Beneficiation method for efficiently separating scheelite, wolframite and cassiterite in tungsten-tin bulk concentrate

Abstract

The invention discloses a beneficiation method for efficiently separating scheelite, wolframite and cassiterite in tungsten-tin bulk concentrate. The beneficiation method comprises the following steps that (1) the tungsten-tin bulk concentrate is firstly subjected to ore grinding, flotation desulfurization and magnetic separation iron removal, and iron-removed tailings are obtained; (2) performing scheelite normal-temperature flotation on the iron-removed tailings to obtain scheelite rough concentrate and scheelite flotation tailings; (3) the scheelite rough concentrate is subjected to flotation upgrading, scheelite upgraded rough concentrate is obtained, and wolframite and cassiterite are deeply inhibited in the flotation upgrading process; the scheelite quality-improved rough concentrate is subjected to quality-improved fine selection, and scheelite concentrate is obtained; (4) the scheelite flotation tailings are subjected to magnetic separation to achieve separation of wolframite and cassiterite, and wolframite concentrate and tin rough concentrate are obtained; and (5) gangue minerals are removed from the tin rough concentrate through electric separation, and tin concentrate is obtained. According to the beneficiation method, tungsten and tin resources can be efficiently and comprehensively recycled.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing, and particularly relates to a mineral processing method for tungsten-tin mixed concentrate. Background Technology

[0002] The industrially valuable tungsten minerals in the Earth's crust are mainly wolframite and scheelite, while the industrially valuable tin mineral is mainly cassiterite. Due to the similar geochemical behaviors of tungsten and tin, many tungsten deposits often co-exist with tin minerals. Furthermore, tungsten and tin minerals have similar specific gravities and floatability, so mining companies typically use gravity separation, flotation, or a combination of both processes to simultaneously enrich and recover tungsten and tin minerals, obtaining a mixed tungsten-tin concentrate. However, since tungsten and tin are impurities in each other during smelting, this affects the market sales and pricing of the mixed tungsten-tin concentrate, harming the economic benefits of enterprises and causing a serious waste of tungsten and tin resources. Therefore, developing a new, economical, and efficient tungsten-tin separation technology for mixed tungsten-tin concentrate is of great significance.

[0003] Because cassiterite has poor floatability and is prone to over-grinding and sliming, it is greatly affected by ore slime. In industrial applications, the method of preferentially flotating tin to separate tungsten-tin mixed concentrates generally suffers from problems such as high reagent consumption and high flotation costs. Furthermore, cassiterite is easily lost in the middlings during the refining process, resulting in a loss of tin recovery. For example, patent application CN118080167A discloses a Pb-BHA-SDBS collector and a method for separating tungsten and tin in tungsten-tin polymetallic ores. After obtaining a tungsten-tin mixed concentrate through flotation, NaOH is first added to adjust the pulp pH to >11, and the mixture is vigorously stirred for more than 15 minutes. Then, a large amount of sulfuric acid, oxalic acid, and citric acid are added to adjust the pH to around 4 for cassiterite flotation recovery. This ultimately yields a tin concentrate with a Sn grade of 14-18.40% and a Sn recovery rate of 37.69%, and a tungsten concentrate with a WO3 grade of 28-30.64% and a WO3 recovery rate of only 73-80.09%. The tungsten-suppressing and tin-floating process uses an alkali-then-acid separation method, which not only consumes a large amount of sulfuric acid, but also causes severe corrosion damage to the flotation equipment under low pH (≤4) conditions, which is not conducive to stable production operation. Furthermore, the obtained tin concentrate has a Sn grade of <20% and a Sn recovery rate of less than 50%, resulting in a certain degree of waste of tungsten and tin resources.

[0004] Therefore, it is urgent to design and develop an efficient separation and beneficiation method for scheelite, wolframite and cassiterite in tungsten-tin mixed concentrate based on the physicochemical properties and beneficiation differences of wolframite, scheelite and cassiterite in tungsten-tin mixed concentrate, so as to achieve efficient and comprehensive recovery and utilization of tungsten and tin resources. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a mineral processing method for efficient separation of scheelite, wolframite and cassiterite in tungsten-tin mixed concentrate that can achieve efficient comprehensive recycling of tungsten and tin resources.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A beneficiation method for efficient separation of scheelite, wolframite and cassiterite in a tungsten-tin mixed concentrate includes the following steps: (1) The tungsten-tin mixed concentrate is first ground, desulfurized by flotation, and de-ironized by magnetic separation to obtain iron-removed tailings; (2) The iron-removed tailings are subjected to scheelite flotation at room temperature to obtain scheelite rough concentrate and scheelite flotation tailings; (3) The scheelite rough concentrate is subjected to flotation and upgrading to obtain scheelite upgraded rough concentrate. During the flotation and upgrading process, wolframite and cassiterite are deeply suppressed. The scheelite upgraded rough concentrate is then upgraded and finely selected to obtain scheelite concentrate. (4) The scheelite flotation tailings are separated from cassiterite by magnetic separation to obtain scheelite concentrate and tin rough concentrate; (5) The tin crude concentrate is subjected to electrostatic separation to remove gangue minerals such as quartz and feldspar to obtain tin concentrate.

[0007] In the above-mentioned mineral processing method, preferably, during the room temperature flotation of scheelite, the scheelite collector includes the following components in parts by weight: 10-35 parts sodium lauroyl sarcosinate, 30-50 parts oxidized paraffin soap, and 45-60 parts isopropanol.

[0008] In the above-mentioned mineral processing method, preferably, during the flotation upgrading process, the mass concentration of the scheelite rough concentrate slurry is controlled to be ≥40%, and a depth inhibitor is added. The depth inhibitor includes salt-modified water glass and citric acid in a weight ratio of 10:(1-2). The salt-modified water glass is prepared by mixing water glass and aluminum sulfate in a weight ratio of 10:(0.5-2).

[0009] The scheelite collector and depth inhibitor used in this invention act on the scheelite rough concentrate flotation system. The two work synergistically to achieve efficient separation of scheelite from wolframite and cassiterite.

[0010] In the above-mentioned beneficiation method, preferably, the grinding process involves grinding the tungsten-tin mixed concentrate to a particle size of -0.075 mm with a content of ≤75%, and the degree of liberation of scheelite, wolframite, and cassiterite in the tungsten-tin mixed concentrate is ≥90%. By controlling the above grinding conditions, the deterioration of flotation caused by over-grinding and mudding of tungsten and tin minerals can be avoided.

[0011] In the above-mentioned mineral processing method, preferably, flotation desulfurization includes the following steps: performing full flotation desulfurization on the grinding product to obtain full flotation rough concentrate and full flotation rough tailings; performing full flotation cleaning 1-3 times on the full flotation rough concentrate to obtain sulfur concentrate and full flotation cleaning middlings, the full flotation cleaning middlings being sequentially returned to the previous operation; performing full flotation scavenging 1-3 times on the full flotation rough tailings to obtain full flotation tailings and full flotation scavenging concentrate, the full flotation scavenging concentrate being sequentially returned to the previous operation.

[0012] In the above-mentioned mineral processing method, preferably, the magnetic separation for iron removal includes the following steps: subjecting the fully floated tailings to weak magnetic separation to obtain weak magnetite concentrate and iron-removed tailings; when performing weak magnetic separation, the number of cleaning cycles is 1-2 times, the number of scavenging cycles is 1-3 times, and the magnetic field strength is 0.05-0.30T.

[0013] In the above-mentioned beneficiation methods, the preferred process flow for room temperature flotation of scheelite is one roughing, one to three cleaning, and one to three scavenging to obtain scheelite rough concentrate and scheelite flotation tailings; the modifiers in the flotation process include one or more of sodium carbonate, sodium hydroxide, water glass, aluminum sulfate, and sodium hexametaphosphate.

[0014] In the above-mentioned beneficiation method, preferably, a scheelite collector and a depth inhibitor are added during flotation upgrading to obtain scheelite upgraded rough concentrate and scheelite upgraded tailings, and the scheelite upgraded tailings are returned to the scheelite room temperature roughing operation.

[0015] In the above-mentioned mineral processing methods, the preferred method is to perform 3-5 blank cleaning processes on the scheelite ore to obtain scheelite concentrate and middlings from the ore to be improved. The middlings from the ore to be improved are then returned to the next higher-level operation in sequence.

[0016] In the aforementioned mineral processing methods, the preferred method for separating wolframite and cassiterite using magnetic separation is to employ high-intensity magnetic separation to obtain wolframite concentrate and tin rough concentrate. The high-intensity magnetic separation process consists of one roughing, one cleaning, and one scavenging operation, with a magnetic field strength of 0.5-2.0T. High-intensity magnetic separation can achieve the separation of wolframite and cassiterite by utilizing the difference in their magnetic properties.

[0017] Among the above-mentioned beneficiation methods, the preferred method utilizes the difference in electrical conductivity between cassiterite and gangue such as quartz and feldspar to remove non-conductive gangue through electrostatic separation, thereby significantly improving the quality of tin concentrate and obtaining high-quality tin concentrate products.

[0018] This invention addresses the differences in physicochemical properties and beneficiability of scheelite, wolframite, and cassiterite in tungsten-tin mixed concentrates, aiming to achieve economical and efficient development and utilization of these difficult-to-process tungsten-tin mixed concentrate resources, thereby improving the comprehensive utilization rate and security of my country's tungsten and tin resources. More specifically, the method may include the following steps: (1) The sulfur-containing tungsten-tin mixed rough concentrate is subjected to a first-stage grinding process to obtain a grinding product with a particle size of -0.075 mm and a content of ≤75%, or the degree of liberation of target minerals such as scheelite, wolframite and cassiterite in the tungsten-tin mixed concentrate is ≥90%; (2) The grinding product described in step (1) is subjected to full flotation desulfurization to obtain full flotation rough concentrate and full flotation rough tailings; (3) Perform full flotation cleaning on the full flotation rough concentrate described in step (2) 1-3 times to obtain sulfur concentrate and full flotation cleaning middlings. The cleaning middlings are returned to the upper-level operation in sequence. (4) Perform full flotation roughing tailings from step (2) on full flotation scavenging 1-3 times to obtain full flotation tailings and full flotation scavenging concentrate. The full flotation scavenging concentrate is then returned to the upper-level operation in sequence. (5) The fully floated tailings described in step (4) are subjected to weak magnetic separation to obtain weak magnetic concentrate and weak magnetic tailings; (6) The weak magnetic tailings described in step (5) are subjected to scheelite flotation at room temperature. The process flow is one roughing, one to three cleaning, and one to three scavenging to obtain scheelite rough concentrate and scheelite flotation tailings. (7) The scheelite rough concentrate obtained in step (6) is subjected to deep suppression flotation to improve its quality, thereby obtaining scheelite improved rough concentrate and scheelite improved tailings. The scheelite improved tailings are returned to the scheelite room temperature roughing operation. (8) The scheelite rough concentrate described in step (7) is subjected to 3-5 upgrades and refinements to obtain scheelite concentrate and middlings from the upgrades and refinements. The middlings from the upgrades and refinements are then returned to the next higher-level operation in sequence. (9) The scheelite flotation tailings obtained in step (6) are separated from cassiterite by strong magnetic separation to obtain scheelite concentrate and tin rough concentrate; (10) Remove gangue minerals such as quartz and feldspar from the tin crude concentrate obtained in step (9) by electrostatic separation to obtain tin concentrate.

[0019] In steps (2), (3), and (4) above, flotation desulfurization is carried out on the grinding product to obtain sulfur concentrate product while eliminating the adverse effects of sulfide ore on subsequent tungsten-tin separation.

[0020] This invention abandons the traditional Petrov process for scheelite flotation and instead employs a stepwise method for scheelite flotation and collection under ambient temperature conditions. The first step involves a roughing and cleaning process to obtain a rough scheelite concentrate, maximizing the flotation recovery rate. The second step uses a combination of saline water glass and citric acid as a depressant for deep impurity removal from the rough scheelite concentrate. Under high-concentration pulp conditions (≥40%), citric acid is used to target the Sn surface active sites of cassiterite minerals. 4+The chelate formed adheres to the surface of cassiterite minerals, hindering the adsorption of scheelite collectors. Through its own hydrophilic polar groups, it enhances the hydrophilicity of the cassiterite surface via hydration, achieving efficient separation of scheelite and cassiterite. At the same time, the salt-treated water glass strongly inhibits wolframite, widening the hydrophobic difference between scheelite and wolframite. This achieves efficient separation of scheelite, wolframite, and cassiterite, significantly reducing flotation energy consumption costs, improving the economic benefits of mineral processing, and eliminating the safety hazards caused by complex heating systems.

[0021] This invention employs a stable emulsion formed by the synergistic combination of sodium lauroyl sarcosinate, oxidized paraffin soap, and isopropanol as the thymol flotation collector CY-12. Sodium lauroyl sarcosinate, a surfactant possessing characteristics of both fatty acid soap and alkyl sulfonate, efficiently emulsifies the oxidized paraffin soap, promoting its dispersion in aqueous solution and eliminating oil-phase aggregation while enhancing flotation foam stability. Isopropanol is then used as a solvent and co-emulsifier to adjust the viscosity of the collector system, further strengthening the dispersion effect of sodium lauroyl sarcosinate. This invention overcomes the shortcomings of traditional fatty acid and saponified modified thymol collectors, such as poor water solubility, poor selectivity, poor low-temperature resistance, and significant influence from calcium and magnesium ions. It boasts advantages such as being environmentally friendly, requiring low reagent dosage, exhibiting good selectivity, strong collection capacity, and stable separation indicators, making it crucial for achieving efficient enrichment and recovery of thymol.

[0022] The collectors and inhibitors of the present invention can regulate the surface properties of various ores in tin concentrate, facilitating subsequent electrostatic separation. By utilizing the difference in electrical conductivity between cassiterite and gangue minerals such as quartz and feldspar, the conductive mineral cassiterite can be rapidly and efficiently separated from the non-conductive gangue minerals through electrostatic separation, thereby obtaining a high-quality tin concentrate product with a Sn grade ≥60%.

[0023] Compared with the prior art, the advantages of the present invention are as follows: The present invention discloses a beneficiation method for the efficient separation of scheelite, wolframite, and cassiterite in a tungsten-tin mixed concentrate. Under ambient temperature conditions, a stepwise flotation method is used for scheelite flotation. During the scheelite flotation process, wolframite and cassiterite are deeply suppressed, and scheelite is efficiently collected, which is beneficial for the efficient separation of scheelite from wolframite and cassiterite. Then, utilizing the magnetic difference between wolframite and cassiterite, high-intensity magnetic separation is used to achieve efficient separation of wolframite and cassiterite, which has advantages such as low beneficiation cost and good separation index. Finally, utilizing the difference in electrical conductivity between cassiterite and gangue minerals such as calcite, electrostatic separation is used to achieve rapid and efficient separation of cassiterite and non-conductive calcium-containing gangue minerals such as calcite, which have very similar floatability, resulting in a high-quality tin concentrate product with a Sn grade ≥ 60%.

[0024] This invention utilizes a combined flotation-magnetic-electric multi-force field process to obtain wollastonite and wolframite concentrates with WO3 grades ≥65% (containing Sn ≤0.3%) and tin concentrate with Sn grades ≥60%, both meeting the requirements for high-quality tungsten and tin concentrates for sale. These concentrates have a wide market reach, and the recovery rates of WO3 and Sn are both ≥97%, resulting in high comprehensive utilization of tungsten and tin. The process boasts advantages such as a compact structure, low energy consumption, stable operation, high-quality tungsten and tin concentrate products, and high target metal recovery rates. It can significantly improve the economic benefits of enterprises and provides a new approach and strategy for the comprehensive utilization of similar tungsten and tin mixed concentrate resources. Attached Figure Description

[0025] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a process flow diagram of the efficient separation and beneficiation method of scheelite, wolframite and cassiterite in tungsten-tin mixed concentrate of the present invention. Detailed Implementation

[0027] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0030] Example 1: A highly efficient separation and beneficiation method for scheelite, wolframite, and cassiterite in a tungsten-tin mixed concentrate is disclosed. The ore sample processed is a tungsten-tin mixed concentrate obtained by gravity separation from a beneficiation plant in Yunnan Province. The WO3 grade is 36.96%, Sn grade is 19.41%, S grade is 1.73%, and TFe grade is 4.73%. The tungsten minerals are mainly wolframite and scheelite, with a ratio of approximately 1:3. The tin mineral is mainly cassiterite, and the sulfur is mainly pyrite with a small amount of magnetic iron. The gangue minerals are mainly quartz, garnet, and fluorite. Figure 1 As shown, the mineral processing method includes the following steps: (1) The sulfur-containing tungsten-tin mixed rough concentrate is subjected to a first-stage grinding process to obtain a grinding product with a particle size of -0.075 mm accounting for 50% of the total content; (2) Add 200g / t of copper sulfate, 250g / t of butyl xanthate, and 20g / t of No. 2 oil to the grinding product in step (1) for full flotation desulfurization to obtain full flotation sulfur rough concentrate and full flotation rough tailings; (3) The full flotation rough concentrate in step (2) is subjected to three blank cleaning processes to obtain a sulfur concentrate with a yield of 4.24% and an S grade of 38.88%. The middlings from the cleaning process are then returned to the next higher-level operation in sequence. (4) The tailings from the full flotation roughing process in step (2) are subjected to two full flotation scavenging processes. The scavenging reagent regimes are as follows: Scavenging 1: 50g / t of butyl xanthate and 10g / t of No. 2 oil; Scavenging 2: 25g / t of butyl xanthate and 5g / t of No. 2 oil, to obtain full flotation tailings and full flotation scavenging concentrate. The full flotation scavenging concentrate is returned to the upper-level operation in sequence. (5) The fully floated tailings in step (4) are subjected to two weak magnetic separations: one rough and one clean. The magnetic field strength of the rough separation is 0.20T, and the magnetic field strength of the clean separation is 0.15T, to obtain an iron concentrate with a yield of 4.62% and a TFe grade of 63.45%. The tailings from the weak magnetic rough separation and the middlings from the weak magnetic clean separation are combined and fed into a thickener for concentration, which is used as weak magnetic tailings. (6) The weak magnetic tailings in step (5) are subjected to scheelite flotation at room temperature. The process flow is "one roughing, one cleaning, and one scavenging". The roughing reagent system is: sodium carbonate 1500g / t, water glass 3000g / t, scheelite collector CY-12 350g / t. The scavenging reagent system is: scheelite collector CY-12 50g / t. The scheelite cleaning adopts the blank cleaning method to obtain scheelite rough concentrate and scheelite flotation tailings. The middlings of the cleaning and the scavenging concentrate are combined and returned to the roughing operation. The scheelite collector CY-12 is a compound of 20 parts of sodium lauroyl sarcosinate, 40 parts of oxidized paraffin soap, and 50 parts of isopropanol. (7) Concentrate the scheelite rough concentrate in step (6) to a pulp concentration of 50%, add 50g / t of scheelite collector CY-12, 5000g / t of saline water glass (water glass and aluminum sulfate are prepared in a weight ratio of 10:0.5), and 500g / t of citric acid for flotation upgrading to obtain upgraded scheelite rough concentrate and upgraded scheelite tailings. The upgraded scheelite tailings are returned to the scheelite room temperature roughing operation. (8) The scheelite upgrading concentrate from step (7) is subjected to four blank cleaning processes to obtain scheelite concentrate with a yield of 40.49%, a WO3 grade of 65.98% (Sn content 0.22%), and a WO3 recovery rate of 72.28%. The ore from the upgrading and cleaning process is sequentially returned to the next higher-level operation. (9) The scheelite flotation tailings from step (6) are subjected to strong magnetic separation with “1 rougher, 1 cleaner, 1 scavenger”. The field strengths of roughing, cleaning, and scavenging are 1.2T, 1.0T, and 1.5T, respectively, to obtain scheelite rough concentrate (Sn content 0.28%) with a yield of 13.20%, WO3 grade of 70.73%, and WO3 recovery rate of 25.26%. The middlings from strong magnetic cleaning and the concentrate from strong magnetic scavenging are combined and returned to the strong magnetic roughing operation. (10) The tin crude concentrate from step (9) is electro-separated to obtain a tin concentrate with a yield of 30.77%, a Sn grade of 61.87%, and a Sn recovery rate of 98.08%.

[0031] The mineral processing method of this embodiment is used to process the tungsten-tin mixed concentrate obtained by gravity separation in a mineral processing plant in Yunnan Province. It achieves efficient separation of tungsten and tin, with a combined WO3 recovery rate of scheelite and wolframite concentrate of 97.54% and a Sn recovery rate of tin concentrate of 98.08%. At the same time, sulfur concentrate and iron concentrate are also recovered, which significantly improves the economic benefits of the mineral processing plant.

[0032] Example 2: A highly efficient separation and beneficiation method for scheelite, wolframite, and cassiterite in a tungsten-tin mixed concentrate is disclosed. The ore sample processed is a tungsten-tin mixed concentrate obtained by gravity separation from a beneficiation plant in Inner Mongolia. The WO3 grade is 40.15%, Sn grade is 15.11%, S grade is 2.28%, and TFe grade is 6.62%. The tungsten minerals are mainly wolframite and scheelite, with a ratio close to 1:1. The tin mineral is mainly cassiterite, with sulfur mainly in pyrite and a small amount of magnetic iron. The remaining gangue components are present in low amounts. Figure 1 As shown, the mineral processing method includes the following steps: (1) The sulfur-containing tungsten-tin mixed rough concentrate is subjected to a first-stage grinding process to obtain a grinding product with a particle size of -0.075 mm accounting for 55% of the total content. (2) Add 250g / t of copper sulfate, 200g / t of butyl xanthate, and 20g / t of No. 2 oil to the grinding product in step (1) for full flotation desulfurization to obtain full flotation sulfur rough concentrate and full flotation rough tailings; (3) Perform three blank cleaning processes on the full flotation rough concentrate in step (2) to obtain a sulfur concentrate with a yield of 4.96% and an S grade of 40.15%. The middlings from the cleaning process are sequentially returned to the next higher-level operation. (4) The tailings from the full flotation roughing process in step (2) are subjected to two full flotation scavenging processes. The scavenging reagent regimes are as follows: Scavenging 1: 60g / t of butyl xanthate and 10g / t of No. 2 oil; Scavenging 2: 30g / t of butyl xanthate and 5g / t of No. 2 oil, to obtain full flotation tailings and full flotation scavenging concentrate. The full flotation scavenging concentrate is returned to the upper-level operation in sequence. (5) The fully floated tailings in step (4) are subjected to two weak magnetic separations: one rough and one clean. The magnetic field strength of the rough separation is 0.20T, and the magnetic field strength of the clean separation is 0.15T, to obtain an iron concentrate with a yield of 8.96% and a TFe grade of 60.18%. The tailings from the weak magnetic rough separation and the middlings from the weak magnetic clean separation are combined and fed into a thickener for concentration, which is used as weak magnetic tailings. (6) The weak magnetic tailings in step (5) are subjected to scheelite flotation at room temperature. The process flow is "one roughing, one cleaning, and one scavenging". The roughing reagent system is: sodium carbonate 2000g / t, water glass 4000g / t, scheelite collector CY-12 400g / t. The scavenging reagent system is: scheelite collector CY-12 80g / t. The scheelite cleaning adopts the blank cleaning method to obtain scheelite rough concentrate and scheelite flotation tailings. The middlings of the cleaning and the scavenging concentrate are combined and returned to the roughing operation. The scheelite collector CY-12 is a compound of 15 parts of sodium lauroyl sarcosinate, 35 parts of oxidized paraffin soap, and 45 parts of isopropanol. (7) Concentrate the scheelite rough concentrate in step (6) to a pulp concentration of 55%, add 50g / t of scheelite collector CY-12, 4000g / t of saline water glass (water glass and aluminum sulfate are prepared in a weight ratio of 10:0.5), and 450g / t of citric acid for flotation upgrading to obtain upgraded scheelite rough concentrate and upgraded scheelite tailings. The upgraded scheelite tailings are returned to the scheelite room temperature roughing operation. (8) The scheelite upgrading concentrate from step (7) is subjected to four blank cleaning processes to obtain scheelite concentrate with a yield of 27.20%, a WO3 grade of 67.45% (Sn content 0.20%), and a WO3 recovery rate of 45.70%. The ore from the upgrading and cleaning processes is sequentially returned to the next higher-level operation. (9) The scheelite flotation tailings from step (6) are subjected to strong magnetic separation with “1 rougher, 1 cleaner, 1 scavenger”. The field strengths of roughing, cleaning, and scavenging are 1.2T, 1.0T, and 1.5T, respectively, to obtain scheelite rough concentrate (Sn content 0.25%) with a yield of 29.33%, WO3 grade of 71.43%, and WO3 recovery rate of 52.19% and tin rough concentrate. The middlings from strong magnetic cleaning and the concentrate from strong magnetic scavenging are combined and returned to the strong magnetic roughing operation. (10) The tin crude concentrate from step (9) is electro-separated to obtain a tin concentrate with a yield of 22.35%, a Sn grade of 65.26%, and a Sn recovery rate of 96.53%.

[0033] The mineral processing method described in this embodiment was used to process a mixed tungsten-tin concentrate obtained from gravity separation at a mineral processing plant in Yunnan Province. This method achieved efficient separation of tungsten and tin, with a combined WO3 recovery rate of 97.89% for scheelite and wolframite concentrates and a Sn recovery rate of 96.53% for tin concentrate. At the same time, sulfur concentrate and iron concentrate were also recovered, resulting in significant economic benefits.

[0034] Comparative Example 1: The mineral sample used in this comparative example is the same as that in Example 1. The main difference from Example 1 is that the electrostatic separation operation in Example 1 is omitted. The specific steps and reagent system are as follows: (1) The sulfur-containing tungsten-tin mixed rough concentrate is subjected to a first-stage grinding process to obtain a grinding product with a particle size of -0.075 mm accounting for 50% of the total content; (2) Add 200g / t of copper sulfate, 250g / t of butyl xanthate, and 20g / t of No. 2 oil to the grinding product in step (1) for full flotation desulfurization to obtain full flotation sulfur rough concentrate and full flotation rough tailings; (3) The full flotation rough concentrate in step (2) is subjected to three blank cleaning processes to obtain a sulfur concentrate with a yield of 4.24% and an S grade of 38.88%. The middlings from the cleaning process are then returned to the next higher-level operation in sequence. (4) The tailings from the full flotation roughing process in step (2) are subjected to two full flotation scavenging processes. The scavenging reagent regimes are as follows: Scavenging 1: 50g / t of butyl xanthate and 10g / t of No. 2 oil; Scavenging 2: 25g / t of butyl xanthate and 5g / t of No. 2 oil, to obtain full flotation tailings and full flotation scavenging concentrate. The full flotation scavenging concentrate is returned to the upper-level operation in sequence. (5) The fully floated tailings in step (4) are subjected to two weak magnetic separations: one rough and one clean. The magnetic field strength of the rough separation is 0.20T, and the magnetic field strength of the clean separation is 0.15T, to obtain an iron concentrate with a yield of 4.62% and a TFe grade of 63.45%. The tailings from the weak magnetic rough separation and the middlings from the weak magnetic clean separation are combined and fed into a thickener for concentration, which is used as weak magnetic tailings. (6) The weak magnetic tailings in step (5) are subjected to scheelite flotation at room temperature. The process flow is "one roughing, one cleaning, and one scavenging". The roughing reagent system is: sodium carbonate 1500g / t, water glass 3000g / t, scheelite collector CY-12 350g / t. The scavenging reagent system is: scheelite collector CY-12 50g / t. The scheelite cleaning adopts the blank cleaning method to obtain scheelite rough concentrate and scheelite flotation tailings. The middlings of the cleaning and the scavenging concentrate are combined and returned to the roughing operation. The scheelite collector CY-12 is a compound of 20 parts of sodium lauroyl sarcosinate, 40 parts of oxidized paraffin soap, and 50 parts of isopropanol. (7) Concentrate the scheelite rough concentrate in step (6) to a pulp concentration of 50%, add 50g / t of scheelite collector CY-12, 5000g / t of saline water glass (water glass and aluminum sulfate are prepared in a weight ratio of 10:0.5), and 500g / t of citric acid for flotation upgrading to obtain upgraded scheelite rough concentrate and upgraded scheelite tailings. The upgraded scheelite tailings are returned to the scheelite room temperature roughing operation. (8) The scheelite upgrading concentrate from step (7) is subjected to four blank cleaning processes to obtain scheelite concentrate with a yield of 40.49%, a WO3 grade of 65.98% (Sn content 0.22%), and a WO3 recovery rate of 72.28%. The ore from the upgrading and cleaning process is sequentially returned to the next higher-level operation. (9) The scheelite flotation tailings from step (6) are subjected to strong magnetic separation with a "1 rougher, 1 cleaner, 1 scavenger" process. The field strengths for roughing, cleaning, and scavenging are 1.2T, 1.0T, and 1.5T, respectively, to obtain a black tungsten concentrate with a yield of 13.20%, a WO3 grade of 70.73%, and a WO3 recovery rate of 25.26% (Sn content 0.28%), and a tin concentrate with a yield of 37.45%, a Sn grade of 51.46%, and a Sn recovery rate of 99.21%. The middlings from the strong magnetic cleaning process and the concentrate from the strong magnetic scavenging process are combined and returned to the strong magnetic roughing process.

[0035] When the tungsten-tin mixed concentrate in Example 1 was processed using the above-mentioned beneficiation method, the Sn grade of the tin concentrate was 10.41 percentage points lower than that in Example 1, and the tin concentrate product was reduced from grade 3 to grade 5.

[0036] Comparative Example 2: The mineral sample used in this comparative example is the same as that in Example 1. The main difference is that the scheelite flotation uses a conventional reagent system and does not involve electrostatic separation. The specific steps and reagent system are as follows: (1) For the weak magnetic tailings in Example 1, scheelite was subjected to ambient temperature flotation. The process flow was "one roughing, four cleaning, and one scavenging". The reagent system for roughing scheelite was: sodium carbonate 1500g / t, water glass 6000g / t, sodium oleate 400g / t. The reagent system for cleaning scheelite was: Cleaner 1: water glass 1000g / t, aluminum sulfate 200g / t; Cleaner 2: water glass 500g / t, aluminum sulfate 100g / t; Cleaner 3: water glass 100g / t, aluminum sulfate 100g / t. The reagents used in the flotation process were: 300g / t of water glass, 60g / t of aluminum sulfate, and 200g / t of water glass and 40g / t of aluminum sulfate. The scavenging reagents were: 50g / t of sodium oleate. The resulting scheelite concentrate (Sn content 12.42%) had a yield of 45.21%, a WO3 grade of 45.45%, and a WO3 recovery rate of 55.59%. The scheelite concentrate and scheelite flotation tailings were returned sequentially to the next stage of flotation operation along with the middlings from the beneficiation process. (2) The scheelite flotation tailings from step (1) are subjected to strong magnetic separation with a "1 rougher, 1 cleaner, 1 scavenger" process. The field strengths for roughing, cleaning, and scavenging are 1.2T, 1.0T, and 1.5T, respectively, to obtain a black tungsten concentrate with a yield of 10.25%, a WO3 grade of 69.45%, and a WO3 recovery rate of 19.26% (Sn content 0.24%), and a tin concentrate with a yield of 35.68%, a Sn grade of 38.56%, and a Sn recovery rate of 70.83%. The middlings from the strong magnetic cleaning process and the concentrate from the strong magnetic scavenging process are combined and returned to the strong magnetic roughing process.

[0037] When the above-mentioned beneficiation method was used to process the tungsten-tin mixed concentrate in Example 1, the separation effect of tungsten and tin was not ideal. Tungsten and tin were severely inter-containing in scheelite and tin concentrate. The Sn content in scheelite concentrate was 12.42%, and the WO3 content in tin concentrate was 26.01%. The combined WO3 recovery rate of scheelite and wolframite concentrate was only 74.85%, a decrease of 22.69 percentage points. The Sn recovery rate in tin concentrate also decreased by 28.38 percentage points, resulting in economic losses for the beneficiation plant.

[0038] Example 3: The mineral sample used in this embodiment is the same as that in Example 1. The main difference is that the scheelite flotation collector used is a traditional oxidized paraffin soap for flotation collection. The specific steps and reagent system are as follows: (1) For the weak magnetic tailings in Example 1, scheelite was subjected to ambient temperature flotation. The process flow was "one roughing, one cleaning, and one scavenging". The roughing reagent system was: sodium carbonate 1500g / t, water glass 4000g / t, scheelite collector oxidized paraffin soap 500g / t. The scavenging reagent system was: scheelite collector oxidized paraffin soap 80g / t. The scheelite cleaning adopted the blank cleaning method to obtain scheelite rough concentrate and scheelite flotation tailings. The middlings of the cleaning and the scavenging concentrate were combined and returned to the roughing operation. (2) Concentrate the scheelite rough concentrate in step (1) to a pulp concentration of 50%, add 60g / t of scheelite collector oxidized paraffin soap, 5500g / t of saline water glass (water glass and aluminum sulfate are prepared in a weight ratio of 10:0.5), and 500g / t of citric acid for flotation upgrading to obtain upgraded scheelite rough concentrate and upgraded scheelite tailings. The upgraded scheelite tailings are returned to the scheelite room temperature roughing operation. (3) The scheelite upgrading rough concentrate from step (2) is subjected to four blank cleaning processes to obtain scheelite concentrate with a yield of 48.12%, a WO3 grade of 55.24% (Sn content 4.88%), and a WO3 recovery rate of 71.92%. The ore from the upgrading and cleaning process is sequentially returned to the next higher-level operation. (4) The scheelite flotation tailings from step (3) are subjected to strong magnetic separation with “1 rougher, 1 cleaner, 1 scavenger”. The field strengths of roughing, cleaning, and scavenging are 1.2T, 1.0T, and 1.5T respectively, to obtain scheelite rough concentrate (Sn content 0.78%) with a yield of 8.43%, WO3 grade of 69.64%, and WO3 recovery rate of 15.89% and tin rough concentrate. The middlings from strong magnetic cleaning and the concentrate from strong magnetic scavenging are combined and returned to the strong magnetic roughing operation. (5) The tin crude concentrate from step (4) is electro-separated to obtain a tin concentrate with a yield of 27.91%, a Sn grade of 60.12%, and a Sn recovery rate of 86.45%.

[0039] Using oxidized paraffin soap as the flotation collector for scheelite resulted in a significant increase in scheelite concentrate yield due to insufficient selectivity. The WO3 grade decreased by 10.74 percentage points compared to Example 1, and the Sn content in the scheelite concentrate increased by 4.66 percentage points, directly causing substantial tin mineral loss. Replacing CY-12 with oxidized paraffin soap as the scheelite collector reduced the overall WO3 recovery rate of scheelite and wolframite concentrates by 9.74 percentage points, and the Sn recovery rate in tin concentrate decreased by 11.64 percentage points, resulting in losses of both tungsten and tin resources.

Claims

1. A beneficiation method for efficient separation of scheelite, wolframite, and cassiterite in a tungsten-tin mixed concentrate, characterized in that, Includes the following steps: (1) The tungsten-tin mixed concentrate is first ground, desulfurized by flotation, and de-ironized by magnetic separation to obtain iron-removed tailings; (2) The iron-removed tailings are subjected to scheelite flotation at room temperature to obtain scheelite rough concentrate and scheelite flotation tailings; (3) The scheelite rough concentrate is subjected to flotation and upgrading to obtain scheelite upgraded rough concentrate. During the flotation and upgrading process, wolframite and cassiterite are deeply suppressed. The scheelite upgraded rough concentrate is then upgraded and finely selected to obtain scheelite concentrate. (4) The scheelite flotation tailings are separated from cassiterite by magnetic separation to obtain scheelite concentrate and tin rough concentrate; (5) The tin crude concentrate is subjected to electrostatic separation to remove gangue minerals, thereby obtaining tin concentrate.

2. The mineral processing method according to claim 1, characterized in that, In the room temperature flotation process of scheelite, the scheelite collector includes the following components in parts by weight: 10-35 parts sodium lauroyl sarcosinate, 30-50 parts oxidized paraffin soap, and 45-60 parts isopropanol.

3. The mineral processing method according to claim 1, characterized in that, During the flotation and upgrading process, the mass concentration of the scheelite rough concentrate pulp is controlled to be ≥40%, and a depth inhibitor is added. The depth inhibitor includes salt-modified water glass and citric acid in a weight ratio of 10:(1-2). The salt-modified water glass is prepared by mixing water glass and aluminum sulfate in a weight ratio of 10:(0.5-2).

4. The mineral processing method according to claim 1, characterized in that, The grinding process involves grinding the tungsten-tin mixed concentrate to a particle size of -0.075 mm with a content of ≤75%, and the degree of liberation of scheelite, wolframite, and cassiterite in the tungsten-tin mixed concentrate is ≥90%.

5. The mineral processing method according to claim 1, characterized in that, Flotation desulfurization includes the following steps: The grinding product is subjected to full flotation desulfurization to obtain a full flotation rough concentrate and full flotation rougher tailings; the full flotation rough concentrate is subjected to 1-3 full flotation cleaning processes to obtain a sulfur concentrate and full flotation cleaning middlings, which are then sequentially recycled back to the previous stage; the full flotation rougher tailings are subjected to 1-3 full flotation scavenging processes to obtain full flotation tailings and full flotation scavenging concentrate, which are then sequentially recycled back to the previous stage.

6. The mineral processing method according to claim 5, characterized in that, The magnetic separation for iron removal includes the following steps: weak magnetic separation is performed on the fully floated tailings to obtain weak magnetic concentrate and iron-removed tailings; when performing weak magnetic separation, the number of cleaning times is 1-2 times, the number of scavenging times is 1-3 times, and the magnetic field strength is 0.05-0.30T.

7. The mineral processing method according to claim 1, characterized in that, The process flow for room temperature flotation of scheelite consists of one roughing flotation, one to three cleaning flotations, and one to three scavenging flotations to obtain scheelite rough concentrate and scheelite flotation tailings. The modifiers used in the flotation process include one or more of sodium carbonate, sodium hydroxide, water glass, aluminum sulfate, and sodium hexametaphosphate.

8. The mineral processing method according to claim 1, characterized in that, During flotation upgrading, scheelite collectors and depth inhibitors are added to obtain upgraded scheelite rough concentrate and upgraded scheelite tailings. The upgraded scheelite tailings are returned to the scheelite room temperature roughing operation.

9. The mineral processing method according to claim 1, characterized in that, The upgrading and beneficiation process involves 3-5 blank beneficiation processes on the scheelite rough concentrate to obtain scheelite concentrate and middlings from the upgrading and beneficiation process. The middlings from the upgrading and beneficiation process are then sequentially returned to the next higher-level operation.

10. The mineral processing method according to claim 1, characterized in that, Magnetic separation is used to separate tungsten and cassiterite by using strong magnetic separation to obtain tungsten concentrate and tin rough concentrate. The process flow of strong magnetic separation is one roughing, one cleaning, and one scavenging, with a magnetic field strength of 0.5-2.0T.

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