Beneficiation method for sulfur-containing iron ore concentrate desulfurization

Abstract

The invention provides a beneficiation method for sulfur-containing iron ore concentrate desulfurization, and relates to the field of beneficiation. The beneficiation method for sulfur-containing iron ore concentrate desulfurization comprises the steps that sulfur-containing iron ore concentrate is sampled and screened, multiple groups of graded products with different particle sizes are obtained, and the graded particle size is determined; the sulfur-containing iron ore concentrate is conveyed into first separation and classification equipment, and first coarse-fraction iron ore concentrate and first fine-fraction iron ore concentrate are obtained; the first coarse-fraction iron ore concentrate is conveyed into second separation and classification equipment, second coarse-fraction iron ore concentrate and second fine-fraction iron ore concentrate are obtained, and the first fine-fraction iron ore concentrate and the second fine-fraction iron ore concentrate serve as first iron ore concentrate; and the second coarse-fraction iron ore concentrate is sequentially subjected to ore grinding and low-intensity magnetic separation, second iron ore concentrate and a sulfur-containing product are obtained, and the first iron ore concentrate and the second iron ore concentrate serve as total iron ore concentrate. The sulfur content in the sulfur-containing iron ore concentrate can be reduced, the iron grade in the iron ore concentrate is improved, the iron recovery rate is increased, and the method has the advantages of being simple in process, stable in performance, environmentally friendly and the like.

Description

Technical Field

[0001] The present application relates to the field of mineral processing, and in particular to a mineral processing method for desulfurizing sulfur-containing iron concentrate. Background Art

[0002] Iron ore is the main raw material for the steel industry, and magnetite (Fe3O4) is one of the most widely used raw material minerals. Magnetite is a strong magnetic mineral and is mainly recovered by magnetic separation. Faced with the current situation of relatively scarce resources, the application of sulfur-containing magnetite has received more and more attention. The sulfur in this type of ore mainly comes from pyrrhotite (Fe 1-x S), and pyrrhotite is also a strong magnetic mineral, so when magnetite is recovered by magnetic separation, some pyrrhotite will also enter the magnetite. A small amount of sulfur exists in pyrite (FeS2) and other non-magnetic sulfide ores in a co-existing or associated form. Magnetite with excessive sulfur content is difficult or even impossible to sell. As we all know, sulfur is a harmful element in steel. (1) Sulfur exists in steel as an inclusion in the form of non-metallic sulfides, which has a strong segregation effect, reducing the impact toughness, fatigue resistance and corrosion resistance. The low melting point caused by sulfides makes steel prone to hot cracking during welding, increases the hot brittleness of steel, and significantly reduces welding performance; (2) It increases the consumption of coke and solvents in the blast furnace, reduces the production capacity of the blast furnace, and increases the production cost of the blast furnace; (3) Toxic and harmful gases such as sulfur dioxide are released during the smelting process, causing environmental pollution. Therefore, it is necessary to desulfurize the iron ore concentrate.

[0003] At present, the main process used for desulfurization of iron ore concentrate is flotation. However, the flotation method has many problems such as complex operation, large consumption of reagents, long beneficiation time, low desulfurization efficiency, environmental unfriendliness, and high production power consumption. Therefore, it is necessary to improve the beneficiation method for desulfurization of sulfur-containing iron concentrate. Summary of the invention

[0004] The purpose of this application is to provide a beneficiation method for desulfurization of sulfur-containing iron concentrate to solve the above problems.

[0005] To achieve the above objectives, this application adopts the following technical solutions: A method for desulfurizing a sulfur-containing iron concentrate, comprising: The sulfur-containing iron concentrate is sampled and screened to obtain multiple groups of graded products with different particle sizes, and each group of graded products is chemically analyzed to determine the graded particle size; The sulfur-containing iron concentrate is transported to a first separation and classification device to obtain a first coarse-grained iron concentrate and a first fine-grained iron concentrate; transporting the first coarse-grained iron concentrate to a second separation and classification device to obtain a second coarse-grained iron concentrate and a second fine-grained iron concentrate, and combining the first fine-grained iron concentrate and the second fine-grained iron concentrate as a first iron concentrate; The second coarse-grained iron concentrate is subjected to grinding and weak magnetic separation in sequence to obtain a second iron concentrate and a sulfur-containing product, and the first iron concentrate and the second iron concentrate are combined as a total iron concentrate product.

[0006] According to an embodiment of the present application, the chemical analysis of each group of graded products includes: analyzing the sulfur content in each group of graded products.

[0007] According to an embodiment of the present application, determining the grading particle size includes: comparing the sulfur content in each group of graded products with the qualified sulfur content, and determining the minimum value of the screening particle size corresponding to the graded products exceeding the qualified sulfur content as the grading particle size.

[0008] According to an embodiment of the present application, the sulfur content in the sulfur-containing iron concentrate decreases as the particle size decreases.

[0009] According to an embodiment of the present application, the first separation and classification equipment includes any one of a spiral classifier and a cyclone; The particle size of the first coarse-grained iron concentrate is greater than the particle size of the first fine-grained iron concentrate, and the particle size of the first fine-grained iron concentrate is less than or equal to the classification particle size.

[0010] According to an embodiment of the present application, the second separation and classification device comprises a high-frequency vibration screen, and the high-frequency vibration screen comprises a single-layer structure or a multi-layer structure; The particle size of the second coarse-grained iron concentrate is greater than the particle size of the second fine-grained iron concentrate, and the particle size of the second fine-grained iron concentrate is less than or equal to the classification particle size.

[0011] According to an embodiment of the present application, the grinding equipment includes any one of a vertical mill, a tower mill, a stirred mill, a scrubbing mill, and an abrasive mill.

[0012] According to an embodiment of the present application, the grinding medium used in the grinding equipment is a non-ferrous medium; And / or, the non-ferrous medium includes ceramic balls.

[0013] According to an embodiment of the present application, the content of products with a particle size of less than 0.020 mm after the grinding treatment is not less than 65%.

[0014] According to an embodiment of the present application, the magnetic field strength of the weak magnetic separation is 700-1800 Oe.

[0015] Compared with the prior art, the beneficial effects of this application include: The method of the present application can reduce the sulfur content in sulfur-containing iron concentrate, increase the iron grade in iron concentrate, and improve the recovery rate of iron. Moreover, compared with the traditional flotation method, the method of the present application has the advantages of simple process, concise process, short beneficiation time, high desulfurization efficiency, stable performance, etc. In addition, the method of the present application does not need to add any chemical agents and does not cause any pollution to the environment. It improves the defects of the traditional flotation method, such as complex operation, need to add a large amount of reagents, long beneficiation time, low desulfurization efficiency, unfriendly environment, and high production power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0017] Figure 1 The flowchart of the ore dressing method for desulfurization of sulfur-containing iron concentrate in Example 1; Figure 2 This is the flow chart of flotation desulfurization in Comparative Example 3. DETAILED DESCRIPTION

[0018] As used herein: "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0019] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0020] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0021] In these examples, parts and percentages are by mass unless otherwise indicated.

[0022] "Mass parts" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0023] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0024] At present, the main process used for desulfurization of iron ore concentrate is flotation. The main difficulties of flotation are as follows: (1) Due to the large variation in the crystal structure composition, pyrrhotite has the characteristics of poor crystallinity, easy to break, easy to muddy, easy to oxidize, and slow floating speed. It is an iron sulfide mineral that is easily inhibited but difficult to float, which greatly affects its effective flotation removal; (2) The embedding pattern of pyrrhotite, pyrite and other sulfide minerals is relatively complex, and they are often closely coexisting with magnetite, making the desulfurization of magnetite more difficult; (3) Due to the residual magnetism after magnetic separation, there is a strong magnetic agglomeration effect between pyrrhotite and magnetite, and the two are prone to magnetic agglomeration. Especially when the mineral particle size is fine, the magnetic agglomeration phenomenon is particularly serious, resulting in the enrichment of harmful impurity sulfur in the iron ore concentrate, which seriously affects the quality of the iron ore concentrate. The measures taken to address difficulty (1) are to add a large amount of activators to the flotation pulp to activate pyrrhotite and other sulfide ores, such as sulfuric acid, copper sulfate, oxalic acid, sodium fluorosilicate, etc., and then add a large amount of collectors for desulfurization. At the same time, a large number of flotation machines are connected in series to extend the flotation time, which brings about many problems such as high reagent costs, high power consumption, environmental pollution, chemical management and safety hazards. Regarding difficulty (2), it is necessary to grind the sulfur-containing iron concentrate to separate the sulfur-containing minerals from the magnetite monomers. The energy consumption of grinding is the highest energy consumption operation link in a mineral processing plant, which greatly increases the production cost. Regarding difficulty (3), it is necessary to perform demagnetization before flotation desulfurization, which will also increase fixed asset investment and operating management expenses.

[0025] Moreover, flotation desulfurization requires a long flotation time, multiple roughing operations in series, and several rounds of fine cleaning of the roughing concentrate, making the process structure relatively complex. A large amount of activators, collectors, and frothers need to be added during the flotation process, resulting in high reagent costs, environmental pollution, and safety risks in reagent management and use. In particular, the activators used in the flotation process, such as sulfuric acid, oxalic acid, copper sulfate, and sodium fluorosilicate, are corrosive and toxic, and pose safety hazards in management, storage, and use. Moreover, the desulfurization efficiency of the flotation method is not high: (1) pyrrhotite has poor floatability; (2) the ball mill grinding product is uneven, often with more coarse and fine particles, while the content of the intermediate particle size with better floatability is not high. Therefore, the sulfur-containing minerals in the coarse part are still not dissociated and cannot be removed. The pyrrhotite in the fine part is extremely fine due to over-grinding, and the flotation removal rate is not high; (3) magnetic agglomeration caused by residual magnetism also affects sulfur removal.

[0026] In order to improve the above technical problems, the present application provides a beneficiation method for desulfurization of sulfur-containing iron concentrate, comprising: The sulfur-containing iron concentrate is sampled and screened to obtain multiple groups of graded products with different particle sizes, and each group of graded products is chemically analyzed to determine the graded particle size; The sulfide-containing iron concentrate is transported to a first separation and classification device to obtain a first coarse-grained iron concentrate and a first fine-grained iron concentrate; transporting the first coarse-grained iron concentrate to a second separation and classification device to obtain a second coarse-grained iron concentrate and a second fine-grained iron concentrate, and combining the first fine-grained iron concentrate and the second fine-grained iron concentrate as a first iron concentrate; The second coarse-grained iron concentrate is subjected to grinding and weak magnetic separation in sequence to obtain a second iron concentrate and a sulfur-containing product, and the first iron concentrate and the second iron concentrate are combined as a total iron concentrate product.

[0027] According to an embodiment of the present application, the chemical analysis of each group of graded products includes: analyzing the sulfur content in each group of graded products.

[0028] According to an embodiment of the present application, determining the grading particle size includes: comparing the sulfur content in each group of graded products with the qualified sulfur content, and determining the minimum value of the screening particle size corresponding to the graded products exceeding the qualified sulfur content as the grading particle size.

[0029] Furthermore, the qualified sulfur content refers to the sales standard of sulfur content in iron ore concentrate products of different specifications. For example, the qualified sulfur content may be 0.3% or 0.5%.

[0030] Further, the classified particle size may be 0.020-0.15 mm. For example, the classified particle size may be 0.020 mm, 0.038 mm, 0.045 mm, 0.074 mm or 0.15 mm.

[0031] Exemplarily, a sample of sulfur-containing iron concentrate is taken and screened into graded products of less than 0.020 mm, 0.020 mm-0.038 mm, 0.038 mm-0.045 mm, 0.045 mm-0.074 mm, 0.074 mm-0.15 mm, and 0.15 mm and above. If the qualified sulfur content is 0.3%, and the sulfur content in the graded products of 0.074 mm-0.15 mm and 0.15 mm and above is greater than 0.3%, then the minimum value of the screening particle size corresponding to the graded products exceeding the qualified sulfur content, 0.074 mm, is determined as the graded particle size.

[0032] According to the embodiments of the present application, the sulfur content in the sulfur-containing iron concentrate decreases as the particle size decreases. Since the monomer dissociation degree of the fine-grained product magnetite is high, the sulfur content is low. The present application samples and tests the sulfur-containing iron concentrate, and directly uses the fine-grained sulfur-containing iron concentrate with low sulfur content and meeting the sales standards as the iron concentrate product, and the coarse-grained grade needs to be further desulfurized.

[0033] According to an embodiment of the present application, the first separation and classification equipment includes any one of a spiral classifier and a cyclone; the spiral classifier and the cyclone have the advantage of large processing capacity, which is conducive to improving the efficiency of mineral processing.

[0034] The particle size of the first coarse-grained iron concentrate is greater than the particle size of the first fine-grained iron concentrate, and the particle size of the first fine-grained iron concentrate is less than or equal to the classification particle size.

[0035] According to an embodiment of the present application, the second separation and classification device comprises a high-frequency vibration screen, and the high-frequency vibration screen comprises a single-layer structure or a multi-layer structure; The particle size of the second coarse-grained iron concentrate is greater than the particle size of the second fine-grained iron concentrate, and the particle size of the second fine-grained iron concentrate is less than or equal to the classification particle size.

[0036] The first coarse-grained iron concentrate will contain some fine-grained iron concentrate. By using a high-frequency vibrating screen to perform secondary classification on the first coarse-grained iron concentrate, it can be ensured that the products under the screen are all qualified particle sizes. When the coarse-grained content in the first coarse-grained iron concentrate is high and the particle size is large, a multi-layer high-frequency vibrating screen can be used, with the upper layer coarse and the lower layer fine. The multi-layer high-frequency vibrating screen can effectively solve the problem of screen hole blockage.

[0037] Traditional flotation desulfurization requires grinding of the coarse-grained products after separation and classification, which has a large grinding capacity and high energy consumption. The present application adopts the combination of the first separation and classification equipment and the second separation and classification equipment. The present application only needs to grind the second coarse-grained iron concentrate, which reduces the grinding capacity, reduces the grinding energy consumption, and greatly improves the production capacity.

[0038] According to the embodiments of the present application, the grinding equipment includes any one of a vertical mill, a tower mill, a stirred mill, a scrubbing mill, and an argon sand mill. Traditional flotation desulfurization uses a ball mill for grinding. The grinding medium of the ball mill is an iron ball. The ball mill needs to lift the iron balls to a certain height and drop them to achieve the effect of grinding, which will consume a lot of electricity. The higher impact crushing energy of the iron balls will also cause the ore to be over-crushed. The optimal particle size for flotation is above 0.038 mm. Over-crushing in the ball mill causes the floatability of sulfur-containing minerals below 0.038 mm to deteriorate, and some sulfur-containing minerals are difficult to remove. The grinding equipment of the present application uses a vertical mill, a tower mill, a scrubbing mill, an argon sand mill, etc. The working principle of such equipment is to stir the grinding medium and achieve the purpose of grinding through friction. There is no need to lift the grinding medium to do work, and the energy consumption is lower.

[0039] According to an embodiment of the present application, the grinding medium used in the grinding equipment is a non-ferrous medium; And / or, the non-ferrous medium includes ceramic balls. The grinding medium used in the grinding equipment of the present application has a low specific gravity and a small particle size, which greatly reduces the energy consumption of grinding and improves the grinding efficiency. Specifically, the specific gravity of ceramic balls (2.2-3.6g / cm³) is much lower than that of iron balls (7.86g / cm³), and the energy consumption of the grinding equipment used in the present application is lower than the working energy consumption of the ball mill. The particle size of the ceramic balls of the grinding medium in the grinding equipment used in the present application is small (less than 0.5cm), while the particle size of the iron balls of the grinding medium in the ball mill is large (greater than 2-5cm). The smaller particle size brings a larger specific surface area and a smaller grinding gap, thereby improving the grinding efficiency, making the particle size of the grinding product finer, and effectively breaking up the magnetic agglomerate flocs.

[0040] According to an embodiment of the present application, the content of products with a particle size of less than 0.020 mm after the grinding treatment is not less than 65%.

[0041] For example, the content of the product with a particle size of less than 0.020 mm after grinding is not less than 65%, 70%, 75%, 80%, 85%, 90% or 95%.

[0042] According to the embodiment of the present application, the magnetic field strength of the weak magnetic separation is 700-1800 Oe, thereby achieving effective separation of non-magnetic sulfide ore and magnetite, and achieving separation of pyrrhotite and magnetite.

[0043] Specifically, non-magnetic sulfide ores include pyrite (FeS2), chalcopyrite (CuFeS2), galena (PbS), sphalerite (ZnS), etc. 1-x Although it is a strongly magnetic mineral, its specific magnetic susceptibility is lower than that of magnetite (Fe3O4). The specific magnetic susceptibility of pyrrhotite is about 5400×10 -6 cm 3 / g, the specific magnetic susceptibility of magnetite is 80000×10 -6 cm 3 / g, within the above magnetic field strength range, pyrrhotite and magnetite can be separated.

[0044] Exemplarily, the magnetic field strength of the weak magnetic separation can be 700 Oe, 800 Oe, 900 Oe, 1000 Oe, 1100 Oe, 1200 Oe, 1300 Oe, 1400 Oe, 1500 Oe, 1600 Oe, 1700 Oe, 1800 Oe or any value between 700-1800 Oe.

[0045] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0046] Example 1 Example 1 provides a method for desulfurization of sulfur-containing iron concentrate, referring to Figure 1 , the specific steps are as follows: The raw ore comes from an iron mine in Sichuan.

[0047] Process A1, sampling and testing: the sulfur-containing iron concentrate is sampled and graded, and the graded products are chemically analyzed. The analysis results are shown in Table 1.

[0048] Table 1 Classification chemical analysis results of sulfur-containing iron concentrate in Example 1

[0049] The manufacturer's iron concentrate sales standard is a sulfur content of less than 0.3%. As shown in Table 1, 0.074mm can be selected as the grading particle size. Iron concentrate products with a particle size below 0.074mm can be directly sold as the first iron concentrate. The coarse-grained iron concentrate that requires further processing is about 15.09%.

[0050] Step A2, classification: the sulfur-containing iron concentrate is classified by a cyclone to obtain a first coarse particle size and a first fine particle size, and the first coarse particle size is screened by a high-frequency vibrating screen to obtain a second coarse particle size and a second fine particle size, wherein the first coarse particle size is a coarse particle size iron concentrate having a particle size greater than 0.074 mm, and the first fine particle size is combined with the second fine particle size to obtain a fine particle size iron concentrate having a particle size less than or equal to 0.074 mm, and the fine particle size iron concentrate is output as the first iron concentrate; Step A3, ultrafine grinding: the second coarse iron ore concentrate is ground by a vertical mill to a particle size of 0.020 mm or less and a content of not less than 85% to obtain a finely ground product; Step A4, weak magnetic separation: the grinding product is subjected to magnetic separation by a magnetic separator at a magnetic field strength of 1200 Oe to obtain a second iron concentrate and a sulfur-containing product.

[0051] The first iron concentrate, the second iron concentrate and the sulfur-containing product were chemically analyzed, and the specific results are shown in Table 2. The total iron concentrate is the product of the first iron concentrate and the second iron concentrate.

[0052] Table 2 Index test table of Example 1

[0053] Example 2 Example 2 provides a method for desulfurization of sulfur-containing iron concentrate, and the specific steps are as follows: The raw ore comes from an iron mine in Anhui.

[0054] Process B1, sampling and testing: The sulfur-containing iron concentrate is sampled and graded, and the graded products are chemically analyzed. The analysis results are shown in Table 3.

[0055] Table 3 Classification chemical analysis results of sulfur-containing iron concentrate in Example 2

[0056] The manufacturer's iron concentrate sales standard is a sulfur content of less than 0.3%. As shown in Table 3, 0.074mm can be selected as the grading particle size. Iron concentrate products with a particle size below 0.074mm can be directly sold as the first iron concentrate. The coarse-grained iron concentrate that requires further processing accounts for about 11.78%.

[0057] Step B2, classification: the sulfur-containing iron concentrate is classified by a spiral classifier to obtain a first coarse particle size and a first fine particle size. The first coarse particle size is screened by a high-frequency vibrating screen to obtain a second coarse particle size and a second fine particle size. The first coarse particle size is a coarse particle size iron concentrate larger than 0.074 mm. The first fine particle size and the second fine particle size are combined to obtain a fine particle size iron concentrate less than or equal to 0.074 mm. The fine particle size iron concentrate is output as the first iron concentrate. Process B3, ultrafine grinding: the second coarse iron ore concentrate is ground by a vertical mill to a particle size of 0.020 mm or less and a content of not less than 90% to obtain a finely ground product; Step B4, weak magnetic separation: the grinding product is subjected to magnetic separation by a magnetic separator at a magnetic field strength of 1000 Oe to obtain a second iron concentrate and a sulfur-containing product.

[0058] The first iron concentrate, the second iron concentrate and the sulfur-containing product were chemically analyzed, and the specific results are shown in Table 4. The total iron concentrate is the product of the first iron concentrate and the second iron concentrate.

[0059] Table 4 Index test table of Example 2

[0060] Example 3 Example 3 provides a method for desulfurization of sulfur-containing iron concentrate, and the specific steps are as follows: The raw ore comes from an iron mine in Xinjiang.

[0061] Process C1, sampling and testing: The sulfur-containing iron concentrate is sampled and graded, and the graded products are chemically analyzed. The analysis results are shown in Table 5.

[0062] Table 5 Classification chemical analysis results of sulfur-containing iron concentrate in Example 3

[0063] The manufacturer's iron concentrate sales standard is a sulfur content of less than 0.5%. As shown in Table 5, 0.074mm can be selected as the grading particle size. Iron concentrate products with a particle size below 0.074mm can be directly sold as the first iron concentrate. The coarse-grained iron concentrate that requires further processing accounts for about 20.94%.

[0064] Step C2, classification: the sulfur-containing iron concentrate is classified by a cyclone to obtain a first coarse particle size and a first fine particle size. The first coarse particle size is screened by a double-layer high-frequency vibrating screen, the first layer of the screen hole size is 0.1 mm, and the second layer of the screen hole size is 0.074 mm. The second coarse particle size and the second fine particle size are screened to obtain a coarse particle size iron concentrate greater than 0.074 mm. The first fine particle size and the second fine particle size are combined as a fine particle size iron concentrate less than or equal to 0.074 mm. The fine particle size iron concentrate is output as the first iron concentrate; Process C3, ultrafine grinding: the second coarse-grained iron ore concentrate is ground by a vertical mill to a particle size of 0.020 mm or less and a content of not less than 80%, to obtain a finely ground product; Step C4, weak magnetic separation: the grinding product is subjected to magnetic separation by a magnetic separator at a magnetic field strength of 1400 Oe to obtain a second iron concentrate and a sulfur-containing product.

[0065] The first iron concentrate, the second iron concentrate and the sulfur-containing product were chemically analyzed, and the specific results are shown in Table 6. The total iron concentrate is the product of the first iron concentrate and the second iron concentrate.

[0066] Table 6 Index test table of Example 3

[0067] Example 4 Example 4 provides a beneficiation method for desulfurization of sulfur-containing iron concentrate. The raw ore and other steps of Example 4 are the same as those of Example 1, except that in step A4, the magnetic field strength of Example 4 is 600 Oe.

[0068] Chemical analysis was performed on the first iron concentrate, the second iron concentrate and the sulfur-containing product obtained in Example 4. The specific results are shown in Table 7.

[0069] Table 7 Index test table of Example 4

[0070] From the comparison between Table 7 and Table 2, it can be seen that the total iron concentrate recovery rate of Example 4 is lower than that of Example 1. This is because the magnetic field strength of Example 4 is weak, resulting in the inability to effectively recover iron, which in turn causes the recovery rate (distribution rate) of the total iron concentrate to decrease.

[0071] Example 5 Example 5 provides a beneficiation method for desulfurization of sulfur-containing iron concentrate. The raw ore and other steps of Example 5 are the same as those of Example 1, except that in step A4, the magnetic field strength of Example 5 is 2000 Oe.

[0072] Chemical analysis was performed on the first iron concentrate, the second iron concentrate and the sulfur-containing product obtained in Example 5. The specific results are shown in Table 8.

[0073] Table 8 Index test table of Example 5

[0074] From the comparison between Table 8 and Table 2, it can be seen that the iron grade of the total iron concentrate of Example 5 is lower than that of the total iron concentrate of Example 1, and the sulfur grade of the total iron concentrate of Example 5 is higher than that of the total iron concentrate of Example 1. This is because the magnetic field intensity of Example 5 is relatively high, resulting in poor separation of magnetite and pyrrhotite, and most of the pyrrhotite is mixed into the second iron concentrate, resulting in a decrease in the iron grade of the total iron concentrate and an increase in the sulfur grade.

[0075] Comparative Example 1 Comparative Example 1 provides a beneficiation method for desulfurization of sulfur-containing iron concentrate. Compared with Example 1, the original ore used is the same, and the difference is that Comparative Example 1 adopts a traditional flotation method for desulfurization. The specific steps are as follows: Step a1: Grind the sulfur-containing iron concentrate with a ball mill to obtain grinding slurry with a grinding fineness of less than 0.074 mm and a content of not less than 90%; Step a2: adding 2000g / t sulfuric acid as a sulfur-containing mineral activator, 200g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 50g / t pine oil as a foaming agent to the grinding slurry; Step a3: performing the first desulfurization roughing to obtain the first desulfurization rough concentrate and the first desulfurization roughing tailings; Step a4: add 500g / t sulfuric acid as a sulfur-containing mineral activator, 100g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 15g / t pine oil as a foaming agent to the first desulfurization roughing tailings; Step a5: performing a second desulfurization roughing to obtain a second desulfurization rough concentrate and a second desulfurization roughing tailings; Step a6: Add 200g / t sulfuric acid as a sulfur-containing mineral activator, 50g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 5g / t pine oil as a foaming agent to the second desulfurization roughing tailings; Step a7: performing the first desulfurization scavenging to obtain the first desulfurization scavenging concentrate and the first desulfurization scavenging tailings; Step a8: Add 100g / t sulfuric acid as a sulfur-containing mineral activator and 30g / t sodium amyl xanthate as a sulfur-containing mineral collector to the first desulfurization scavenging tailings; Step a9: performing a second desulfurization scavenging to obtain a second desulfurization scavenging concentrate and a second desulfurization scavenging tailings, and the second desulfurization scavenging tailings are output as the final iron concentrate; Step a10: The first desulfurization rougher concentrate and the second desulfurization rougher concentrate are combined as feed ore, and the first desulfurization and concentration operation is carried out to obtain the first desulfurization and concentration concentrate and the first desulfurization and concentration tailings. The first desulfurization and concentration concentrate is output as the final sulfur-containing product.

[0076] The final iron ore concentrate and sulfur-containing products were chemically analyzed and the specific results are shown in Table 9.

[0077] Table 9 Index test table of comparative example 1

[0078] Comparative Example 2 Comparative Example 2 provides a beneficiation method for desulfurization of sulfur-containing iron concentrate. Compared with Example 2, the original ore used is the same, but the difference is that Comparative Example 2 adopts a traditional flotation method for desulfurization. The specific steps are as follows: Step b1: Grind the sulfur-containing iron concentrate with a ball mill to obtain grinding slurry with a grinding fineness of less than 0.074 mm and a content of not less than 90%; Step b2: adding 1500g / t sulfuric acid as a sulfur-containing mineral activator, 150g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 60g / t pine oil as a foaming agent to the grinding slurry; Step b3: performing the first desulfurization roughing to obtain the first desulfurization rough concentrate and the first desulfurization roughing tailings; Step b4: Add 400g / t sulfuric acid as a sulfur-containing mineral activator, 80g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 15g / t pine oil as a foaming agent to the first desulfurization roughing tailings; Step b5: performing a second desulfurization roughing to obtain a second desulfurization rough concentrate and a second desulfurization roughing tailings; Step b6: Add 200g / t sulfuric acid as a sulfur-containing mineral activator, 50g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 5g / t pine alcohol oil as a foaming agent to the second desulfurization roughing tailings; Step b7: performing a third desulfurization roughing to obtain a third desulfurization roughing concentrate and a third desulfurization roughing tailings; Step b8: Add 100g / t sulfuric acid as a sulfur-containing mineral activator and 30g / t sodium amyl xanthate as a sulfur-containing mineral collector to the third desulfurization roughing tailings; Step b9: performing the first desulfurization scavenging to obtain the first desulfurization scavenging concentrate and the first desulfurization scavenging tailings, and the first desulfurization scavenging tailings are output as the final iron concentrate; Step b10: combining the first desulfurization rougher concentrate, the second desulfurization rougher concentrate and the third desulfurization rougher concentrate as feed ore, carrying out the first desulfurization and concentration operation, and obtaining the first desulfurization and concentration concentrate and the first desulfurization and concentration tailings; Step b11: subjecting the first desulfurization concentrated concentrate to a second desulfurization concentrated concentrate to obtain a second desulfurization concentrated concentrate and a second desulfurization concentrated tailings; the second desulfurization concentrated concentrate is output as the final sulfur-containing product; The final iron ore concentrate and sulfur-containing products were chemically analyzed and the specific results are shown in Table 10.

[0079] Table 10 Index test table of comparative example 2

[0080] Comparative Example 3 Comparative Example 3 provides a method for desulfurization of sulfur-containing iron concentrate. Compared with Example 3, the original ore used is the same, except that Comparative Example 3 adopts traditional flotation desulfurization. Figure 2 , the specific steps of Comparative Example 3 are as follows: Step c1: Grind the sulfur-containing iron concentrate with a ball mill to obtain grinding slurry with a grinding fineness of less than 0.074 mm and a content of not less than 85%; Step c2: demagnetizing the grinding slurry; Step c3: adding 2500g / t sulfuric acid as a sulfur-containing mineral activator, 220g / t sodium amyl xanthate as a sulfur-containing mineral collector, and 45g / t pine oil as a foaming agent to the grinding slurry; Step c4: performing the first desulfurization roughing to obtain the first desulfurization rough concentrate and the first desulfurization roughing tailings; Step c5: add 1200g / t sulfuric acid as sulfur-containing mineral activator, 100g / t sodium amyl xanthate as sulfur-containing mineral collector, and 16g / t pine oil as foaming agent to the first desulfurization roughing tailings; Step c6: performing a second desulfurization roughing to obtain a second desulfurization rough concentrate and a second desulfurization roughing tailings; Step c7: add 300g / t sulfuric acid as sulfur-containing mineral activator, 50g / t sodium amyl xanthate as sulfur-containing mineral collector, and 5g / t pine oil as foaming agent to the second desulfurization rougher tailings; Step c8: performing a third desulfurization roughing to obtain a third desulfurization roughing concentrate and a third desulfurization roughing tailings; Step c9: add 100g / t sulfuric acid as a sulfur-containing mineral activator and 20g / t sodium amyl xanthate as a sulfur-containing mineral collector to the third desulfurization roughing tailings; Step c10: performing the fourth desulfurization roughing to obtain the fourth desulfurization roughing concentrate and the fourth desulfurization roughing tailings; Step c11: adding 50 g / t sulfuric acid as a sulfur-containing mineral activator and 20 g / t sodium amyl xanthate as a sulfur-containing mineral collector to the fourth desulfurization roughing tailings; Step c12: Perform the first desulfurization scavenging to obtain the first desulfurization scavenging concentrate and the first desulfurization rougher tailings, and the first desulfurization scavenging tailings are output as the final iron concentrate; Step c13: combine the first desulfurization rougher concentrate, the second desulfurization rougher concentrate, the third desulfurization rougher concentrate and the fourth desulfurization rougher concentrate as feed ore, carry out the first desulfurization concentration operation, and obtain the first desulfurization concentration concentrate and the first desulfurization concentration tailings; Step c14: subjecting the first desulfurization concentrated concentrate to a second desulfurization concentrated concentrate to obtain a second desulfurization concentrated concentrate and a second desulfurization concentrated tailings; the second desulfurization concentrated concentrate is output as the final sulfur-containing product; The final iron ore concentrate and sulfur-containing products were chemically analyzed and the specific results are shown in Table 11.

[0081] Table 11 Index test table of comparative example 3

[0082] In the flotation method, the scavenged concentrate and selected tailings of each operation are returned to the previous operation in sequence.

[0083] It can be seen from Examples 1-5 and Comparative Examples 1-3 that: (1) the sulfur content of the total iron concentrate obtained by the method of the present application is effectively reduced and reaches the saleable standard, and the sulfur content of the iron concentrate obtained by the traditional flotation method is lower; (2) the total iron concentrate obtained by the method of the present application has a higher iron grade and a higher iron recovery rate than the iron concentrate obtained by the traditional flotation method; (3) the method of the present application has a shorter process structure, simpler process and more stable performance than the traditional flotation method; (4) the method of the present application does not require the addition of any chemical agents and does not cause any pollution to the environment, while the traditional flotation method A large amount of flotation agents need to be added, which has high production costs, safety hazards in the storage, management and use of agents, and is not environmentally friendly; (5) The method of this application only needs to grind a small portion of the coarse-grained sulfur-containing iron ore concentrate, with low production energy consumption and high processing capacity; (6) The method of this application adopts new mills such as vertical mills, tower mills, scrubbing mills, and sand mills to achieve grinding in a stirring manner, which has lower energy consumption than the traditional ball mill that uses lifting and dropping steel balls for grinding; (7) The method of this application adopts low specific gravity and small particle size ceramic balls, which greatly reduces the energy consumption of grinding and improves the grinding efficiency.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0085] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for desulfurizing a sulfur-containing iron concentrate, characterized in that: include: The sulfur-containing iron concentrate is sampled and screened to obtain multiple groups of graded products with different particle sizes, and each group of graded products is chemically analyzed to determine the graded particle size; The sulfide-containing iron concentrate is transported to a first separation and classification device to obtain a first coarse-grained iron concentrate and a first fine-grained iron concentrate; transporting the first coarse-grained iron concentrate to a second separation and classification device to obtain a second coarse-grained iron concentrate and a second fine-grained iron concentrate, and combining the first fine-grained iron concentrate and the second fine-grained iron concentrate as a first iron concentrate; The second coarse-grained iron concentrate is subjected to grinding and weak magnetic separation in sequence to obtain a second iron concentrate and a sulfur-containing product, and the first iron concentrate and the second iron concentrate are combined as a total iron concentrate product.

2. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: The chemical analysis of each group of graded products includes: analyzing the sulfur content in each group of graded products.

3. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 2, characterized in that: The determining of the classification particle size includes: comparing the sulfur content in each group of classified products with the qualified sulfur content, and determining the minimum value of the screening particle size corresponding to the classified products exceeding the qualified sulfur content as the classification particle size.

4. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: The sulfur content in the sulfur-containing iron concentrate decreases as the particle size decreases.

5. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: The first separation and classification equipment includes any one of a spiral classifier and a cyclone; The particle size of the first coarse-grained iron concentrate is greater than the particle size of the first fine-grained iron concentrate, and the particle size of the first fine-grained iron concentrate is less than or equal to the classification particle size.

6. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: The second separation and classification device comprises a high-frequency vibration screen, and the high-frequency vibration screen comprises a single-layer structure or a multi-layer structure; The particle size of the second coarse-grained iron concentrate is greater than the particle size of the second fine-grained iron concentrate, and the particle size of the second fine-grained iron concentrate is less than or equal to the classification particle size.

7. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: The grinding equipment includes any one of a vertical mill, a tower mill, a stirring mill, a scrubbing mill and an abrasive mill.

8. The ore dressing method for desulfurization of sulfur-containing iron concentrate according to claim 7, characterized in that: The grinding medium used in the grinding equipment is a non-ferrous medium; And / or, the non-ferrous medium includes ceramic balls.

9. The method for desulfurization of sulfur-containing iron concentrate according to claim 1, characterized in that: After the grinding treatment, the content of products with a particle size below 0.020 mm is not less than 65%.

10. The method for desulfurizing sulfur-containing iron concentrate according to any one of claims 1 to 9, characterized in that: The magnetic field strength of the weak magnetic separation is 700-1800 Oe.

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