Operation method for copper smelting

Abstract

This operating method for copper smelting is characterized in that it comprises: adding an S source to a matte generated by the reaction of a smelting feed containing a copper concentrate and a metal Cu-containing feedstock with a reaction gas in a reaction shaft of a flash smelting furnace when a metal phase of metal Cu is formed in the matte.

Description

TECHNICAL FIELD

[0001] The present application relates to an operating method of copper smelting. BACKGROUND

[0002] In the reaction shaft of a copper smelting flash smelting furnace, a reaction gas is fed together with smelting raw material such as copper concentrate and flux from a concentrate burner. The copper concentrate undergoes an oxidation reaction due to the reaction gas, thereby generating matte and slag at the bottom of the reaction shaft (see, for example, Patent Documents 1 to 3).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2002-363659

[0006] Patent Document 2: Japanese Patent Application Publication No. H11-140554

[0007] Patent Document 3: Japanese Patent Application Publication No. H01-036539 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In recent years, the ratio of recycled raw material as smelting raw material has been increasing. However, the recycled raw material can contain metallic Cu. As the amount of processed recycled raw material increases, the ratio of metallic Cu supplied to the copper smelting furnace increases. When the amount of metallic Cu supplied to the flash smelting furnace, which is a matte smelting furnace, increases and exceeds the solubility of metallic Cu in matte, three phases of slag, matte, and metal coexist in the furnace. When the metal accumulates at the bottom of the flash smelting furnace, it promotes the concentration of impurity elements in the metal phase, the penetration of low-melting-point metals into the joint of the bricks at the bottom of the furnace, and the impregnation of the bricks themselves, thereby increasing the risk of leakage of smelted metal from the bottom of the furnace. In addition, if the amount of metal exceeds a certain amount and reaches the matte discharge outlet level, the metal will be suddenly discharged from the matte outlet, which can cause the metal matte stream tank to melt, and there is also a risk that high-impurity metal is supplied to the converter, thereby causing an operation problem.

[0010] The present application was completed based on consideration of the above-described problems, and aims to provide an operating method of copper smelting that can reduce the formation of a metallic Cu phase.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] A method for copper smelting, characterized by the following steps: adding sulfur (S) source to matte produced by the reaction of a smelting feed containing copper concentrate and a raw material containing metallic Cu with a reaction gas in the reactor body of a flash smelting furnace, when a metallic phase of metallic Cu is formed in the matte. The S source can be added to the matte when the smelting feed contains metallic Cu in an amount exceeding its solubility in the matte. The S source can be added to the matte when a metallic phase of metallic Cu is observed in the matte by sampling. The S source can be added to the matte by mixing it with the smelting feed. The S source can be added to the matte by injecting it along with an inert gas from an injection nozzle toward the matte. The S source can be added in briquettes. The S source can be mixed with other smelting feed to form briquettes, and then the briquettes are added to the matte. When the S source is mixed with other smelting feeds to form briquettes, the specific gravity of the briquettes can be adjusted. The S source can be mixed with recycled materials or other smelting feeds to form briquettes, thereby increasing the throughput of recycled materials. The specific surface area of ​​the S source can be 20 mm². 2 / g or more. The S source can be supplied to the matte in an amount sufficient to completely convert the metallic Cu into matte. When the total amount of S contained in the S source is 100% by mass, and assuming that 90% by mass of S contributes to the matte formation of the metallic Cu, the S source can be supplied to the matte in an amount sufficient to convert the entire amount of metallic Cu into matte. The S source may include elemental sulfur or sulfides. The S source may contain Fe. The Fe-containing S source may be chalcopyrite, pyrite, or pyrrhotite.

[0013] Invention Effects

[0014] According to the present invention, a copper smelting operation method capable of reducing the formation of metallic Cu phase can be provided. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a flash furnace configuration for copper smelting according to one implementation scheme;

[0016] Figure 2 It is a detailed picture of the concentrate burner;

[0017] Figure 3 This is a phase diagram showing the solubility of Cu in matte;

[0018] Figure 4 This is a diagram of the injection nozzle;

[0019] Figure 5 It is a diagram of the experimental equipment;

[0020] Figure 6 (a) is a photograph of the results of Comparative Example; and Figure 6 (b) is a photograph of the results of Example 1. DETAILED DESCRIPTION

[0021] (Embodiments)

[0022] Figure 1 is a diagram of a schematic configuration of a flash smelting furnace 100 for copper smelting according to an embodiment. As shown, the flash smelting furnace 100 includes a reaction shaft 1 in which a concentrate and a reaction gas are mixed, a settler 2, and a vertical pipe 3. A concentrate burner 4 is provided on a top floor of the reaction shaft 1. The concentrate burner 4 supplies a copper concentrate, fluxes, recycled raw materials, and the like (hereinafter, these solid raw materials are referred to as smelting raw materials), and a main reaction gas, an auxiliary reaction gas, and a dispersion gas (which also contribute to the reaction) into the reaction shaft 1. For example, the main reaction gas and the auxiliary reaction gas are oxygen-enriched air, and the dispersion gas is air or oxygen-enriched air. Figure 1

[0023] Figure 2 is an explanatory diagram of details of the concentrate burner 4, and shows an input section 10 through which the smelting raw materials, the main reaction gas, the auxiliary reaction gas, and the dispersion gas are input into the reaction shaft 1.

[0024] The input section 10 of the concentrate burner 4 is provided with a lance 16, and within the lance 16, a first passage 11 through which the dispersion gas passes and a fourth passage 14 through which the auxiliary reaction gas passes are formed. The fourth passage 14 is provided at 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 on the outside (more specifically, on the outer periphery) of the lance 16. The input section 10 also has a third passage 13 through which the main reaction gas passes, provided on the outside (more specifically, on the outer periphery) of the second passage 12. The third passage 13 is formed by a tubular portion provided so as to surround the second passage 12, and is connected to 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.

[0025] The first passage 11 supplies the dispersion gas into the reaction shaft 1. The second passage 12 supplies the concentrate into the reaction shaft 1. The third passage 13 supplies the main reaction gas from the air chamber 17 into the reaction shaft 1. The fourth passage 14 supplies the auxiliary reaction gas into the reaction shaft 1.

[0026] ​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 the lower side 151 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 input direction is perpendicular to the bottom circle of the dispersion cone 15.

[0027] When the smelting raw material is fed from the concentrate burner 4 into the reaction shaft 1, the copper concentrate containing sulfides undergoes an oxidation reaction according to the following reaction formula (1) and is separated into matte 5 and molten slag 6 at the bottom of the reaction shaft 1, as shown in Figure 1 In the following reaction formula (1), Cu2S•FeS corresponds to the main component of the matte 5, and FeO•SiO2 corresponds to the main component of the molten slag 6. Silica ore is used as a flux.

[0028] CuFeS2 + SiO2 + O2 → Cu2S•FeS + FeO•SiO2 + SO2 + reaction heat (1)

[0029] The recycled raw material can contain metallic Cu. If the amount of metallic Cu is small, the metallic Cu is sulfurized to become matte 5 during the falling process from the concentrate burner 4. Therefore, a metallic phase is not generated.

[0030] However, as the amount of the recycled raw material to be treated 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 can be 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.

[0031] When the proportion of metallic Cu in the smelting raw material increases, the metallic Cu is not completely sulfurized during the falling process from the concentrate burner 4 and falls as metallic Cu. In the matte 5, the metallic Cu is dissolved to some extent, but there is a solubility limit. Figure 3 is a phase diagram of the solubility of Cu in matte at 1250°C. In Figure 3 In the phase diagram in "Joewal Koh, Yazawa Akira, 1983, Senken Iho", "matte (l)" indicates a range in which metallic Cu can be dissolved in matte. "Matte (l) + Cu (l)" indicates a range in which metallic Cu cannot be dissolved in matte and a metallic phase is generated. Figure 3 The phase diagram in "Joewal Koh, Yazawa Akira, 1983, Senken Iho" is based on "Joewal Koh, Yazawa Akira, 1983, Senken Iho".

[0032] In this embodiment, when the amount of the metal Cu supplied to the flash smelting furnace 100 exceeds the solubility thereof in the matte 5, a raw material containing Fe and S (hereinafter referred to as "S source") is supplied as a matte source for the metal Cu. For example, based on the phase diagram in Fig. 8, the S source is supplied in an amount equal to or greater than the amount that would cause all of the metal Cu to become matte. This causes the metal Cu to become a sulfide containing Fe and S, which will become matte and dissolve in the matte 5. As a result, the generation of a metal Cu phase at the bottom of the flash smelting furnace 100 can be suppressed. Figure 3

[0033] Whether the amount of the metal Cu supplied exceeds the solubility in the matte 5 can be determined by sampling the smelted raw material and analyzing the composition. Alternatively, if a metal phase is observed by sampling the matte 5 of the reaction shaft 1, it can be determined that the amount of the metal Cu supplied exceeds the solubility in the matte 5.

[0034] As the S source, an FeS mineral (pyrrhotite), an FeS2 mineral (pyrite), a CuFeS2 mineral (chalcopyrite), a mineral containing FeS • FeS2, a copper concentrate containing S, and the like can be used. When comparing the FeS mineral and the FeS2 mineral, it is preferable to use the FeS2 mineral, which contains more sulfur necessary for matte formation. Alternatively, as the S source, a S-containing tailings produced in the ore processing process of non-ferrous metal raw materials can be used. For example, tailings produced in the flotation process are one example of S-containing tailings.

[0035] If the total S contained in the S source is 100 mass%, there is a risk that not all of the 100 mass% of the S contributes to the matte formation of the metal Cu. Therefore, it is preferable to feed an excess amount of the S source into the smelting furnace. For example, if it is assumed that 90 mass% of the S contributes to the matte formation of the metal Cu when the total S contained in the S source is 100 mass%, it is preferable to supply the S source in an amount equal to or greater than the amount that would cause all of the metal Cu to become matte based on the phase diagram in Fig. 8. If it is assumed that 80 mass% of the S contributes to the matte formation of the metal Cu when the total S contained in the S source is 100 mass%, it is preferable to supply the S source in an amount equal to or greater than the amount that would cause all of the metal Cu to become matte based on the phase diagram in Fig. 9. If it is assumed that 70 mass% of the S contributes to the matte formation of the metal Cu when the total S contained in the S source is 100 mass%, it is preferable to supply the S source in an amount equal to or greater than the amount that would cause all of the metal Cu to become matte based on the phase diagram in Fig. 10. If it is assumed that 60 mass% of the S contributes to the matte formation of the metal Cu when the total S contained in the S source is 100 mass%, it is preferable to supply the S source in an amount equal to or greater than the amount that would cause all of the metal Cu to become matte based on the phase diagram in Fig. 11. Figure 3 Figure 3 Figure 3

[0036] ​​​​If a powdered raw material having a large specific surface area is used as the S source, the S source can be oxidized before reacting with the metal Cu due to the oxidizing ability of the reaction gas in the reaction shaft 1. Therefore, it is preferable to use a bulk S source. If the S source has a bulk shape with a small specific surface area, oxidation loss during its time through the reaction shaft 1 can be suppressed, and it will fall into the molten material drop zone just below the reaction shaft 1 and contact and react with the matte 5 and the metal Cu. As the S source having a bulk shape, a granulated powdered raw material containing S, a natural mineral, or a melt-formed material can be used.

[0037] On the other hand, if the specific surface area is too small, there is a risk that unreacted S source will remain in the matte 5 and be discharged from the flash smelting furnace. Because 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 settling tank 2. Therefore, specifically, the specific surface area of the S source is preferably 20 mm 2 / g or more.

[0038] The S source can be added by mixing it with the smelting raw material. Alternatively, an inert gas can be used as a carrier to inject the S source into the reaction shaft 1. By using an inert gas, the S source can be brought into contact with the matte 5 and the metal Cu while suppressing oxidation of the S source. For example, as shown in Figure 4 the injection nozzle 40 can be provided in the reaction shaft 1, and the S source can be injected into the reaction shaft 1 from the injection nozzle 40. Alternatively, a briquetted S source or a bulk S source can be added toward the settling tank bath just below the reaction shaft 1. For example, molten droplets mainly composed of the slag and the matte generated in the reaction shaft 1 fall like a shower from above on the surface of the settling bath, and when a briquetted S source or a bulk S source is supplied to the surface of the bath at the position where the molten droplets fall, the S source comes into contact with the matte 5 and supplies S to the matte 5. In order to avoid oxidation of the S source in the gas zone as much as possible, it is effective to make the specific surface area of the briquette small. Furthermore, instead of just briquetting the S source, adjusting the specific gravity by mixing with other smelting raw materials and briquetting can more effectively supply sulfur to the matte 5. For example, by mixing the S source with a powdered recycled raw material mainly composed of Cu, a briquette having a specific gravity greater than that of the slag can be formed, which can easily reach the matte 5. For example, when only a copper concentrate is briquetted as the S source, the specific gravity of the briquette varies depending on the compaction pressure conditions and is 1.4 to 3.8 g / cm 3 . However, by mixing the copper concentrate with a Cu-based recycled raw material in a weight ratio of 5:3 to form a briquette, the specific gravity increases to 2.1 to 4.8 g / cm 3The mixed recycled raw materials are used not only to increase the specific gravity of the briquettes but also to form matte within the matte phase, making it a method for effectively increasing the amount of recycled raw materials processed in the flash smelting furnace. The raw materials for briquettes can be fed into the furnace via a concentrate burner or from the top plate of the settling tank 2, but preferably into the area directly below the reactor body 1 where droplets generated there fall in a shower-like manner. Furthermore, to improve the stability of the briquette raw materials, binders can be added or the moisture content can be adjusted, and the particle size distribution and ratio of the S source and recycled raw materials can be adjusted. As binders, fine powder raw materials processed in the flash smelting furnace and byproducts such as powders or liquids generated during various processes in the smelting furnace can be used. Furthermore, to improve the stability of the briquette raw materials, processes such as high-temperature treatment in an inert atmosphere or sintering can be included.

[0039] Example

[0040] (Example 1)

[0041] like Figure 5 As shown, matte 52 is pre-filled into a quartz Tammann crucible 51, which is then fixed within an alumina crucible. Next, the alumina crucible is placed in an electric furnace, and the temperature of the molten matte is raised to 1250°C. Next, metallic Cu 53 is added to the molten matte 52 in an amount exceeding its solubility on the phase diagram, and the mixture is held for 2 minutes. Spherical Cu (100% purity) with a diameter of 5 mm is used as the metallic Cu 53. At this point, the composition of the melt in the quartz Tammann crucible 51 is such that two liquid phases (matte and Cu) coexist.

[0042] Next, in order to form matte from the Cu coexisting in the melt, the material that has been pressurized to a diameter of approximately 300 to 500 mm is subjected to an argon atmosphere. 2 FeS2 reagent 54 with a specific surface area of ​​ / g was added as an S source to the quartz Taman crucible 51 and held for 10 minutes. The FeS2 concentration in the FeS2 reagent 54 used was 87.9% by mass. Next, to prevent Cu precipitation during the cooling process, the alumina crucible with the quartz Taman crucible 51 was removed from the electric furnace and quenched in ice water.

[0043] (Comparative Example)

[0044] In the comparative example, no S source was added. Other conditions were the same as in Example 1.

[0045] (analyze)

[0046] For the Examples 1 and Comparative Examples, the presence or absence of residual Cu phase (metallic Cu) in the quenched sample was observed. The residual Cu phase was evaluated by CT scanning and microscopic observation of the cross section of the sample. The cross section of the sample was observed by polishing a cylindrical sample having a diameter of 17.0 mm in increments of 0.5 mm, and the observation was repeated to confirm the presence or absence of the Cu phase. The evaluation accuracy was improved by using CT in combination.

[0047] The compositions of the 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 content in the matte) of the matte 52 charged into the quartz Tammann crucible 51, the amount of the matte 52 charged into the quartz Tammann crucible 51, the amount of the metallic Cu 53 added to the quartz Tammann crucible 51, the amount of the FeS2 reagent 54 added to the quartz Tammann crucible 51, and the average composition of each component in the quenched sample.

[0048] [Table 1]

[0049]

[0050] [Table 2]

[0051]

[0052] Figure 6 (a) is a photograph of the results of the Comparative Example. Figure 6 (b) is a photograph of the results of Example 1. As Figure 6 (a) shows, the Cu phase was observed in the sample of the Comparative Example, but as Figure 6 (b) shows, the Cu phase was not observed in the sample of Example 1. In Figure 6 (a), the small circles under the black circle are the Cu phase. In Figure 6 Figure 6 (b), it shows that the Cu phase is dissolved into the matte. From this result, it was confirmed that even if the metallic Cu is present in an amount exceeding the solubility on the phase diagram, the metallic Cu can be dissolved into the matte by adding the S source.

[0053] The solubility of the metallic Cu in the matte phase was investigated using the sample of the Comparative Example. It was confirmed that the measured solubility generally corresponds to the phase diagram.

[0054] (Examples 2 and 3)

[0055] Next, the contribution of the FeS2 reagent 54 is examined. Example 2 is an example in which it is assumed that 70 mass% of S contained in the FeS2 reagent 54 contributes to the formation of matte with respect to the metal Cu, and the FeS2 reagent 54 is supplied in a larger amount than the amount of FeS2 reagent 54 that would result in all of the amount of the metal Cu becoming matte. Example 3 is an example in which it is assumed that 90 mass% of S contained in the FeS2 reagent 54 contributes to the formation of matte with respect to the metal Cu, and the FeS2 reagent 54 is supplied in a larger amount than the amount of FeS2 reagent 54 that would result in all of the amount of the metal Cu becoming matte.

[0056] Table 3 shows the matte grade (copper content in matte) of the matte 52 charged in the quartz Tammann crucible 51, the amount of the matte 52 charged in the quartz Tammann crucible 51, the amount of the metal Cu 53 added to the quartz Tammann crucible 51, the amount of the FeS2 reagent 54 added to the quartz Tammann crucible 51, and the average composition of the quenched sample.

[0057] [Table 3]

[0058]

[0059] In Example 3, the amount of the Cu phase is smaller than in the comparative example. From this result, it is confirmed that, assuming that 90 mass% of S contained in the FeS2 reagent 54 contributes to the formation of matte with respect to the metal Cu, the generation of the metal Cu is suppressed by adding the FeS2 in an amount equal to or greater than the amount that promotes the formation of matte with respect to all of the metal Cu. In Example 2, the Cu phase was not observed. From these results, it is concluded that, assuming that 100 mass% of the total S contained in the FeS2 reagent 54 and 70 mass% of S contributes to the formation of matte with respect to the metal Cu, it is preferable to supply the FeS2 reagent 54 in an amount equal to or greater than the amount that promotes the formation of matte with respect to all of the amount of the metal Cu.

[0060] While embodiments of the present application have been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the scope of the present application.

Claims

1. A method of operating a copper smelting process, characterized by The operation method includes: adding a S source to matte generated by reaction of a smelting feed containing a copper concentrate and a metal-Cu-containing raw material with a reaction gas in a reaction shaft of a flash smelting furnace, when a metal phase of metal Cu is formed in the matte.

2. The operation method of copper smelting according to claim 1, characterized in that adding the S source to the matte when the metal Cu is contained in the smelting feed in an amount exceeding its solubility in the matte.

3. The operation method of copper smelting according to claim 1, characterized in that adding the S source to the matte when a metal phase of the metal Cu is observed in the matte by sampling the matte.

4. The operation method of copper smelting according to claim 1, characterized in that adding the S source to the matte by mixing the S source with the smelting feed.

5. The operation method according to claim 1, characterized in that adding the S source to the matte by injecting the S source from an injection nozzle toward the matte together with an inert gas.

6. The method of operating a copper smelting as claimed in claim 1, characterized in that, adding the S source to the matte in the form of a briquette.

7. The operation method according to claim 1, characterized in that mixing the S source with other smelting feed to form a briquette, and then adding the briquette to the matte.

8. The operation method of copper smelting according to claim 7, characterized in that adjusting the specific gravity of the briquette when the S source is mixed with the other smelting feed to form a briquette.

9. The operation method according to claim 1, characterized in that mixing the S source with a recycled raw material or other smelting feed to form a briquette, thereby increasing the processing amount of recycled raw material.

10. The operation method according to claim 1, characterized in that The specific surface area of the S source is 20 mm 2 / g or more.

11. The operation method according to claim 1, characterized in that supplying the S source to the matte in an amount sufficient to convert the metal Cu completely into matte.

12. The operation method according to claim 1, characterized in that when the total amount of S contained in the S source is 100 mass%, and assuming that 90 mass% of S contributes to matte formation of the metal Cu, supplying the S source to the matte in an amount sufficient to convert the entire amount of the metal Cu into matte.

13. The operation method according to claim 1, characterized in that the S source includes elemental sulfur or a sulfide.

14. The operation method according to claim 1, characterized in that the S source contains Fe.

15. The operation method according to claim 14, characterized in that the S source containing Fe is chalcopyrite, pyrite, or pyrrhotite.

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