A beneficiation method for reducing tin and zinc in high-impurity iron concentrate

Abstract

This invention discloses a beneficiation method for reducing tin and zinc in high-impurity iron concentrate. The method involves pre-classification of the iron concentrate before grinding, followed by the addition of flotation reagents and thorough stirring before reverse flotation to obtain a rough iron concentrate. This is then subjected to one or two cleaning processes to obtain a reverse-flotation iron concentrate. Finally, the reverse-flotation iron concentrate is further processed using ammonium sulfide flotation to obtain a high-quality iron concentrate with low tin and zinc content. This invention utilizes the differences in floatability caused by the differences in surface electrical properties and active sites of tin and zinc minerals. After appropriate fine grinding, the first step prioritizes reverse flotation to remove zinc and tin minerals with better floatability and higher degree of liberation. The second step uses ammonium sulfide flotation to deeply remove the difficult-to-remove zinc minerals with poor floatability from the iron concentrate. This represents a breakthrough in the industrial technology of reducing zinc and tin in high-impurity iron concentrate using a two-step method.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing flotation technology, and particularly relates to a beneficiation method for reducing tin and zinc in high-iron concentrate. Background Technology

[0002] As an important raw material for iron and steel metallurgy, the standard for iron concentrate in my country is a zinc content of ≤0.10% and a tin content of ≤0.08%. Excessive zinc and tin content in iron concentrate not only directly affects the quality of steel but also causes many hazards in subsequent smelting processes.

[0003] Zinc in iron concentrate is almost not absorbed by the slag and iron during blast furnace ironmaking. It circulates and accumulates within the furnace, leading to numerous problems such as disordered blast furnace gas distribution, upward deformation of tuyeres, erosion and leakage of the hearth, expansion and damage of the furnace lining, nodule formation, material collapse, and increased shutdown rate, thus affecting the normal operation of the blast furnace. Tin in iron concentrate is easily reduced and dissolves in molten iron to form alloys with pig iron during blast furnace smelting. Tin also enters the steel during steelmaking. When the tin content in steel exceeds 0.08 wt%, it causes hot brittleness and temper brittleness, resulting in reduced mechanical properties. It is one of the five harmful elements in steelmaking.

[0004] Therefore, during blast furnace smelting, it is desirable to have as low a zinc and tin content as possible in the iron concentrate fed into the furnace.

[0005] Zinc in iron concentrate can generally be classified into zinc sulfide, zinc oxide, and zinc in zinc-iron spinel. Currently, the main method for reducing zinc content in iron concentrate, both domestically and internationally, is flotation. This involves adding one or more activators such as copper sulfate, sulfuric acid, and ammonium fluorosilicate under appropriate fine grinding conditions, followed by flotation using sulfide mineral collectors such as long-chain xanthates and butanol black. The zinc content in iron concentrate can typically be reduced to below 0.10%. However, this process is only effective when zinc in the iron concentrate exists as zinc sulfide. When the zinc in the iron concentrate is zinc oxide or zinc in zinc-iron spinel, the sulfide mineral collectors cannot effectively collect the zinc minerals, significantly increasing the difficulty of removal. This remains a technical bottleneck and constraint in the current iron concentrate zinc reduction industry.

[0006] Tin in iron concentrate usually exists in the form of cassiterite, which has an extremely complex intergrowth relationship with magnetite. It is distributed in magnetite as fine particles (<38 micrometers). Therefore, even if the cassiterite is finely ground, it will still exist in the form of cassiterite-magnetite intergrowth, making it difficult for the tin content of iron concentrate to meet the standard.

[0007] For high-iron concentrates where zinc and tin are mainly composed of zinc-iron spinel and cassiterite, respectively, and are embedded in magnetite with fine particles (2-10 micrometers), conventional magnetic separation or magnetic-levitation combined processes in the industry cannot effectively reduce zinc and tin content. There is an urgent need to develop a high-efficiency, economical, and environmentally friendly beneficiation method for upgrading high-iron concentrates and reducing zinc and tin content. Summary of the Invention

[0008] To overcome the problems in the prior art, this invention provides a beneficiation method for reducing tin and zinc in high-iron concentrates. Specifically, for high-iron concentrates where the zinc-bearing mineral is zinc-iron spinel and the tin-bearing mineral is cassiterite, with both zinc-iron spinel and cassiterite having a particle size of 2-10 μm, a two-step beneficiation method for reducing zinc and tin is employed. This enables the economical development and utilization of such difficult-to-process iron ore resources and improves the security of my country's iron ore resources.

[0009] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0010] This invention provides a beneficiation method for reducing tin and zinc content in high-iron concentrates, comprising the following steps:

[0011] S1. The high-iron-content concentrate is screened and classified to obtain the oversize product and the undersize product.

[0012] S2. Grind the oversize product obtained in step S1, and then perform at least one weak magnetic separation on the ground slurry to obtain a weak magnetic concentrate, which is then returned to the screening and grading system in step S1.

[0013] S3. The undersize product obtained in step S1 is added to the flotation reagent and stirred before iron concentrate reverse flotation to obtain iron rough concentrate; the flotation reagent includes an oxidizing ore collector, which is selected from one or two of oxidized paraffin soap, benzoyl hydroxamic acid, salicylic acid and sodium linoleate.

[0014] S4. Perform at least one fine cleaning process on the iron rough concentrate obtained in step S3 to obtain reverse flotation iron concentrate.

[0015] S5. The iron concentrate obtained in step S4 is further processed by ammonium sulfide flotation to obtain high-quality iron concentrate with low tin and zinc content.

[0016] This invention employs pre-classification of iron concentrate before grinding, screening out fine-grained materials with high monomer liberation to prevent over-grinding during the grinding process. Only coarse-grained sand (high gangue intergrowth) undergoes fine grinding, reducing mill load and grinding energy consumption while improving grinding efficiency. Utilizing the differences in floatability caused by the surface electrical properties and active sites of tin and zinc minerals, after appropriate fine grinding, the first step prioritizes reverse flotation to remove zinc and tin minerals with better floatability and higher monomer liberation. The second step uses ammonium sulfide flotation to deeply remove the difficult-to-remove zinc minerals with poor floatability from the iron concentrate, achieving an industrial technological breakthrough in the two-step zinc and tin reduction of high-impurity iron concentrate.

[0017] In this invention, an oxidizing mineral collector is used to simultaneously and efficiently collect cassiterite and zinc-iron spinel. It has a strong collecting ability and good selectivity for both cassiterite and zinc-iron spinel. When the collector is adsorbed on the surface of cassiterite and zinc-iron spinel minerals, it can form a strong hydrophobicity, thereby achieving the simultaneous removal of cassiterite-magnetite and zinc-iron spinel-magnetite intergrowths, which significantly reduces the zinc and tin content in iron concentrate.

[0018] As an optional implementation, in the mineral processing method provided by the present invention, a roughing tailings is also obtained in step S3. The roughing tailings are then scavenged with reagents to obtain a scavenging concentrate, which is then sequentially returned to the iron concentrate reverse flotation process in step S3.

[0019] As an optional implementation method, in the mineral processing method provided by the present invention, the zinc-containing mineral in the high-iron concentrate is zinc-iron spinel, the tin-containing mineral is cassiterite, the Zn mass percentage is ≥0.13%, the Sn mass percentage is ≥0.15%, and the particle size of the zinc-iron spinel and cassiterite is 2-10μm.

[0020] As an optional implementation, in the mineral processing method provided by the present invention, in step S3, the flotation reagent further includes a pH adjuster, an inhibitor, and calcium oxide. The amount of pH adjuster added is 800-2000 g / t, the amount of inhibitor added is 300-800 g / t, the amount of calcium oxide added is 100-500 g / t, and the amount of oxidized ore collected is 500-1500 g / t.

[0021] As an optional implementation, in the mineral processing method provided by the present invention, the pH adjuster is selected from one or both of sodium carbonate and sodium hydroxide.

[0022] As an optional implementation, in the mineral processing method provided by the present invention, the inhibitor is selected from one or more of causticized starch, tannic acid, or carboxymethyl cellulose.

[0023] As an optional implementation, in the mineral processing method provided by the present invention, in step S4, the reagents used in the fine processing are causticized starch and oxidizing mineral collector, wherein the oxidizing mineral collector is selected from one or two of oxidized paraffin soap, benzoyl hydroxamic acid, salicylic acid and sodium linoleate.

[0024] As an optional implementation, in the mineral processing method provided by the present invention, the oxidized ore collector is composed of oxidized paraffin soap and sodium linoleate.

[0025] As an optional implementation, in the mineral processing method provided by the present invention, the mass ratio of the oxidized paraffin soap to sodium linoleate is 1:9-1:5.

[0026] As an optional implementation, in the mineral processing method provided by the present invention, in step S5, the reagents used in the ammonium sulfide flotation method are activators and amine cationic collectors.

[0027] As an optional implementation, in the mineral processing method provided by the present invention, in step S5, the amount of activator added is 5000-8000 g / t, and the amount of amine cationic collector added is 100-500 g / t.

[0028] In this invention, the pH of the slurry is adjusted to ≥10 by an activator to prevent heterogeneous aggregation and intermingling of fine mineral particles in the slurry, while simultaneously increasing the negative charge on the surface of zinc oxide minerals and increasing the Zn content. 2+ Enclosed on the mineral surface, it reduces the solubility of zinc oxide minerals, improves the selectivity of amine collectors during flotation, and further removes zinc mineral content from iron concentrate through electrostatic adsorption and semi-micelle adsorption.

[0029] As an optional implementation, in the mineral processing method provided by the present invention, the amine cationic collector is selected from one or more of dodecylamine, octadecylamine, etheramine, and cocoamine; the activator is sodium sulfide.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention utilizes the differences in floatability caused by the differences in surface electrical properties and active sites of tin and zinc minerals. After appropriate fine grinding, the first step preferentially removes zinc and tin minerals with better floatability and higher degree of monomer dissociation by reverse flotation. In the second step, through the activation of an activator and in conjunction with an amine cationic collector, the difficult-to-remove zinc minerals with poor floatability in the iron concentrate are deeply removed. This invention achieves a breakthrough in the industrial technology of reducing zinc and tin in high-impurity iron concentrate in two steps, providing a new approach and idea for the comprehensive utilization of similar high-zinc and tin difficult-to-process iron ore resources. Attached Figure Description

[0032] 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.

[0033] Figure 1 This is a process flow diagram of the two-step beneficiation method for reducing tin and zinc content in high-iron concentrates according to the present invention.

[0034] Figure 2 The flowchart shows a conventional zinc reduction process for sulfide ore flotation. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Example 1

[0039] The beneficiation method for reducing tin and zinc content in high-iron concentrates is as follows:

[0040] The ore sample processed in this embodiment is an iron concentrate product from a large concentrator in Indonesia, with a TFe grade ≥65%, Zn content 0.13%, Sn content 0.15%, and both zinc and tin contents exceeding the standards for iron concentrate entering the furnace (Zn≤0.10%, Sn≤0.08%). Zinc in this iron concentrate exists mainly in the form of zinc oxide and zinc-iron spinel, with a small amount of zinc sulfide. The zinc-iron spinel is sparsely distributed within the magnetite, locally agglomerated into beaded or needle-like aggregates. Tin in the iron concentrate mainly exists in the form of cassiterite, distributed along the intergranular, edge, fissure, and pore filling areas of magnetite, exhibiting a complex intergrowth relationship with magnetite. It enters the iron concentrate as a cassiterite-magnetite intergrowth, with the intergrowth particle size of both zinc-iron spinel and cassiterite being 2-10 μm.

[0041] Process flow as follows Figure 1 As shown, the specific steps are as follows:

[0042] (1) The high-iron concentrate produced by the concentrator is screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0043] (2) The coarse sand obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075mm particle size of 90%. The slurry is subjected to two weak magnetic separations, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step (1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0044] (3) Add 1500g / t of sodium carbonate, 600g / t of causticized starch, 200g / t of calcium oxide, and 400g / t of collector CYT to the screened product obtained in step (1). The collector CYT is prepared by mixing oxidized paraffin soap and sodium linoleate in a mass ratio of 1:1. After thorough stirring, carry out reverse flotation of iron concentrate to obtain iron rough concentrate and rough tailings.

[0045] (4) Perform a blank scavenging on the roughing tailings obtained in step (3) to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is then returned to the iron concentrate reverse flotation process.

[0046] (5) Add 100g / t of causticized starch and 100g / t of collector CYT to the iron crude concentrate obtained in step (3) for one cleaning to obtain reverse flotation iron concentrate and middlings. The middlings are then returned to the iron concentrate reverse flotation process.

[0047] (6) Add 6000g / t of sodium sulfide and 300g / t of dodecylamine to the reverse flotation concentrate obtained in step (5) to obtain qualified iron concentrate with Zn and Sn mass of 0.025% and 0.05% respectively. The flotation tailings are discharged into the tailings pond.

[0048] Using the mineral processing method of this invention, the Zn and Sn contents in the iron concentrate produced by the concentrator are reduced from 0.13% and 0.15% to 0.025% and 0.05%, respectively, the TFe grade is increased from 65.53% to 68.89%, the TFe recovery rate is as high as 90.28%, the zinc and tin removal effect is good, and the magnetite loss is small, bringing significant economic benefits to the concentrator.

[0049] Example 2

[0050] The beneficiation method for reducing tin and zinc content in high-iron concentrates is as follows:

[0051] The ore sample processed in this embodiment is a complex and difficult-to-process iron ore deposit in Inner Mongolia. Due to the hydrothermal alteration of the iron ore phase during the formation of the deposit, a complex intergrowth relationship exists between minerals, with close symbiotic relationships among multiple elements such as iron, zinc, and tin. The ore processed in this embodiment is an iron concentrate obtained by two stages of weak magnetic separation through step milling and beneficiation. The TFe grade is approximately 66%, the Zn content is 0.15%, and the Sn content is 0.20%. In the iron concentrate, zinc and tin mainly exist in the form of zinc-iron spinel and cassiterite, respectively, and are distributed along the intergranular, edge, fracture, and pore filling of magnetite. Therefore, in the iron concentrate, zinc and tin mainly enter the weakly magnetic concentrate in the form of intergrowths of zinc-iron spinel-magnetite and cassiterite-magnetite. The intergrowth particle size of zinc-iron spinel and cassiterite is 2-10 μm.

[0052] Process flow as follows Figure 1 As shown, the specific steps are as follows:

[0053] (1) The high-iron concentrate was screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0054] (2) The coarse sand obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.045mm particle size of 80%. The slurry is subjected to two weak magnetic separations, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step (1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0055] (3) Add 1500g / t of sodium carbonate, 600g / t of causticized starch, 150g / t of calcium oxide, and 500g / t of collector CYT to the screened product obtained in step (1). The collector CYT is prepared by mixing oxidized paraffin soap and sodium linoleate in a mass ratio of 1:3. After thorough stirring, carry out reverse flotation of iron concentrate to obtain iron rough concentrate and rough tailings.

[0056] (4) Perform a blank scavenging on the roughing tailings obtained in step (3) to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is then returned to the iron concentrate reverse flotation process.

[0057] (5) Add 100g / t of causticized starch and 150g / t of collector CYT to the iron crude concentrate obtained in step (3) for a first cleaning to obtain reverse flotation iron concentrate and middlings. The middlings are then returned to the iron concentrate reverse flotation process.

[0058] (6) Add 6000g / t of sodium sulfide and 300g / t of ether amine to the reverse flotation concentrate obtained in step (5) to obtain qualified iron concentrate with Zn and Sn mass of 0.028% and 0.055% respectively. The flotation tailings are discharged into the tailings pond.

[0059] Using the mineral processing method of this invention, an iron concentrate product with a TFe grade of 69.22% and a TFe recovery rate of 86.49% can be obtained. The Zn and Sn contents in the iron concentrate are reduced from 0.15% and 0.20% to 0.028% and 0.055%, respectively, achieving a breakthrough in the comprehensive utilization of this type of complex and difficult-to-process iron ore resources.

[0060] Example 3

[0061] The beneficiation method for reducing tin and zinc content in high-iron concentrates is as follows:

[0062] The ore sample processed in this embodiment is a high-tin, zinc-iron concentrate product from Yunnan Province. The TFe grade is about 63%, the Zn content is 0.13%, and the Sn content is 0.18%. The tin in the iron concentrate is mainly cassiterite with a relatively fine particle size. It is mostly embedded along the edges of magnetite or gangue, and a few are encapsulated in magnetite in the form of fine or micro-fine grains. The zinc in the iron concentrate is mainly zinc oxide, followed by zinc-iron spinel and a small amount of iron sphalerite. The particle size of zinc-iron spinel and cassiterite is 2-10 μm.

[0063] Process flow as follows Figure 1 As shown, the specific steps are as follows:

[0064] (1) The high-iron concentrate produced by the concentrator is screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0065] (2) The coarse sand obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075mm particle size of 93%. The slurry is subjected to two weak magnetic separations, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step (1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0066] (3) Add 1500g / t of sodium carbonate, 500g / t of causticized starch, 200g / t of calcium oxide, and 450g / t of collector CYT to the screened product obtained in step (1). The collector is prepared by mixing oxidized paraffin soap and sodium linoleate in a mass ratio of 1.5:5. After thorough stirring, carry out reverse flotation of iron concentrate to obtain iron rough concentrate and rough tailings.

[0067] (4) Perform a blank scavenging on the roughing tailings obtained in step (3) to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is then returned to the iron concentrate reverse flotation process.

[0068] (5) Add 150g / t of causticized starch and 100g / t of collector CYT to the iron crude concentrate obtained in step (3) for one cleaning to obtain reverse flotation iron concentrate and middlings. The middlings are then returned to the iron concentrate reverse flotation process.

[0069] (6) Add 4000g / t of sodium sulfide and 200g / t of coconut oil amine to the reverse flotation concentrate obtained in step (5) to obtain qualified iron concentrate with Zn and Sn contents of 0.022% and 0.052% respectively. The flotation tailings are discharged into the tailings pond.

[0070] Using the mineral processing method of this invention, the Zn and Sn content in the iron concentrate product was reduced from 0.13% and 0.18% to 0.022% and 0.052%, respectively, while the TFe grade was increased from 63.61% to 67.78%, and the TFe recovery rate was 87.90%. This successfully solved the problem of unsold products caused by excessive zinc and tin content in the iron concentrate, enabling the company to turn losses into profits.

[0071] Comparative Example 1

[0072] The ore sample used was the same as in Example 1, and the conventional sulfide ore flotation process for zinc reduction was employed. Figure 2 As shown, the specific steps and pharmaceutical preparation methods are as follows:

[0073] 1) The high-iron concentrate produced by the concentrator is screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0074] 2) Grind the coarse sand obtained from step 1) on the screen to obtain a grinding slurry with a grinding fineness of -0.075mm particle size accounting for 90%. Perform two weak magnetic separations on the slurry, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step 1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0075] 3) Add 3000g / t of sulfuric acid, 200g / t of pentyl xanthate, 200g / t of butyl ammonium black powder, and 30g / t of pine oil to the slurry obtained in step 1). After thorough stirring, carry out reverse flotation of iron concentrate to reduce zinc content, and obtain iron rough concentrate and roughing tailings.

[0076] 4) Add 100g / t·time of pentyl xanthate, 100g / t·time of butyl ammonium black powder, and 15g / t·time of pine oil to the iron crude concentrate obtained in step 3) and perform two reverse flotation to obtain iron concentrate and middlings. The middlings are then returned to the iron concentrate zinc reduction reverse flotation process.

[0077] Using the above process, the iron concentrate obtained has a TFe grade of 65.65%, and the Zn and Sn contents in the iron concentrate are 0.12% and 0.15% respectively, which are far higher than the zinc and tin content requirements for iron concentrate entering the furnace in my country, directly restricting the market sales and application of this iron concentrate.

[0078] Comparative Example 2

[0079] The ore sample used was the same as in Example 1. Sodium oleate, a conventional anionic collector, was selected as the zinc-tin collector. The specific steps and reagent formulation are as follows:

[0080] (1) The high-iron concentrate produced by the concentrator is screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0081] (2) The coarse sand obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075mm particle size of 90%. The slurry is subjected to two weak magnetic separations, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step (1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0082] (3) Add 1500g / t of sodium carbonate, 600g / t of causticized starch, 200g / t of calcium oxide and 200g / t of sodium oleate to the screened product obtained in step (1), stir thoroughly and then carry out reverse flotation of iron concentrate to obtain iron rough concentrate and rough tailings.

[0083] (4) Perform a blank scavenging on the roughing tailings obtained in step (3) to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is returned to the reverse flotation roughing process in sequence, and the flotation tailings are discharged into the tailings pond.

[0084] (5) Add 100g / t of causticized starch and 50g / t of sodium oleate to the iron crude concentrate obtained in step (3) for one cleaning to obtain reverse flotation iron concentrate and middlings. The middlings are returned to the iron concentrate reverse flotation in sequence.

[0085] Although the above method can yield iron concentrate products with Zn and Sn content of 0.028% and 0.048% respectively, the iron concentrate yield is only 73.88%, the TFe grade decreases from 68.89% to 68.03%, the TFe recovery rate decreases by 13.58 percentage points, and the magnetite loss rate in the flotation tailings increases significantly, which is not conducive to improving the economic efficiency indicators of the concentrator and the comprehensive utilization rate of iron ore resources.

[0086] Comparative Example 3

[0087] The ore sample used was the same as in Example 1, but deep zinc removal using the amine sulfide method was not performed; only a one-step zinc and tin removal process was used. The specific steps and reagent formulation are as follows:

[0088] (1) The high-iron concentrate produced by the concentrator is screened and classified using a 0.075mm aperture screen to obtain coarse sand on the screen and fine slurry on the screen.

[0089] (2) The coarse sand obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075mm particle size accounting for 90%. The slurry is subjected to two weak magnetic separations, one coarse and one fine, to obtain weak magnetic concentrate, weak magnetic middlings and weak magnetic tailings. The weak magnetic concentrate is returned to step 1) for screening and classification, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0090] (3) Add 1500g / t of sodium carbonate, 600g / t of causticized starch, 200g / t of calcium oxide, and 400g / t of collector CYT to the screened product obtained in step (1). The collector is prepared by mixing oxidized paraffin soap and sodium linoleate in a mass ratio of 1:1. After thorough stirring, carry out reverse flotation of iron concentrate to obtain iron rough concentrate and rough tailings.

[0091] (4) Perform a blank scavenging on the roughing tailings obtained in step (3) to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is returned to the reverse flotation roughing process in sequence, and the flotation tailings are discharged into the tailings pond.

[0092] (5) Add 100g / t of causticized starch and 100g / t of collector CYT to the iron rough concentrate obtained in step (3) for one cleaning to obtain reverse flotation iron concentrate and middlings. The middlings are then returned to the reverse flotation roughing process.

[0093] Using the above-mentioned beneficiation method, an iron concentrate with a TFe grade of 68.02% and a TFe recovery rate of 93.52% can be obtained. The Zn and Sn content in the iron concentrate is 0.046% and 0.058%, respectively. Although this meets the blast furnace feed standards (Zn≤0.10%, Sn≤0.08%), some large steel companies in China have stricter requirements for the quality of iron concentrate in order to improve the quality of high-end special steel and ensure the efficient and long-term smooth operation of blast furnaces. They usually control the Zn content of the iron concentrate fed into the furnace to be below 0.03%. Therefore, although using only a one-step dezincification and detinning method for this iron concentrate can produce qualified iron concentrate products, its market sales are limited, which is not conducive to the optimization of the enterprise's market economy and the maximization of enterprise benefits.

[0094] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. However, it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A beneficiation method for reducing tin and zinc content in high-iron concentrate, characterized in that, Includes the following steps: S1. Screening and classifying the high-iron-content concentrate to obtain the oversize product and the undersize product. S2. Grind the oversize product obtained in step S1, and then perform at least one weak magnetic separation on the grinding slurry to obtain weak magnetic concentrate, which is then returned to the screening and grading system in step S1. S3. The undersize product obtained in step S1 is added to the flotation reagent and stirred before iron concentrate reverse flotation to obtain iron rough concentrate; the flotation reagent includes an oxidizing ore collector, which is selected from one or two of oxidized paraffin soap, benzoyl hydroxamic acid, salicylic acid and sodium linoleate. S4. Perform at least one fine cleaning process on the iron rough concentrate obtained in step S3 to obtain reverse flotation iron concentrate; S5. The iron concentrate obtained in step S4 is further processed by ammonium sulfide flotation to obtain high-quality iron concentrate with low tin and zinc content.

2. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 1, characterized in that, In step S3, roughing tailings are also obtained. After adding reagents to the roughing tailings for scavenging, scavenging concentrate is obtained. The scavenging concentrate is then sequentially returned to the iron concentrate reverse flotation process in step S3.

3. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 1, characterized in that, The zinc-containing mineral in the high-iron concentrate is zinc-iron spinel, and the tin-containing mineral is cassiterite. The Zn mass percentage is ≥0.13%, and the Sn mass percentage is ≥0.15%. The particle size of the zinc-iron spinel and cassiterite is 2-10 μm.

4. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 1, characterized in that, In step S3, the flotation reagent further includes a pH adjuster, an inhibitor, and calcium oxide. The amount of pH adjuster added is 800-2000 g / t, the amount of inhibitor added is 300-800 g / t, the amount of calcium oxide added is 100-500 g / t, and the amount of oxidized ore collected is 500-1500 g / t. The pH adjuster is selected from one or two of sodium carbonate or sodium hydroxide, and the inhibitor is selected from one or more of causticized starch, tannic acid, or carboxymethyl cellulose.

5. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 1, characterized in that, In step S4, the reagents used in the selection process are causticized starch and oxidized mineral collector, wherein the oxidized mineral collector is selected from one or two of oxidized paraffin soap, benzoyl hydroxamic acid, salicylic acid and sodium linoleate.

6. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 4 or 5, characterized in that, The oxidized mineral collector is composed of oxidized paraffin soap and sodium linoleate.

7. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 6, characterized in that, The mass ratio of the oxidized paraffin soap to sodium linoleate is 1:1 to 1:

5.

8. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 1, characterized in that, In step S5, the reagents used in the ammonium sulfide flotation method are activators and amine cationic collectors.

9. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 8, characterized in that, In step S5, the amount of activator added is 5000-8000 g / t, and the amount of amine cationic collector added is 100-500 g / t.

10. The beneficiation method for reducing tin and zinc content in high-iron concentrate according to claim 8, characterized in that, The amine cationic collector is selected from one or more of dodecylamine, octadecylamine, etheramine, and cocoamine; the activator is sodium sulfide.

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