Beneficiation method of low-grade tin ore using magnetic separation and flotation

Abstract

The application discloses a beneficiation method of low-grade tin ore by using magnetic separation and flotation. The beneficiation method of low-grade tin ore by using magnetic separation and flotation comprises the following steps: step (1), crushing and grinding the low-grade tin ore, using water as a leaching agent, and separating by a wet magnetic separator to obtain magnetic minerals and magnetic tailings; step (2), drying the magnetic tailings after the magnetic separation, and then placing the tailings in a flotation agent to perform a flotation treatment to obtain flotation minerals and flotation tailings; step (3), concentrating the flotation tailings after the flotation treatment to obtain concentrated tailings; and step (4), smelting the concentrated tailings to finally obtain tin metal, sulfide, silicate, oxide and impurities. The application combines the magnetic separation and the flotation to improve the ore separation efficiency and the recovery rate, the water is used as a leaching liquid in the magnetic separation process to reduce the cost, and no new impurities are introduced, and the flotation agent can reduce the surface tension of the tin ore to improve the leaching rate.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a mineral processing method for low-grade tin ore using magnetic separation and flotation. Background Technology

[0002] Low-grade tin ore refers to tin ore with a low tin content. Currently, gravity separation, flotation, and magnetic separation are the main methods used for tin ore beneficiation. Gravity separation separates valuable ore and impurities based on density differences through physical methods such as gravity separation, centrifugal separation, and sieving. It is simple to operate and has simple equipment, but its separation effect is poor for fine-grained and complex ores. Flotation utilizes the different hydrophilicities of ore and flotation reagents in water, using bubble adsorption to rise ore particles to the surface, thus separating ore from impurities. It can be applied to the separation of fine-grained and complex ores, but the selection and control of flotation reagents are crucial. Magnetic separation utilizes the magnetic differences between magnetic and non-magnetic minerals in the ore, using magnetic materials to separate magnetic minerals. It is simple to operate and convenient, but its separation effect for non-magnetic minerals is poor. Combining magnetic separation and flotation can leverage their respective strengths to achieve better beneficiation results. By combining the two, the beneficiation efficiency and recovery rate of tin ore can be improved, leading to better ore separation and resource utilization.

[0003] Patent CN 103495493 B discloses a beneficiation method for low-grade fine-grained tin ore. This method first involves sulfide flotation of the raw ore to obtain sulfide concentrate and sulfide flotation tailings. Subsequently, the sulfide flotation tailings are subjected to magnetic separation to obtain iron concentrate and magnetic separation tailings. A modifier and collector are added to the magnetic separation tailings, and after three rounds of beneficiation, cassiterite concentrate is obtained. This method reduces beneficiation interference factors, is stable in operation, technically mature and reliable, and has strong adaptability to different ores, improving the recovery rate of cassiterite. However, there is still room for improvement in its ore separation efficiency and recovery rate. Summary of the Invention

[0004] The purpose of this invention is to provide a beneficiation method for low-grade tin ore using magnetic separation and flotation, in order to solve the technical problems of low ore separation efficiency and recovery rate in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for beneficiating low-grade tin ore by magnetic separation and flotation, comprising the following steps:

[0007] Step (1) The low-grade tin ore is crushed and ground, and water is used as the leaching agent. Wet magnetic separation is carried out by magnetic separator to separate the magnetic minerals in the low-grade tin ore, and magnetic minerals and magnetic separation tailings are obtained.

[0008] In the above process, a wet magnetic separation method is adopted. This method utilizes the different forces experienced by magnetic and non-magnetic minerals in a magnetic field. Through the impact of water flow and the magnetic force of the minerals, magnetic minerals are separated from other minerals. In a magnetic field, magnetic minerals are attracted by the magnetic force and move towards the magnetic field, while non-magnetic minerals are not attracted by the magnetic force and move away from the magnetic field. By adjusting the size and direction of the water flow, as well as the strength and direction of the magnetic field, the separation of magnetic minerals can be effectively achieved. This method can effectively separate magnetic minerals from other minerals in low-grade tin ore, improving the mineral recovery rate. Because magnetic minerals are effectively separated from other minerals during the magnetic separation process, the subsequent process flow is simplified, reducing energy consumption and costs. Furthermore, the use of water as the leaching agent in this invention avoids the use of harmful chemicals, reducing environmental pollution. Compared with dry magnetic separation, wet magnetic separation consumes less energy and is more energy-efficient.

[0009] Step (2) After drying the magnetic separation tailings, place them in a flotation agent for flotation treatment to obtain flotation minerals and flotation tailings;

[0010] In the above process, 1,3-distearate-2-oleic acid triglyceride is used as a flotation agent. This molecular structure contains both hydrophilic and hydrophobic groups. During the mixing of magnetic separation tailings and the flotation agent, the hydrophilic groups bind with the mineral particles in the tailings, while the hydrophobic groups move towards the air-water interface, making the mineral particles easier to float. Furthermore, this flotation agent has low surface tension, which effectively reduces the interaction between the tailings and the flotation agent, improving the flotation effect. The synthesized 1,3-distearate-2-oleic acid triglyceride also has good dispersibility and emulsifying properties, which can effectively reduce the amount of flotation agent used, saving costs. Moreover, this emulsifier is easily degraded in the environment and will not cause pollution.

[0011] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0012] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0013] Preferably, in step (1), the crushing and grinding process reduces the particle size of the low-grade tin ore to 0.2-2 mm. During the grinding process, a jaw crusher is used to initially crush the tin ore in the coarse grinding stage, and a ball mill is used to further grind the coarsely ground tin ore in the fine grinding stage.

[0014] Preferably, in step (1), the ratio of water to low-grade ore is 1L:(5-25)g, and the magnetic separation time is 60-120min.

[0015] Preferably, in step (2), the drying temperature is 70-90℃ and the drying time is 2-4h.

[0016] Preferably, the preparation method of the flotation agent includes the following steps:

[0017] S1: After heating stearic acid to complete melting, add sulfuric acid solution and anhydrous ethanol. Then, place the mixture solution in a microwave oven for heating. After heating, cool down, wash the crude product with distilled water, and separate it with a separatory funnel. After separation, measure the pH of the washing solution. When the pH reaches 7, stop washing, dehydrate, and obtain ethyl stearate.

[0018] S2: High oleic peanut oil and ethyl stearate are preheated to the reaction temperature in a constant temperature magnetic stirrer, then a specific lipase is added and the reaction is carried out under constant stirring. After the reaction is completed, the lipase is removed by filtration to obtain the flotation agent.

[0019] The reactions that occur during the above process are as follows:

[0020]

[0021]

[0022] The mass spectrometry analysis results of 1,3-distearate-2-oleic acid triglyceride were as follows: m / z: 888.81 (100.0%), 889.82 (63.1%), 890.82 (20.8%), 891.82 (4.5%).

[0023] Preferably, in step S1, the heating temperature of stearic acid is 70-80℃, the output power of the microwave oven is 200-220W, the heating temperature is 55-60℃, the heating reaction time is 40-50min, the temperature is cooled to 40-50℃, the ratio of stearic acid to anhydrous ethanol is 1g:(2.5-3.8)mL, and the mass fraction of sulfuric acid is 6.4wt%.

[0024] Preferably, in step S2, the molar ratio of ethyl stearate to high oleic peanut oil is 1:(0.8-1.2), the reaction temperature is 53-60℃, the specific lipase is NS4086, the ratio of ethyl stearate to specific lipase is 1:(0.036-0.040), and the reaction time is 4-6h.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. This invention combines magnetic separation and flotation to beneficiate low-grade tin ore. During magnetic separation, water is used as the leaching agent, forming a wet magnetic separation method. Compared to dry magnetic separation, this method consumes less energy and is more energy-efficient. The tailings after magnetic separation are dried and then placed in a flotation agent for flotation treatment. The flotation agent is synthesized from ethyl stearate and high-oleic peanut oil. The synthesized flotation agent is easily degraded in the environment and will not cause pollution. It can also effectively improve the recovery rate of tin ore in the magnetic separation tailings. The combination of these two methods can improve the beneficiation efficiency and recovery rate of tin ore, achieving good ore separation and resource utilization.

[0027] 2. The magnetic separation method used in this invention is wet magnetic separation, which can effectively separate magnetic minerals from other minerals in low-grade tin ore, thereby improving the mineral recovery rate. Since magnetic minerals are effectively separated from other minerals during the magnetic separation process, the subsequent process flow is simplified, reducing energy consumption and costs. Furthermore, the use of water as the leaching agent in this invention avoids the use of harmful chemicals, reducing environmental pollution. Compared with dry magnetic separation, wet magnetic separation has lower energy consumption and better energy-saving effect.

[0028] 3. In this invention, 1,3-distearate-2-oleic acid triglyceride is used as a flotation agent. The molecular structure contains both hydrophilic and hydrophobic groups. During the mixing process of magnetic separation tailings and flotation agent, the hydrophilic groups combine with the mineral particles in the tailings, while the hydrophobic groups move toward the air-water interface, making the mineral particles easier to float. In addition, the flotation agent has low surface tension, which can reduce the energy required in the flotation process. Furthermore, the emulsifier is easily degraded in the environment and will not cause pollution to the environment. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of the mineral processing method for low-grade tin ore using magnetic separation and flotation, as described in this invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment discloses a method for preparing a flotation agent, including the following steps:

[0034] S1: Heat 10g of stearic acid to 75℃ until it is completely melted, then add 6.4wt% sulfuric acid solution and 38mL anhydrous ethanol. Then, place the mixture in a microwave oven with an output power of 200W and heat it to 55℃. After reacting for 45min, cool it down to 45℃, wash the crude product with distilled water, and separate it with a separatory funnel. After separation, measure the pH of the washing solution. When the pH reaches 7, stop washing, dehydrate, and obtain ethyl stearate.

[0035] S2: 1 mol of high oleic peanut oil and 1 mol of ethyl stearate were preheated to a reaction temperature of 60°C in a constant temperature magnetic stirrer. Then, 0.038 g of specific lipase NS4086 was added and the mixture was stirred continuously for 5 h. After the reaction was completed, the lipase was removed by filtration to obtain the flotation agent.

[0036] Example 2

[0037] See Figure 1 As shown, this embodiment discloses a beneficiation method for low-grade tin ore using magnetic separation and flotation, including the following steps:

[0038] Step (1) Crush and grind 20g of low-grade tin ore to make the particle size of low-grade tin ore reach 0.8mm. In the coarse grinding stage, use a jaw crusher to perform preliminary crushing of tin ore. In the fine grinding stage, use a ball mill to grind the coarsely ground tin ore. Use 1L of water as leaching agent and perform wet magnetic separation by magnetic separator. The magnetic separation time is 120min to separate the magnetic minerals in the low-grade tin ore and obtain magnetic minerals and magnetic separation tailings.

[0039] Step (2) After drying the magnetic separation tailings at 80°C for 3 hours, place them in the flotation agent prepared in Example 1 for flotation treatment to obtain flotation minerals and flotation tailings;

[0040] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0041] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0042] Example 3

[0043] See Figure 1 As shown, this embodiment discloses a beneficiation method for low-grade tin ore using magnetic separation and flotation, including the following steps:

[0044] Step (1) Crush and grind 15g of low-grade tin ore to make the particle size of low-grade tin ore reach 0.8mm. In the coarse grinding stage, use a jaw crusher to perform preliminary crushing of tin ore. In the fine grinding stage, use a ball mill to grind the coarsely ground tin ore. Use 1L of water as leaching agent and perform wet magnetic separation by magnetic separator. The magnetic separation time is 120min to separate the magnetic minerals in the low-grade tin ore and obtain magnetic minerals and magnetic separation tailings.

[0045] Step (2) After drying the magnetic separation tailings at 80°C for 3 hours, place them in the flotation agent prepared in Example 1 for flotation treatment to obtain flotation minerals and flotation tailings;

[0046] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0047] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0048] Example 4

[0049] See Figure 1 As shown, this embodiment discloses a beneficiation method for low-grade tin ore using magnetic separation and flotation, including the following steps:

[0050] Step (1) Crush and grind 5g of low-grade tin ore to make the particle size of low-grade tin ore reach 0.8mm. In the coarse grinding stage, use a jaw crusher to perform preliminary crushing of tin ore. In the fine grinding stage, use a ball mill to further grind the coarsely ground tin ore. Use 1L of water as leaching agent and perform wet magnetic separation by magnetic separator. The magnetic separation time is 60-120min to separate the magnetic minerals in the low-grade tin ore.

[0051] Step (2) After drying the magnetic separation tailings at 80°C for 3 hours, place them in the flotation agent prepared in Example 1 for flotation treatment to obtain flotation minerals and flotation tailings;

[0052] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0053] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0054] Example 5

[0055] See Figure 1 As shown, this embodiment discloses a beneficiation method for low-grade tin ore using magnetic separation and flotation, including the following steps:

[0056] Step (1) Crush and grind 12g of low-grade tin ore to make the particle size of low-grade tin ore reach 0.8mm. In the coarse grinding stage, use a jaw crusher to perform preliminary crushing of tin ore. In the fine grinding stage, use a ball mill to grind the coarsely ground tin ore. Use 1L of water as leaching agent and perform wet magnetic separation by magnetic separator. The magnetic separation time is 120min to separate the magnetic minerals in the low-grade tin ore and obtain magnetic minerals and magnetic separation tailings.

[0057] Step (2) After drying the magnetic separation tailings at 80°C for 3 hours, place them in the flotation agent prepared in Example 1 for flotation treatment to obtain flotation minerals and flotation tailings;

[0058] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0059] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0060] Example 6

[0061] See Figure 1 As shown, this embodiment discloses a beneficiation method for low-grade tin ore using magnetic separation and flotation, including the following steps:

[0062] Step (1) Crush and grind 23g of low-grade tin ore to make the particle size of low-grade tin ore reach 0.8mm. In the coarse grinding stage, use a jaw crusher to perform preliminary crushing of tin ore. In the fine grinding stage, use a ball mill to grind the coarsely ground tin ore. Use 1L of water as leaching agent and perform wet magnetic separation by magnetic separator. The magnetic separation time is 60-120min to separate the magnetic minerals in the low-grade tin ore and obtain magnetic minerals and magnetic separation tailings.

[0063] Step (2) After drying the magnetic separation tailings at 80°C for 3 hours, place them in the flotation agent prepared in Example 1 for flotation treatment to obtain flotation minerals and flotation tailings;

[0064] Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings;

[0065] Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities.

[0066] Comparative Example 1

[0067] Compared with Example 2, Comparative Example 1 did not add water as a leaching agent in step (1), and all other conditions remained unchanged.

[0068] Comparative Example 2

[0069] Compared with Example 2, Comparative Example 2 replaced the flotation agent with water in step (2), while other conditions remained unchanged.

[0070] Experimental Example

[0071] The tin metals obtained in Examples 2-6 and Comparative Examples 1-2 were tested.

[0072] Untreated and treated samples were obtained during the mineral processing. Semi-quantitative spectral analysis and multi-element chemical analysis were performed on the samples to determine the content of target and non-target minerals in the ore. Based on the experimental results, the tin grade and tin recovery rate were calculated. The results are shown in Table 1.

[0073]

[0074] As shown in Table 1, the tin grade and tin recovery rate obtained in Examples 2-6 of this invention are good. A comparison between Comparative Example 1 and Examples 2-6 shows that using water as the leaching agent and employing wet magnetic separation can effectively improve the tin grade and tin recovery rate. A comparison between Comparative Example 2 and Examples 2-6 shows that using 1,3-distearate-2-oleic acid triglyceride as the flotation agent can effectively improve the tin grade and tin recovery rate.

[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0076] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for beneficiating low-grade tin ore using magnetic separation and flotation, characterized in that, Includes the following steps: Step (1) The low-grade tin ore is crushed and ground, and water is used as the leaching agent. Wet magnetic separation is carried out by magnetic separator to separate the magnetic minerals in the low-grade tin ore, and magnetic minerals and magnetic separation tailings are obtained. Step (2) After drying the magnetic separation tailings, place them in a flotation agent for flotation treatment to obtain flotation minerals and flotation tailings; Step (3) Concentrate the flotation tailings after flotation treatment to obtain concentrated tailings; Step (4) involves smelting the concentrated tailings to obtain tin metal, sulfides, silicates, oxides and impurities; The preparation method of the flotation agent includes the following steps: S1: After heating stearic acid to complete melting, add sulfuric acid solution and anhydrous ethanol. Then, place the mixture solution in a microwave oven for heating. After heating, cool down, wash the crude product with distilled water, and separate it with a separatory funnel. After separation, measure the pH of the washing solution. When the pH reaches 7, stop washing, dehydrate, and obtain ethyl stearate. S2: High oleic peanut oil and ethyl stearate are preheated to the reaction temperature in a constant temperature magnetic stirrer, then a specific lipase is added and the reaction is carried out under constant stirring. After the reaction is completed, the lipase is removed by filtration to obtain the flotation agent. In step S1, the heating temperature of stearic acid is 70-80℃, the output power of the microwave oven is 200-220W, the heating temperature is 55-60℃, the heating reaction time is 40-50min, the temperature is cooled to 40-50℃, the ratio of stearic acid to anhydrous ethanol is 1g:(2.5-3.8)mL, and the mass fraction of sulfuric acid is 6.4wt%. In step S2, the molar ratio of ethyl stearate to high oleic peanut oil is 1:(0.8-1.2), the reaction temperature is 53-60℃, the specific lipase is NS4086, the ratio of ethyl stearate to specific lipase is 1:(0.036-0.040), and the reaction time is 4-6h.

2. The beneficiation method for low-grade tin ore by magnetic separation and flotation according to claim 1, characterized in that, In step (1), the crushing and grinding process reduces the particle size of the low-grade tin ore to 0.2-2 mm. During the grinding process, a jaw crusher is used to initially crush the tin ore in the coarse grinding stage, and a ball mill is used to grind the coarsely ground tin ore in the fine grinding stage.

3. The beneficiation method for low-grade tin ore by magnetic separation and flotation according to claim 1, characterized in that, In step (1), the ratio of water to low-grade ore is 1L:(5-25)g, and the magnetic separation time is 60-120min.

4. The beneficiation method for low-grade tin ore by magnetic separation and flotation according to claim 1, characterized in that, In step (2), the drying temperature is 70-90℃ and the drying time is 2-4h.

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