A method for tin recovery from secondary tailings

Abstract

This invention provides a method for tin recovery from secondary tailings, comprising the following steps: (1) feeding; (2) physical gravity separation; (3) thickening; (4) flotation process: S1, feeding; S2, slurry preparation: add xanthate and No. 2 oil to the slurry, remove sulfide ore by flotation to obtain sulfide ore and desulfurized tailings; concentrate the iron-removed tailings to 22-25%, add sodium carbonate, and stir for 5-8 minutes; add sodium hexametaphosphate, and stir for 3-5 minutes; add tributyl phosphate, and stir for 12-16 minutes; then add hydroxamic acid collector, and stir for 3-5 minutes; then add 30-50 g / t of No. 2 oil, and stir for 1-2 minutes to obtain rougher concentrate and rougher tailings; S3, aeration; S4, separation; (5) secondary concentrate upgrading to obtain tin concentrate. The beneficiation method of this invention produces tin concentrate with high tin content and high recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a method for tin recovery from secondary tailings. Background Technology

[0002] Secondary tailings refer to the waste residue remaining after further processing of mineral resources that were not effectively recovered during the primary beneficiation process. Due to the limited recovery rate in the primary beneficiation process, secondary tailings may still contain a certain amount of valuable metals, such as tin. With the increasing scarcity of resources and stricter environmental protection requirements, the recovery of valuable metals from secondary tailings is becoming increasingly important.

[0003] The tin content in secondary tailings is typically low, generally between 0.1% and 1%, depending on the primary beneficiation process and efficiency. Although the content is low, the large volume of tailings means that the overall tin resource still has considerable economic value. Furthermore, with the gradual depletion of tin resources, the recovery of low-grade tin ore is becoming increasingly important. Flotation is a method of separation that utilizes differences in the surface properties of minerals. By adding collectors, frothers, and other reagents, cassiterite particles adhere to air bubbles, rising to the surface of the slurry to form a foam layer, thus separating from gangue minerals. Flotation is suitable for processing fine and very fine-grained cassiterite, effectively improving tin recovery rates. Especially for tailings with high mud content, flotation can remove muddy minerals and improve concentrate grade. Magnetic separation is a separation method based on differences in the magnetic properties of minerals. Although cassiterite itself is not magnetic, pre-oxidation or reduction treatment can generate weakly magnetic compounds on its surface, allowing it to be separated by magnetic separation equipment. Magnetic separation is suitable for processing tailings containing magnetic minerals such as iron and titanium, and can simultaneously recover multiple valuable metals. For certain types of tailings, magnetic separation can serve as an effective pre-enrichment method.

[0004] Tin content in secondary tailings is typically low, making efficient tin recovery from low-grade ores a significant challenge. Traditional beneficiation methods offer low recovery rates for low-grade ores, failing to meet economic requirements. Introducing green beneficiation technologies and environmentally friendly reagents can reduce environmental impact. For example, bioleaching is a green and environmentally friendly technology that can be carried out at normal temperature and pressure, with low energy consumption and minimal environmental pollution. Furthermore, using a closed-loop system can effectively reduce wastewater and exhaust gas emissions.

[0005] Therefore, there is an urgent need for a method for tin recovery from secondary tailings. Summary of the Invention

[0006] The purpose of this invention is to provide a method for tin recovery from secondary tailings.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for tin recovery from secondary tailings includes the following steps:

[0009] (1) Feeding: For secondary tin tailings of fine-grained tin ore, the ore is first concentrated by a high-efficiency inclined plate thickener, with the concentration controlled at 14%~18%. After the concentration is increased, the ore is thoroughly stirred and then passed through a pressure stabilizing box before entering the physical mineral processing machine.

[0010] (2) Physical gravity separation: The centrifugal drum of the physical concentrator rotates horizontally, generating a radially uniform centrifugal force field on the inner surface of the drum. The slurry is fed to the inner surface of the drum by the feeding device and rotates with the drum under the drive of the centrifugal drum. The inner surface of the centrifugal drum has a slope along the axial direction. The slurry flows along the axial direction at a certain flow rate while rotating.

[0011] (3) Thickening: The physical mineral processing machine discharges the heavy products into the mineral separation device and into the concentrate receiving tank, and then into the high-efficiency inclined plate thickening box for thickening. The discharge port of the thickening box is designed with a timed air pump mechanism to carry out air intake and stirring. The concentration is controlled at 35%~45% before entering the flotation for upgrading.

[0012] (4) Flotation process:

[0013] The basic steps of the flotation process include:

[0014] S1. Feeding: The products with a high specific gravity from the physical mineral processing machine are flushed off into the concentrate receiving tank of the mineral separation device, and then enter the high-efficiency inclined plate thickener for concentration. The discharge port of the thickener is designed with a timed air pump mechanism to carry out air intake and stirring. The concentration is controlled at 35%~45% before entering the flotation for upgrading.

[0015] S2. Slurry Preparation: Add 150-170 g / t of butyl xanthate and 24-28 g / t of No. 2 oil to the slurry for flotation to remove sulfide ore, obtaining sulfide ore and desulfurized tailings; under a magnetic field strength of 0.2-0.3T, magnetically separate the desulfurized tailings to remove iron, obtaining iron concentrate and iron-removed tailings; concentrate the iron-removed tailings to 22-25%, add 250-280 g / t of sodium carbonate, and stir for 5-8 minutes; add 120-150 g / t of sodium hexametaphosphate, and stir for 3-5 minutes; add 90-100 g / t of tributyl phosphate, and stir for 12-16 minutes; then add 700-800 g / t of hydroxamic acid collector, and stir for 3-5 minutes; finally add 30-50 g / t of No. 2 oil, and stir for 1-2 minutes to obtain rougher concentrate and rougher tailings.

[0016] S3, Aeration: Air is introduced into the roughing concentrate to form a large number of bubbles.

[0017] S4. Separation: Hydrophobic mineral particles adhere to the air bubbles and float to the surface, forming a mineralized foam layer, while hydrophilic mineral particles remain in the slurry. The mineralized foam is discharged, achieving the purpose of separation.

[0018] (5) Secondary concentrate upgrading: The flotation concentrate is then put into a physical concentrator for secondary upgrading to obtain tin concentrate. The tailings are fully recovered and recycled into a high-efficiency inclined plate thickener for concentration. The concentration is adjusted to 35%~45% and then returned to the flotation machine for repeated screening.

[0019] In the secondary tin recovery process, a series of refined flotation, magnetic separation, and reagent addition operations can significantly improve the tin grade in the concentrate and the tin recovery rate. In the method of this invention, butyl xanthate, a commonly used sulfide ore collector, selectively adsorbs onto the surface of sulfide ores (such as pyrite and molybdenite), making them hydrophobic. This allows them to float with air bubbles during flotation and separate from gangue minerals. A dosage of 150-170 g / t of butyl xanthate is appropriate, effectively collecting sulfide ores without affecting tin minerals and avoiding interference with subsequent tin recovery. Removing sulfide ores through flotation reduces the sulfide content in the tailings, decreases the encapsulation and interference of sulfide ores on tin minerals, helps improve the separation efficiency of subsequent tin minerals, and thus increases the tin grade in the concentrate. No. 2 oil is a frother that produces a stable foam layer, helping sulfide mineral particles adsorbed by the collector to adhere to the bubbles. These particles rise with the bubbles to the surface of the pulp, forming a foam layer that is then discharged. A dosage of 24-28 g / t of No. 2 oil is appropriate, providing sufficient foam stability to ensure effective flotation of sulfide minerals without excessive foaming, which could affect the stability and efficiency of the flotation process. By using an appropriate amount of No. 2 oil, efficient flotation of sulfide minerals is ensured, further improving the removal rate and creating favorable conditions for subsequent tin mineral separation.

[0020] During magnetic separation for iron removal, magnetic separation is conducted under a magnetic field strength of 0.2-0.3T, which can effectively separate iron minerals (such as magnetite and hematite) from the tailings. Iron minerals have strong magnetism and are adsorbed onto the drum of the magnetic separator under the influence of the magnetic field, while tin minerals and other non-magnetic minerals remain in the tailings. Magnetic separation reduces the iron mineral content in the tailings, avoids the encapsulation and interference of iron minerals with tin minerals, and helps improve the separation efficiency of subsequent tin minerals, thereby increasing the tin grade in the concentrate. Concentrating the iron-removed tailings to a solid-liquid ratio of 22-25% reduces the water content in the pulp, increases the pulp concentration, and facilitates the subsequent flotation process. A higher pulp concentration increases the processing capacity of the flotation machine, reduces pulp loss, and thus increases the tin recovery rate. Thickening and adjusting the pulp improves the processing efficiency of the flotation machine, reduces pulp loss, ensures more tin minerals enter the flotation process, and further increases the tin recovery rate.

[0021] Sodium carbonate is an alkaline adjuster that regulates the pH of the pulp, typically used to adjust it to a slightly alkaline state (pH 8-9). Under slightly alkaline conditions, the hydrophilicity of the tin mineral surface decreases, which is beneficial for collector adsorption, thereby improving the flotation performance of tin minerals. A suitable dosage of 250-280 g / t of sodium carbonate effectively adjusts the pH of the pulp, ensuring that the surface properties of the tin minerals are suitable for flotation. By adjusting the pH of the pulp, the hydrophobicity of the tin minerals is enhanced, promoting the binding of tin minerals with the collector, improving the flotation efficiency of tin minerals, and ultimately increasing the tin grade in the concentrate.

[0022] Sodium hexametaphosphate is a dispersant that inhibits the flotation of gangue minerals (such as quartz and feldspar), preventing them from entering the concentrate along with tin minerals. Furthermore, sodium hexametaphosphate can dissolve impurities on the mineral surface, improving the flotation environment for tin minerals. Dosage: A moderate dosage of 120-150 g / t of sodium hexametaphosphate effectively inhibits the flotation of gangue minerals, reducing their encapsulation and interference with tin minerals. By inhibiting the flotation of gangue minerals, the gangue content in the concentrate is reduced, increasing the purity of the concentrate and consequently improving the tin grade within it.

[0023] Tributyl phosphate (TBP) is an activator that can activate the surface of tin minerals and enhance their binding ability with collectors. TBP can react with oxides or hydroxides on the surface of tin minerals to form hydrophobic complexes, promoting the flotation of tin minerals. Dosage: A moderate dosage of 90-100 g / t of TBP is sufficient to effectively activate tin minerals and enhance their flotation performance. By activating the surface of tin minerals, the binding ability between tin minerals and collectors is enhanced, improving the flotation efficiency of tin minerals and thus increasing the tin content in the concentrate.

[0024] Hydroxime acid collectors (such as ethyl hydroxime acid) are highly efficient collectors for tin minerals. They selectively adsorb onto the surface of tin minerals, making them hydrophobic, thus allowing them to float with air bubbles during flotation and separate from gangue minerals. Dosage: 700-800 g / t of hydroxime acid collector is relatively high, but this is to ensure sufficient collection of tin minerals, especially in the case of fine and very fine-grained tin minerals, where a larger dosage can improve the collection effect. By using hydroxime acid collectors, efficient flotation of tin minerals is ensured, particularly for fine and very fine-grained tin minerals, resulting in a significant improvement in tin recovery.

[0025] Adding No. 2 oil again provides sufficient foam stability, ensuring that tin minerals float with the bubbles to form a stable foam layer, facilitating subsequent concentrate collection. Dosage: A moderate dosage of 30-50 g / t of No. 2 oil provides sufficient foam stability to ensure effective flotation of tin minerals without excessive foaming, which would affect the stability and efficiency of the flotation process. By using an appropriate amount of No. 2 oil, efficient flotation of tin minerals is ensured, further improving the tin recovery rate.

[0026] Furthermore, the feed characteristics of the physical mineral processing machine are: a processing capacity of 1.3~1.8T dry ore / hour, a feed concentration of 14%~18%, and an initial feed velocity of 0.8~1m / s.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: the method of the present invention can remove sulfide minerals and ferromagnetic minerals by flotation and magnetic separation, respectively, thereby effectively reducing the interference of sulfide minerals and ferromagnetic minerals on the subsequent flotation of cassiterite, and can further improve the feed grade of the flotation operation.

[0028] The method of this invention, through a series of operations, particularly flotation to remove sulfide minerals, magnetic separation to remove iron, adjusting the pulp pH, suppressing gangue minerals, activating tin minerals, and using a highly efficient collector, can significantly improve the tin grade in the concentrate and the tin recovery rate. By removing sulfide minerals through flotation and iron through magnetic separation, interference from gangue and iron minerals is reduced, ensuring efficient separation of tin minerals. Adjusting the pulp pH, suppressing gangue minerals, and activating tin minerals further improves the flotation performance of tin minerals, reduces the contamination of gangue minerals, and thus increases the tin grade in the concentrate. The use of a highly efficient collector and a suitable frother ensures sufficient collection of tin minerals, particularly for fine and very fine-grained tin minerals, significantly improving the tin recovery rate. Attached Figure Description

[0029] Figure 1 This is a process flow diagram of the tin recovery method from secondary tailings of the present invention;

[0030] Figure 2 This is a top view schematic diagram of a physical mineral processing machine;

[0031] Figure 3 This is a side view schematic diagram of a physical mineral processing machine;

[0032] Figure 4 A frontal view of a physical mineral processing machine. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0034] Example 1

[0035] This embodiment provides a method for tin recovery from secondary tailings, including the following steps:

[0036] (1) Feeding: For secondary tin tailings of fine-grained tin ore, the material is first concentrated by a high-efficiency inclined plate thickener, with the concentration controlled at 15%. After the concentration is increased, the material is thoroughly stirred and then enters the physical mineral processing machine through a pressure stabilizing box.

[0037] (2) Physical gravity separation: The centrifugal drum of the physical concentrator rotates horizontally, generating a radially uniform centrifugal force field on the inner surface of the drum. The slurry is fed to the inner surface of the drum by the feeding device and rotates with the drum under the drive of the centrifugal drum. The inner surface of the centrifugal drum has a slope along the axial direction. The slurry flows along the axial direction at a certain velocity while rotating. The slurry moves in a spiral shape along the axial direction on the inner surface of the drum. Under the combined action of the weakly turbulent flow film and the centrifugal force field, the slurry flows in a spiral motion, and mineral particles of different densities are selectively separated. Heavy mineral particles settle to the inner surface of the centrifugal drum in a very short time, forming a compacted thin layer of particles that rotate with the drum. Light mineral particles, due to the diffusion effect of the fluid film pulsation, cannot reach the bottom layer of the fluid film and are discharged along the slope of the drum with the liquid phase, becoming light products (tailings, fine mud, impurities), which are discharged into the tailings collection tank through the ore separation device. When feeding is paused, the flushing device flushes the heavy products (concentrate, heavy metals) into the concentrate collection tank through the ore separation device.

[0038] Physical mineral processing machines (centrifuges) are based on the principle of film separation within a centrifugal force field. To ensure effective centrifugal separation, stable feed properties (processing capacity 1.5T (dry ore) / hour, feed concentration 15%, initial feed velocity 0.9m / s) are crucial. Therefore, the feed must first enter a pressure stabilizing (separation) tank before being fed to the centrifugal concentrator. Furthermore, the centrifugal concentrator's rinsing and washing water are filtered to remove impurities up to +0.5mm. The rinsing water pressure must reach 0.1MPa, and the washing water pressure must reach 0.6MPa.

[0039] (3) Thickening: The physical mineral processing machine discharges heavy products (concentrates, heavy metals) into the mineral sorting device and into the concentrate receiving tank, and then into the high-efficiency inclined plate thickening box for thickening. The discharge port of the thickening box is designed with a timed air pump mechanism to carry out air intake and stirring (20S / time / 3S), which can ensure the stability of the discharge concentration at the discharge port. The concentration is controlled at 40% before entering the flotation for upgrading.

[0040] (4) The principle of flotation: Flotation is a method of mineral separation based on the differences in the physicochemical properties of mineral surfaces. The core of flotation lies in utilizing the difference between the hydrophobic and hydrophilic properties of mineral surfaces. By introducing air bubbles into the slurry, hydrophobic mineral particles adhere to the air bubbles and float to the surface, thereby achieving separation. Flotation is widely used in the beneficiation of non-ferrous metals (such as copper, zinc, lead, nickel, gold, tin, tungsten, etc.) and non-metallic minerals, and is particularly suitable for processing fine and micro-fine particles. Its advantages include a wide range of applications, strong adaptability, and the ability to process various types of ores.

[0041] The basic steps of the flotation process include:

[0042] S1. Feeding: The high-density products (concentrates, heavy metals) from the physical mineral processing machine (centrifuge) are discharged into the concentrate receiving trough of the ore separating device, and then enter the high-efficiency inclined plate thickener for concentration. The discharge port of the thickener is designed with a timed air pump mechanism for air intake and stirring (20 seconds / time / 3 seconds), which can ensure the stability of the discharge concentration. The concentration is controlled at 40% before entering the flotation for upgrading. The ore is made to meet the particle size required for flotation, so that the useful minerals are basically liberated into individual particles for separation. The lower the content of mud, iron, and sulfur, the easier it is to separate.

[0043] S2. Slurry Preparation: Add 150 g / t of xanthate and 24 g / t of No. 2 oil to the slurry. Remove sulfide ore by flotation to obtain sulfide ore and desulfurized tailings. Remove iron from the desulfurized tailings by magnetic separation under a magnetic field strength of 0.2 T to obtain iron concentrate and iron-removed tailings. Concentrate the iron-removed tailings to 22%, add 250 g / t of sodium carbonate, and stir for 5 minutes. Add 120 g / t of sodium hexametaphosphate and stir for 3 minutes. Add 90 g / t of tributyl phosphate and stir for 12 minutes. Add 700 g / t of hydroxamic acid collector and stir for 3 minutes. Add 30 g / t of No. 2 oil and stir for 1 minute to obtain rougher concentrate and rougher tailings.

[0044] S3, Aeration: Air is introduced into the roughing concentrate to form a large number of bubbles.

[0045] S4. Separation: Hydrophobic mineral particles adhere to the air bubbles and float to the surface, forming a mineralized foam layer, while hydrophilic mineral particles remain in the slurry. The mineralized foam is then discharged, achieving the purpose of separation.

[0046] (5) Secondary concentrate upgrading: The flotation concentrate is then fed into a physical concentrator (centrifuge) for secondary upgrading, which can greatly improve the grade of the concentrate. The higher the grade of the feed, the higher the enrichment ratio of the upgrading. The tailings are fully recovered and recycled into a high-efficiency inclined plate thickener for concentration. The concentration is adjusted to 40%, and then returned to the flotation machine for repeated screening to maximize the comprehensive recovery rate and realize the recovery and recycling of resources. Finally, the tin concentrate is dewatered by thickening and filtration.

[0047] Example 2

[0048] This embodiment provides a method for tin recovery from secondary tailings, including the following steps:

[0049] (1) Feeding: For secondary tin tailings of fine-grained tin ore, the material is first concentrated by a high-efficiency inclined plate thickener, with the concentration controlled at 18%. After the concentration is increased, the material is thoroughly stirred and then enters the physical mineral processing machine through a pressure stabilizing box.

[0050] (2) Physical gravity separation: The centrifugal drum of the physical concentrator rotates horizontally, generating a radially uniform centrifugal force field on the inner surface of the drum. The slurry is fed to the inner surface of the drum by the feeding device and rotates with the drum under the drive of the centrifugal drum. The inner surface of the centrifugal drum has a slope along the axial direction. The slurry flows along the axial direction at a certain velocity while rotating. The slurry moves in a spiral shape along the axial direction on the inner surface of the drum. Under the combined action of the weakly turbulent flow film and the centrifugal force field, the slurry flows in a spiral motion, and mineral particles of different densities are selectively separated. Heavy mineral particles settle to the inner surface of the centrifugal drum in a very short time, forming a compacted thin layer of particles that rotate with the drum. Light mineral particles, due to the diffusion effect of the fluid film pulsation, cannot reach the bottom layer of the fluid film and are discharged along the slope of the drum with the liquid phase, becoming light products (tailings, fine mud, impurities), which are discharged into the tailings collection tank through the ore separation device. When feeding is paused, the flushing device flushes the heavy products (concentrate, heavy metals) into the concentrate collection tank through the ore separation device.

[0051] Physical mineral processing machines (centrifuges) are based on the principle of film separation within a centrifugal force field. To ensure effective centrifugal separation, stable feed properties (processing capacity 1.8T (dry ore) / hour, feed concentration 14%, initial feed velocity 1m / s) are crucial. Therefore, the feed must first enter a pressure stabilizing (separation) tank before being fed to the centrifugal concentrator. Furthermore, the centrifugal concentrator's rinsing and washing water are filtered to remove impurities up to +0.5mm. The rinsing water pressure must reach 0.1MPa, and the washing water pressure must reach 0.6MPa.

[0052] (3) Thickening: The physical mineral processing machine discharges heavy products (concentrates, heavy metals) into the mineral sorting device and into the concentrate receiving tank, and then into the high-efficiency inclined plate thickening box for thickening. The discharge port of the thickening box is designed with a timed air pump mechanism to carry out air intake and stirring (20S / time / 3S), which can ensure the stability of the discharge concentration at the discharge port. The concentration is controlled at 45% before entering the flotation for upgrading.

[0053] (4) The principle of flotation: Flotation is a method of mineral separation based on the differences in the physicochemical properties of mineral surfaces. The core of flotation lies in utilizing the difference between the hydrophobic and hydrophilic properties of mineral surfaces. By introducing air bubbles into the slurry, hydrophobic mineral particles adhere to the air bubbles and float to the surface, thereby achieving separation. Flotation is widely used in the beneficiation of non-ferrous metals (such as copper, zinc, lead, nickel, gold, tin, tungsten, etc.) and non-metallic minerals, and is particularly suitable for processing fine and micro-fine particles. Its advantages include a wide range of applications, strong adaptability, and the ability to process various types of ores.

[0054] The basic steps of the flotation process include:

[0055] S1. Feeding: The high-density products (concentrates, heavy metals) from the physical mineral processing machine (centrifuge) are discharged into the concentrate receiving trough of the ore separating device, and then enter the high-efficiency inclined plate thickener for concentration. The thickener discharge port is designed with a timed air pump mechanism for air intake and stirring (20 seconds / time / 3 seconds), which can ensure the stability of the discharge concentration. The concentration is controlled at 45% before entering the flotation for upgrading. The ore is made to meet the particle size required for flotation, so that the useful minerals are basically liberated into individual particles for separation. The lower the content of mud, iron, and sulfur, the easier it is to separate.

[0056] S2. Slurry Preparation: Add 170 g / t of butyl xanthate and 28 g / t of No. 2 oil to the slurry. Remove sulfide ore by flotation to obtain sulfide ore and desulfurized tailings. Remove iron from the desulfurized tailings by magnetic separation under a magnetic field strength of 0.3 T to obtain iron concentrate and iron-removed tailings. Concentrate the iron-removed tailings to 25%, add 280 g / t of sodium carbonate, and stir for 8 minutes. Add 150 g / t of sodium hexametaphosphate and stir for 5 minutes. Add 100 g / t of tributyl phosphate and stir for 16 minutes. Add 800 g / t of hydroxamic acid collector and stir for 5 minutes. Add 50 g / t of No. 2 oil and stir for 2 minutes to obtain rougher concentrate and rougher tailings.

[0057] S3, Aeration: Air is introduced into the roughing concentrate to form a large number of bubbles.

[0058] S4. Separation: Hydrophobic mineral particles adhere to the air bubbles and float to the surface, forming a mineralized foam layer, while hydrophilic mineral particles remain in the slurry. The mineralized foam is then discharged, achieving the purpose of separation.

[0059] (5) Secondary concentrate upgrading: The flotation concentrate is then fed into a physical concentrator (centrifuge) for secondary upgrading, which can greatly improve the grade of the concentrate. The higher the grade of the feed, the higher the enrichment ratio of the upgrading. The tailings are fully recovered and recycled into a high-efficiency inclined plate thickener for concentration. The concentration is adjusted to 45%, and then returned to the flotation machine for repeated screening to maximize the comprehensive recovery rate and realize the recovery and recycling of resources. Finally, the tin concentrate is dewatered by thickening and filtration.

[0060] Comparative Example 1

[0061] The difference between this comparative example and Example 1 is that 28g / t of No. 2 butter was not added.

[0062] Comparative Example 2

[0063] The difference between this comparative example and Example 1 is that 100g / t of butyl xanthate and 70g / t of No. 2 oil were added to the slurry.

[0064] Comparative Example 3

[0065] The difference between this comparative example and Example 1 is that sodium carbonate is not added.

[0066] Comparative Example 4

[0067] The difference between this comparative example and Example 1 is that sodium hexametaphosphate is not added.

[0068] Comparative Example 5

[0069] The difference between this comparative example and Example 1 is that no No. 2 oil (30g / t) was added.

[0070] Performance testing

[0071] The tin concentrates prepared in Example 1 and Comparative Examples 1-5 were analyzed, and the results are shown in Tables 1-2:

[0072] Table 1. Comparative Analysis of Tin Index (%)

[0073]

[0074] Table 2 Comparison of Tin Concentrate Particle Size Analysis (%)

[0075]

[0076] As can be seen from Table 1, the method of the present invention has an excellent recovery rate.

[0077] Comparing Example 1 with Comparative Examples 1-6, it can be seen that the conditions and reagent ratios for flotation removal of sulfide ore and magnetic separation removal of iron in this invention can significantly improve the recovery rate. It also affects the particle size distribution of tin concentrate.

[0078] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for tin recovery from secondary tailings, characterized in that, Includes the following steps: (1) Feeding: For secondary tin tailings of fine-grained tin ore, the material is first concentrated by a high-efficiency inclined plate thickener to increase the concentration. After being thoroughly stirred, it is then fed into a physical mineral concentrator through a pressure stabilizing box. (2) Physical gravity separation: The centrifugal drum of the physical concentrator rotates horizontally, generating a radially uniform centrifugal force field on the inner surface of the drum. The slurry is fed to the inner surface of the drum by the feeding device and rotates with the drum under the drive of the centrifugal drum. The inner surface of the centrifugal drum has a slope along the axial direction. The slurry flows along the axial direction at a certain flow rate while rotating. (3) Thickening: The physical mineral processing machine discharges the heavy products into the mineral separation device and into the concentrate receiving tank, and then into the high-efficiency inclined plate thickening box for thickening. The discharge port of the thickening box is designed with a timed air pump mechanism to introduce air and stir, and then enters the flotation for upgrading. (4) Flotation process: The basic steps of the flotation process include: S1. Feeding: The products with a high specific gravity from the physical mineral processing machine are flushed off and discharged into the concentrate receiving tank of the mineral separation device, and then enter the high-efficiency inclined plate thickener for concentration. The discharge port of the thickener is designed with a timed air pump mechanism to carry out air intake and stirring for quality improvement. S2. Slurry Preparation: Add 150-170 g / t of butyl xanthate and 24-28 g / t of No. 2 oil to the slurry for flotation to remove sulfide ore, obtaining sulfide ore and desulfurized tailings; under a magnetic field strength of 0.2-0.3T, magnetically separate the desulfurized tailings to remove iron, obtaining iron concentrate and iron-removed tailings; concentrate the iron-removed tailings to 22-25%, add 250-280 g / t of sodium carbonate, and stir for 5-8 minutes; add 120-150 g / t of sodium hexametaphosphate, and stir for 3-5 minutes; add 90-100 g / t of tributyl phosphate, and stir for 12-16 minutes; then add 700-800 g / t of hydroxamic acid collector, and stir for 3-5 minutes; finally add 30-50 g / t of No. 2 oil, and stir for 1-2 minutes to obtain rougher concentrate and rougher tailings. S3, Aeration: Air is introduced into the roughing concentrate to form a large number of bubbles; S4. Separation: Hydrophobic mineral particles adhere to the air bubbles and float to the surface, forming a mineralized foam layer, while hydrophilic mineral particles remain in the slurry. The mineralized foam is discharged, achieving the purpose of separation. (5) Secondary concentrate upgrading: The flotation concentrate is then put into a physical concentrator for secondary upgrading to obtain tin concentrate. The tailings are fully recovered and recycled into a high-efficiency inclined plate thickener for concentration. The concentration is adjusted to 35%~45% and then returned to the flotation machine for repeated screening.

2. The method for tin recovery from secondary tailings according to claim 1, characterized in that, The feed characteristics of the physical mineral processing machine are: a processing capacity of 1.3~1.8T dry ore / hour, a feed concentration of 14%~18%, and an initial feed velocity of 0.8~1m / s.

3. The method for tin recovery from secondary tailings according to claim 1, characterized in that, The dosage of butyl xanthate is 150-170g / t of slurry.

4. The method for tin recovery from secondary tailings according to claim 3, characterized in that, The dosage of the first addition of No. 2 oil is 24-28g / t of slurry.

5. The method for tin recovery from secondary tailings according to claim 1, characterized in that, The dosage of sodium carbonate is 250-280 g / t of slurry.

6. The method for tin recovery from secondary tailings according to claim 5, characterized in that, The dosage of sodium hexametaphosphate is 120-150 g / t of slurry.

7. The method for tin recovery from secondary tailings according to claim 5, characterized in that, The dosage of tributyl phosphate is 90-100 g / t slurry.

8. The method for tin recovery from secondary tailings according to claim 5, characterized in that, The dosage of hydroxamic acid collectors is 700-800 g / t slurry.

9. The method for tin recovery from secondary tailings according to claim 5, characterized in that, The amount of No. 2 oil added for the second time is 30-50g / t of slurry.

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