Desulfurization method for high-sulfur magnetite concentrate

Abstract

The invention provides a high-sulfur magnetite concentrate desulfurization method, and relates to the technical field of high-sulfur magnetite treatment. The method comprises the steps that after target concentrate is subjected to size mixing, two-stage pipeline demagnetizing treatment is conducted, and demagnetized ore pulp is obtained; the demagnetized ore pulp is subjected to combined surface cleaning treatment; carrying out surface modification treatment on the demagnetized ore pulp subjected to combined surface cleaning treatment to obtain demagnetized ore pulp with a hydrophilic-sulfuphobic surface, and then carrying out synergistic activation treatment to obtain activated slurry; and the activated slurry is subjected to flotation treatment through a combined collecting agent based on dixanthate, butyl xanthate and dithiophosphate, and desulfurized magnetite concentrate is obtained. The method synergistically solves the problems of magnetic agglomeration, surface passivation, insufficient activation and the like, the desulfurization efficiency is remarkably improved, the sulfur content of concentrate is reduced, and meanwhile, conditions are created for resource recycling of sulfur in tailings.

Description

Technical Field

[0001] The present invention relates to the technical field of high-sulfur magnetite processing, in particular to a method for desulfurizing high-sulfur magnetite concentrate. Background Art

[0002] In the field of mineral processing, desulfurization of high-sulfur magnetite concentrate is a crucial step in the iron ore beneficiation process. High-sulfur magnetite concentrate typically contains a high proportion of pyrrhotite, with a sulfur content generally ranging from 1% to 6%. To meet the low-sulfur content requirements of iron ore concentrate in steel production, an effective desulfurization process is necessary to reduce the sulfur content to below 0.3%. Traditional desulfurization processes rely primarily on physical and chemical methods, using techniques such as flotation to separate pyrrhotite from magnetite, thereby reducing the sulfur content.

[0003] Among existing technologies for desulfurizing high-sulfur magnetite concentrates, a common process combines single demagnetization with xanthate capture. This method is suitable for desulfurizing iron concentrates with low pyrrhotite content, but its desulfurization efficiency is significantly insufficient when treating pyrrhotite with a high degree of oxidation, typically falling below 80%, and the final concentrate sulfur content remains above 0.5%. In addition, a patented technology proposes using ultrasonic cleaning combined with acid treatment to improve desulfurization effectiveness. However, this method fails to include surface modification and copper-ammonium composite activation steps, resulting in a sulfur enrichment ratio of less than 5 times in the tailings, making it impossible to effectively enrich and recover sulfur.

[0004] Conventional technologies have many defects when processing high-sulfur magnetite concentrate. First, the process of single demagnetization and xanthate capture cannot effectively solve the oxidation problem of pyrrhotite, resulting in a low desulfurization rate, which makes it difficult to meet the requirements of low sulfur content in iron ore concentrate in industrial production. Secondly, although the technology of ultrasonic cleaning combined with acid treatment has improved the desulfurization effect to a certain extent, it has failed to synergistically solve key problems such as magnetic agglomeration interference, surface passivation and insufficient activation. The magnetic agglomeration phenomenon will interfere with the flotation process and reduce the separation effect of pyrrhotite and magnetite; surface passivation will affect the binding of the collector to the mineral surface and reduce the flotation efficiency; and insufficient activation will not be able to fully play the role of the collector, resulting in unsatisfactory desulfurization effect.

[0005] In summary, conventional technologies for treating high-sulfur magnetite concentrate, whether using a single demagnetization and xanthate capture process or a combined ultrasonic cleaning and acid treatment method, have failed to fully address the issues of magnetic agglomeration interference, surface passivation, and insufficient activation faced during the desulfurization process. These issues not only limit desulfurization efficiency but also result in low sulfur enrichment ratios in the tailings, making it impossible to effectively recycle resources, thus affecting the economic and environmental performance of the entire high-sulfur magnetite concentrate desulfurization process.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The object of the present invention is to provide a method for desulfurization of high-sulfur magnetite concentrate, which synergistically solves the problems of magnetic agglomeration, surface passivation and insufficient activation, significantly improves the desulfurization efficiency, reduces the sulfur content of the concentrate, and creates conditions for the resource recovery of sulfur in the tailings.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: In a first aspect, the present invention provides a method for desulfurizing high-sulfur magnetite concentrate, comprising: After the target concentrate is slurried, it is subjected to a two-stage pipeline demagnetization process to obtain demagnetized ore pulp; The demagnetized slurry is subjected to a combined surface cleaning treatment using ultrasonic waves and a sulfuric acid-oxalic acid mixed solution; performing surface modification treatment on the demagnetized ore pulp that has undergone the combined surface cleaning treatment to obtain a demagnetized ore pulp having a hydrophilic-sulfophobic surface; Performing a synergistic activation treatment on the demagnetized ore pulp having a hydrophilic-sulfophobic surface to obtain an activated slurry; The activated slurry is subjected to flotation treatment by using a combined collector to obtain desulfurized magnetite concentrate; the combined collector comprises dixanthate, butyl xanthate and dithiophosphate.

[0009] In an optional embodiment, the magnetic field strength of the two-stage pipeline demagnetization treatment is 100mT~300mT.

[0010] Furthermore, in the two-stage pipeline demagnetization treatment, the second-stage demagnetization magnetic field strength is 20mT to 50mT higher than the first-stage demagnetization magnetic field strength.

[0011] In an optional embodiment, the slurry concentration after slurry adjustment is 30% to 50%.

[0012] In an optional embodiment, the combined surface cleaning process comprises: The demagnetized slurry is placed in a stirring barrel equipped with an ultrasonic cleaning device and subjected to ultrasonic surface cleaning using the sulfuric acid-oxalic acid mixed solution; Wherein, the molar ratio of the sulfuric acid-oxalic acid mixed solution is (1-2):1; and / or the pH value of the sulfuric acid-oxalic acid mixed solution is 3-5.

[0013] In an optional embodiment, the frequency of the ultrasonic wave is 50 Hz; and / or, The power density of the ultrasonic surface cleaning process is 0.5 W / cm 3 ~2W / cm 3 and / or, The ultrasonic surface cleaning process lasts for 10 to 15 minutes.

[0014] In an optional embodiment, the surface modification treatment is to perform surface modification treatment on the demagnetized slurry using sodium silicate and sodium hexametaphosphate; Among them, the dosage of sodium silicate is 600 g / t~1000 g / t; the dosage of sodium hexametaphosphate is 200 g / t~500 g / t.

[0015] In an optional embodiment, the synergistic activation treatment is to synergistically activate the demagnetized slurry using a cuprammonium composite activator; Wherein, the copper ammonium composite activator comprises copper sulfate and ammonium sulfate; and / or, The synergistic activation treatment is to add copper sulfate and ammonium sulfate in the cuprammonium composite activator in stages according to a mass ratio of 1: (1-1.5); and / or, The amount of copper sulfate used is 100g / t~250g / t; and / or, The dosage of ammonium sulfate is 150g / t~300g / t.

[0016] In an optional embodiment, the combined collector includes dixanthate, butyl xanthate and dithiophosphate.

[0017] In an optional embodiment, the mass ratio of dixanthate, butyl xanthate and dithiophosphate in the combined collector is 1:(2-3):1.

[0018] In an optional embodiment, the amount of double xanthate used is 40 g / t to 80 g / t; and / or, The amount of butyl xanthate used is 80 g / t~150 g / t; and / or; The dosage of dithiophosphate is 40 g / t~80 g / t.

[0019] The method provided in the present application can effectively eliminate the magnetic agglomeration phenomenon between magnetite particles through two-stage pipeline demagnetization treatment, creating favorable conditions for subsequent flotation separation. The ultrasonic surface cleaning treatment using the sulfuric acid-oxalic acid mixed solution in a stirring barrel equipped with an ultrasonic cleaning device can eliminate impurities on the surface of sulfur-containing ore particles in the slurry, which is beneficial to the combination of flotation agents and the surface of sulfur-containing minerals; at the same time, the demagnetized ore pulp is surface-modified to obtain a surface with hydrophilic-sulfur-phobic properties, which significantly improves the properties of the ore surface and enhances the surface property difference between pyrrhotite and magnetite, thereby improving the separation effect of the two during the flotation process. In addition, the synergistic activation treatment further enhances the flotation activity of pyrrhotite, and the staged addition of the activator can more accurately regulate the activity of the ore surface, so that it is more fully combined with the collector, thereby improving the flotation recovery rate of pyrrhotite. Ultimately, flotation treatment was performed using a combined collector based on dixanthate, butyl xanthate, and dithiophosphate. This combined collector was able to form a stable adsorption layer on the surface of pyrrhotite at varying degrees of oxidation, further improving the selectivity and efficiency of flotation and effectively separating pyrrhotite from magnetite, thereby reducing the sulfur content in the concentrate. Through these synergistic optimization steps, the method effectively addresses issues such as magnetic agglomeration interference, surface passivation, and insufficient activation, achieving efficient desulfurization and improving concentrate quality. It also opens the door to the potential for resource recovery of sulfur in tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in conventional technologies, the following briefly introduces the drawings required for use in the specific embodiments or conventional technical descriptions. 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 any creative work.

[0021] Figure 1 This is a schematic diagram of the processing flow of an embodiment of the high-sulfur magnetite concentrate desulfurization method of the present application; Figure 2 This is a schematic diagram of the technical route of an embodiment of the high-sulfur magnetite concentrate desulfurization method of the present application; Figure 3 This is a schematic diagram of the process flow of an embodiment of the high-sulfur magnetite concentrate desulfurization method of the present application; Figure 4 This is a schematic diagram of a curve showing the effect of different activator ratios on the desulfurization rate in an embodiment of the high-sulfur magnetite concentrate desulfurization method of the present application; Figure 5 This is a curve diagram showing the effect of the amount of copper sulfate and ammonium sulfate on the sulfur content of the iron concentrate in the embodiment of the high-sulfur magnetite concentrate desulfurization method of this application. DETAILED DESCRIPTION

[0022] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all commercially available conventional products.

[0023] refer to Figure 1 The present application provides a method for desulfurization of high-sulfur magnetite concentrate, comprising: Step S1: After the target concentrate is slurried, it is subjected to a two-stage pipeline demagnetization treatment to obtain demagnetized ore slurry.

[0024] As mentioned above, the two-stage pipeline demagnetization treatment is a process technology used to eliminate the magnetic agglomeration phenomenon between magnetic mineral particles. Through two treatments of the pipeline demagnetizer, the magnetic attraction between the magnetic particles in the ore slurry is effectively removed, thereby improving the effect of the subsequent processing process.

[0025] The target concentrate for this application is a high-sulfur magnetite concentrate with a sulfur content between 1% and 6%, primarily due to the high proportion of pyrrhotite in the concentrate. This concentrate, primarily composed of magnetite and pyrrhotite, has a high sulfur content due to the presence of pyrrhotite, which does not meet the low sulfur content requirements for iron ore concentrates used in steel production (typically ≤0.3%). Therefore, an effective desulfurization process is needed to reduce the sulfur content while effectively separating pyrrhotite from magnetite to improve the iron grade and meet industrial production requirements.

[0026] The preparation of the demagnetized slurry is a crucial step in the desulfurization process for high-sulfur magnetite concentrates. Its purpose is to create favorable conditions for subsequent flotation separation through proper slurry concentration and demagnetization. Specifically, the target concentrate is mixed with water and stirred to achieve uniform dispersion. Slurry preparation can be performed using a stirring tank or inline mixer, with a moderate stirring speed to avoid excessive agitation that can lead to particle breakage.

[0027] Step S2: performing a combined surface cleaning treatment on the demagnetized slurry using ultrasonic waves and a sulfuric acid-oxalic acid mixed solution.

[0028] Flotation is a mineral separation method that uses the differences in the physical and chemical properties of the mineral surface to separate minerals. Since the surface of the pyrrhotite in the demagnetized slurry is contaminated during the previous separation process, resulting in poor floatability, it is necessary to use ultrasonic waves and a sulfuric acid-oxalic acid mixed solution for a combined surface cleaning treatment to achieve the purpose of cleaning the pyrrhotite surface and create conditions for the next step of modifying the mineral surface.

[0029] Step S3, performing surface modification treatment on the demagnetized ore pulp that has undergone the combined surface cleaning treatment to obtain a demagnetized ore pulp having a hydrophilic-sulfophobic surface.

[0030] In the desulfurization treatment of high-sulfur magnetite concentrate, the demagnetized pulp is surface modified to give it a hydrophilic-sulfophobic surface, mainly to improve the efficiency and selectivity of subsequent flotation separation.

[0031] The primary purpose of surface modification is to alter the physicochemical properties of the ore particle surface to enhance the separation of pyrrhotite from magnetite. The surface properties of pyrrhotite and magnetite differ only slightly, making direct flotation separation difficult. Surface modification can adjust the hydrophilicity and hydrophobicity of the ore particle surface, making the surface properties of pyrrhotite and magnetite more distinct. Pyrrhotite is susceptible to oxidation, forming a passivation film that reduces its ability to bind to collectors and affects flotation efficiency. Surface modification can remove or modify this passivation film, enhancing the flotation activity of pyrrhotite. Surface-modified ore particles are more likely to bind to collectors during flotation, thereby improving flotation selectivity and efficiency and minimizing magnetite loss.

[0032] Imparting a hydrophilic-sulfophobic surface to the demagnetized slurry is intended to achieve effective separation of pyrrhotite from magnetite. Magnetite is a strongly magnetic mineral with a typically highly hydrophilic surface. Surface modification can further enhance the hydrophilicity of magnetite, making it more likely to remain in the slurry during flotation rather than be carried away by bubbles. Pyrrhotite is a sulfur-containing mineral with a relatively hydrophobic surface. Surface modification can further enhance the hydrophobicity of pyrrhotite, making it more likely to bind to the collector during flotation, thereby being carried away by bubbles and separated from the magnetite. By adjusting the hydrophilicity and hydrophobicity of the ore particle surface, pyrrhotite and magnetite exhibit different behaviors during flotation, resulting in efficient separation. The formation of a hydrophilic-sulfophobic surface is key to improving flotation selectivity and efficiency.

[0033] Step S4, performing a synergistic activation treatment on the demagnetized slurry having a hydrophilic-sulfophobic surface to obtain an activated slurry.

[0034] The aforementioned synergistic activation process is a chemical treatment of the mineral surface. Its goal is to gradually enhance the mineral surface activity by adding activators in stages, thereby improving its binding capacity with the collector. In the desulfurization of high-sulfur magnetite concentrate, synergistic activation is a key step in achieving efficient separation of pyrrhotite and magnetite.

[0035] Synergistic activation treatment involves adding the activator to the slurry in multiple steps, depending on the mineral's properties and treatment requirements. Stir thoroughly after each addition to allow the activator to fully interact with the mineral surface. By adding the activator in stages, the mineral surface activity is gradually enhanced, allowing it to better bind to the collector. This gradual enhancement approach avoids the potential for over- or under-activation caused by adding a large amount of activator all at once. By controlling the amount of activator added and the reaction time, activation conditions can be optimized to ensure optimal activation of the mineral surface.

[0036] The primary purpose of synergistic activation treatment is to enhance the flotation activity of pyrrhotite and improve its binding capacity with collectors, thereby achieving effective separation of pyrrhotite from magnetite. The surface activity of pyrrhotite is crucial to flotation performance. Synergistic activation treatment gradually enhances the surface activity of pyrrhotite, making it more resilient to collector binding, thereby improving flotation efficiency. Adding a large amount of activator all at once can lead to overactivation, resulting in excessive surface activity and negatively impacting flotation performance. Adding activator in stages can avoid this, ensuring uniform and stable activation. Pyrrhotite surface properties vary with its degree of oxidation. Synergistic activation treatment allows for gradual adjustment of activation conditions based on the degree of pyrrhotite oxidation, ensuring optimal activation for pyrrhotite of varying oxidation levels. Synergistic activation treatment significantly enhances the binding capacity of pyrrhotite to collectors while maintaining the hydrophilicity of magnetite, thereby improving flotation selectivity and minimizing magnetite loss.

[0037] In step S5, the activated slurry is subjected to flotation treatment using a combined collector to obtain a desulfurized magnetite concentrate. The combined collector comprises dixanthate, butyl xanthate, and dithiophosphate.

[0038] Among the combined collectors mentioned above, dixanthate and butyl xanthate are flotation collectors that bind to active sites on mineral surfaces, forming a hydrophobic film. This enhances the adhesion of mineral particles to bubbles, making them more easily lifted by bubbles during flotation. Dithiophosphates are also highly effective flotation collectors used to treat difficult-to-float minerals. They form stable chemical bonds with mineral surfaces, further enhancing the hydrophobicity of the mineral and improving flotation efficiency.

[0039] The combination of dixanthate, butyl xanthate, and dithiophosphate can fully utilize the advantages of several collectors to improve flotation selectivity and efficiency. This combination of collectors can better adapt to pyrrhotite with different oxidation levels, ensuring its effective capture during the flotation process.

[0040] After the previous demagnetization, surface modification, and synergistic activation treatments, the surface properties of pyrrhotite and magnetite have been significantly altered. The enhanced surface activity of pyrrhotite makes it more susceptible to collector binding, while the surface of magnetite remains hydrophilic and less susceptible to collector binding. During flotation, pyrrhotite (a sulfur-containing mineral) is carried by bubbles into the froth product, while magnetite (an iron mineral) remains in the slurry. This allows the higher-sulfur pyrrhotite to be separated from the magnetite, thereby reducing the sulfur content in the final concentrate and achieving desulfurization.

[0041] The flotation process can be described as "1 roughing, 2 scavenging, 2 finishing." "Roughing" is the first step in the flotation process, intended to initially separate the target mineral (pyrrhotite in this application) from the ore pulp. "Scavenging" is the further processing of the rougher tailings (the portion of the ore pulp that is not floated after roughing) to recover the target mineral remaining in the tailings. "Finishing" is the further processing of the rough concentrate obtained from roughing to improve the concentrate grade and remove impurities. Through roughing, two scavenging stages, and two finishing stages, the target mineral (pyrrhotite) is effectively separated from non-target minerals (magnetite), improving the concentrate grade and reducing the sulfur content, ensuring that the final concentrate quality meets industrial production requirements.

[0042] In some embodiments, the magnetic field strength of the two-stage pipeline demagnetization treatment is 100 mT to 300 mT. For example, the magnetic field strength can be 100 mT, 200 mT, 300 mT, etc.

[0043] In some embodiments, in the two-stage pipeline demagnetization process, the second-stage demagnetization magnetic field strength is 20mT to 50mT higher than the first-stage demagnetization magnetic field strength, for example, 20mT, 30mT, 40mT, 50mT, etc.

[0044] During the two-stage pipeline demagnetization process, the magnetic field strengths of the two demagnetizers differ, with the second-stage demagnetizer having a higher magnetic field strength than the first, specifically 20 to 50 millitesla (mT). This design is intended to more effectively eliminate magnetic agglomeration between magnetic mineral particles, ensuring uniform dispersion during subsequent processing.

[0045] The slurry first passes through the first-stage pipeline demagnetizer, which initially eliminates magnetic agglomeration between magnetic particles. The magnetic field strength of the first-stage demagnetizer is typically low, for example, 100-200 mT. After the first-stage demagnetization, the slurry enters the second-stage pipeline demagnetizer, where the magnetic field strength is 20 to 50 mT higher than the first-stage. This gradually increasing magnetic field strength more thoroughly eliminates any remaining magnetic agglomeration.

[0046] By gradually increasing the magnetic field strength, magnetic agglomeration between magnetic particles can be more effectively eliminated, ensuring that the mineral particles are evenly dispersed during subsequent processing. Magnetic particles in the slurry may have different magnetic strengths. The first stage of demagnetization eliminates most magnetic agglomeration, while the second stage further treats particles with stronger magnetic properties. This elimination of magnetic agglomeration allows for more uniform contact between the mineral particles and the collector during flotation, improving both selectivity and efficiency.

[0047] In some embodiments, the slurry concentration after slurry adjustment is 30% to 50%. For example, the slurry concentration can be 30%, 40%, 50%, etc.

[0048] In some embodiments, the combined surface cleaning process comprises: The demagnetized slurry is placed in a stirring barrel equipped with an ultrasonic cleaning device and subjected to ultrasonic surface cleaning using the sulfuric acid-oxalic acid mixed solution; Wherein, the molar ratio of the sulfuric acid-oxalic acid mixed solution is (1-2):1; for example, the molar ratio can be 1:1, 1.5:1, 2:1, etc.

[0049] In some embodiments, the pH value of the sulfuric acid-oxalic acid mixed solution is 3-5; for example, the pH value may be 3, 4, 5, etc.

[0050] In some embodiments, the surface cleaning treatment is to place the demagnetized slurry in the sulfuric acid-oxalic acid mixed solution and perform an ultrasonic-based surface cleaning treatment.

[0051] In some embodiments, the frequency of the ultrasound wave is 50 Hz. In some embodiments, the power density of the ultrasonic surface cleaning process is 0.5 W / cm 3 ~2W / cm 3 For example, the power density can be 0.5 W / cm 3 , 0.6 W / cm 3 , 0.8 W / cm 3 , 1.0 W / cm 3 , 1.2 W / cm 3 , 1.5W / cm 3 , 1.8 W / cm 3 , 2.0 W / cm 3 etc.

[0052] In some embodiments, the ultrasonic surface cleaning treatment lasts for 10 to 15 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, and the like.

[0053] In some embodiments, the surface modification treatment is to add sodium silicate and sodium hexametaphosphate to perform surface modification treatment on the demagnetized slurry; In some embodiments, the amount of sodium silicate is 600 g / t to 1000 g / t; In some embodiments, the amount of sodium hexametaphosphate used is 200 g / t to 500 g / t.

[0054] In some embodiments, the synergistic activation treatment is to synergistically activate the demagnetized slurry using a cuprammonium composite activator.

[0055] Wherein, the cuprammonium composite activator comprises copper sulfate and ammonium sulfate.

[0056] In some embodiments, the synergistic activation is performed by adding copper sulfate and ammonium sulfate in the cuprammonium composite activator in stages at a mass ratio of 1:1 to 1.5. For example, the mass ratio can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, and the like.

[0057] It should be noted that adding the activator in stages can gradually enhance the surface activity of pyrrhotite, avoiding over-activation or under-activation caused by adding a large amount of activator all at once. Over-activation may lead to excessive surface activity, which in turn affects flotation performance; under-activation, on the other hand, fails to effectively improve flotation efficiency. By adding the activator in stages, the dosage can be gradually adjusted according to the actual reaction of the slurry, ensuring optimal activation results at each step.

[0058] Pyrrhotite's surface properties vary depending on its degree of oxidation. The phased addition of activators allows for better adaptation to varying degrees of pyrrhotite oxidation, ensuring optimal activation for each oxidized state. This gradual activation allows for more precise control of pyrrhotite surface activity, making it more susceptible to collector binding during flotation, thereby improving flotation selectivity and efficiency.

[0059] It should be noted that in the desulfurization method of high-sulfur magnetite concentrate, copper sulfate and ammonium sulfate are used as copper-ammonium composite activators and are added in stages in order to better enhance the flotation activity of pyrrhotite and improve flotation efficiency and selectivity.

[0060] Copper sulfate reacts chemically with sulfides on the pyrrhotite surface, forming a highly active copper ion film. This film significantly enhances the activity of the pyrrhotite surface, making it more receptive to collectors. Copper ions form stable chemical bonds with collectors (such as dixanthate, butyl xanthate, and dithiophosphates), thereby increasing the collector's adsorption capacity on the pyrrhotite surface and enhancing flotation efficiency.

[0061] Ammonium sulfate can adjust the pH and ionic strength of the slurry, optimizing the chemical environment and thus enhancing the activation effect. Ammonium sulfate and copper sulfate work synergistically to further enhance the activity of the pyrrhotite surface. The ammonium ions in ammonium sulfate can form complexes with copper ions, which can more effectively adsorb on the pyrrhotite surface, enhancing the activation effect.

[0062] In some embodiments, the amount of copper sulfate used is 100 g / t to 250 g / t; for example, the concentration can be 100 g / t, 120 g / t, 150 g / t, 180 g / t, 200 g / t, 220 g / t, 250 g / t, and the like.

[0063] In some embodiments, the amount of ammonium sulfate used is 150 g / t to 300 g / t; for example, the concentration can be 150 g / t, 160 g / t, 180 g / t, 200 g / t, 220 g / t, 250 g / t, 280 g / t, 300 g / t, and the like.

[0064] In some embodiments, the mass ratio of dixanthate, butyl xanthate and dithiophosphate in the combined collector is 1:(2-3):1; for example, the mass ratio can be 1:2:1, 1:2.2:1, 1:2.3:1, 1:2.5:1, 1:2.8:1, 1:2.9:1, 1:3:1, and the like.

[0065] In some embodiments, the amount of double xanthate used is 40 g / t to 80 g / t. For example, the concentration can be 40 g / t, 50 g / t, 60 g / t, 70 g / t, 80 g / t, and the like.

[0066] In some embodiments, the amount of butyl xanthate used is 80 g / t to 150 g / t; for example, the concentration can be 80 g / t, 90 g / t, 100 g / t, 110 g / t, 120 g / t, 130 g / t, 140 g / t, 150 g / t, and the like.

[0067] In some embodiments, the amount of dithiophosphate used is 40 g / t to 80 g / t. For example, the concentration can be 40 g / t, 50 g / t, 60 g / t, 70 g / t, 80 g / t, etc.

[0068] refer to Figure 2 and Figure 3The high-sulfur magnetite concentrate desulfurization method provided in this application achieves significant desulfurization effects and economic benefits through a series of synergistically optimized process steps. Specifically, the method includes two-stage pipeline demagnetization treatment, surface modification, synergistic activation, and flotation treatment based on a combination of dixanthate, butyl xanthate and dithiophosphate collectors. The organic combination of these steps enables the desulfurization rate to reach more than 95%, the sulfur content of the concentrate is reduced to less than 0.3%, and the sulfur enrichment ratio of the tailings exceeds 10 times, which provides the possibility for the resource recovery and utilization of sulfur in the tailings. In addition, by optimizing the use of reagents and the process flow, the cost of reagents has been reduced by 25%-40%, and zero wastewater discharge has been achieved, which significantly improves the economy and environmental protection of the entire desulfurization process.

[0069] The present invention is further described below by way of specific examples. However, it should be understood that these examples are merely provided for more detailed description and are not to be construed as limiting the present invention in any form.

[0070] Table 1. Process parameters in Examples and Comparative Examples

[0071] Example 1 In this embodiment, desulfurization treatment is performed on the target concentrate.

[0072] The target concentrate contains 62.12% TFe, 3.4% S and 88% pyrrhotite.

[0073] Treatment process (refer to Table 1): (1) Pulping and demagnetization: The ore pulp concentration is 35%, and it is processed by a two-stage pipeline demagnetizer (the first stage demagnetization magnetic field strength is 100mT, and the second stage demagnetization magnetic field strength is 150mT); (2) Surface treatment: 50 kHz ultrasonic cleaning (power density 0.8 W / cm³) in a pH 3 sulfuric acid-oxalic acid mixed solution (molar ratio 2:1) for 10 min; (3) Composite modification: adding sodium silicate (600 g / t) and sodium hexametaphosphate (200 g / t) to form hydrophilic-sulfophobic surface properties; (4) Synergistic activation: copper sulfate (200 g / t) and ammonium sulfate (250 g / t) are activated in stages at a mass ratio of 1:1 to 1:1.5; (5) Enhanced flotation: A ternary collection system of double xanthate (50 g / t), butyl xanthate (150 g / t) and dithiophosphate (50 g / t) was used, and the flotation process was 1 coarse, 2 scavenging and 2 fine.

[0074] Example 2 In this embodiment, desulfurization treatment is performed on the target concentrate.

[0075] The target concentrate is an iron concentrate containing highly oxidized pyrrhotite, of which TFe is 61.7%, S is 5.2%, and monoclinic pyrrhotite accounts for 85%.

[0076] Treatment process: Basically the same as Example 1, refer to Table 1 for the differences.

[0077] Example 3 In this embodiment, desulfurization treatment is performed on the target concentrate.

[0078] The target concentrate is an iron concentrate containing pyrrhotite, of which TFe is 63.7%, S is 4.2%, and pyrrhotite accounts for 85%.

[0079] Treatment process: Basically the same as Example 1, refer to Table 1 for the differences.

[0080] Example 4 In this embodiment, desulfurization treatment is performed on the target concentrate.

[0081] The target concentrate is an iron concentrate containing pyrrhotite, of which TFe is 63.5%, S is 2.2%, and pyrrhotite accounts for 90%.

[0082] Treatment process: Basically the same as Example 1, refer to Table 1 for the differences.

[0083] Comparative Example 1 In this comparative example, desulfurization treatment was performed on the target iron concentrate.

[0084] The target concentrate is an iron concentrate containing pyrrhotite, of which TFe is 63.7%, S is 4.2%, and pyrrhotite accounts for 85%.

[0085] Treatment process: (1) Pulping and demagnetization: The ore pulp concentration is 40%, and it is processed by a two-stage pipeline demagnetizer (the first stage demagnetization magnetic field strength is 150mT, and the second stage demagnetization magnetic field strength is 150mT); (2) Surface treatment: 50 kHz ultrasonic cleaning (power density 0.8 W / cm³) in a mixture of sulfuric acid and oxalic acid (molar ratio 1:1) at pH 4 for 5 min; (3) Activation: Add copper sulfate (500g / t) for activation; (4) Enhanced flotation: Butyl xanthate (250 g / t) was used as the collector, and the flotation process was 1 coarse, 2 scavenging, and 2 fine.

[0086] Comparative Example 2 In this comparative example, desulfurization treatment was performed on the target concentrate.

[0087] The target concentrate is an iron concentrate containing pyrrhotite, of which TFe is 63.5%, S is 2.2%, and pyrrhotite accounts for 90%.

[0088] Treatment process: (1) Pulping and demagnetization: The ore pulp concentration is 50%, and it is processed by a pipeline demagnetizer (demagnetization magnetic field intensity is 200mT); (2) Surface treatment: 50 kHz ultrasonic cleaning (power density 1.2 W / cm³) in a pH 3 sulfuric acid-oxalic acid mixed solution (molar ratio 1:0) for 15 minutes; (3) Modification: Sodium silicate (400 g / t) and sodium hexametaphosphate (400 g / t) were added for modification; (4) Activation: Add copper sulfate (600 g / t) as an activator; (5) Enhanced flotation: A butyl xanthate (300 g / t) collection system was used, and the flotation process was 1 coarse, 2 scavenging, and 2 fine.

[0089] Test experiment 1: (1) Test method: The same flotation machine was used to process different raw materials and tests were conducted based on the experimental conditions (parameters) of different embodiments and comparative examples in Table 1.

[0090] (2) Test results: Table 2, test results in Examples and Comparative Examples ( Figure 4 )

[0091] analyze: 1) Refer to the data in Table 2 and Figure 4 In Examples 1 to 4, the sulfur content of the iron ore concentrate was significantly reduced, all below 0.3%, meeting the low sulfur content requirement of iron ore concentrate in steel production. This demonstrates that the method of this application, based on the combination of process parameters, can effectively reduce sulfur content.

[0092] 2) The sulfur content in Comparative Example 1 was 1.00%, and the sulfur content in Comparative Example 2 was 0.80%, both higher than those in the Examples. Comparative Example 1 did not employ synergistic activation and a combined collector, relying solely on copper sulfate activation and butyl xanthate collection, resulting in unsatisfactory desulfurization results. Comparative Example 2 also lacked synergistic activation, and the molar ratio of the sulfuric acid-oxalic acid mixed solution and ultrasonic cleaning parameters were not optimized, resulting in poor desulfurization results.

[0093] 3) The Example significantly improved desulfurization efficiency through the synergistic effects of two-stage pipeline demagnetization, surface cleaning, surface modification, synergistic activation, and combined collectors. The Comparative Example, lacking certain key steps (such as optimized surface cleaning, synergistic activation, and combined collectors), exhibited significantly poorer desulfurization results.

[0094] 4) The optimized process parameters in the examples (such as slurry concentration, demagnetization magnetic field strength, surface cleaning time and power density, activator ratio, etc.) play a key role in reducing sulfur content.

[0095] In summary, by comparing the test results of the Examples and Comparative Examples, it is clear that the desulfurization method of high-sulfur magnetite concentrate of the present invention significantly improves desulfurization efficiency and reduces the sulfur content of the concentrate by synergistically optimizing multiple process steps. The process parameter optimization of the Examples provides an effective technical solution for industrial production, while the shortcomings of the Comparative Examples further verify the innovation and effectiveness of the present invention.

[0096] Test experiment 2: (1) Test method: In this test experiment, in order to investigate the ratio of copper sulfate and ammonium sulfate in the copper-ammonium composite activator, based on the target concentrate in Example 2, the method and conditions in Example 2 were used to test copper sulfate and ammonium sulfate in the copper-ammonium composite activator at different mass ratios (see Table 3 for details).

[0097] (2) Test results: Table 3. Activator dosage, mass ratio and content results of different test groups

[0098] analyze: In this test, the effects of different ratios of copper sulfate and ammonium sulfate in the copper-ammonium composite activator on the desulfurization effect were investigated in detail.

[0099] According to the test results in Table 3, and reference Figure 5 When the total amount of copper sulfate and ammonium sulfate is fixed at 300g / t, the mass ratio of the two has a significant effect on the sulfur content of the iron ore concentrate. Specifically, when the mass ratio is 1:1, the sulfur content of the iron ore concentrate is the lowest, only 0.3%. This shows that under this ratio, copper sulfate and ammonium sulfate can work synergistically to achieve the best activation effect, significantly improving the flotation selectivity and recovery rate of pyrrhotite. When the mass ratio deviates from 1:1, the sulfur content gradually increases, indicating that the optimization of the ratio is crucial to improving the desulfurization efficiency. This result provides important parameter guidance for the use of copper ammonium composite activator in actual production, confirming the effectiveness and scientific nature of the synergistic activation step in the present invention.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above 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 invention.

Claims

1. A method for desulfurization of high-sulfur magnetite concentrate, characterized in that: include: After the target concentrate is slurried, it is subjected to a two-stage pipeline demagnetization process to obtain demagnetized ore slurry; The demagnetized slurry is subjected to a combined surface cleaning treatment using ultrasonic waves and a sulfuric acid-oxalic acid mixed solution; performing surface modification treatment on the demagnetized ore pulp that has undergone the combined surface cleaning treatment to obtain a demagnetized ore pulp having a hydrophilic-sulfophobic surface; Performing a synergistic activation treatment on the demagnetized slurry having a hydrophilic-sulfophobic surface to obtain an activated slurry; The activated slurry is subjected to flotation treatment by using a combined collector to obtain desulfurized magnetite concentrate; the combined collector comprises dixanthate, butyl xanthate and dithiophosphate.

2. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The magnetic field intensity of the two-stage pipeline demagnetization treatment is 100mT~300mT.

3. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: In the two-stage pipeline demagnetization treatment, the second-stage demagnetization magnetic field intensity is 20 mT to 50 mT higher than the first-stage demagnetization magnetic field intensity.

4. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The slurry concentration after slurry adjustment is 30% to 50%.

5. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The combined surface cleaning process comprises: The demagnetized slurry is placed in a stirring barrel equipped with an ultrasonic cleaning device and subjected to ultrasonic surface cleaning using the sulfuric acid-oxalic acid mixed solution; Wherein, the molar ratio of the sulfuric acid-oxalic acid mixed solution is (1-2):1; and / or the pH value of the sulfuric acid-oxalic acid mixed solution is 3-5.

6. The method for desulfurization of high-sulfur magnetite concentrate according to claim 5, characterized in that: The frequency of the ultrasonic wave is 50 Hz; and / or, The power density of the ultrasonic surface cleaning process is 0.5 W / cm 3 ~2W / cm 3 and / or, The ultrasonic surface cleaning process lasts for 10 to 15 minutes.

7. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The surface modification treatment is to perform surface modification treatment on the demagnetized slurry using sodium silicate and sodium hexametaphosphate; Among them, the dosage of sodium silicate is 600 g / t~1000 g / t; the dosage of sodium hexametaphosphate is 200 g / t~500 g / t.

8. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The synergistic activation treatment is to use a cuprammonium composite activator to synergistically activate the demagnetized slurry; Wherein, the cuprammonium composite activator comprises copper sulfate and ammonium sulfate; and / or, The synergistic activation treatment is to add copper sulfate and ammonium sulfate in the cuprammonium composite activator in stages according to a mass ratio of 1: (1-1.5); and / or, The amount of copper sulfate used is 100g / t~250g / t; and / or, The dosage of ammonium sulfate is 150g / t~300g / t.

9. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The mass ratio of dixanthate, butyl xanthate and dithiophosphate in the combined collector is 1:(2-3):

1.

10. The method for desulfurization of high-sulfur magnetite concentrate according to claim 1, characterized in that: The dosage of double xanthate is 40 g / t~80 g / t; and / or the dosage of butyl xanthate is 80 g / t~150 g / t; and / or the dosage of dithiophosphate is 40 g / t~80 g / t.

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