Copper smelting operation method

Abstract

To provide a method for operating copper smelting that is capable of suppressing the generation of a metallic Cu phase.SOLUTION: A method for operating copper smelting is characterized in that, in a matte that is produced by reacting a smelting raw material containing copper concentrate and a raw material containing metallic Cu with a reaction gas in a reaction shaft of a flash smelting furnace, an S source is added to the matte when a metallic phase of the metallic Cu is generated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a copper smelting operation. [Background technology]

[0002] In the reaction shaft of a copper smelting flash furnace, a reaction gas is introduced from a concentrate burner together with smelting raw materials such as copper concentrate and solvent. The copper concentrate undergoes an oxidation reaction in the reaction gas, producing matte and slag at the bottom of the reaction shaft (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-363659 [Patent Document 2] Japanese Patent Application Publication No. 11-140554 [Patent Document 3] Special Publication No. 01-036539 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the proportion of recycled materials used in smelting has increased. However, recycled materials sometimes contain metallic copper. As the amount of recycled materials processed increases, the proportion of metallic copper fed to copper smelting furnaces also increases. When the metallic copper feed rate to a matte smelting furnace (a flash smelting furnace) increases and exceeds its solubility in matte, three phases—slag, matte, and metal—coexist within the furnace. Metal accumulation at the bottom of a flash smelting furnace promotes the concentration of impurity elements in the metal phase, the penetration of low-melting-point metal into the hearth brick joints, and impregnation of the bricks themselves, increasing the risk of melt leakage from the hearth. Furthermore, if the amount of metal exceeds a certain level and reaches the matte taphole level, metal may suddenly be discharged from the matte hole, potentially damaging the metal matte trough and disrupting operation by supplying high-impurity metal to the converter.

[0005] The present invention has been made in view of the above problems, and has an object to provide a copper smelting operation method capable of reducing the formation of metallic Cu phase. [Means for solving the problem]

[0006] The copper smelting operation method according to the present invention is characterized in that, in matte produced by reacting a smelting raw material containing copper concentrate and a raw material containing metallic Cu with a reaction gas in a reaction shaft of a flash smelting furnace, a sulfur source is added to the matte when a metal phase of the metallic Cu is produced. The sulfur source may be added to the matte when the metallic Cu is contained in the smelting raw material in an amount exceeding the solubility of the matte. The sulfur source may be added to the matte when the metal phase of metallic Cu is confirmed in the matte by sampling the matte. The sulfur source may be added to the matte by mixing the sulfur source with the smelting raw material. The sulfur source may be added to the matte by injecting the sulfur source together with an inert gas from an injection nozzle toward the matte. The sulfur source may be added in a briquette form to the matte. The sulfur source may be mixed with other smelting raw materials to form briquettes and then added to the matte. The specific gravity of the briquettes may be adjusted when the sulfur source is mixed with other smelting raw materials to form briquettes. The S source may be mixed with recycled materials or other smelting materials to form briquettes, thereby increasing the throughput of the recycled materials. 2 / g or more. The S source may be supplied to the matte in an amount sufficient to matte the entire metallic Cu. Assuming that 90 mass% of S contributes to matting the metallic Cu when the total S contained in the S source is 100 mass%, the S source may be supplied to the matte in an amount sufficient to matte the entire metallic Cu. The S source may contain elemental sulfur or a sulfide. The S source may further contain Fe. The S source containing Fe may be chalcopyrite, pyrite, or pyrrhotite. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a copper smelting operation method that can reduce the formation of metallic Cu phases. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a flash furnace for copper smelting according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the details of a concentrate burner 4. [Figure 3] FIG. 1 is a phase diagram showing the solubility of Cu in the matte. [Figure 4] FIG. 2 is a diagram illustrating an example of an injection nozzle. [Figure 5] FIG. 1 illustrates an experimental setup. [Figure 6] Photograph (a) shows the results of the comparative example, and photograph (b) shows the results of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment) FIG. 1 is a diagram illustrating a schematic configuration of a flash smelting furnace 100 for copper smelting according to an embodiment. As shown in FIG. 1, the flash smelting furnace 100 includes a reaction shaft 1 in which concentrate and reaction gas are mixed, a settler 2, and an uptake 3. A concentrate burner 4 is provided on the ceiling of the reaction shaft 1. The concentrate burner 4 supplies a main reaction blast gas, an auxiliary reaction gas, and a dispersion gas (which also contributes to the reaction) into the reaction shaft 1, along with copper concentrate, solvents, recycled materials, etc. (hereinafter, these solid materials will be referred to as smelting materials). For example, the main reaction blast gas and the auxiliary reaction gas are oxygen-enriched air, and the dispersion gas is air or oxygen-enriched air.

[0010] FIG. 2 is a diagram illustrating the details of the concentrate burner 4, and is an explanatory diagram showing the input section 10 through which the smelting raw material, the main reaction gas, the auxiliary reaction gas, and the dispersion gas are input to the reaction shaft 1.

[0011] The input section 10 of the concentrate burner 4 is equipped with a lance 16, which is provided with a first passage 11 through which a dispersion gas passes and a fourth passage 14 through which a reaction auxiliary gas passes. The fourth passage 14 is provided in the center of the lance 16, and the first passage 11 is provided around the fourth passage 14. The input section 10 also has a second passage 12 as a raw material flow path provided outside the lance 16, more specifically, on the outer periphery of the lance 16. The input section 10 further has a third passage 13 provided outside the second passage 12, more specifically, on the outer periphery of the second passage 12, through which a reaction main blast gas passes. The third passage 13 is formed by a tubular portion provided to surround the second passage 12 and communicates with a funnel-shaped air chamber 17 provided above it. The second passage 12 and the third passage 13 are separated by a cylindrical partition wall 21.

[0012] The first passage 11 supplies dispersion gas into the reaction shaft 1. The second passage 12 supplies concentrate into the reaction shaft 1. The third passage 13 supplies main reaction gas from the air chamber 17 into the reaction shaft 1. The fourth passage 14 supplies auxiliary reaction gas into the reaction shaft 1.

[0013] A hollow truncated cone-shaped dispersion cone 15 is formed at the tip (lower end) of the lance 16. A plurality of supply holes 152 are formed in a lower part 151 of the side surface of the dispersion cone 15 to discharge the dispersion gas that has passed through the first passage 11 into the reaction shaft 1. The supply holes 152 are arranged so that the gas is discharged in the normal direction to the bottom circle of the dispersion cone 15.

[0014] When smelting raw materials are fed into the reaction shaft 1 from the concentrate burner 4, the copper concentrate containing sulfides undergoes an oxidation reaction according to the following reaction formula (1), and as shown in Figure 1, it separates into matte 5 and slag 6 at the bottom of the reaction shaft 1. In the following reaction formula (1), Cu2S·FeS corresponds to the main component of matte 5, and FeO·SiO2 corresponds to the main component of slag 6. Silica ore is used as the flux. CuFeS2+SiO2+O2→Cu2S·FeS+FeO·SiO2+SO2+ Reaction heat (1)

[0015] The recycled raw material may contain metallic Cu. If the amount of metallic Cu is small, the metallic Cu is sulfidized to form matte 5 during the process of falling from the concentrate burner 4. Therefore, no metal phase is generated.

[0016] However, as the amount of recycled raw materials processed increases, the proportion of metallic Cu in the smelting raw material tends to increase. In recent years, the proportion of metallic Cu in the Cu component of the smelting raw material has sometimes been 6.0 mass% or more and 28.0 mass% or less, or 9.0 mass% or more and 18.0 mass% or less, or 9.0 mass% or more and 12.0 mass% or less.

[0017] As the proportion of metallic Cu in the smelting raw material increases, metallic Cu is not completely sulfidized during the process of falling from the concentrate burner 4 and falls as metallic Cu. While metallic Cu dissolves in matte 5 to a certain extent, there is a solubility limit. Figure 3 is a phase diagram showing the solubility of Cu in matte at 1250°C. In Figure 3, "matte(l)" indicates the range in which metallic Cu can dissolve in matte. "matte(l) + Cu(l)" indicates the range in which metallic Cu cannot dissolve in matte and a metal phase is formed. The phase diagram in Figure 3 is based on "Report of the Selection and Research Institute, Takazai and Yazawa, 1983."

[0018] In this embodiment, when the amount of metallic Cu supplied into the flash smelting furnace 100 exceeds the solubility of metallic Cu in matte 5, a raw material containing Fe and S (hereinafter referred to as "S source") is supplied as a matte source for metallic Cu. For example, based on the phase diagram of FIG. 3, an S source is supplied in an amount sufficient to matte all of the metallic Cu. This causes metallic Cu to take the form of sulfides containing Fe and S, matte, and dissolve in matte 5. As a result, the generation of metallic Cu phase at the hearth of the flash smelting furnace 100 can be suppressed.

[0019] Whether or not the supply amount of metallic Cu exceeds the solubility in matte 5 can be determined by sampling the smelting raw material and measuring the composition ratio. Alternatively, if sampling is performed on matte 5 in the reaction shaft 1 and a metal phase is confirmed, it may be determined that the supply amount of metallic Cu exceeds the solubility in matte 5.

[0020] Examples of sulfur sources that can be used include FeS minerals (pyrrhotite), FeS2 minerals (pyrite), CuFeS2 minerals (chalcopyrite), minerals containing FeS·FeS2, and copper concentrates containing sulfur. When comparing FeS minerals and FeS2 minerals, it is preferable to use FeS2 minerals, which are believed to contain more sulfur, which is necessary for matte formation. Alternatively, sulfur-containing tailings generated during the beneficiation process of non-ferrous metal raw materials can be used as a sulfur source. For example, tailings generated during the flotation process are an example of sulfur-containing tailings.

[0021] When the total amount of S contained in the S source is 100 mass%, there is a risk that 100 mass% of S may not contribute to matting the metallic Cu. Therefore, it is preferable to charge an excess amount of S source into the furnace. For example, when the total amount of S contained in the S source is 100 mass%, assuming that 90 mass% of S contributes to matting the metallic Cu, it is preferable to supply an S source in an amount sufficient to matte the entire metallic Cu, based on the phase diagram of FIG. 3. When the total amount of S contained in the S source is 100 mass%, assuming that 80 mass% of S contributes to matting the metallic Cu, it is preferable to supply an S source in an amount sufficient to matte the entire metallic Cu, based on the phase diagram of FIG. 3. When the total amount of S contained in the S source is 100 mass%, assuming that 70 mass% of S contributes to matting the metallic Cu, it is preferable to supply an S source in an amount sufficient to matte the entire metallic Cu, based on the phase diagram of FIG. 3.

[0022] If a powdered raw material with a large specific surface area is used as the S source, the S source may be oxidized by the oxidizing power of the reaction gas in the reaction shaft 1 before reacting with the metallic Cu. Therefore, it is preferable to use a lump-shaped S source. If the S source has a lump shape with a small specific surface area, oxidation loss during the time it passes through the reaction shaft 1 can be suppressed, and it will arrive directly in the molten metal drop area directly below the reaction shaft 1, come into contact with and react with the matte 5 and metallic Cu. As an S source having a lump shape, pelletized powdered raw material containing S, natural minerals, and melt-formed materials can be used.

[0023] On the other hand, if the specific surface area is too small, there is a risk that the unreacted S source will remain in the matte 5 and be extracted from the flash smelting furnace. Since it is unreacted, it cannot contribute to matte formation, and as a result, there is a risk that a metal phase will be formed on the floor of the settler 2. Therefore, specifically, the specific surface area of ​​the S source is set to 20 mm 2 / g or more is preferable.

[0024] The S source may be added by mixing it with the smelting raw materials. Alternatively, the S source may be introduced into the reaction shaft 1 using an inert gas as a carrier. The use of an inert gas allows the S source to come into contact with the matte 5 and metallic Cu while suppressing oxidation of the S source. For example, as illustrated in Figure 4, an injection nozzle 40 may be provided in the reaction shaft 1, and the S source may be introduced into the reaction shaft 1 through the injection nozzle 40. Alternatively, a briquette or agglomerate of the S source may be added toward the settler bath directly below the reaction shaft 1. For example, molten droplets, mainly consisting of slag and matte, generated in the reaction shaft 1 rain down from above on the settler bath surface like a shower. If the briquette or agglomerate of the S source is supplied to the molten bath surface where the molten droplets are falling, the S source will come into contact with the matte 5, and S will be supplied to the matte 5. Briquettes with a small specific surface area are effective in minimizing oxidation of the S source in the gas phase. Furthermore, instead of briquetting only the S source, by adjusting the specific gravity by mixing and briquetting with other smelting raw materials, it is possible to supply S more efficiently to the matte 5. For example, by mixing the S source with powdered recycled raw materials mainly composed of Cu, it is possible to form briquettes with a specific gravity greater than that of slag, making it easier for the S to reach the matte 5. For example, when only copper concentrate is briquetted as the S source, the specific gravity varies depending on the pressure conditions and is 1.4 to 3.8 g / cm 3 However, by mixing copper concentrate with Cu-based recycled materials in a weight ratio of 5:3 and forming them into briquettes, the specific gravity can be reduced to 2.1 to 4.8 g / cm 3The mixed recycled material not only increases the specific gravity of the briquettes, but also forms matte within the matte, effectively increasing the recycled material throughput in the flash smelting furnace. Briquetted raw materials can be fed into the furnace via a concentrate burner or from the ceiling of the settler 2. It is preferable to feed the briquetted raw materials so that they land in the area directly below the reaction shaft 1 where the generated droplets fall in a shower. To improve the stability of the briquetted raw materials, binders can be added, the moisture content can be adjusted, and the particle size distribution and ratio of the sulfur source and recycled raw materials can be adjusted. Fine powder raw materials processed in the flash smelting furnace or by-products such as powders and liquids generated in various smelting processes can also be used as binders. Furthermore, to improve the stability of the briquetted raw materials, processes such as high-temperature treatment in an inert atmosphere or sintering can be included. [Example]

[0025] Example 1 As shown in FIG. 5, matte 52 was filled in a quartz Tammann tube 51 in advance, and the quartz Tammann tube 51 was fixed to an alumina crucible. Next, the alumina crucible was placed in an electric furnace, and the molten metal temperature was raised to 1250°C. Next, metallic Cu 53 was added to the molten matte 52 in an amount exceeding the solubility on the phase diagram, and the mixture was held for 2 minutes. φ5mm spherical Cu (100% purity) was used as the metallic Cu 53. At this time, the solution in the quartz Tammann tube 51 was a two-liquid phase coexistence composition of matte and Cu.

[0026] Next, in order to matte the coexisting Cu in the solution, a S source containing sintered copper with a specific surface area of ​​300 to 500 mm 2 The FeS reagent 54, which had been press-molded to a concentration of about 1 / g, was added to the quartz Tammann tube 51 together with argon gas and held for 10 minutes. The FeS concentration in the FeS reagent 54 used was 87.9 mass%. Next, in order to prevent Cu precipitation during the cooling process, the alumina crucible was removed from the electric furnace and immersed together with the quartz Tammann tube 51 in ice water for rapid cooling.

[0027] (Comparative Example) In the comparative example, no S source was added. Other conditions were the same as in Example 1.

[0028] (analysis) For Example 1 and the Comparative Example, the presence or absence of a residual Cu phase (metallic Cu) in the samples after quenching was confirmed. The residual Cu phase was evaluated by CT scanning and microscopic observation of the sample cross section. For observation of the sample cross section, a cylindrical sample with a diameter of 17.0 mm was polished in 0.5 mm increments and the observation was repeated to confirm the presence or absence of a Cu phase. By using CT in combination, the evaluation accuracy was improved.

[0029] The compositions of matte 52, metallic Cu 53, and FeS2 reagent 54 used in the test are shown in Table 1. Table 2 shows the matte grade (copper grade) of matte 52 packed in quartz Tammann tube 51, the amount of matte 52 packed in quartz Tammann tube 51, the amount of metallic Cu 53 added to quartz Tammann tube 51, the amount of FeS2 reagent 54 added to quartz Tammann tube 51, and the average composition of each component in the quenched sample. [Table 1] [Table 2]

[0030] FIG. 6(a) is a photograph showing the results of the comparative example. FIG. 6(b) is a photograph showing the results of Example 1. As shown in FIG. 6(a), a Cu phase was confirmed in the sample of the comparative example, but as shown in FIG. 6(b), a Cu phase was not confirmed in the sample of Example 1. In FIG. 6(a), the small circle below the black circle is the Cu phase. In FIG. 6(b), it can be seen that the Cu phase is matted. From these results, it was confirmed that even if metallic Cu is present in an amount exceeding the solubility on the phase diagram, matting can be achieved by adding an S source.

[0031] The solubility of metallic Cu in the matte phase was confirmed using the comparative sample, and it was confirmed that the measured solubility generally agreed with the phase diagram.

[0032] (Examples 2 and 3) Next, the contribution of the FeS2 reagent 54 was investigated. Example 2 is an example in which, assuming that 70 mass% of S contributes to matting metallic Cu when the total amount of S contained in the FeS2 reagent 54 is 100 mass%, an amount of FeS2 reagent 54 greater than or equal to the amount required to matte the entire amount of metallic Cu was supplied. Example 3 is an example in which, assuming that 90 mass% of S contributes to matting metallic Cu when the total amount of S contained in the FeS2 reagent 54 is 100 mass%, an amount of FeS2 reagent 54 greater than or equal to the amount required to matte the entire amount of metallic Cu was supplied.

[0033] Table 3 shows the matte quality (copper quality) of the matte 52 packed in the quartz Tammann tube 51, the amount of matte 52 packed in the quartz Tammann tube 51, the amount of metallic Cu 53 added to the quartz Tammann tube 51, the amount of FeS2 reagent 54 added to the quartz Tammann tube 51, and the average composition of each component in the quenched sample. [Table 3]

[0034] In Example 3, the amount of Cu phase was smaller than in the comparative example. From this result, it was confirmed that, assuming that 90 mass% of S contributes to matting metallic Cu when the total S contained in the FeS2 reagent 54 is 100 mass%, the generation of metallic Cu is suppressed by adding FeS2 in an amount sufficient to matte the entire metallic Cu phase. In Example 2, no Cu phase was confirmed. From this result, it was confirmed that, assuming that 70 mass% of S contributes to matting metallic Cu when the total S contained in the FeS2 reagent 54 is 100 mass%, it is preferable to supply FeS2 reagent 54 in an amount sufficient to matte the entire metallic Cu phase.

[0035] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0036] 1 Reaction Shaft 2 Setra 3 Uptake 4 Concentrate burner 5. Matt 6. Slug 10 Input section 11 1st aisle 12 2nd aisle 13 3rd aisle 14 4th aisle 16 Lance 40 injection nozzle 51 Quartz Tammann tube 52 Matt 53 Metallic Cu 54 FeS2 Reagent 100 Flash furnace

Claims

1. A copper smelting operation method, comprising the steps of: adding a sulfur source to matte produced by reacting a smelting raw material, which comprises copper concentrate and a raw material containing metallic Cu, with a reaction gas in a reaction shaft of a flash smelting furnace, when a metal phase of the metallic Cu is produced in the matte.

2. 2. The copper smelting method according to claim 1, wherein the sulfur source is added to the matte when the metallic Cu contained in the smelting raw material exceeds the solubility of the metallic Cu in the matte.

3. 2. The copper smelting operation method according to claim 1, wherein the sulfur source is added to the matte when a metal phase of the metallic Cu is confirmed in the matte by sampling the matte.

4. 2. The copper smelting method according to claim 1, wherein the sulfur source is added to the matte by mixing the sulfur source with the smelting feedstock.

5. 2. The copper smelting method according to claim 1, wherein the sulfur source is added to the matte by injecting the sulfur source together with an inert gas from an injection nozzle toward the matte.

6. 2. The copper smelting method according to claim 1, wherein the briquetted sulfur source is added to the matte.

7. 2. The copper smelting method according to claim 1, wherein the sulfur source is mixed with other smelting raw materials to form briquettes, which are then added to the matte.

8. 8. The copper smelting operating method according to claim 7, wherein the specific gravity of the briquettes is adjusted when the S source is mixed with other smelting raw materials to form briquettes.

9. 2. The copper smelting method according to claim 1, wherein the S source is mixed with recycled raw materials or other smelting raw materials to form briquettes, thereby increasing the throughput of the recycled raw materials.

10. The specific surface area of ​​the S source is 20 mm ２ 2. The copper smelting method according to claim 1, wherein the copper content is 1 / g or more.

11. 2. The copper smelting method according to claim 1, wherein the sulfur source is supplied to the matte in an amount equal to or greater than the amount required to completely convert the metallic Cu into matte.

12. 2. The copper smelting operation method according to claim 1, wherein, assuming that 90 mass% of S contributes to matte formation of the metallic Cu when total S contained in the S source is 100 mass%, the S source is supplied to the matte in an amount equal to or greater than that which causes the entire metallic Cu to matte.

13. 2. The copper smelting method according to claim 1, wherein the S source comprises elemental sulfur or a sulfide.

14. 2. The copper smelting method according to claim 1, wherein the S source further contains Fe.

15. 15. The copper smelting method according to claim 14, wherein the Fe-containing S source is chalcopyrite, pyrite, or pyrrhotite.

Images