Potassium mixed salt ore fine silt inhibitor, application and flotation method

Abstract

The invention relates to a potassium mixed salt mine fine silt inhibitor. The inhibitor is composed of oxalic acid and a high-molecular polymer. The method is applied to flotation of kainite or picromerite in potassium mixed salt ore containing fine silt. And the flotation step comprises the following steps: grinding the potassium mixed salt raw ore to dissociate a kainite mineral monomer or a picromerite mineral monomer and achieve a particle size suitable for flotation. Adding a fine silt inhibitor into the ore pulp of the potassium mixed salt raw ore subjected to ore grinding treatment, and stirring; and adding the collecting agent and stirring. And carrying out flotation operation to obtain kainite concentrate or picromerite concentrate. According to the fine silt inhibitor, through the synergistic effect of the oxalic acid and the polyacrylic acid / sodium, the oxalic acid reduces adhesion of fine silt by complexing metal ions, and the polyacrylic acid / sodium enhances the inhibition capacity through steric hindrance, so that the adverse effect of the fine silt on flotation can be effectively reduced. The efficient and stable separation effect is achieved, and the content of fine silt in a product is reduced. A physical desliming step is not needed, and the inhibition efficiency of fine silt is improved to 90% or above.

Description

Technical Field

[0001] The invention belongs to the field of potassium salt processing, and in particular relates to a potassium mixed salt ore fine mud inhibitor and an application thereof. The invention also relates to a flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud by applying the potassium mixed salt ore fine mud inhibitor. Background Art

[0002] As an important potassium resource, the development and utilization of potassium mixed salt mines is of great significance to agriculture, chemical industry and other fields. However, in the mining and processing of potassium mixed salt mines, the generation of fine mud is a common problem. Fine mud not only affects the purity and quality of the product, but also increases production costs and reduces production efficiency. Therefore, it is particularly important to develop an efficient and environmentally friendly potassium mixed salt mine fine mud inhibitor.

[0003] 1. Characteristics and Challenges of Potash Mixed Salt Mines ‌Complexity of composition‌: Potassium mixed salt ores usually contain a variety of ion components, such as K + 、Na + Mg 2+ and Cl - 、SO4 2- Etc. This complexity makes it easy to produce fine mud during its processing and utilization.

[0004] ‌Fine mud problem‌: During the mining and processing of potassium mixed salt ore, the generation of fine mud is a common problem. These fine muds not only affect the purity and quality of the product, but also increase production costs and reduce production efficiency. The existing technology (such as patent CN 102515881 B) uses physical screening to desludging and relies on a single inhibitor such as polyacrylamide, which has the problems of complex process, high energy consumption, and low fine mud inhibition efficiency (only 60-70%).

[0005] Limitations of traditional methods: Traditional physical or chemical methods often have problems such as poor results, complicated processes, high costs or environmental pollution when dealing with fine mud problems.

[0006] 2. Research and development needs of fine mud inhibitors ‌Improve separation efficiency‌: The main function of fine mud inhibitor is to improve the separation efficiency between minerals and fine mud, reduce the content of fine mud in the product, and thus improve the purity and quality of the product.

[0007] ‌Reduce production costs‌: By developing effective fine mud inhibitors, the additional costs caused by fine mud problems in the production process, such as the costs of washing, filtration, etc., can be reduced.

[0008] ‌Environmental protection requirements‌: With the improvement of environmental awareness, higher requirements are placed on the environmental protection of fine sludge inhibitors. An ideal fine sludge inhibitor should be able to reduce the impact on the environment while meeting the separation effect.

[0009] 3. Deficiencies of Existing Technologies Unstable effect: Some existing fine mud inhibitors are unstable in actual application and are easily affected by factors such as mineral composition, temperature, and pH value.

[0010] ‌High cost‌: Although some highly efficient fine mud inhibitors can meet the requirements of separation effect, their high cost is not conducive to large-scale promotion and application.

[0011] Poor environmental protection: Some fine mud inhibitors may produce harmful substances during use and cause environmental pollution. Summary of the invention

[0012] The purpose of the present invention is to provide a new fine mud inhibitor to effectively reduce the adverse effects of fine mud on flotation by addressing the technical problems existing in the prior art. The present invention uses the synergistic effect of oxalic acid and polyacrylic acid / sodium to increase the fine mud inhibition efficiency to more than 90% without the need for a physical desludging step.

[0013] Another technical problem to be solved by the present invention is to provide a use of the above-mentioned fine mud inhibitor.

[0014] Another technical problem to be solved by the present invention is to provide a flotation method for kainite or kainite in a potassium mixed salt ore containing fine mud.

[0015] The technical problem to be solved by the present invention is achieved by the following technical solutions. The present invention is a potassium mixed salt ore fine mud inhibitor, which is characterized in that the inhibitor is composed of oxalic acid and a high molecular polymer, and the high molecular polymer contained is a mixture of polyacrylic acid or sodium polyacrylate in any proportion; The mass ratio of the high molecular weight polymer to oxalic acid is 1:4-400, and more preferably 1:20-200.

[0016] The present invention also discloses the use of the fine mud inhibitor mentioned above, which is characterized in that the inhibitor is applied to the flotation of kainite or soft kainite in potassium mixed salt ore containing fine mud.

[0017] The invention also discloses a flotation method for kainite or kainite in a potassium mixed salt ore containing fine mud, wherein the method is characterized in that the above-mentioned fine mud inhibitor is used.

[0018] The flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud described in the present invention has a further preferred technical solution that the flotation method comprises the following steps: (1) grinding the potassium mixed salt ore to dissociate the potassium salt kainite mineral or the soft potassium kainite mineral monomer and achieve a particle size suitable for flotation; (2) first adding a fine mud inhibitor to the potassium mixed salt ore pulp after grinding and stirring; then adding a collector and stirring; (3) flotation the potassium mixed salt ore pulp obtained in step (2), wherein the flotation includes roughing and concentrating operations; the flotation operation obtains potassium salt magnesia concentrate or soft potassium magnesia concentrate.

[0019] The flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud described in the present invention has a further preferred technical solution that the content of fine mud in the potassium mixed salt ore is calculated as water-insoluble matter, and the water-insoluble matter content is 1% to 8%.

[0020] The present invention discloses a method for flotation of kainite or kainite in a potassium mixed salt ore containing fine mud, and a further preferred technical solution thereof is that the dosage of the high molecular weight polymer polyacrylic acid or sodium polyacrylate in the inhibitor during flotation is 5 to 50 g / ton of the original ore.

[0021] The present invention discloses a method for flotation of kainite or kainite in a potassium mixed salt ore containing fine mud, and a further preferred technical solution thereof is that the amount of oxalic acid in the inhibitor during flotation is 200 to 2000 g / ton of the original ore.

[0022] The flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud described in the present invention has a further preferred technical solution that the grinding fineness of -80 mesh in step (1) is 10% to 90%.

[0023] The flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud described in the present invention has a further preferred technical solution that the collector described in step (2) is sodium dodecyl sulfate or octadecylamine, and the stirring time of the collector is 1 to 10 minutes.

[0024] The flotation method of kainite or kainite in a potassium mixed salt ore containing fine mud described in the present invention has a further preferred technical solution that the flotation selection times in step (3) is 1 to 3 times.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The fine mud inhibitor of the present invention can effectively reduce the adverse effects of fine mud on flotation, achieve efficient and stable separation effects, and reduce the content of fine mud in the product. Compared with the traditional method, the fine mud inhibition efficiency of the present invention is improved by 20%.

[0026] 2. The present invention uses the synergistic effect of oxalic acid and polyacrylic acid / sodium, without the need for a physical desludging step, and the fine mud inhibition efficiency is increased to more than 90%. The core of the present invention lies in the synergistic effect of oxalic acid and polyacrylic acid / sodium. Oxalic acid reduces fine mud adhesion by complexing metal ions, while polyacrylic acid / sodium enhances inhibition ability by steric hindrance. The combination of the two is significantly better than a single inhibitor.

[0027] 3. The flotation method of kainite or kainite in potassium mixed salt ore containing fine mud of the present invention adopts a fine mud inhibitor, which can simplify the process: that is, it can simplify the operation of removing fine mud by physical screening in the prior art, so that the process does not need to remove fine mud by physical method to carry out flotation operation, which plays the role of simplifying the process, reducing investment and reducing cost. Compared with the traditional method, the production cost of the present invention is reduced by 40%.

[0028] 4. The flotation method of kainite or soft kainite in potassium mixed salt ore containing fine mud of the present invention is low-cost: on the premise of ensuring the separation effect, environmentally friendly raw materials and process conditions are selected to reduce environmental pollution in the production process. DETAILED DESCRIPTION

[0029] The specific technical solutions of the present invention are further described below to facilitate further understanding of the present invention by those skilled in the art, but do not constitute a limitation on the rights thereof.

[0030] Example 1, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of soft potassium magnesium sulfate, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )8.73%, sodium ion (Na + ) 14.58%, magnesium ion (Mg 2+ )6.07%, chloride ion (C1 - )31.48%, sulfate ion (S0 4 2- )23.74%, and the water-insoluble matter content was 2.34%.

[0031] The flotation steps of soft kaolinite are as follows: (1) Add the raw ore into a mixing barrel, add 40% of the water of the raw ore, and stir for 60 minutes to convert kainite into soft kainite.

[0032] (2) The converted soft potassium magnesium alum slurry is fed into a grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0033] (3) The ore pulp after grinding enters the inhibitor stirring tank, and 20 g of sodium polyacrylate per ton of raw ore and 1000 g of oxalic acid per ton of raw ore are added, and stirred for 5 minutes; the ore pulp after adding the inhibitor enters the collector stirring tank, and 1000 g of sodium dodecyl sulfate per ton of raw ore is added, and stirred for 5 minutes.

[0034] (4) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0035] The obtained soft potassium kainite concentrate potassium ion (K + )16.57%, sodium ion (Na + )1.45%, magnesium ion (Mg 2+ )6.34%, chloride ion (C1 - )5.66%, sulfate ion (S0 4 2- )38.35%, water insoluble matter content is 0.42%, potassium ion (K + ) The flotation recovery rate is 94.28%, the total recovery rate is 79.76%, and the water-insoluble matter removal rate is 93.09%. The kainite concentrate can be used as potassium sulfate fertilizer, and can also be further processed into potassium sulfate fertilizer.

[0036] Example 2, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of soft potassium magnesium sulfate, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )8.73%, sodium ion (Na + ) 14.58%, magnesium ion (Mg 2+ )6.07%, chloride ion (C1 - )31.48%, sulfate ion (S0 4 2- )23.74%, and the water-insoluble matter content was 2.34%.

[0037] The flotation steps of soft kainite are as follows: (1) Add the raw ore into a mixing barrel, add 40% of the water of the raw ore, and stir for 60 minutes to convert kainite into soft kainite.

[0038] (2) The converted soft potassium magnesium alum slurry is fed into a grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0039] (3) The ore pulp after grinding enters the inhibitor stirring tank, and 5 g of polyacrylic acid per ton of raw ore and 2000 g of oxalic acid per ton of raw ore are added, and stirred for 5 minutes; the ore pulp after adding the inhibitor enters the collector stirring tank, and 1000 g of collector sodium dodecyl sulfate per ton of raw ore is added, and stirred for 5 minutes.

[0040] (4) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0041] The obtained soft potassium kainite concentrate potassium ion (K + )16.51%, sodium ion (Na + )1.57%, magnesium ion (Mg 2+ )6.24%, chloride ion (C1 - )5.61%, sulfate ion (S0 4 2- )38.48%, water insoluble matter content is 0.48%, potassium ion (K + ) The flotation recovery rate is 93.31%, the total recovery rate is 79.33%, and the water-insoluble matter removal rate is 91.40%. The kainite concentrate can be used as potassium sulfate fertilizer, and can also be further processed into potassium sulfate fertilizer.

[0042] Example 3, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of soft potassium magnesium sulfate, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )8.73%, sodium ion (Na + ) 14.58%, magnesium ion (Mg 2+ )6.07%, chloride ion (C1 - )31.48%, sulfate ion (S0 4 2- )23.74%, and the water-insoluble matter content was 2.34%.

[0043] The flotation steps of soft kainite are as follows: (1) Add the raw ore into a mixing barrel, add 40% of the water of the raw ore, and stir for 60 minutes to convert kainite into soft kainite.

[0044] (2) The converted soft potassium magnesium alum slurry is fed into a grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0045] (3) The ore pulp after grinding enters the inhibitor stirring tank, and 25 g of sodium polyacrylate per ton of raw ore, 25 g of polyacrylic acid per ton of raw ore, and 200 g of oxalic acid per ton of raw ore are added, and stirred for 5 minutes; the ore pulp after adding the inhibitor enters the collector stirring tank, and 1000 g of collector sodium dodecyl sulfate per ton of raw ore is added, and stirred for 5 minutes.

[0046] (4) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0047] The obtained soft potassium kainite concentrate potassium ion (K + )16.42%, sodium ion (Na +)1.57%, magnesium ion (Mg 2+ )6.46%, chloride ion (C1 - )5.72%, sulfate ion (S0 4 2- )38.44%, water insoluble matter content is 0.52%, potassium ion (K + ) The flotation recovery rate is 94.04%, the total recovery rate is 79.53%, and the water-insoluble matter removal rate is 90.60%. The kainite concentrate can be used as potassium sulfate fertilizer, and can also be further processed into potassium sulfate fertilizer.

[0048] Example 4, a comparative test of flotation of soft kainite with polyacrylamide added but no oxalic acid added in the prior art A polyacrylamide as a fine mud inhibitor for potassium mixed salt mines is used for the flotation of soft potassium magnesium sulfate, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )8.73%, sodium ion (Na + ) 14.58%, magnesium ion (Mg 2+ )6.07%, chloride ion (C1 - )31.48%, sulfate ion (S0 4 2- )23.74%, and the water-insoluble matter content was 2.34%.

[0049] The flotation steps of soft kainite are as follows: (1) Add the raw ore into a mixing barrel, add 40% of the water of the raw ore, and stir for 60 minutes to convert kainite into soft kainite.

[0050] (2) The converted soft potassium magnesium alum slurry is fed into a grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0051] (3) The ore pulp after grinding enters the inhibitor stirring tank, and 25 g polyacrylamide per ton of raw ore is added and stirred for 5 minutes; the ore pulp after adding the inhibitor enters the collector stirring tank, and 1000 g sodium dodecyl sulfate per ton of raw ore is added and stirred for 5 minutes.

[0052] (4) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0053] The obtained soft potassium kainite concentrate potassium ion (K + )15.25%, sodium ion (Na + )1.89%, magnesium ion (Mg 2+ )6.57%, chloride ion (C1 - )5.93%, sulfate ion (S0 4 2-)38.17%, water insoluble matter content is 1.32%, potassium ion (K + ) The flotation recovery rate is 83.86%, the total recovery rate is 70.95%, and the water-insoluble matter removal rate is 77.09%. The kainite concentrate is used as potassium sulfate fertilizer, and can also be further processed into potassium sulfate fertilizer.

[0054] Example 5, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of potassium salt kainite, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )6.62%, sodium ion (Na + ) 14.22%, magnesium ion (Mg 2+ )6.05%, chloride ion (C1 - )28.50%, sulfate ion (S0 4 2- )23.29%, and the water-insoluble matter content was 3.42%.

[0055] The flotation steps of kainite are as follows: (1) Add the raw ore (containing potassium salt magnesium alum) into the grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0056] (2) The ore pulp after grinding enters the inhibitor stirring tank, adds 30 g of sodium polyacrylate per ton of raw ore, adds 1500 g of oxalic acid per ton of raw ore, and stirs for 5 minutes. The ore pulp after adding the inhibitor enters the collector stirring tank, adds 300 g of collector octadecylamine per ton of raw ore, and stirs for 5 minutes.

[0057] (3) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0058] The potassium ion (K + )13.12%, sodium ion (Na + )4.15%, magnesium ion (Mg 2+ )8.80%, chloride ion (C1 - )18.01%, sulfate ion (S0 4 2- )35.58%, water insoluble matter content is 0.32%, potassium ion (K + ) The flotation recovery rate is 87.27%, and the water-insoluble matter removal rate is 95.88%. The potassium salt magnesium sulfate concentrate can be converted into potassium sulfate fertilizer products by adding water, and can also be further processed to produce potassium sulfate fertilizer.

[0059] Example 6, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of potassium salt kainite, the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K+ )6.62%, sodium ion (Na + ) 14.22%, magnesium ion (Mg 2+ )6.05%, chloride ion (C1 - )28.50%, sulfate ion (S0 4 2- )23.29%, and the water-insoluble matter content was 3.42%.

[0060] The flotation steps of kainite are as follows: (1) Add the raw ore (containing potassium salt magnesium alum) into the grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0061] (2) The ore pulp after grinding enters the inhibitor stirring tank, and 5 g of sodium polyacrylate per ton of raw ore and 2000 g of oxalic acid per ton of raw ore are added, and stirred for 5 minutes. The ore pulp after adding the inhibitor enters the collector stirring tank, and 300 g of octadecylamine per ton of raw ore is added, and stirred for 5 minutes.

[0062] (3) After adding the collector and stirring, the slurry enters the flotation operation. The flotation process is one roughing and two fine separations.

[0063] The potassium ion (K + )13.24%, sodium ion (Na + )4.27%, magnesium ion (Mg 2+ )8.64%, chloride ion (C1 - )18.14%, sulfate ion (S0 4 2- )35.43%, water insoluble matter content is 0.42%, potassium ion (K + ) The flotation recovery rate is 87.33%, and the water-insoluble matter removal rate is 94.64%. The potassium salt magnesium sulfate concentrate can be converted into potassium sulfate fertilizer products by adding water, and can also be further processed to produce potassium sulfate fertilizer.

[0064] Example 7, a potassium mixed salt ore fine mud inhibitor, which is used for the flotation of potassium salt kainite, the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )6.62%, sodium ion (Na + ) 14.22%, magnesium ion (Mg 2+ )6.05%, chloride ion (C1 - )28.50%, sulfate ion (S0 4 2- )23.29%, and the water-insoluble matter content was 3.42%.

[0065] The flotation steps of kainite are as follows: (1) Add the raw ore (containing potassium salt magnesium alum) into the grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0066] (2) The ore pulp after grinding enters the inhibitor stirring tank, and 50 g of sodium polyacrylate per ton of raw ore and 200 g of oxalic acid per ton of raw ore are added, and stirred for 5 minutes. The ore pulp after adding the inhibitor enters the collector stirring tank, and 300 g of octadecylamine per ton of raw ore is added, and stirred for 5 minutes.

[0067] (3) After adding the collector and stirring, the ore pulp enters the flotation operation. The flotation process is one roughing and two fine separations.

[0068] The potassium ion (K + )13.34%, sodium ion (Na + )4.07%, magnesium ion (Mg 2+ )8.71%, chloride ion (C1 - )18.14%, sulfate ion (S0 4 2- )35.65%, water insoluble matter content is 0.30%, potassium ion (K + ) The flotation recovery rate is 87.57%, and the water-insoluble matter removal rate is 96.19%. The potassium salt magnesium sulfate concentrate can be converted into potassium sulfate fertilizer products by adding water, and can also be further processed to produce potassium sulfate fertilizer.

[0069] The following is a comparative experiment, which is a flotation comparison experiment of potassium salt magnesium sulfate using the prior art of adding polyacrylamide but not adding the oxalic acid described in the present invention: Comparative Example 1: A polyacrylamide as a fine mud inhibitor for potassium mixed salt ore is used for the flotation of potassium salt kainite, and the steps and conditions are as follows: A potassium mixed salt mine contains potassium ions (K + )6.62%, sodium ion (Na + ) 14.22%, magnesium ion (Mg 2+ )6.05%, chloride ion (C1 - )28.50%, sulfate ion (S0 4 2- )23.29%, and the water-insoluble matter content was 3.42%.

[0070] The flotation steps of kainite are as follows: (1) Add the raw ore (containing potassium salt magnesium alum) into the grinding machine for grinding to a fineness of -80 mesh and a content of 40%.

[0071] (2) The ore pulp after grinding enters the inhibitor stirring tank, adds 25 g polyacrylamide / ton of raw ore, and stirs for 5 minutes. The ore pulp after adding the inhibitor enters the collector stirring tank, adds 300 g octadecylamine / ton of raw ore, and stirs for 5 minutes.

[0072] (3) After adding the collector and stirring, the ore pulp enters the flotation operation. The flotation process is one roughing and two fine separations.

[0073] The potassium ion (K + )11.93%, sodium ion (Na + )5.42%, magnesium ion (Mg 2+ )8.94%, chloride ion (C1 - )18.85%, sulfate ion (S0 4 2- )35.74%, water insoluble matter content is 1.44%, potassium ion (K + ) The flotation recovery rate was 76.40%, and the water-insoluble matter removal rate was 82.15%.

Claims

1. A potassium mixed salt ore fine mud inhibitor, characterized in that: The inhibitor is composed of oxalic acid and a high molecular polymer, wherein the high molecular polymer is a mixture of polyacrylic acid or sodium polyacrylate in any proportion; The mass ratio of the high molecular polymer to oxalic acid is 1:4-400.

2. The use of the fine mud inhibitor according to claim 1, characterized in that: The use is to apply the inhibitor to the flotation of kainite or soft kainite in a potassium mixed salt ore containing fine mud.

3. A flotation method for kainite or kainite in a potassium mixed salt ore containing fine mud, characterized in that: This method uses the fine mud inhibitor described in claim 1.

4. The flotation method according to claim 3, characterized in that: The flotation method comprises the following steps: (1) grinding the potassium mixed salt ore to dissociate the potassium salt kainite mineral or the soft potassium kainite mineral monomer and achieve a particle size suitable for flotation; (2) first adding a fine mud inhibitor to the potassium mixed salt ore pulp after grinding and stirring; then adding a collector and stirring; (3) flotation the potassium mixed salt ore pulp obtained in step (2), wherein the flotation includes roughing and concentrating operations; the flotation operation obtains potassium salt magnesia concentrate or soft potassium magnesia concentrate.

5. The flotation method according to claim 4, characterized in that: The content of fine mud in the potassium mixed salt mine is calculated based on water-insoluble matter, and the content of water-insoluble matter is 1% to 8%.

6. The flotation method according to claim 4, characterized in that: During flotation, the dosage of the high molecular weight polymer polyacrylic acid or sodium polyacrylate in the inhibitor is 5 to 50 g / ton of raw ore.

7. The flotation method according to claim 4, characterized in that: The amount of oxalic acid used as a depressant during flotation is 200 to 2000 g / ton of raw ore.

8. The flotation method according to claim 4, characterized in that: The grinding fineness of step (1) is -80 mesh content 10% to 90%.

9. The flotation method according to claim 4, characterized in that: The collector described in step (2) is sodium dodecyl sulfonate or octadecylamine, and the collector is stirred for 1 to 10 minutes.

10. The flotation method according to claim 4, characterized in that: The number of flotation selections in step (3) is 1 to 3 times.