Beneficiation method for reducing tin and zinc in high-impurity-content iron ore concentrate

Abstract

The invention discloses a beneficiation method for reducing tin and zinc in high-impurity-content iron ore concentrate, which comprises the following steps: pre-grading the iron ore concentrate before grinding, then adding a flotation reagent, fully stirring, then carrying out reverse flotation on the iron ore concentrate to obtain rough iron ore concentrate, and then carrying out concentration for 1-2 times to obtain reverse flotation iron ore concentrate; and finally, the reverse flotation iron ore concentrate is further treated through an ammonium sulfide flotation method, and high-quality iron ore concentrate with low tin and zinc is obtained. According to the method, floatability difference caused by surface electrical property and active site difference of tin and zinc minerals is utilized, after proper fine grinding, zinc and tin minerals with good floatability and high monomer dissociation degree are preferentially removed through reverse flotation in the first step, and zinc minerals which are poor in floatability and difficult to remove in iron ore concentrate are deeply removed through an ammonium sulfide flotation method in the second step; the industrial technical breakthrough of reducing zinc and tin in the high-impurity-content iron ore concentrate by a two-step method is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing and flotation, and in particular relates to a beneficiation method for reducing tin and zinc in a high-content impurity iron concentrate. Background Art

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

[0003] Zinc in iron concentrate can hardly be absorbed by slag iron during blast furnace ironmaking, and circulates and accumulates in the furnace, leading to many problems such as disordered blast furnace gas distribution, upward deformation of tuyere, erosion and leakage of hearth, expansion and damage of furnace lining, nodules in the furnace, collapse of materials, and increased wind stop rate, which affect the normal production of blast furnace. Tin in iron concentrate is easily reduced and dissolved in molten iron to form alloy with pig iron during blast furnace smelting. Tin will also enter steel during steelmaking. When the tin content in steel exceeds 0.08 wt%, it will cause hot brittleness and temper brittleness of steel, resulting in reduced mechanical properties. It is one of the five harmful elements of steel.

[0004] Therefore, during the blast furnace smelting process, the zinc and tin content in the iron ore entering the furnace is required to be as low as possible.

[0005] Zinc in iron concentrate can usually be divided into zinc sulfide, zinc oxide and zinc in zinc-iron spinel. At present, the main method of reducing zinc in iron concentrate at home and abroad is flotation process, that is, under appropriate fine grinding conditions, one or more activators such as copper sulfate, sulfuric acid, ammonium fluorosilicate are added for activation, and then long-chain xanthate, butyl ammonium black medicine and other sulfide collectors are used for flotation removal of zinc. The zinc content in iron concentrate can usually be reduced to less than 0.10%. However, the above process is only effective for the case where zinc in iron concentrate exists in the form of zinc sulfide. When the zinc in the iron concentrate is zinc oxide or zinc in zinc-iron spinel, the sulfide collector cannot capture the zinc minerals, and the difficulty of removal increases sharply. This is the technical bottleneck and shackle of reducing zinc in iron concentrate in the industry.

[0006] Tin in iron ore concentrate usually exists in the form of cassiterite, which has a very complex mosaic relationship with magnetite and is distributed in the magnetite in the form of fine particles (<38 microns). Therefore, even if some cassiterite is finely ground, it will still exist in the form of cassiterite-magnetite conjoints, making it difficult to meet the tin content of the iron ore concentrate.

[0007] In the high-iron-containing concentrate, zinc and tin are mainly spinel and cassiterite, respectively, and are embedded in magnetite with fine particles (2-10 microns). At present, conventional magnetic separation or magnetic-flotation combined processes in the industry cannot effectively reduce zinc and tin. With the deterioration of my country's iron ore resources and the current national conditions where high-quality iron concentrate is highly dependent on imports, it is urgent to develop an efficient, economical and environmentally friendly beneficiation method for improving the quality of high-iron-containing concentrate and reducing zinc and tin. Summary of the invention

[0008] In order to overcome the problems in the prior art, the present invention provides a beneficiation method for reducing tin and zinc in high-iron-containing concentrate. For high-iron-containing concentrate in which the zinc-containing mineral is ferrospinite and the tin-containing mineral is cassiterite, and the embedded particle sizes of the ferrospinite and cassiterite are both 2-10μm, a two-step beneficiation method for reducing zinc and tin is adopted to achieve the economic development and utilization of such difficult-to-select and difficult-to-treat iron ore resources, and improve the security of my country's iron ore resources.

[0009] In order to solve the above technical problems, the technical solution proposed by the present invention is: The present invention provides a method for reducing tin and zinc in a high-content iron concentrate, comprising the following steps: S1. Screen and grade the high-iron-containing concentrate to obtain the oversize product and the undersize product.

[0010] S2, grinding the oversize product obtained in step S1, and then subjecting the ground slurry to at least one weak magnetic separation to obtain a weak magnetic concentrate, which is returned to the screening and grading system in step S1.

[0011] S3, adding flotation reagent to the undersize product obtained in step S1, stirring and then reverse flotation of the iron concentrate to obtain a rough iron concentrate; the flotation reagent includes an oxide ore collector, and the oxide ore collector is selected from one or two of oxidized paraffin soap, benzohydroxamic acid, salicylic acid and sodium linoleate.

[0012] S4, beneficiating the rough iron concentrate obtained in step S3 at least once to obtain reverse flotation iron concentrate.

[0013] S5. The reverse flotation iron concentrate obtained in step S4 is further treated by ammonium sulfide flotation to obtain a high-quality iron concentrate with low tin and zinc content.

[0014] In the present invention, the iron concentrate is pre-classified before grinding to screen out fine-grained materials with high monomer dissociation, so as to prevent the fine-grained materials from being over-grinded during the grinding process, and only the coarse-grained sediment (high-content gangue conjoined bodies) is finely ground, thereby reducing the mill load and grinding energy consumption while improving the grinding efficiency. By utilizing the difference in floatability caused by the difference in surface electrical properties and active sites of tin and zinc minerals, the zinc and tin minerals with good floatability and high monomer dissociation degree are preferentially removed by reverse flotation in the first step after appropriate fine grinding, and the difficult-to-remove zinc minerals with poor floatability in the iron concentrate are deeply removed by ammonium sulfide flotation in the second step, achieving an industrial technological breakthrough in the two-step reduction of zinc and tin in high-content impure iron concentrate.

[0015] The present invention adopts an oxide ore collector to simultaneously and efficiently collect cassiterite and galvanneal, and has a strong collecting ability and good selectivity for both cassiterite and galvanneal. When the collector is adsorbed on the surface of cassiterite and galvanneal minerals, it can form a strong hydrophobicity, realize the synchronous removal of cassiterite-magnetite and galvanneal-magnetite intergrowths, and significantly reduce the zinc and tin contents in the iron concentrate.

[0016] As an optional embodiment, in the mineral processing method provided by the present invention, roughing tailings are also obtained in step S3, and the roughing tailings are scavenged by adding reagents to obtain scavenged concentrate, and the scavenged concentrate is sequentially returned to the iron concentrate reverse flotation process in step S3.

[0017] As an optional embodiment, in the mineral processing method provided by the present invention, the zinc-containing mineral in the high-iron-containing concentrate is ferrospinite, and the tin-containing mineral is cassiterite, the mass proportion of Zn is ≥0.13%, and the mass proportion of Sn is ≥0.15%, and the embedded particle size of the ferrospinite and cassiterite is 2-10μm.

[0018] As an optional embodiment, in the mineral processing method provided by the present invention, in step S3, the flotation reagent also includes a pH adjuster, an inhibitor and calcium oxide, the added amount of the pH adjuster is 800-2000g / t, the added amount of the inhibitor is 300-800g / t, the added amount of calcium oxide is 100-500g / t, and the added amount of the oxide ore capture is 500-1500g / t.

[0019] As an optional embodiment, 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.

[0020] As an optional embodiment, 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.

[0021] As an optional embodiment, in the mineral processing method provided by the present invention, in step S4, the reagents used in the concentration process are causticized starch and oxidized ore collectors, and the oxidized ore collectors are selected from one or two of oxidized paraffin soap, benzohydroxamic acid, salicylic acid and sodium linoleate.

[0022] As an optional embodiment, in the mineral processing method provided by the present invention, the oxidized ore collector consists of oxidized paraffin soap and sodium linoleate.

[0023] As an optional embodiment, 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.

[0024] As an optional embodiment, in the mineral processing method provided by the present invention, in step S5, the reagents used in the ammonium sulfide flotation method are an activator and an amine cationic collector.

[0025] As an optional embodiment, in the mineral processing method provided by the present invention, in step S5, the amount of the activator added is 5000-8000 g / t, and the amount of the amine cationic collector added is 100-500 g / t.

[0026] In the present invention, the pH value of the slurry is adjusted to ≥ 10 by an activator to prevent heterogeneous agglomeration and mutual inclusion between fine mineral particles in the slurry, while increasing the negative charge on the surface of the zinc oxide mineral and converting Zn 2+ It is sealed on the mineral surface, reducing the solubility of zinc oxide minerals, improving the selectivity of amine collectors in the flotation process, and further deeply removing the zinc mineral content in the iron ore concentrate through electrostatic adsorption and semi-micelle adsorption.

[0027] As an optional embodiment, 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 coconut amine; and the activator is sodium sulfide.

[0028] Compared with the prior art, the present invention has the following beneficial effects: The present invention utilizes the difference in floatability caused by the difference in surface electrical properties and active sites of tin and zinc minerals. After appropriate fine grinding, zinc and tin minerals with good floatability and high monomer dissociation degree are preferentially removed by reverse flotation in the first step. In the second step, the difficult-to-remove zinc minerals with poor floatability in the iron concentrate are deeply removed by using the activation effect of an activator in combination with an amine cationic collector, thereby achieving an industrial technological breakthrough in the two-step reduction of zinc and tin in high-iron-containing concentrates, and providing a new approach and idea for the comprehensive utilization of similar high-zinc and tin difficult-to-treat iron ore resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 The present invention is a two-step method for reducing the tin and zinc content in a high-iron concentrate beneficiation process flow chart; Figure 2 This is a comparative example of the process flow chart for zinc reduction by flotation of conventional sulfide ore. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0032] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0033] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0034] Example 1 The beneficiation method for reducing tin and zinc in high-iron-containing concentrate is as follows: The ore sample processed in this embodiment is an iron ore concentrate product produced by a large ore dressing plant in Indonesia, with a TFe grade of ≥65%, a Zn content of 0.13%, and a Sn content of 0.15%. The zinc and tin contents both exceed the iron ore furnace entry standard (Zn≤0.10%, Sn≤0.08%). The zinc in the iron ore concentrate mainly exists in the form of zinc oxide and zinc-iron spinel, as well as a small amount of zinc sulfide. Among them, the zinc-iron spinel is distributed sporadically in the magnetite, and can be locally aggregated into beaded and needle-like aggregates for output. Tin in the iron ore concentrate mainly exists in the form of cassiterite, which is distributed along the intergranular, edge, crack and hole filling of magnetite, and has a complex mosaic relationship with magnetite. It enters the iron ore concentrate in the form of cassiterite-magnetite intergrowth, and the embedded particle size of zinc-iron spinel and cassiterite is 2-10μm.

[0035] Process flow such as Figure 1 As shown, the specific steps are: (1) The high-iron content concentrate produced by the concentrator is screened and graded using a 0.075 mm aperture screen to obtain coarse-grained sand on the screen and fine-grained slurry under the screen.

[0036] (2) The coarse sand sediment on the sieve obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075 mm particle size accounting for 90%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0037] (3) Adding 1500 g / t of sodium carbonate, 600 g / t of causticized starch, 200 g / t of calcium oxide and 400 g / t of collector CYT to the undersize product obtained in step (1), wherein the collector CYT is prepared by oxidized paraffin soap and sodium linoleate in a mass ratio of 1:1, and performing reverse flotation of the iron concentrate after sufficient stirring to obtain a rough iron concentrate and a rougher tailings.

[0038] (4) The rougher tailings obtained in step (3) are subjected to one blank scavenging to obtain scavenging concentrate and flotation tailings, and the scavenging concentrate is sequentially returned to the iron concentrate reverse flotation process.

[0039] (5) The crude iron concentrate obtained in step (3) is added with 100 g / t of causticized starch and 100 g / t of collector CYT to carry out a first concentration to obtain reverse flotation iron concentrate and concentrated middlings, and the concentrated middlings are sequentially returned to the iron concentrate reverse flotation process.

[0040] (6) Add 6000 g / t of sodium sulfide and 300 g / t of dodecylamine to the reverse flotation concentrate obtained in step (5) to obtain a qualified iron concentrate with Zn and Sn contents of 0.025% and 0.05%, respectively. The flotation tailings are discharged into a tailings pond.

[0041] By adopting the ore dressing method of the present invention, the contents of Zn and Sn in the iron ore 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, the loss of magnetite is small, and significant economic benefits are brought to the concentrator.

[0042] Example 2 The beneficiation method for reducing tin and zinc in high-iron-containing concentrate is as follows: The ore sample processed in this embodiment is a difficult-to-process complex iron ore in Inner Mongolia. Due to the hydrothermal replacement of the iron ore phase in the late stage of the ore deposit formation, a complex intercalation relationship between minerals is formed, and multiple elements such as iron, zinc, and tin have a close symbiotic relationship. The ore processed in this embodiment is the iron concentrate obtained by the two-stage weak magnetic separation of the iron concentrate after step grinding and step selection, with a TFe grade of about 66%, a Zn content of 0.15%, and a Sn content of 0.20%. Zinc and tin in the iron concentrate are mainly present in the form of zinc-iron spinel and cassiterite, respectively, and are distributed along the magnetite grains, edges, cracks, and holes. Therefore, in the iron concentrate, zinc and tin mainly enter the weak magnetite concentrate in the form of zinc-iron spinel-magnetite and cassiterite-magnetite intergrowths, and the intercalation particle size of zinc-iron spinel and cassiterite is 2-10μm.

[0043] Process flow such as Figure 1 As shown, the specific steps are: (1) The high-iron content concentrate is screened and graded using a 0.075 mm aperture sieve to obtain coarse-grained sand on the sieve and fine-grained slurry under the sieve.

[0044] (2) The coarse sand on the sieve obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.045 mm particle size accounting for 80%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0045] (3) Add 1500 g / t of sodium carbonate, 600 g / t of causticized starch, 150 g / t of calcium oxide, and 500 g / t of collector CYT to the undersize product obtained in step (1), wherein the collector CYT is prepared by oxidized paraffin soap and sodium linoleate in a mass ratio of 1:3, and after sufficient stirring, reverse flotation of the iron concentrate is performed to obtain a rough iron concentrate and a rougher tailings.

[0046] (4) The rougher tailings obtained in step (3) are subjected to one blank scavenging to obtain scavenging concentrate and flotation tailings, and the scavenging concentrate is sequentially returned to the iron concentrate reverse flotation process.

[0047] (5) The crude iron concentrate obtained in step (3) is added with 100 g / t of causticized starch and 150 g / t of collector CYT to carry out a first concentration to obtain reverse flotation iron concentrate and concentrated middlings, and the concentrated middlings are sequentially returned to the iron concentrate reverse flotation process.

[0048] (6) The reverse flotation concentrate obtained in step (5) is added with 6000 g / t of sodium sulfide and 300 g / t of etheramine to obtain a qualified iron concentrate with Zn and Sn contents of 0.028% and 0.055%, respectively. The flotation tailings are discharged into a tailings pond.

[0049] By adopting the mineral processing method of the present invention, an iron ore 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 ore concentrate are reduced from 0.15% and 0.20% to 0.028% and 0.055%, respectively, realizing a breakthrough comprehensive utilization of this type of complex and difficult-to-process iron ore resources.

[0050] Example 3 The beneficiation method for reducing tin and zinc in high-iron-containing concentrate is as follows: The ore sample processed in this embodiment is a high-tin and zinc iron concentrate product in Yunnan, with a TFe grade of about 63%, a Zn content of 0.13%, and a Sn content of 0.18%. The tin in the iron concentrate is mainly cassiterite, with fine particle size, mostly embedded along the edge of magnetite or gangue, and a few are wrapped in magnetite in the form of fine or micro-fine particles; the zinc in the iron concentrate is mainly zinc oxide, followed by zinc-iron spinel and a small amount of marmatite, and the embedded particle size of zinc-iron spinel and cassiterite is 2-10μm.

[0051] Process flow such as Figure 1 As shown, the specific steps are: (1) The high-iron content concentrate produced by the concentrator is screened and graded using a 0.075 mm aperture screen to obtain coarse-grained sand on the screen and fine-grained slurry under the screen.

[0052] (2) The coarse sand sediment on the sieve obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075 mm particle size accounting for 93%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0053] (3) Adding 1500 g / t of sodium carbonate, 500 g / t of causticized starch, 200 g / t of calcium oxide and 450 g / t of collector CYT to the undersize product obtained in step (1), wherein the collector is prepared by oxidized paraffin soap and sodium linoleate in a mass ratio of 1.5:5, the mixture is fully stirred and then reverse flotation of the iron concentrate is performed to obtain a rough iron concentrate and a rougher tailings.

[0054] (4) The rougher tailings obtained in step (3) are subjected to one blank scavenging to obtain scavenging concentrate and flotation tailings, and the scavenging concentrate is sequentially returned to the iron concentrate reverse flotation process.

[0055] (5) The crude iron concentrate obtained in step (3) is added with 150 g / t of causticized starch and 100 g / t of collector CYT for primary concentration to obtain reverse flotation iron concentrate and concentrated middlings, and the concentrated middlings are sequentially returned to the iron concentrate reverse flotation process.

[0056] (6) The reverse flotation concentrate obtained in step (5) is added with 4000 g / t of sodium sulfide and 200 g / t of coconut amine to obtain a qualified iron concentrate with Zn and Sn contents of 0.022% and 0.052%, respectively. The flotation tailings are discharged into a tailings pond.

[0057] By adopting the mineral processing method of the present invention, the qualities of Zn and Sn in the iron concentrate product are reduced from 0.13% and 0.18% to 0.022% and 0.052% respectively, the TFe grade is increased from 63.61% to 67.78%, and the TFe recovery rate is 87.90%. The problem of unsalable products caused by excessive zinc and tin content in the iron concentrate is successfully solved, and the enterprise is turned from loss to profit.

[0058] Comparative Example 1 The ore sample used was the same as that in Example 1, and the conventional sulfide ore flotation zinc reduction process was adopted. Figure 2 As shown, the specific steps and pharmaceutical system are as follows: 1) The high-iron content concentrate produced by the concentrator is screened and graded using a 0.075mm aperture screen to obtain coarse-grained sand on the screen and fine-grained slurry under the screen.

[0059] 2) The coarse sand on the sieve obtained in step 1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075 mm particle size accounting for 90%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0060] 3) Add 3000 g / t of sulfuric acid, 200 g / t of amyl xanthate, 200 g / t of butyl ammonium black powder, and 30 g / t of pine oil to the undersize pulp obtained in step 1), stir thoroughly, and then perform reverse flotation of the iron concentrate to reduce zinc, to obtain a rough iron concentrate and a roughing tailing.

[0061] 4) Add 100 g / t of amyl xanthate, 100 g / t of butyl ammonium black powder and 15 g / t of pine oil to the crude iron concentrate obtained in step 3), and perform two reverse flotation separations to obtain iron concentrate and selected middlings. The selected middlings are sequentially returned to the reverse flotation process for zinc reduction of the iron concentrate.

[0062] The above process flow produces an iron ore concentrate with a TFe grade of 65.65%. The Zn and Sn contents in the iron ore are 0.12% and 0.15% respectively, which are much higher than the standard requirements for zinc and tin contents in iron ore entering the furnace in my country, and directly restrict the market sales and application of the iron ore concentrate.

[0063] Comparative Example 2 The ore sample used is the same as that in Example 1, and the zinc-tin collector is a conventional anion collector, sodium oleate. The specific steps and reagent system are as follows: (1) The high-iron content concentrate produced by the concentrator is screened and graded using a 0.075 mm aperture screen to obtain coarse-grained sand on the screen and fine-grained slurry under the screen.

[0064] (2) The coarse sand sediment on the sieve obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075 mm particle size accounting for 90%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0065] (3) Add 1500 g / t of sodium carbonate, 600 g / t of causticized starch, 200 g / t of calcium oxide and 200 g / t of sodium oleate to the undersize product obtained in step (1), stir thoroughly and then perform reverse flotation of the iron concentrate to obtain a rough iron concentrate and rougher tailings.

[0066] (4) The rougher tailings obtained in step (3) are subjected to one blank scavenging to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is sequentially returned to the reverse flotation rougher, and the flotation tailings are discharged into the tailings pond.

[0067] (5) The crude iron concentrate obtained in step (3) is added with 100 g / t of causticized starch and 50 g / t of sodium oleate for primary concentration to obtain reverse flotation iron concentrate and concentrated middlings, and the concentrated middlings are sequentially returned to the iron concentrate for reverse flotation.

[0068] Although the above method can obtain iron ore concentrate products with Zn and Sn contents of 0.028% and 0.048% respectively, the iron ore concentrate yield is only 73.88%, the TFe grade is reduced from 68.89% to 68.03%, the TFe recovery is reduced by 13.58 percentage points, and the magnetite loss rate in the flotation tailings is significantly increased, which is not conducive to improving the economic benefit indicators of the concentrator and the comprehensive utilization rate of iron ore resources.

[0069] Comparative Example 3 The ore sample used is the same as that in Example 1, but the sulfidation amine method is not used for deep zinc reduction, and only one-step zinc and tin removal is performed. The specific steps and reagent system are as follows: (1) The high-iron content concentrate produced by the concentrator is screened and graded using a 0.075 mm aperture screen to obtain coarse-grained sand on the screen and fine-grained slurry under the screen.

[0070] (2) The coarse sand on the sieve obtained in step (1) is finely ground to obtain a grinding slurry with a grinding fineness of -0.075 mm particle size accounting for 90%, and 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 grading, and the weak magnetic middlings and weak magnetic tailings are combined and discharged into the tailings pond.

[0071] (3) Adding 1500 g / t of sodium carbonate, 600 g / t of causticized starch, 200 g / t of calcium oxide and 400 g / t of collector CYT to the undersize product obtained in step (1), wherein the collector is prepared by oxidized paraffin soap and sodium linoleate in a mass ratio of 1:1, and performing reverse flotation of the iron concentrate after sufficient stirring to obtain a rough iron concentrate and a rougher tailings.

[0072] (4) The rougher tailings obtained in step (3) are subjected to one blank scavenging to obtain scavenging concentrate and flotation tailings. The scavenging concentrate is sequentially returned to the reverse flotation rougher, and the flotation tailings are discharged into the tailings pond.

[0073] (5) The iron ore concentrate obtained in step (3) was added with 100 g / t of causticized starch and 100 g / t of collector CYT to carry out a first concentration to obtain reverse flotation iron concentrate and concentrated middlings, and the concentrated middlings were sequentially returned to the reverse flotation roughing.

[0074] By adopting 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 contents in the iron concentrate are 0.046% and 0.058% respectively. Although it meets the blast furnace ironmaking entry standards (Zn≤0.10%, Sn≤0.08%), some large domestic steel companies have stricter requirements on the quality of iron concentrate in order to improve the quality of high-end special steel and ensure the efficient and long-term operation of blast furnaces. They usually control the Zn content of the iron concentrate entering the furnace to be less than 0.03%. Therefore, only one-step dezincification and tin removal is used for this iron concentrate. Although qualified iron concentrate products can be produced, the market sales have certain limitations, which is not conducive to the optimization of the market economy and the maximization of corporate benefits.

[0075] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for reducing tin and zinc in a high-iron concentrate, characterized in that: The following steps are involved: S1. Screening and grading the high-iron-containing concentrate to obtain an oversize product and an undersize product; S2, grinding the oversize product obtained in step S1, and then subjecting the ground slurry to at least one weak magnetic separation to obtain a weak magnetic concentrate, which is returned to the screening and grading system in step S1; S3, adding a flotation agent to the undersize product obtained in step S1, stirring the product, and then reversely flotating the iron concentrate to obtain a rough iron concentrate; the flotation agent includes an oxide ore collector, and the oxide ore collector is selected from one or two of oxidized paraffin soap, benzohydroxamic acid, salicylic acid and sodium linoleate; S4, beneficiating the rough iron concentrate obtained in step S3 at least once to obtain a reverse flotation iron concentrate; S5. The reverse flotation iron concentrate obtained in step S4 is further treated by ammonium sulfide flotation to obtain a high-quality iron concentrate with low tin and zinc content.

2. The ore dressing method for reducing tin and zinc in high-iron content concentrate according to claim 1, characterized in that: In step S3, rougher tailings are also obtained, and the rougher tailings are scavenged by adding reagents to obtain scavenged concentrates, which are sequentially returned to the iron concentrate reverse flotation process in step S3.

3. The ore dressing method for reducing tin and zinc in high-iron-containing concentrate according to claim 1, characterized in that: The zinc-containing mineral in the high-iron-containing concentrate is ferrospinite, and the tin-containing mineral is cassiterite, with the mass proportion of Zn being ≥0.13% and the mass proportion of Sn being ≥0.15%. The embedded particle sizes of the ferrospinite and cassiterite are both 2-10 μm.

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

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

6. The ore dressing method for reducing tin and zinc in high-iron-containing concentrate according to claim 4 or 5, characterized in that: The oxidized ore collector consists of oxidized paraffin soap and sodium linoleate.

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

5.

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

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

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

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