A method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores

Abstract

The present invention discloses a method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores, comprising the steps of: (1) open-circuit concentration and impurity removal; (2) ultrafine grinding of the open-circuit concentrated concentrate; (3) rough separation of the ultrafine ground product; and (4) concentration of the ultrafine ground product. The present invention adopts the "open-circuit concentration and impurity removal + ultrafine grinding + closed-circuit flotation" technology to obtain qualified cryptocrystalline graphite concentrate from carbon tailings. The open-circuit concentration can effectively remove sulfide impurities and fine-grained gangue minerals with good floatability in the carbon concentrate, significantly improving the grade of the graphite concentrate; adding a regulator during the ultrafine grinding process can effectively reduce the adhesion of nano-impurity minerals generated during the ultrafine grinding process and graphite minerals, thereby improving the separation efficiency of the ultrafine ground product; the ultrafine ground product adopts a closed-circuit flotation process, which can ensure the quality of the graphite concentrate while improving its recovery rate.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive recycling and utilization of mine tailings and mineral processing, and in particular to a method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores. Background Art

[0002] Flotation of carbonaceous sulfide ores primarily addresses the separation of carbonaceous materials from sulfide minerals. Currently, there are three main methods for carbon removal: decarbonization, carbon suppression, and co-floating carbon and useful minerals for subsequent separation. Decarbonization or partial decarbonization produces carbon tailings with a high carbon content, typically between 15% and 40%. These tailings are typically combined with on-site flotation tailings and discharged into a tailings pond. If these tailings are primarily graphite, this can result in a waste of graphite resources. Therefore, there is a need to develop a method for obtaining cryptocrystalline graphite concentrate from the decarbonized tailings of carbonaceous sulfide ores. This would avoid wasting graphite resources, reduce mine tailings stockpiling, and offer both economic and environmental benefits.

[0003] While much research has been conducted on the development and utilization of cryptocrystalline graphite, there have been no reports on recovering cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores. Chinese patent application CN111135957A discloses a method for recovering carbon by flotation from barium slag. The method involves screening and crushing the barium slag to obtain a fine-grained fraction. A fixed amount of the fine-grained fraction is then weighed and added to a flotation cell. After slurrying for a specified period of time, a pH adjuster, diesel fuel as a collector, and pine oil as a foaming agent are added sequentially and stirred. The mixture is then aerated for a specified period of time, and then scraped to produce a carbon concentrate. This method is simple and unsuitable for the development and utilization of finely embedded cryptocrystalline graphite. Chinese patent application CN114178053A discloses a flotation method for cryptocrystalline graphite, which is mainly used for flotation purification of cryptocrystalline graphite ore with a carbon content of approximately 60% to 80%, ultimately obtaining high-purity cryptocrystalline graphite powder. It is not suitable for obtaining low-end graphite concentrate products from cryptocrystalline graphite ore with a low cryptocrystalline graphite content. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores comprises the following steps:

[0007] (1) Open circuit concentration and impurity removal: the carbon tailings obtained by decarbonization of carbon-containing sulfide ore are fed into a flotation machine, the pulp mass concentration is adjusted to 20-25%, and 1-3 stages of open circuit concentration operations are carried out. Lime is added in each stage of concentration operation to adjust the pulp pH to 11-12, and 1000-3000 g / t of water glass, sulfide ore inhibitor, 50-100 g / t of collector kerosene and 15-40 g / t of foaming agent 2# oil are added in sequence based on the dry weight of each ton of carbon tailings, and stirred to obtain open circuit concentration concentrate and open circuit concentration tailings. The open circuit concentration concentrate enters the next stage of concentration operation, and the open circuit concentration tailings of each stage of concentration operation are combined as tailings 1;

[0008] (2) Ultrafine grinding of open-circuit concentrated ore: The open-circuit concentrated ore finally obtained in step (1) is fed into a sand mill disperser for ultrafine grinding, and lime is added to the sand mill disperser to adjust the slurry pH to 11-12, and 500-2000 g / t of water glass and sulfide ore inhibitor are added based on the dry weight of each ton of carbon tailings to obtain an ultrafine ground product;

[0009] (3) Roughing of ultrafine grinding products: pouring the ultrafine grinding products obtained in step (2) into a flotation machine, adjusting the pulp mass concentration to 10-15%, and performing 1-2 stages of roughing operations; adding 40-100 g / t of kerosene as a collector and 15-40 g / t of 2# oil as a foaming agent to each stage of roughing operations based on the dry weight of carbon tailings per ton, to obtain ultrafine grinding roughing concentrate and tailings II;

[0010] (4) Ultrafine grinding product selection: The ultrafine grinding rough concentrate obtained in step (3) is combined and subjected to 4-6 rounds of selection operations. According to the dry weight of carbon tailings per ton, 100-800 g / t of water glass as an adjusting agent, 10-60 g / t of kerosene as a collecting agent, and 0-20 g / t of 2# oil as a foaming agent are added in each round of selection operation to obtain ultrafine grinding concentrated ore and ultrafine grinding concentrated middlings. The ultrafine grinding concentrated ore obtained in each round of selection operation enters the next round of selection operation, and the ultrafine grinding middlings obtained in each round of selection operation are sequentially returned to the previous round of selection operation. The ultrafine grinding concentrated ore in the last round of selection operation is cryptocrystalline graphite concentrate.

[0011] Furthermore, the main component of the carbon tailings is cryptocrystalline graphite, and the mass fraction of carbon is 15-40%.

[0012] Furthermore, in step (1) and step (2), the sulfide ore inhibitor is one or a combination of zinc sulfate, sodium sulfite, sodium humate, and sodium sulfide. Based on the dry weight of each ton of carbon tailings, the amount of zinc sulfate is 1000-3000 g / t, the amount of sodium sulfite is 500-1500 g / t, the amount of sodium humate is 100-500 g / t, and the amount of sodium sulfide is 100-300 g / t.

[0013] Furthermore, in step (2), the fineness of the ultrafine grinding product is D80≤10μm.

[0014] Furthermore, the selection operation in step (1) is open-circuit selection, and the selection operation of 4ˉ6 sections in step (4) is closed-circuit selection.

[0015] The beneficial effects of the present invention are:

[0016] 1. The carbon tailings produced by decarbonization of carbon-containing sulfide ores during the production process generally contain between 15% and 40% carbon. The present invention recovers cryptocrystalline graphite resources in the tailings through regrinding and reselection operations to obtain qualified graphite concentrate products, avoiding the waste of graphite resources and reducing the storage of mine tailings, thereby achieving good economic and environmental benefits.

[0017] 2. The present invention adopts the "open-circuit concentration and impurity removal + ultrafine grinding + closed-circuit flotation" technology to obtain qualified cryptocrystalline graphite concentrate from carbon tailings. Among them, the open-circuit concentration can effectively remove the sulfide impurities and fine-grained gangue minerals with good floatability in the carbon concentrate, significantly improving the grade of the graphite concentrate; the addition of a regulator during the ultrafine grinding process can effectively reduce the adhesion of nano-impurity minerals generated during the ultrafine grinding process and graphite minerals, thereby improving the sorting efficiency of the ultrafine grinding product; the ultrafine grinding product adopts a closed-circuit flotation process, which can improve its recovery rate while ensuring the quality of the graphite concentrate.

[0018] 3. The flotation process adopted in the present invention is simple and easy to implement, and the flotation reagents used are all conventional flotation reagents.

[0019] 4. Without changing the original process flow of the production site, the present invention obtains qualified cryptocrystalline graphite concentrate products by regrinding and reselecting the carbon tailings, thereby improving the comprehensive utilization rate of resources and providing technical support for the rational recovery of graphite resources in complex carbon-containing sulfide ores.

[0020] 5. The cryptocrystalline graphite concentrate obtained by the present invention is a low-quality graphite concentrate product. Due to its high fixed carbon content and fine particle size, it is a good raw material for purifying nano-level high-purity graphite concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of the method of Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0023] Example 1

[0024] A carbonaceous lead-zinc polymetallic sulfide ore in Inner Mongolia is a sericite-graphite schist-type zinc-lead ore. Its raw ore contains 6.84% carbon. Kerosene is used for decarbonization at the production site to produce carbon tailings. The carbon tailings contain an average of 26% carbon. Its main component is cryptocrystalline graphite. The graphite particle size is fine as a whole. Except for individual particles with a particle size of >5μm, the rest are less than 5μm, mainly between 2-4μm. The impurity minerals are mainly silicates, pyrite, pyrite, sphalerite, galena, etc. The carbon tailings are treated by obtaining cryptocrystalline graphite concentrate from the decarbonization tailings of carbonaceous sulfide ore, such as Figure 1 As shown ( Figure 1 A1 represents lime, A2 represents water glass, A3 represents a sulfide ore inhibitor, B represents a collector kerosene, and C represents a foaming agent 2# oil), comprising the following steps:

[0025] (1) Open circuit concentration and impurity removal: The carbon tailings are fed into a flotation machine, and the pulp concentration is adjusted to 25%, and two stages of open circuit concentration are carried out. According to the dry weight of each ton of carbon tailings, in the first stage of concentration, 1000g / t of lime is added in sequence to adjust the pulp pH to 11, and 3000g / t of water glass, 2000g / t of sulfide ore inhibitor zinc sulfate, 100g / t of collector kerosene and 30g / t of frother 2# oil are added, stirred, and floated to obtain open circuit concentration concentrate and open circuit concentration tailings; the open circuit concentration concentrate is subjected to the second stage of concentration, 500g / t of lime is added to adjust the pulp pH to 11, and 1500g / t of water glass, 500g / t of sulfide ore inhibitor sodium sulfite, 50g / t of collector kerosene and 15g / t of frother 2# oil are added in sequence, stirred, and floated to obtain open circuit concentration concentrate and open circuit concentration tailings. The tailings of each stage of open circuit concentration are combined as tailings one.

[0026] (2) Ultrafine grinding of open-circuit concentrated ore: The open-circuit concentrated ore obtained in step (1) is fed into a sand mill disperser for ultrafine grinding. According to the dry weight of each ton of carbon tailings, 300 g / t of lime is added into the sand mill disperser to adjust the slurry pH to 11, 500 g / t of water glass and 500 g / t of sodium sulfite as a sulfide ore inhibitor are added to obtain an ultrafine ground product with a particle size of D80 ≤ 5 μm.

[0027] (3) Roughing of ultrafine grinding products: The ultrafine grinding products obtained in step (2) are poured into a flotation machine, and the pulp concentration is adjusted to 15%, and two roughing operations are performed. According to the dry weight of each ton of carbon tailings, in the first roughing operation, 100g / t of kerosene as a collector and 40g / t of 2# oil as a foaming agent are added in sequence to obtain ultrafine grinding roughing concentrate and ultrafine grinding roughing tailings; the fine grinding roughing tailings are subjected to a second roughing operation, and 40g / t of kerosene as a collector and 15g / t of 2# oil as a foaming agent are added in sequence to obtain an ultrafine grinding roughing concentrate and a final ultrafine grinding roughing tailings. The final ultrafine grinding roughing tailings are tailings 2.

[0028] (4) Ultrafine grinding product selection: The ultrafine grinding rough concentrate obtained in step (3) is combined to carry out five selection operations. Each selection operation obtains ultrafine grinding concentrated ore and ultrafine grinding concentrated middlings. The ultrafine grinding concentrated ore of each selection operation enters the next selection operation. The last ultrafine grinding concentrated ore is cryptocrystalline graphite concentrate. The ultrafine grinding concentrate middlings of each selection operation are sequentially returned to the previous selection operation. Calculated on the basis of dry weight per ton of carbon tailings, in the first section of the beneficiation operation, 500g / t of water glass as the adjusting agent, 30g / t of kerosene as the collecting agent, and 10g / t of 2# oil as the foaming agent are added in sequence; in the second section of the beneficiation operation, 300g / t of water glass as the adjusting agent, 20g / t of kerosene as the collecting agent, and 10g / t of 2# oil as the foaming agent are added in sequence; in the third section of the beneficiation operation, 150g / t of water glass as the adjusting agent and 10g / t of kerosene as the collecting agent are added in sequence; in the fourth section of the beneficiation operation, 100g / t of water glass as the adjusting agent, 10g / t of kerosene as the collecting agent, and 5g / t of 2# oil as the foaming agent are added in sequence; in the fifth section of the beneficiation operation, 100g / t of water glass as the adjusting agent and 10g / t of kerosene as the collecting agent are added in sequence.

[0029] Example 2

[0030] A lead-zinc-sulfur deposit is a strata-bound metamorphic deposit. The main metal minerals are pyrite, galena, sphalerite, and pyrrhotite. The main gangue minerals are dolomite, calcite, quartz, tremolite, and carbonaceous materials. The carbonaceous materials are mainly cryptocrystalline graphite. The original ore contains 6.49% carbon. The floatability of carbon in the ore varies. Some carbon is very easy to float, while the floatability of other carbon is similar to that of lead and zinc. Kerosene is used as a carbon collector for decarbonization on site to obtain carbon tailings with a carbon content of 29%. The carbon tailings are treated by obtaining cryptocrystalline graphite concentrate from the decarbonized tailings of carbon-containing sulfide ores, such as Figure 1 As shown ( Figure 1 A1 represents lime, A2 represents water glass, A3 represents a sulfide ore inhibitor, B represents a collector kerosene, and C represents a foaming agent 2# oil), comprising the following steps:

[0031] (1) Open circuit selection and impurity removal: Take the carbon tailings from the production site and feed them into the flotation machine. Adjust the pulp concentration to 20% and perform two-stage open circuit selection operations. Based on the dry weight of each ton of carbon tailings, in the first stage of concentration operation, 800g / t of lime is added to adjust the slurry pH to 12, and 2000g / t of water glass, 2000g / t of zinc sulfate as a sulfide ore inhibitor, 100g / t of kerosene as a collector, and 40g / t of 2# oil as a foaming agent are added in sequence, stirred, and floated to obtain open-circuit concentrated concentrate and open-circuit concentrated tailings; the open-circuit concentrated concentrate is subjected to the second stage of concentration operation, 400g / t of lime is added to adjust the slurry pH to 12, and 1500g / t of water glass, 100g / t of sodium humate as a sulfide ore inhibitor, 50g of kerosene as a collector, and 15g / t of 2# oil as a foaming agent are added, stirred for a certain period of time, and floated to obtain open-circuit concentrated concentrate and open-circuit concentrated tailings. The open-circuit concentrated tailings obtained from each stage of open-circuit concentration operation are combined as tailings one.

[0032] (2) Ultrafine grinding of open-circuit concentrated ore: The open-circuit concentrated ore obtained in step (1) is fed into a sand mill disperser for ultrafine grinding. According to the dry weight of carbon tailings per ton, 300 g / t of lime is added to the sand mill disperser in sequence, the slurry pH is adjusted to 12, 500 g / t of water glass and 500 g / t of sodium sulfite as a sulfide ore inhibitor are added to obtain an ultrafine ground product with a particle size of D80 ≤ 5 μm.

[0033] (3) Ultrafine grinding product roughing: The ultrafine grinding product obtained in step (2) is poured into a flotation machine, and the pulp concentration is adjusted to 10%, and two roughing operations are performed. According to the dry weight of each ton of carbon tailings, in the first roughing operation, 80g / t of kerosene collector and 30g / t of 2# oil frother are added in sequence to obtain ultrafine grinding roughing concentrate and ultrafine grinding roughing tailings; the ultrafine grinding roughing tailings are subjected to a second roughing operation, in which 40g / t of kerosene collector and 15g / t of 2# oil frother are added in sequence to obtain ultrafine grinding roughing concentrate and fine grinding roughing tailings. The ultrafine grinding roughing tailings are tailings 2.

[0034] (4) Ultrafine grinding product selection: The ultrafine grinding rough concentrate obtained in step (3) is combined to carry out 6 selection operations, and each selection operation obtains ultrafine grinding concentrated ore and ultrafine grinding concentrated middlings. The ultrafine grinding concentrated ore of each selection operation enters the next selection operation, and the ultrafine grinding concentrated ore of the last selection operation is cryptocrystalline graphite concentrate. The ultrafine grinding concentrate middlings of each selection operation return to the previous operation in sequence; according to the dry weight of carbon tailings per ton, the first selection operation sequentially adds 400g / t of water glass as an adjusting agent, 20g / t of kerosene as a collecting agent, and 10g / t of 2# oil as a foaming agent; the second selection operation , add 300g / t of water glass as adjusting agent, 20g / t of kerosene as collecting agent, and 10g / t of frother 2# oil in sequence; in the third section of the concentrating operation, add 150g / t of water glass as adjusting agent and 10g / t of kerosene as collecting agent in sequence; in the fourth section of the concentrating operation, add 100g / t of water glass as adjusting agent, 10g / t of kerosene as collecting agent, and 5g / t of frother 2# oil in sequence; in the fifth section of the concentrating operation, add 100g / t of water glass as adjusting agent and 10g / t of kerosene as collecting agent in sequence; in the sixth section of the concentrating operation, add 100g / t of water glass as adjusting agent and 10g / t of kerosene as collecting agent in sequence.

[0035] The implementation effects of Example 1 and Example 2 are shown in Table 1.

[0036] Table 1

[0037]

[0038] Those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts, and all of these changes and modifications should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for obtaining cryptocrystalline graphite concentrate from decarbonized tailings of carbon-containing sulfide ores, characterized in that: The steps include: (1) Open circuit concentration and impurity removal: the carbon tailings obtained by decarbonization of carbon-containing sulfide ore are fed into a flotation machine, the pulp mass concentration is adjusted to 20-25%, and 1-3 stages of open circuit concentration operations are carried out. Lime is added in each stage of concentration operation to adjust the pulp pH to 11-12, and 1000-3000 g / t of water glass, sulfide ore inhibitor, 50-100 g / t of collector kerosene and 15-40 g / t of foaming agent 2# oil are added in sequence based on the dry weight of each ton of carbon tailings, and stirred to obtain open circuit concentration concentrate and open circuit concentration tailings. The open circuit concentration concentrate enters the next stage of concentration operation, and the open circuit concentration tailings of each stage of concentration operation are combined as tailings 1; (2) Ultrafine grinding of open-circuit concentrated ore: The open-circuit concentrated ore finally obtained in step (1) is fed into a sand mill disperser for ultrafine grinding, and lime is added to the sand mill disperser to adjust the slurry pH to 11-12, and 500-2000 g / t of water glass and sulfide ore inhibitor are added based on the dry weight of each ton of carbon tailings to obtain an ultrafine ground product; (3) Roughing of ultrafine grinding products: pouring the ultrafine grinding products obtained in step (2) into a flotation machine, adjusting the pulp mass concentration to 10-15%, and performing 1-2 stages of roughing operations; adding 40-100 g / t of kerosene as a collector and 15-40 g / t of 2# oil as a foaming agent to each stage of roughing operations based on the dry weight of carbon tailings per ton, to obtain ultrafine grinding roughing concentrate and tailings II; (4) Ultrafine grinding product selection: The ultrafine grinding rough concentrate obtained in step (3) is combined and subjected to 4-6 rounds of selection operations. According to the dry weight of carbon tailings per ton, 100-800 g / t of water glass as an adjusting agent, 10-60 g / t of kerosene as a collecting agent, and 0-20 g / t of 2# oil as a foaming agent are added in each round of selection operation to obtain ultrafine grinding concentrated ore and ultrafine grinding concentrated middlings. The ultrafine grinding concentrated ore obtained in each round of selection operation enters the next round of selection operation, and the ultrafine grinding middlings obtained in each round of selection operation are sequentially returned to the previous round of selection operation. The ultrafine grinding concentrated ore in the last round of selection operation is cryptocrystalline graphite concentrate.

2. The method according to claim 1, characterized in that The main component of the carbon tailings is cryptocrystalline graphite, and the mass fraction of carbon is 15-40%.

3. The method according to claim 1, characterized in that In step (1) and step (2), the sulfide ore inhibitor is one or a combination of zinc sulfate, sodium sulfite, sodium humate, and sodium sulfide. Based on the dry weight of each ton of carbon tailings, the amount of zinc sulfate is 1000-3000 g / t, the amount of sodium sulfite is 500-1500 g / t, the amount of sodium humate is 100-500 g / t, and the amount of sodium sulfide is 100-300 g / t.

4. The method according to claim 1, wherein In step (2), the fineness of the ultrafine grinding product is D80≤10μm.

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