A beneficiation process for carbon-containing low-zinc pyrite

Abstract

The invention discloses a beneficiation process for carbon-containing low-zinc pyrite, which relates to the technical field of mineral processing. The carbon-containing low-zinc pyrite is crushed, ground, and classified by a hydrocyclone to obtain slurry of a required particle size. Subsequently, a desludging cyclone and a flotation machine are used for combined decarbonization. Then, a high-efficiency selective collector is used to float the sulfur-selective flotation ore to obtain pyrite coarse concentrate and pyrite coarse tailings. A "one coarse, two fine, two scavenging, and one fine tailings are separately selected and discarded" process is adopted to improve the flotation rate and the grade of the flotation concentrate. Finally, a magnetic drum is used to scavenger the final tailings, and sulfur-containing magnetic minerals in the final tailings are recovered to improve resource utilization.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing, in particular to a beneficiation process for carbon-containing low-zinc pyrite. Background Art

[0002] Pyrite, one of the world's most important sulfur resources, is a core raw material for the sulfuric acid industry. Its ore composition is complex. In addition to often coexisting with sulfide minerals such as chalcopyrite, galena, and sphalerite, it also contains harmful elements such as carbon, arsenic, and fluorine. For high-carbon, low-zinc pyrite, the carbonaceous components (including organic carbon and graphite) have low density, low hardness, and high surface activity, leading to multiple technical bottlenecks in the beneficiation process. In conventional flotation processes, the natural floatability of carbonaceous minerals interferes with the improvement of sulfur concentrate grade and hinders the effective recovery of zinc metal minerals. Their strong adsorption properties not only significantly increase the amount of reagents such as collectors and frothers, but also reduce bubble mineralization efficiency and foam fluidity, significantly increasing beneficiation costs.

[0003] In the subsequent acid production process, excessive carbon in the sulfur concentrate will cause thermal runaway of the reaction in the furnace, resulting in a surge in energy consumption and a decrease in operational stability; at the same time, the carbon monoxide generated by the incomplete combustion of carbon will poison the sulfur dioxide catalytic conversion system, significantly reducing the sulfur conversion rate and increasing the risk of environmental pollution.

[0004] Currently, carbonaceous pyrite beneficiation technologies primarily encompass flotation and combined beneficiation processes. Single flotation relies on lime, combined depressants, and high-efficiency collectors to selectively concentrate pyrite. Combined beneficiation processes, exemplified by gravity-flotation and magnetic-flotation, utilize physical separation methods to pre-discard carbonaceous gangue before flotation. However, magnetic separation has limited efficiency in separating weakly magnetic minerals, making it difficult to produce high-quality magnetic products. Gravity separation also exhibits significant limitations in separating fine-grained minerals, resulting in significant loss of fine pyrite with tailings, making overall recovery difficult to achieve.

[0005] Based on the above-mentioned industry pain points, the present invention proposes a high-carbon, low-zinc pyrite beneficiation process that is both highly efficient and environmentally friendly. This technological breakthrough will provide a new solution for the green and efficient development of carbonaceous pyrite resources. Therefore, in order to solve the above-mentioned technical problems, the present invention provides a beneficiation process for carbon-containing, low-zinc pyrite. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention provides a beneficiation process for carbon-containing low-zinc pyrite.

[0007] To achieve the above object, the present invention provides the following technical solution: a beneficiation process for carbon-containing low-zinc pyrite, comprising the following steps:

[0008] Crushing and grinding: crushing high-carbon, low-zinc pyrite to the required particle size, then grinding to fully dissociate the minerals and obtain slurry of appropriate particle size;

[0009] Hydrocyclone classification: The slurry ground to a suitable particle size is classified by a hydrocyclone. The overflow from the classification enters the next stage of desludging cyclone, and the settled sand is returned to the grinding mill for regrinding.

[0010] Cyclone decarbonization: The classification overflow is desludged and decarbonized by a desludging cyclone. The decarbonized sediment is used as flotation ore, and the decarbonized overflow enters the next stage of decarbonization flotation;

[0011] Flotation decarbonization: Decarbonization collectors are used to carry out flotation decarbonization treatment on the overflow of the classification, in which the flotation foam is carbon-containing gangue minerals, and the flotation tailings are combined with the decarbonized sediment to serve as the raw ore for sulfur flotation;

[0012] Pyrite roughing: Use high-efficiency selective collectors to float the sulfur flotation ore to obtain pyrite rough concentrate and pyrite rough tailings;

[0013] Pyrite coarse concentrate beneficiation: The pyrite coarse concentrate is subjected to primary beneficiation to obtain first concentrate and first concentrate tailings, and the first concentrate tailings are subjected to re-selection to obtain first concentrate tailings re-selection concentrate and first concentrate tailings re-selection tailings; the first concentrate and the first concentrate tailings re-selection concentrate are combined and sent to secondary beneficiation, and the obtained concentrate is zinc-sulfur concentrate, and the obtained second concentrate tailings are returned to the primary beneficiation in sequence;

[0014] Pyrite rough tailings scavenging: The sulfur rougher tailings are scavenged once to obtain scavenged concentrate and scavenged tailings. The scavenged concentrate is sequentially returned to the rougher, and the scavenged tailings are scavenged twice to obtain scavenged concentrate, which is sequentially returned to the first scavenging. The scavenged tailings are combined with the above-mentioned concentrate tailings and re-selected tailings to form the final tailings.

[0015] Reverse flotation to remove zinc from zinc-containing sulfur concentrate: Add pyrite inhibitor to the zinc-containing sulfur concentrate to suppress the pyrite, and then perform reverse flotation to remove zinc to obtain low-zinc pyrite concentrate and zinc concentrate at the same time;

[0016] Magnetic separation and recovery: The final tailings are swept and separated by magnetic drums to recover the sulfur-containing magnetic minerals in the final tailings. The recovered concentrate is mixed with low-zinc pyrite concentrate to obtain the final pyrite concentrate;

[0017] Dehydration and drying: The final pyrite concentrate and zinc concentrate are dehydrated and dried to obtain qualified products.

[0018] Preferably, in the crushing and grinding step, the high-carbon, low-zinc pyrite is crushed to a particle size of less than 150 mm, the grinding concentration is 65%-75%, and the grinding fineness is -0.074 mm, accounting for 60%-80%.

[0019] Preferably, in the cyclone classification step, the proportion of -0.074 mm in the classification overflow is 60%-80%.

[0020] Preferably, in the cyclone decarburization step, the particle size of the product in the decarburization overflow is -0.019 mm.

[0021] Preferably, in the flotation decarbonization step, the decarbonization collector comprises a mixture of kerosene and 2# oil, with an amount of 30-50 g / t.

[0022] Preferably, in the pyrite roughing step, the high-efficiency selective collector is a mixture of a xanthate collector, a black medicine collector and a foaming agent, and the dosage is 50-100 g / t.

[0023] Preferably, in the steps of selecting the coarse pyrite concentrate and scavenging the coarse pyrite tailings, the high-efficiency selective collector is a mixture of a xanthate collector and a black drug collector, and the dosage is 25-50 g / t.

[0024] Preferably, in the magnetic separation recovery step, the magnetic field strength of the magnetic drum is 0.3-0.6T.

[0025] Compared with the prior art, the present invention provides a beneficiation process for carbon-containing low-zinc pyrite, which has the following beneficial effects:

[0026] 1. High-efficiency graded decarbonization technology: A graded decarbonization system is constructed using hydrocyclones to efficiently remove carbon-containing minerals and sludge based on differences in mineral particle size and density. After the graded overflow is further decarbonized by the desliming cyclone, the removal rate of carbon-containing minerals and sludge can reach over 85%, significantly reducing interference with subsequent flotation operations. Flotation is then used to deeply separate the carbon-containing minerals enriched in the decarbonization overflow from the residual pyrite, forming a dual mechanism of "graded pre-decarbonization-flotation fine separation." This increases the pyrite recovery rate by 10% compared to traditional flotation decarbonization processes, effectively ensuring resource recovery efficiency. The process has a compact overall layout, with smooth connections between each link, making it easy to implement industrial large-scale production.

[0027] 2. Synergistic reagent system: An innovative compound collector solution of xanthate and black medicine is adopted. Based on the principle of synergistic effect of the two, the adsorption characteristics of the reagent molecules and the pyrite surface are optimized. Experimental verification shows that this highly efficient and selective collector significantly improves the hydrophobicity of the pyrite surface while reducing the total reagent dosage. This not only reduces the reagent cost but also enhances the separation effect, achieving dual optimization of economic benefits and mineral processing indicators.

[0028] 3. Streamlined flotation process: The flotation process is simple and stable, with clear pulp flow and easy operation. In particular, in the selection of pyrite rough concentrate, an innovative tailings reselection and direct waste disposal model was designed. This effectively shortens the process flow and reduces material circulation while ensuring a metal recovery rate of at least 88%. This optimization has been calculated to reduce the roughing cycle load by 12%, significantly improving production efficiency and reducing energy consumption and equipment wear.

[0029] 4. Achieving Comprehensive Resource Recovery: This process represents a significant breakthrough in resource recycling. Through a combined decarbonization process prior to flotation, the zinc grade in the zinc-removing tailings from reverse flotation is significantly increased, from 4% before decarbonization to 18%. This creates conditions for the blending and sale of high-grade zinc concentrate, significantly enhancing the economic value of zinc resources. Furthermore, for the difficult-to-float magnetic pyrites in the flotation tailings, magnetic separation technology is employed to specifically recover the low concentration of the tailings, further tapping into the potential of these minerals and integrating them into the comprehensive resource utilization system. This multi-dimensional resource recovery strategy not only improves the utilization rate of various minerals but also expands the product mix, maximizing the utilization of high-carbon, low-zinc pyrite resources and driving the comprehensive development of mining resources to a new level.

[0030] 5. Green and low-carbon economic advantages: Through efficient graded decarbonization, synergistic reagents and optimized processes, this process has achieved remarkable results in reducing production costs. Compared with traditional processes, the overall production cost is reduced by 15%, of which the reagent cost is reduced by 18% and the energy consumption cost is reduced by 10%. At the same time, the reduction in reagent usage and comprehensive resource recovery can reduce the generation of "three wastes" from the source, achieving the organic unity of efficient resource utilization and ecological environmental protection, and achieving both good economic and social benefits, which is in line with the concept of green mine development.

[0031] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 It is a separation process flow chart of the present invention. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1The principles and features of the present invention are described, and the examples given are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and are not to exact scale, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0035] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] Please combine Figure 1 As shown, the carbon low zinc pyrite is analyzed to have an S grade of 18.58%, a TFe grade of 18.55%, a TC grade of 8.30%, and a C 固 The content is 3.61%; the X-ray diffraction analysis results of the raw ore show that the metal mineral in the raw ore is pyrite, and the gangue minerals are mainly quartz, plagioclase, potassium feldspar, magnesium calcite, dolomite, chlorite, and amphibole, and the mineral composition is relatively complex; the iron phase analysis results of the raw ore show that the Fe content in pyrite is 14.51%, and the Fe distribution rate is 77.72%; the Fe content in pyrrhotite is 0.29%, and the Fe distribution rate is 1.55%; the effective sulfur content in the raw ore is 16.73%. For this raw ore, the present invention provides a beneficiation process for carbon-containing low-zinc pyrite, which comprises the following steps:

[0038] Crushing and grinding: crush the high-carbon, low-zinc pyrite to the required particle size, then grind it to fully dissociate the minerals and obtain a slurry of appropriate particle size; the particle size of the high-carbon, low-zinc pyrite after crushing is less than 150mm, the grinding concentration is 65%-75%, and the grinding fineness is -0.074mm, accounting for 60%-80%;

[0039] Hydrocyclone classification: The slurry ground to a suitable particle size is classified by a hydrocyclone. The overflow from the classification enters the next stage of desludging cyclone, and the settled sand is returned to the grinding mill for regrinding. The overflow from the classification has a fineness of -0.074mm, accounting for 60%-80%;

[0040] Cyclone decarbonization: The classification overflow is desludged and decarbonized using a desludging cyclone. The decarbonized sediment is used as the raw ore for sulfur flotation. The decarbonized overflow enters the next stage of decarbonization flotation. The particle size of the decarbonized overflow is -0.019mm.

[0041] Flotation decarbonization: A decarbonization collector is used to flotate the overflow from the classification process. The flotation foam is carbon-containing gangue minerals, and the flotation tailings are combined with the decarbonized sand to serve as the raw ore for sulfur flotation. The decarbonization collector is a mixture of kerosene and No. 2 oil, with a dosage of 30-50g / t.

[0042] Pyrite roughing: Use a high-efficiency selective collector to float the sulfur flotation ore to obtain pyrite rough concentrate and pyrite rough tailings. The high-efficiency selective collector is a mixture of xanthate collector, black powder collector and frother, with a dosage of 50-100g / t.

[0043] Pyrite coarse concentrate beneficiation: The pyrite coarse concentrate is subjected to primary beneficiation to obtain first concentrate and first concentrate tailings, and the first concentrate tailings are subjected to re-selection to obtain first concentrate tailings re-selection concentrate and first concentrate tailings re-selection tailings; the first concentrate and the first concentrate tailings re-selection concentrate are combined and sent to secondary beneficiation, and the obtained concentrate is zinc-sulfur concentrate, and the obtained second concentrate tailings are returned to the primary beneficiation in sequence;

[0044] Pyrite rough tailings scavenging: The sulfur rougher tailings are scavenged once to obtain scavenged concentrate and scavenged tailings. The scavenged concentrate is sequentially returned to the rougher, and the scavenged tailings are scavenged twice to obtain scavenged concentrate, which is sequentially returned to the first scavenging. The scavenged tailings are combined with the above-mentioned concentrate tailings and re-selected tailings to form the final tailings.

[0045] Among them, in the steps of selecting the coarse pyrite concentrate and sweeping the coarse pyrite tailings, the high-efficiency selective collector is a mixture of xanthate collector and black drug collector, and its dosage is 25-50g / t;

[0046] Reverse flotation to remove zinc from zinc-containing sulfur concentrate: Add pyrite inhibitor to the zinc-containing sulfur concentrate to suppress the pyrite, and then perform reverse flotation to remove zinc to obtain low-zinc pyrite concentrate and zinc concentrate at the same time;

[0047] Magnetic separation and recovery: The final tailings are swept and separated by magnetic drums to recover the sulfur-containing magnetic minerals in the final tailings. The recovered concentrate is mixed with low-zinc pyrite concentrate to obtain the final pyrite concentrate. The magnetic field strength of the magnetic drum is 0.3-0.6T.

[0048] Dehydration and drying: The final pyrite concentrate and zinc concentrate are dehydrated and dried to obtain qualified products. Example

[0049] Crushing and grinding: crush the high-carbon, low-zinc pyrite to a particle size of less than 150mm, and then grind it to obtain a slurry with a concentration of 70% and a fineness of -0.074mm accounting for 70%;

[0050] Hydrocyclone classification: Hydrocyclones are used to classify the slurry, with -0.074mm accounting for 75% of the classification overflow;

[0051] Cyclone decarbonization: The classification overflow is deslimed and decarbonized by a desliming cyclone. The decarbonized sediment is used as the flotation ore. The mineral particle size in the decarbonization overflow is -0.019mm.

[0052] Flotation decarbonization: The classified overflow is transferred to the flotation tank, to which a mixture of kerosene and No. 2 oil (35 g / t) is added for carbon flotation, yielding a carbonaceous product with a carbon content of 35.7% and a carbon removal rate of 88.5%. The flotation tailings are mixed with the decarbonized sediment to yield a sulfur flotation ore with an S grade of 17.87%, a C grade of 2.7%, and a Zn grade of 0.41%.

[0053] Pyrite roughing: 80g / t of high-efficiency selective collector is added to the sulfur flotation ore and then flotation is performed to obtain pyrite rough concentrate and pyrite rough tailings; the obtained flotation rough concentrate has an S grade of 40.4% and an S recovery rate of 95.7%;

[0054] Pyrite coarse concentrate beneficiation: 40g / t of high-efficiency selective collector is added to the pyrite coarse concentrate for primary beneficiation. The obtained concentrate tailings are re-selected to obtain concentrate tailings re-selected concentrate and concentrate tailings re-selected tailings. The obtained concentrate tailings re-selected concentrate is combined with the concentrate. The combined concentrate enters the secondary beneficiation, and the concentrate tailings return to the beneficiation. The zinc-containing sulfur concentrate obtained from the secondary beneficiation has an S grade of 44.5%, a C grade of 0.8%, and a Zn grade of 1.4%.

[0055] Pyrite rough tailings scavenging: 40g / t of high-efficiency selective collector is added to the sulfur rougher tailings for a first scavenging process. The first scavenging concentrate obtained is sequentially returned to the rougher process. The first scavenging tailings are scavenged again, and the second scavenging concentrate obtained is sequentially returned to the first scavenging process. The second scavenging tailings are combined with the first scavenging tailings and the re-selected tailings to form the final tailings, in which the Fe content is 6.28%, the S content is 2.73%, the C content is 1.4%, and the Zn content is 0.17%.

[0056] Reverse flotation of zinc from zinc-sulfur concentrate: 3000g / t of lime was added to the zinc-sulfur concentrate to suppress the pyrite. Reverse flotation was then performed to remove zinc, yielding a low-zinc pyrite concentrate with an Fe content of 44.2%, an S content of 48.5%, a C content of 0.7%, and a Zn content of 0.2%. The overall S recovery rate reached 90.1%. A zinc concentrate with a Zn content of 18.22% was also obtained.

[0057] Magnetic separation and recovery: A magnetic drum with a magnetic field strength of 0.45T is used to sweep the final tailings to recover the sulfur-containing magnetic minerals in the final tailings. The recovered concentrate is mixed with low-zinc pyrite concentrate to obtain the final pyrite concentrate;

[0058] Dehydration and drying: The final pyrite concentrate and zinc concentrate are dehydrated and dried to obtain qualified products.

[0059] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in this industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A beneficiation process for carbon-containing low-zinc pyrite, characterized in that: The following steps are involved: Crushing and grinding: crushing high-carbon, low-zinc pyrite to the required particle size, then grinding to fully dissociate the minerals and obtain slurry of appropriate particle size; Hydrocyclone classification: The slurry ground to a suitable particle size is classified by a hydrocyclone. The overflow from the classification enters the next stage of desludging cyclone, and the settled sand is returned to the grinding mill for regrinding. Cyclone decarbonization: The classification overflow is desludged and decarbonized by a desludging cyclone. The decarbonized sediment is used as flotation ore, and the decarbonized overflow enters the next stage of decarbonization flotation; Flotation decarbonization: Decarbonization collectors are used to carry out flotation decarbonization treatment on the overflow of the classification, in which the flotation foam is carbon-containing gangue minerals, and the flotation tailings are combined with the decarbonized sediment to serve as the raw ore for sulfur flotation; Pyrite roughing: Use high-efficiency selective collectors to float the sulfur flotation ore to obtain pyrite rough concentrate and pyrite rough tailings; Pyrite coarse concentrate beneficiation: The pyrite coarse concentrate is subjected to primary beneficiation to obtain first concentrate and first concentrate tailings, and the first concentrate tailings are subjected to re-selection to obtain first concentrate tailings re-selection concentrate and first concentrate tailings re-selection tailings; the first concentrate and the first concentrate tailings re-selection concentrate are combined and sent to secondary beneficiation, and the obtained concentrate is zinc-sulfur concentrate, and the obtained second concentrate tailings are returned to the primary beneficiation in sequence; Pyrite rough tailings scavenging: The sulfur rougher tailings are scavenged once to obtain scavenged concentrate and scavenged tailings. The scavenged concentrate is sequentially returned to the rougher, and the scavenged tailings are scavenged twice to obtain scavenged concentrate, which is sequentially returned to the first scavenging. The scavenged tailings are combined with the above-mentioned concentrate tailings and re-selected tailings to form the final tailings. Reverse flotation to remove zinc from zinc-containing sulfur concentrate: Add pyrite inhibitor to the zinc-containing sulfur concentrate to suppress the pyrite, and then perform reverse flotation to remove zinc to obtain low-zinc pyrite concentrate and zinc concentrate at the same time; Magnetic separation and recovery: The final tailings are swept and separated by magnetic drums to recover the sulfur-containing magnetic minerals in the final tailings. The recovered concentrate is mixed with low-zinc pyrite concentrate to obtain the final pyrite concentrate; Dehydration and drying: The final pyrite concentrate and zinc concentrate are dehydrated and dried to obtain qualified products.

2. The beneficiation process for a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the crushing and grinding step, the high-carbon, low-zinc pyrite is crushed to a particle size of less than 150 mm, the grinding concentration is 65%-75%, and the grinding fineness is -0.074 mm, accounting for 60%-80%.

3. The beneficiation process for a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the cyclone classification step, the proportion of -0.074 mm in the classification overflow is 60%-80%.

4. The beneficiation process for a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the cyclone decarburization step, the particle size of the product in the decarburization overflow is -0.019 mm.

5. The beneficiation process for a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the flotation decarbonization step, the decarbonization collector includes a mixture of kerosene and 2# oil, and the dosage is 30-50 g / t.

6. The beneficiation process for a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the pyrite roughing step, the high-efficiency selective collector is a mixture of a xanthate collector, a black medicine collector and a foaming agent, and the dosage is 50-100 g / t.

7. The beneficiation process for carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the steps of selecting the coarse pyrite concentrate and scavenging the coarse pyrite tailings, the high-efficiency selective collector is a mixture of a xanthate collector and a black medicine collector, and the dosage is 25-50 g / t.

8. The beneficiation process for carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the magnetic separation recovery step, the magnetic field strength of the magnetic drum is 0.3-0.6T.

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