Beneficiation process of carbon-containing low-zinc pyrite

Abstract

The invention discloses a beneficiation process of carbon-containing low-zinc pyrite, and relates to the technical field of mineral processing, after the carbon-containing low-zinc pyrite is subjected to crushing, ore grinding and grading operation through a hydrocyclone, ore pulp with the required granularity is obtained, and then a desliming cyclone and a flotation machine are adopted for combined decarburization; flotation is conducted on the sulfur flotation raw ore through an efficient selective collecting agent, pyrite rough concentrate and pyrite rough tailings are obtained, and the flotation rate and the flotation concentrate grade are improved by adopting the technology that one-time roughing, two-time concentration and two-time sweeping are conducted, and one-time concentration and one-time tailings are independently re-selected and then waste is discarded; and finally, the final tailings are scavenged through a magnetic roller, sulfur-containing magnetic minerals in the final tailings are recycled, and the resource utilization rate is increased.

Description

Technical Field

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

[0002] As one of the most important sulfur resources globally, pyrite is the core raw material for the sulfuric acid industry. Its ore composition is complex. Besides being often symbiotic with sulfide ores such as chalcopyrite, galena, and sphalerite, it also contains harmful elements such as carbon, arsenic, and fluorine. For high-carbon low-zinc pyrite, carbonaceous components (including organic carbon and graphite) have low density, small hardness, and high surface activity, leading to multiple technical bottlenecks in the beneficiation process: In the conventional flotation process, 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 characteristics not only significantly increase the dosage of reagents such as collectors and frothers but also reduce the bubble mineralization efficiency and foam fluidity, resulting in a substantial increase in beneficiation costs. In the subsequent sulfuric acid production process, excessive carbonaceous matter in the sulfur concentrate will cause out-of-control reaction heat in the furnace, leading to a sharp increase in energy consumption and a decline in operation stability. At the same time, carbon monoxide generated by incomplete combustion of carbon will poison the sulfur dioxide catalytic conversion system, significantly reducing the sulfur element conversion rate and exacerbating the environmental pollution risk. Currently, carbonaceous pyrite beneficiation technologies mainly include flotation and combined beneficiation processes. Single flotation technology relies on lime, combined inhibitors, and efficient collectors to achieve selective enrichment of pyrite. Combined beneficiation processes are represented by gravity-flotation combined separation and magnetic-flotation combined separation. After physically removing carbonaceous gangue by beneficiation means, flotation operations are carried out. However, magnetic separation technology has limited separation efficiency for weakly magnetic minerals and is difficult to produce high-quality magnetic products. The gravity separation process has obvious defects in the separation of fine-grained minerals, resulting in a large amount of fine-grained pyrite being lost with the tailings, and the overall recovery rate is difficult to break through. Based on the above industry pain points, the present invention proposes a high-carbon low-zinc pyrite beneficiation process with both high efficiency and environmental friendliness. The breakthrough of this technology will provide a new solution for the green and efficient development of carbonaceous pyrite resources. Therefore, to solve the above technical problems, the present invention provides a beneficiation process for carbon-bearing low-zinc pyrite. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a beneficiation process for carbon-bearing low-zinc pyrite.

[0004] To achieve the above object, the present invention provides the following technical solution: A beneficiation process for carbon-bearing low-zinc pyrite, comprising the following steps: Crushing and grinding: Crushing the high-carbon low-zinc pyrite to the required particle size, and then performing grinding to fully dissociate the minerals, obtaining a pulp with a suitable particle size; Cyclone classification: The pulp ground to an appropriate particle size is classified by a hydrocyclone. The overflow of the classification enters the next-stage desliming cyclone, and the sand is returned to grinding for regrinding. Cyclone decarbonization: The overflow of the classification is deslimed and decarbonized by a desliming cyclone. The decarbonized sand is used as the original ore for flotation, and the decarbonized overflow enters the next-stage decarbonization flotation. Flotation for carbon removal: The overflow of the classification is subjected to flotation decarbonization treatment with a decarbonization collector. The flotation foam is carbon-bearing gangue minerals, and the flotation tailings are combined with the decarbonized sand as the original ore for sulfur flotation. Pyrite roughing: The original ore for sulfur flotation is floated with a high-efficiency selective collector to obtain pyrite rough concentrate and pyrite rough tailings. Pyrite rough concentrate cleaning: The pyrite rough concentrate is subjected to primary cleaning to obtain first-clean concentrate and first-clean tailings. The first-clean tailings are re-selected to obtain re-selected concentrate and re-selected tailings of the first-clean tailings. Among them, the first-clean concentrate and the re-selected concentrate of the first-clean tailings are combined and enter secondary cleaning. The obtained concentrate is zinc-bearing sulfur concentrate, and the obtained second-clean tailings are sequentially returned to primary cleaning. Pyrite rough tailings scavenging: The pyrite rough tailings are subjected to primary scavenging to obtain first-scavenged concentrate and first-scavenged tailings. Among them, the first-scavenged concentrate is sequentially returned to roughing, and the first-scavenged tailings are subjected to secondary scavenging. The obtained second-scavenged concentrate is sequentially returned to primary scavenging, and the second-scavenged tailings are combined with the re-selected tailings of the above first-clean tailings to form the final tailings. Reverse flotation for zinc removal from zinc-bearing sulfur concentrate: A pyrite inhibitor is added to the zinc-bearing sulfur concentrate to inhibit pyrite, and reverse flotation is carried out for zinc removal to obtain low-zinc pyrite concentrate and zinc concentrate. Magnetic separation recovery: The final tailings are scavenged with a magnetic drum to recover the sulfur-bearing magnetic minerals in the final tailings. The recovered concentrate is mixed with the low-zinc pyrite concentrate to obtain the final pyrite concentrate. Dewatering and drying: The final pyrite concentrate and zinc concentrate are dewatered and dried to obtain qualified products.

[0005] Preferably, in the crushing and grinding step, the high-carbon low-zinc pyrite is crushed to a particle size less than 150 mm, the grinding concentration is 65%-75%, and the grinding fineness is that -0.074 mm accounts for 60%-80%.

[0006] Preferably, in the cyclone classification step, the proportion of -0.074 mm in the overflow of the classification is 60%-80%.

[0007] Preferably, in the cyclone decarbonization step, the product particle size in the decarbonized overflow is -0.019 mm.

[0008] Preferably, in the flotation for carbon removal step, the decarbonization collector includes a mixture of kerosene and No. 2 oil, and the dosage is 30-50 g / t.

[0009] Preferably, in the rough selection step of pyrite, the high-efficiency selective collector is a mixture of xanthate collectors, dithiophosphate collectors, and frothers, and the dosage is 50 - 100 g / t.

[0010] Preferably, in the cleaning of rough pyrite concentrate and scavenging of rough pyrite tailings, the high-efficiency selective collector is a mixture of xanthate collectors and dithiophosphate collectors, and the dosage is 25 - 50 g / t.

[0011] Preferably, in the magnetic separation and recovery step, the magnetic field intensity of the magnetic roller is 0.3 - 0.6 T.

[0012] Compared with the prior art, the present invention provides a beneficiation process for low-carbon zinc-bearing pyrite, having the following beneficial effects: I. High-efficiency classification and decarbonization technology: A classification and decarbonization system is constructed through a hydrocyclone. Based on the differences in mineral particle size and density, efficient removal of carbon-bearing minerals and slime is achieved. After the classification overflow is further decarbonized by a desliming hydrocyclone, the removal rate of carbon-bearing minerals and slime can reach more than 85%, significantly reducing the interference in subsequent flotation operations. Then, a flotation process is used to deeply separate the carbon-bearing minerals enriched in the decarbonized overflow and the residual pyrite, forming a dual mechanism of "classification pre-decarbonization - flotation fine separation", increasing the recovery rate of pyrite by 10% compared with the traditional flotation carbon removal process, and effectively ensuring the resource recovery efficiency. The overall layout of this process is compact, and the connection between each link is smooth, making it easy to realize large-scale industrial production. II. Synergistic and efficiency-enhancing reagent system: An innovative compound collector scheme of xanthate and dithiophosphate is adopted. Based on the principle of their synergistic effect, the adsorption characteristics of reagent molecules on the surface of pyrite are optimized. Through experimental verification, while reducing the total dosage of reagents, this high-efficiency selective collector significantly improves the hydrophobicity of the pyrite surface, reducing both reagent costs and enhancing the separation effect, achieving a dual optimization of economic benefits and beneficiation indexes. III. Streamlined flotation process: The flotation process is simple and stable, with a clear slurry flow direction and easy to operate. Especially in the cleaning of rough pyrite concentrate, an innovative treatment mode of reselecting the first-stage tailings and directly discarding waste is designed. On the premise of ensuring that the metal recovery rate is not less than 88%, the process flow is effectively shortened, and the material circulation volume is reduced. Through calculation, this optimization reduces the rough selection cycle load by 12%, significantly improving production efficiency, reducing energy consumption and equipment wear. IV. Realize comprehensive resource recovery: This process has achieved a major breakthrough in resource recovery and utilization; through the combined decarbonization process before flotation, the zinc grade in the reverse flotation zinc tailings is significantly increased, rising from 4% before decarbonization to 18%, creating conditions for the blending and sales of high-grade zinc concentrates and greatly improving the economic value of zinc resources; in addition, for the difficult-to-float magnetic pyrite minerals in the flotation tailings, taking advantage of the low tailings concentration, magnetic separation technology is used for special recovery to further tap the resource potential and incorporate it 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 structure, realizes the maximization of the utilization of high-carbon and low-zinc pyrite resources, and promotes the comprehensive development of mine resources to a new level; V. Advantages of green and low-carbon economy: Through efficient classification decarbonization, synergistic reagents and optimized processes, this process has achieved remarkable results in reducing production costs; compared with traditional processes, the comprehensive 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, reducing the dosage of reagents and comprehensive resource recovery cuts the generation amount of "three wastes" from the source, realizes the organic unity of efficient resource utilization and ecological environment protection, has good economic and social benefits, and conforms to the development concept of green mines.

[0013] The above description is only an overview of the technical solution of the present invention. In order to be able to more clearly understand the technical means of the present invention and implement it in accordance with the content of the specification, the following takes the preferred embodiments of the present invention and describes them in detail in conjunction with the drawings. The specific implementation manners of the present invention are given in detail by the following embodiments and their drawings. Brief Description of the Drawings

[0014] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic 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: Figure 1 is the separation process flow chart of the present invention. Detailed Description of the Invention

[0015] The following combines the attached Figure 1 Describe the principles and features of the present invention. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. In the following paragraphs, the present invention will be described more specifically by way of example with reference to the drawings. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention.

[0016] 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 component centered. 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 component centered. 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 component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0018] 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, the gangue mineral is mainly quartz, and there are also 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 the raw ore, the present invention provides a beneficiation process for carbon-containing low-zinc pyrite, and the beneficiation process comprises the following steps: 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 pulp of suitable 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%; Hydrocyclone classification: The ore pulp ground to a suitable particle size is classified by a hydrocyclone. The classified overflow enters the next stage of desludging cyclone, and the settled sand is returned to the grinding mill for regrinding. The fineness of the classified overflow is -0.074mm, accounting for 60%-80%; Cyclone decarbonization: The classified overflow is desludging and decarbonizing by 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. Among them, the product particle size in the decarbonization overflow is -0.019mm; Flotation for carbon removal: The classified overflow is subjected to flotation for carbon removal using a carbon removal collector. The flotation foam is carbon-bearing gangue minerals, and the flotation tailings are combined with the carbon removal sand settling as the raw ore for sulfur flotation. Among them, the carbon removal collector is a mixture of kerosene and No. 2 oil, with a dosage of 30 - 50 g / t. Rough selection of pyrite: The raw ore for sulfur flotation is subjected to flotation using a high-efficiency selective collector to obtain rough pyrite concentrate and rough pyrite tailings. Among them, the high-efficiency selective collector is a mixture of xanthate collectors, dithiophosphate collectors, and a foaming agent, with a dosage of 50 - 100 g / t. Concentration of rough pyrite concentrate: The rough pyrite concentrate is subjected to primary concentration to obtain first concentrate and first tailings. The first tailings are re-selected to obtain re-selected concentrate from the first tailings and re-selected tailings from the first tailings. Among them, the first concentrate and the re-selected concentrate from the first tailings are combined and fed into secondary concentration. The obtained concentrate is zinc-bearing sulfur concentrate, and the obtained second tailings are sequentially returned to primary concentration. Scavenging of rough pyrite tailings: The rough pyrite tailings are subjected to primary scavenging to obtain first scavenged concentrate and first scavenged tailings. Among them, the first scavenged concentrate is sequentially returned to rough selection, and the first scavenged tailings are subjected to secondary scavenging. The obtained second scavenged concentrate is sequentially returned to primary scavenging, and the second scavenged tailings are combined with the re-selected tailings from the first tailings to form the final tailings. Among them, in the steps of concentration of rough pyrite concentrate and scavenging of rough pyrite tailings, the high-efficiency selective collector is a mixture of xanthate collectors and dithiophosphate collectors, with a dosage of 25 - 50 g / t. Reverse flotation for zinc removal from zinc-bearing sulfur concentrate: A pyrite inhibitor is added to the zinc-bearing sulfur concentrate to inhibit pyrite, and reverse flotation is carried out for zinc removal to obtain low-zinc pyrite concentrate and zinc concentrate at the same time. Magnetic separation recovery: The final tailings are subjected to scavenging using a magnetic roller to recover the sulfur-bearing magnetic minerals in the final tailings. The recovered concentrate is mixed with the low-zinc pyrite concentrate to obtain the final pyrite concentrate. Among them, the magnetic field intensity of the magnetic roller is 0.3 - 0.6 T. Dewatering and drying: The final pyrite concentrate and zinc concentrate are dewatered and dried to obtain qualified products. Example

[0019] Crushing and grinding: The high-carbon low-zinc pyrite is crushed to a particle size less than 150 mm, and then ground to obtain a pulp with a concentration of 70% and a fineness of 70% passing -0.074 mm. Hydrocyclone classification: The pulp is classified using a hydrocyclone, and the proportion of -0.074 mm in the classified overflow is 75%. Hydrocyclone carbon removal: The classified overflow is subjected to desliming and carbon removal using a desliming hydrocyclone. The carbon removal sand settling is used as the raw ore for flotation, and the particle size of the minerals in the carbon removal overflow is -0.019 mm. Flotation for carbon removal: Transfer the classified overflow into a flotation cell, add a mixture of kerosene and No. 2 oil at 35 g / t, conduct the carbon flotation operation, and obtain a carbonaceous product with 35.7% carbon content and 88.5% carbon removal rate; Mix the flotation tailings with the decarbonized sand to obtain a raw ore for sulfur flotation with 17.87% S grade, 2.7% C grade, and 0.41% Zn grade; Rough selection of pyrite: Add 80 g / t of a highly efficient selective collector to the raw ore for sulfur flotation and then conduct flotation to obtain rough pyrite concentrate and rough pyrite tailings; Obtain a rough flotation concentrate with 40.4% S grade and 95.7% S recovery rate; Concentration of rough pyrite concentrate: Add 40 g / t of a highly efficient selective collector to the rough pyrite concentrate for the first concentration. Re-concentrate the obtained concentrate I tailings to obtain concentrate I tailings re-concentrate and concentrate I tailings re-concentrate tailings. The obtained concentrate I tailings re-concentrate is combined with concentrate I concentrate; The combined concentrate enters the second concentration, and the concentrate II tailings are returned to the concentration. Among them, the Zn-bearing sulfur concentrate in the second concentration has 44.5% S grade, 0.8% C grade, and 1.4% Zn grade; Scavenging of rough pyrite tailings: Add 40 g / t of a highly efficient selective collector to the rough pyrite tailings for the first scavenging, and the obtained scavenging I concentrate is sequentially returned to the rough selection; Scavenge the scavenging I tailings again, and the obtained scavenging II concentrate is sequentially returned to the first scavenging; The scavenging II tailings are combined with the concentrate I tailings re-concentrate tailings to form the final tailings, among 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%; Reverse flotation for zinc removal from Zn-bearing sulfur concentrate: Add lime to the Zn-bearing sulfur concentrate at a dosage of 3000 g / t to inhibit the pyrite and conduct reverse flotation for zinc removal to obtain a low-zinc pyrite concentrate with 44.2% Fe content, 48.5% S content, 0.7% C content, and 0.2% Zn content, and the overall S recovery rate reaches 90.1%; At the same time, obtain a zinc concentrate with 18.22% Zn content; Magnetic separation recovery: Use a magnetic roller with a magnetic field intensity of 0.45 T to scavenge the final tailings, recover the sulfur-bearing magnetic minerals in the final tailings, and mix the recovered concentrate with the low-zinc pyrite concentrate to obtain the final pyrite concentrate; Dewatering and drying: Dewater and dry the final pyrite concentrate and zinc concentrate to obtain qualified products.

[0020] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention; any ordinary technician in the industry can smoothly implement the present invention as shown in the accompanying drawings of the specification and as described above; however, any slight changes, modifications and equivalent variations made by those skilled in the art within the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any changes, modifications and equivalent variations made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A beneficiation process for low-carbon zinc-bearing pyrite, characterized in that, It includes the following steps: Crushing and grinding: Crushing the high-carbon low-zinc pyrite to the required particle size, and then performing grinding to fully dissociate the minerals, obtaining a pulp with a suitable particle size; Cyclone classification: Classifying the pulp with a suitable particle size through a hydrocyclone. The overflow of classification enters the next-stage desliming cyclone, and the sand is returned to grinding for re-grinding; Cyclone decarbonization: Performing desliming and decarbonization on the overflow of classification using a desliming cyclone. The decarbonized sand is used as the original ore for flotation, and the decarbonized overflow enters the next-stage decarbonization flotation; Flotation for decarbonization: Performing flotation decarbonization treatment on the overflow of classification using a decarbonization collector. The flotation foam is carbon-bearing gangue minerals, and the flotation tailings are combined with the decarbonized sand as the original ore for sulfur flotation; Rough selection of pyrite: Flotating the original ore for sulfur flotation using an efficient selective collector to obtain rough pyrite concentrate and rough pyrite tailings; Concentration of rough pyrite concentrate: Conducting primary concentration on the rough pyrite concentrate to obtain concentrate I concentrate and concentrate I tailings, and re-selecting the concentrate I tailings to obtain concentrate I tailings re-selected concentrate and concentrate I tailings re-selected tailings; among them, the concentrate I concentrate and the concentrate I tailings re-selected concentrate are combined and enter the secondary concentration. The obtained concentrate is zinc-bearing sulfur concentrate, and the obtained concentrate II tailings are sequentially returned to the primary concentration; Scavenging of rough pyrite tailings: Conducting primary scavenging on the rough pyrite tailings to obtain scavenging I concentrate and scavenging I tailings. Among them, the scavenging I concentrate is sequentially returned to the rough selection, and the scavenging I tailings are subjected to secondary scavenging. The obtained scavenging II concentrate is sequentially returned to the primary scavenging, and the scavenging II tailings are combined with the above-mentioned concentrate I tailings re-selected tailings to form the final tailings; Reverse flotation for zinc removal from zinc-bearing sulfur concentrate: Adding a pyrite inhibitor to the zinc-bearing sulfur concentrate to inhibit the pyrite, and performing reverse flotation for zinc removal to obtain low-zinc pyrite concentrate and zinc concentrate; Magnetic separation and recovery: Conducting scavenging on the final tailings using a magnetic roller to recover the sulfur-bearing magnetic minerals in the final tailings. The recovered concentrate is mixed with the low-zinc pyrite concentrate to obtain the final pyrite concentrate; Dewatering and drying: Dewatering and drying the final pyrite concentrate and zinc concentrate to obtain qualified products.

2. The beneficiation process of 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 less than 150 mm, the grinding concentration is 65%-75%, and the grinding fineness is that -0.074 mm accounts for 60%-80%.

3. The beneficiation process of 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 overflow of classification is 60%-80%.

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

5. The beneficiation process of a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the flotation for decarbonization step, the decarbonization collector includes a mixture of kerosene and No. 2 oil, and the dosage is 30-50 g / t.

6. The beneficiation process of a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the rough selection of pyrite step, the efficient selective collector is a mixture of xanthate collectors, dithiophosphate collectors, and frothers, and the dosage is 50-100 g / t.

7. The beneficiation process of a carbon-containing low-zinc pyrite according to claim 1, characterized in that: In the concentration of rough pyrite concentrate and scavenging of rough pyrite tailings steps, the efficient selective collector is a mixture of xanthate collectors and dithiophosphate collectors, and the dosage is 25-50 g / t.

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

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