.2O.sub.3 Fe.sub.2O.sub.3 Ta.sub.2O.sub.5 Nb.sub.2O.sub.5 (%) (%) (%) (ppm) (ppm) Embodiment 1 64.12 24.35 3.43 67 42 Embodiment 2 64.38 24.84 3.61 52 47 Embodiment 3 63.97 24.17 3.35 61 44 Comparative example 1 64.25 25.37 3.76 63 45 Comparative example 2 64.34 24.95 3.41 59 48 component Li.sub.2O SO.sub.3 CaO Na.sub.2O + K.sub.2O (%) (%) (%) (%) Embodiment 1 1.02 0.33 1.13 0.89 Embodiment 2 0.96 0.19 1.19 0.92 Embodiment 3 0.93 0.25 1.15 0.95 Comparative example 1 0.89 0.21 1.26 0.87 Comparative example 2 0.86 0.21 1.18 0.86

[0152] Note: In view of the low tantalum and niobium content of the lithium rich iron material product, the test results of different batches of lithium rich iron material products have a certain fluctuation range, and the test results of the same lithium rich iron material product samples based on GB/T 15076.1-2017 and GB/T 15076.2-2019 also have fluctuations, which is a normal phenomenon. The results of Nb.sub.2O.sub.5 and Ta.sub.2O.sub.5 in Table 5 are the average values of the same sample after three parallel measurements.

[0153] Seen from Tables 1-4, the sulfur content and iron content in the silicon aluminum micro-powder obtained in the experiment examples 1-2 in Table 1 are both lower than those in the comparative examples 1-2, indicating that the solid-liquid pre-separation is adopted after pulping the lithium extraction acid clinker, and the gypsum in the lithium extraction acid clinker is separated first to avoid the mixing of gypsum and other minerals, and the silicon aluminum micro-powder obtained after treatment of the filter residue has a low sulfur content; meanwhile, due to the solid-liquid pre-separation process, the free iron in the leaching solution of the lithium extraction acid clinker is separated from other minerals, which can avoid the formation of colloids of free iron in the neutralization process and adsorbing no the surface of the silicon aluminum micro-powder. Therefore, the iron content in the silicon aluminum micro-powder product can be reduced through pre-separation; in the traditional process in the comparative examples 1-2, the lithium excavation acid clinker is neutralized after leaching and the colloidal iron produced by free iron is adsorbed no the surface of mineral particles. Although the gypsum product is obtained by flotation desulfurization, since the colloidal iron is non-magnetic material, the iron content is still relatively high in the silicon aluminum micro-powder obtained in the post-treatment process of weak magnetic separation and strong magnetic separation; the low iron and low sulfur silicon aluminum micro-powder products obtained in the embodiments 1 and 2 have a higher whiteness due to the reduction of iron, and when the free iron ion is neutralized with the silicon aluminum micro-powder, the free iron forms colloidal iron and adsorbs to the surface of the silicon aluminum micro-powder, resulting in the silicon aluminum micro-powder in the color of beige.

[0154] In Table 2, the contents of Nb.sub.2O.sub.5 and Ta.sub.2O.sub.5 in the tantalum niobium concentrate product in the embodiments 1-2 are superior to those in the comparative examples 1-2, especially the Nb.sub.2O.sub.5 content, and the Nb.sub.2O.sub.5 content in the embodiment 2 is increased by 35.41% compared with the tantalum niobium concentrate product in the comparative example 1; in the embodiments 1-2, the lithium extraction acid clinker is filtered first, and then the filtrate and the filter residue are treated respectively, which is conducive to improving the quality of the tantalum niobium concentrate; meanwhile, the embodiments 1-2 do not need flotation desulfurization, thus reducing the entailment of tantalum, niobium and other minerals in gypsum, resulting in excellent quality of the tantalum niobium concentrate product, and improving the recovery rate of tantalum niobium.

[0155] In Table 3, the contents of CaO and SO.sub.3 in the gypsum product in the embodiments 1-2 are greater than those in the comparative examples 1-2, and the contents of iron, aluminum and silicon are lower than those in the comparative examples 1-2, indicating that the traditional flotation desulfurization process makes it difficult to separate gypsum from other minerals, resulting in low purity of the obtained gypsum concentrate, and high-grade gypsum can only be obtained through concentration; if concentration is adopted, additional process is needed, and meanwhile a certain amount of secondary slag is produced; the present invention adopts the acid-base neutralization process in liquid and can finally obtain high-grade gypsum product, and no secondary slag is produced in the gypsum separation process.

[0156] In Table 4, both the method of the present invention and the traditional process can obtain higher grade lithium rich iron material, which creates better conditions for the subsequent lithium recovery from lithium rich iron material and is conducive to realizing the purpose of high-value utilization.