Method for producing granule, granule, and method for operating copper smelting furnace

Abstract

To provide a method for producing a granule, a granule, and a method for operating a copper smelting furnace, which enable stable operation when increasing processing of recycled raw material in a copper smelting furnace.SOLUTION: A method for producing a granule includes mixing a powdery sulfur-containing material with a recycled raw material at a predetermined mixing ratio and applying pressure to yield the granule.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for producing granules, the granules, and a method for operating a copper smelting furnace. [Background technology]

[0002] In a copper smelting furnace, reactant gas is introduced into the furnace along with raw materials such as copper concentrate and solvent from a concentrate burner. The raw materials are oxidized by the reactant gas, producing matte and slag. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-092133 [Patent Document 2] Special Publication No. 51-047410 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the proportion of recycled raw materials as smelting raw materials has been increasing. However, recycled raw materials contain metallic elements, such as Cu, Fe, Sn, Zn, Pb, and Al, present as pure metals or alloys, largely without being oxidized or sulfurized. In the present invention, these elements are defined as metallic components. Therefore, when increasing the throughput of recycled raw materials in a copper smelting furnace, it may be desirable to supply metallic components in excess of their solubility in the matte to avoid a situation in which metallic components coexist in the matte, or to stabilize the Cu content in the matte.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for producing granules, granules, and a method for operating a copper smelting furnace, which enable stable operation when increasing the processing of recycled raw materials in a copper smelting furnace. [Means for solving the problem]

[0006] The method for producing granules according to the present invention involves mixing a powdery sulfur-containing material with a recycled raw material at a predetermined mixing ratio and then pressurizing the mixture to obtain granules. 3 The apparent density (g / cm 3 ) of the granules may be adjusted to be equal to or greater than the density of the slag solution produced in a copper smelting furnace. 3 ) may be adjusted to 3.5 or more. When mixing the sulfur-containing material and the recycled raw material, the moisture content may be adjusted to a predetermined range to obtain the granules, and then the granules may be dried. The moisture content may be 1 mass% or more and 6 mass% or less. The sulfur-containing material may be copper concentrate, and the moisture-containing sulfur-containing material may be mixed with the dried recycled raw material to adjust the moisture content to the predetermined range. The recycled raw material may be obtained by passing it through a sieve with a maximum mesh size of 10 mm or less and leaving the undersized particles.

[0007] The granulated material according to the present invention is a granulated material obtained by mixing a powdery sulfur-containing material with a recycled raw material at a predetermined mixing ratio and pressing the mixture. The specific gravity (g / cm 3 ) may be 3.5 or more. The sulfur-containing material may be copper concentrate. The recycled raw material may be obtained by passing it through a sieve with a maximum mesh size of 10 mm or less as the undersize material.

[0008] In a method for operating a copper smelting furnace according to the present invention, when a recycled material is processed in the copper smelting furnace, a powdered sulfur-containing material is mixed with the recycled material in a predetermined mixing ratio, and the mixture is pressurized to obtain granules, which are then charged into the copper smelting furnace. The sulfur-containing material may be copper concentrate. The granules may be charged into the copper smelting furnace when a metal phase coexists in the matte produced in the copper smelting furnace. The granules may be added when the smelting raw material charged into the copper smelting furnace contains a metallic component in an amount exceeding the solubility in the matte produced in the copper smelting furnace. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing a granulated material, a granulated material, and a method for operating a copper smelting furnace, which are capable of matting a metal phase. [Brief explanation of the drawings]

[0010] [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. 1 illustrates a briquetting machine. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment) FIG. 1 is a diagram showing the schematic configuration of a flash smelting furnace 100, which is the location of a copper smelting furnace. As shown in FIG. 1, the flash smelting furnace 100 includes a reaction shaft 1, a settler 2, and an uptake 3, where concentrate and reaction gas are mixed. A concentrate burner 4 is provided on the ceiling of the reaction shaft 1. The concentrate burner 4 supplies copper concentrate, solvent, recycled raw materials, etc. (hereinafter, these solid raw materials will be referred to as smelting raw materials) into the reaction shaft 1, as well as a main reaction blast gas, an auxiliary reaction gas, and a dispersion gas (which also contributes to the reaction). 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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 (slag solution) 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. Silicate ore is used as the flux. CuFeS2+SiO2+O2 → Cu2S·FeS+FeO·SiO2+SO2+ Reaction heat (1)

[0017] The recycled raw material may contain metallic components. If the amount of metallic components is small, the metallic components are sulfidized to form matte 5 during the process of falling from the concentrate burner 4. Therefore, no metal phase is generated.

[0018] However, as the amount of recycled raw materials processed increases, the proportion of metallic components (metallic Cu as an example) 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. In the following explanation, metallic Cu will be described as an example of a metallic component contained in recycled raw materials, but the same can be applied to other metallic components.

[0019] 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."

[0020] Therefore, it is conceivable to introduce a powdered sulfur-containing material into the reaction shaft 1 to sulfurize the metallic Cu contained in the matte 5 and turn it into matte. However, there is a risk that the powdered sulfur-containing material will be oxidized when introduced into the reaction shaft 1. In addition, there is a risk that the powdered sulfur-containing material will be captured by the slag 6 floating on the matte 5 and will not reach the matte 5. Therefore, it is conceivable to supply the sulfur-containing material by injection using an inert gas as a carrier. However, this method is difficult to operate and has many issues.

[0021] Therefore, in this embodiment, a granulated material obtained from a powdered sulfur-containing material and recycled raw materials is used. By using a granulated material obtained from a sulfur-containing material and recycled raw materials, the specific surface area of ​​the powdered sulfur-containing material in contact with the atmosphere in the reaction shaft 1 is reduced. This reduces oxidation of the sulfur-containing material. Furthermore, by using a granulated material, the sulfur-containing material is more likely to sink in the slag 6 and reach the metallic Cu in the matte 5 than when a powdered sulfur-containing material is used. This facilitates sulfurization of the metallic Cu contained in the matte 5 to form matte. For these reasons, stable operation can be achieved when increasing the amount of recycled raw materials processed in a copper smelting furnace.

[0022] The timing for introducing the granulated material into the reaction shaft 1 is not particularly limited. However, for example, when a metallic Cu phase coexists in the matte 5, it is preferable to introduce the granulated material into the reaction shaft 1.

[0023] The granulated material can be obtained by mixing a powdery sulfur-containing material with a recycled raw material at a predetermined mixing ratio, and then pressing the mixture to form briquettes.

[0024] For example, granulated material can be obtained using a briquetting machine. Fig. 4 is a diagram illustrating a briquetting machine 200. As illustrated in Fig. 4, the briquetting machine 200 includes a hopper 210, a screw 220, and a pair of rolls 230. The sulfur-containing material and recycled raw materials are fed into the hopper 210. The screw 220 is provided within the hopper 210, and by rotating, it forcibly sends the raw materials between the pair of rolls 230.

[0025] Each of the pair of rolls 230 has a substantially cylindrical shape and is rotatable around a cylindrical axis as a rotation axis. The shapes of the pair of rolls 230 are substantially the same. The pair of rolls 230 are arranged so that their rotation axes are parallel and their circumferential surfaces face each other. The rotation axes of the pair of rolls 230 are substantially aligned horizontally. The pair of rolls 230 rotate in opposite directions to each other, thereby sandwiching the sulfur-containing material and recycled raw material sent from the screw 220 between their circumferential surfaces, forming lumps 240 and dropping them. The roll 230 may have a substantially cylindrical shape as a whole by combining multiple segments of the same shape, or may be a single, substantially cylindrical member.

[0026] Alternatively, the sulfur-containing material and the recycled raw material may be mixed, melted, and then agglomerated to obtain a granulated material.

[0027] Examples of powdered sulfur-containing materials include FeS minerals (pyrrhotite), FeS2 minerals (pyrite), CuFeS2 minerals (chalcopyrite), minerals containing FeS·FeS2, and sulfur-containing copper concentrates. When comparing FeS minerals and FeS2 minerals, it is preferable to use FeS2 minerals, which are believed to contain a higher amount of sulfur necessary for matte formation. Alternatively, sulfur-containing tailings generated during the ore-dressing process of nonferrous metal raw materials can be used. For example, tailings generated during the flotation process are an example of sulfur-containing tailings. For example, the sulfur content of powdered sulfur-containing materials is approximately 20 mass% to 55 mass%.

[0028] The recycled raw materials can include copper scrap including chips, dust ash, and scrap electrical components. For example, the average composition of the recycled raw materials is 10 to 95 mass% Cu, 0 to 50 mass% Fe, and 0 to 40 mass% Sn, Zn, Pb, Al, and other elements. The recycled raw materials can be, for example, the undersized material obtained by sieving through a sieve with a maximum mesh size of 10 mm or less.

[0029] The recycled material has a true density (g / cm) greater than that of the sulfur-containing material. 3 ) is preferable. This is because the apparent density of the granulated material increases, making it easier to reach the metallic Cu phase contained in the mat 5. It is preferable to adjust the mixing ratio of the sulfur-containing material and the recycled raw material so that the apparent density of the granulated material is equal to or greater than the density of the slag 6. For example, when the density of the slag 6 is 3.5 (g / cm 3 ), so the apparent density of the granulated material is 3.5 (g / cm 3 ) or more. In addition, the granulated material preferably has a mechanical strength sufficient to prevent it from collapsing while falling inside the reaction shaft 1.

[0030] For example, the apparent density of a briquette made of copper concentrate alone is 3.5 (g / cm 3 ), so copper concentrate and true density is 3.5 (g / cm 3 ) and mixed with recycled raw materials exceeding 3.5 (g / cm 3 ) or more. For example, copper concentrate and a mixture with a true density of 6.3 (g / cm 3 ) recycled raw material in a weight ratio of 1:1.4 and granulated, the apparent density was 3.6 (g / cm 3 ) granules are obtained. Note that true density is the density obtained by excluding the volume of pores present on the surface and inside of an object. Apparent density is the density obtained by excluding only the volume of pores that connect to the surface of an object, but including the volume of internal pores. Apparent density is measured based on the Japan Powder Process Industry and Engineering Association standard SAP02-82 "Method for measuring the apparent density of granules."

[0031] Furthermore, when mixing the sulfur-containing material with the recycled raw material, it is preferable to adjust the moisture content of the mixture to a predetermined range, obtain granules, and then dry the granules. In this case, the mechanical strength of the granules is increased, and the collapse of the granules can be suppressed even when impact occurs when dropping into the molten metal. For example, when mixing the sulfur-containing material with the recycled raw material, it is preferable to adjust the moisture content to 1 mass% or more, obtain granules, and then dry the granules. For example, it is preferable to adjust the moisture content of the granules to a predetermined range by mixing copper concentrate containing moisture with dried recycled raw material.

[0032] On the other hand, when mixing the sulfur-containing material with the recycled raw material, if the water content of the mixture is high, the releasability from the roll 230 of the briquetting machine 200 may be deteriorated, which may result in a decrease in yield. Therefore, it is preferable to set an upper limit on the water content of the mixture. In this embodiment, it is preferable to adjust the water content of the mixture to 6 mass% or less.

[0033] It is also preferable to determine the mixing ratio of the sulfur-containing material and the recycled raw material in the granules so that the amount of sulfur contained in the granules exceeds the amount of sulfur required to matte the entire amount of metallic Cu in the recycled raw material contained in the granules under the conditions in the reaction shaft 1. By doing so, the sulfur contained in the granules can be fully used to matte the metallic Cu contained in the matte 5.

[0034] If the diameter of the granules is small, the surface area of ​​the granules may not be sufficiently small. Therefore, it is preferable to set a lower limit for the average diameter of the granules. On the other hand, if the diameter of the granules is large, the mechanical strength may decrease due to an increase in the weight of the briquette. Therefore, it is preferable to set an upper limit for the average diameter of the granules. In this embodiment, the average diameter of the granules in the major axis direction is preferably 20 mm or more and 50 mm or less, or 20 mm or more and 100 mm or less. [Example]

[0035] The weighed copper concentrate and recycled raw materials were placed in a kneader and mixed. The mixed raw materials were then fed into the hopper of a granulator and briquetted to obtain granules. The apparent density (specific gravity (g / cm)) of the obtained granules was 3 )), drop strength and crushing strength were measured, and the changes in apparent density and mechanical strength of the granules were evaluated.

[0036] Apparent density (g / cm 3 ) was calculated from the change in volume when the granules were submerged in 100 ml of liquid paraffin filled in a measuring cylinder and the mass of the granules. Drop strength was determined by dropping the granules three times onto a stainless steel plate from a height of 2 m and then measuring the percentage of granules remaining on a 9.5 mm sieve. Crushing strength was determined from the load applied when the granules were crushed using a Kiya hardness tester.

[0037] (Comparative Example) True density is 4.7g / cm 3 When granules are made from copper concentrate alone, the apparent density of the granules (g / cm 3 ) is 3.3g / cm 3 That was about it.

[0038] (Example) In contrast, the true density is 4.7 g / cm 3 copper concentrate with a true density of 6.3 g / cm 3 When mixed with recycled raw materials and briquetted, the apparent density (g / cm 3 ) is 3.6, and the apparent density (g / cm 3 ) of 3.8 was obtained, confirming that it is possible to increase the apparent density of the granules by mixing copper concentrate with recycled raw materials.

[0039] Apparent density (g / cm 3Granules with a water content of 3.6 were dropped from the top of a smelting furnace and filmed with a camera. The behavior of the granules was evaluated from the video footage. Because a smelting furnace receives and maintains molten slag produced in a flash smelting furnace for copper smelting, a test was conducted to investigate the settling behavior of the granules relative to the slag and their stability upon contact with high-temperature molten metal. The results confirmed that the granules gradually settled after falling to the slag surface, and that granules with a moisture content of approximately 0 mass% were able to maintain their shape and remain stable upon contact with high-temperature molten metal. On the other hand, for granules with a moisture content of approximately 2 mass%, the rapid evaporation of the water in the granules caused fluctuations in the melt surface and damage to the granules.

[0040] Next, we investigated the effect of the moisture content of the raw material before granulation. When copper concentrate was used as the raw material for briquetting, the drop strength was 77.1 at a moisture content of 3 mass%, 42.6 at a moisture content of 6 mass%, and 16.6 at a moisture content of 9 mass%. Furthermore, when the moisture content was between 0 and 1 mass%, moldability was poor, making briquetting difficult. These results confirmed that it is preferable to adjust the moisture content of the mixture to between 1 and 6 mass%. Furthermore, it was found that drying the granulated material in a dryer at 105°C for at least 20 minutes increased the drop strength by up to two times.

[0041] By mixing undried copper concentrate (moisture content approximately 9 mass%) with dried recycled raw material (moisture content 0 mass%) in the above weight ratio, the moisture content of the mixture falls within a range of 2 mass% to 5 mass%. In other words, when copper concentrate is transported from mines, etc., it is often transported with a moisture content of approximately 10 mass%, so the copper concentrate received at the smelter can be used as is to produce the granulated material of the present invention. Therefore, there is no need for dedicated drying equipment for granulated material, and it is possible to easily adjust the moisture content.

[0042] The above-described embodiment is a preferred example of the present invention. However, the present invention is not limited to this, and various modifications are possible within the scope of the gist of the present invention. In this specification, a case where Cu, which is insoluble in the matte, separates as a metal phase is described, but the present invention can also be applied to cases where other metals may separate as a metal phase in the matte. For example, when recycled raw materials containing a large amount of Fe as a metallic component are fed into a smelting furnace, if there is a possibility that a metal phase of Fe may separate in the matte, the present invention can also be implemented. [Explanation of symbols]

[0043] 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 17 Air Chamber 21 Partition Wall 100 Flash furnace 151 Lower side 152 Supply hole 200 Briquetting Machine 210 Hopper 220 Screw 230 rolls 240 Lumps

Claims

1. A method for producing a granulated material, comprising mixing a powdered sulfur-containing material with a recycled raw material in a predetermined mixing ratio and pressurizing the mixture to obtain a granulated material.

2. The apparent density (g / cm ３ 2. The method for producing granules according to claim 1, wherein the density of the slag melt produced in the copper smelting furnace is adjusted to be equal to or higher than the density of the slag melt produced in the copper smelting furnace.

3. The apparent density (g / cm ３ 2. The method for producing a granulated product according to claim 1, wherein the saturation coefficient (S) is adjusted to 3.5 or more.

4. The method for producing a granulated material according to claim 1, wherein the water content of the sulfur-containing material and the recycled raw material is adjusted to a predetermined range when the granulated material is mixed, and then the granulated material is dried.

5. The method for producing a granulated product according to claim 4, wherein the moisture content is 1 mass% or more and 6 mass% or less.

6. the sulfur-containing material is copper concentrate, 5. The method for producing a granulated material according to claim 4, wherein the moisture content is adjusted to the predetermined range by mixing the sulfur-containing material containing moisture with the dried recycled raw material.

7. The method for producing granulated material according to claim 1, wherein the recycled raw material is obtained by passing it through a sieve having a maximum mesh size of 10 mm or less as an undersize sieve.

8. Granules obtained by mixing powdered sulfur-containing material with recycled raw materials in a specified ratio and pressing the mixture.

9. Apparent density (g / cm ３ 9. The granule according to claim 8, wherein the saturation coefficient (S) is 3.5 or more.

10. The granulated material according to claim 8, wherein the sulfur-containing material is copper concentrate.

11. The granulated material according to claim 8, wherein the recycled raw material is obtained by passing it through a sieve having a maximum mesh size of 10 mm or less as the undersize granules.

12. A method for operating a copper smelting furnace, comprising the steps of: mixing a powdered sulfur-containing material with a recycled raw material in a predetermined mixing ratio; pressurizing the mixture; and charging the resulting granulated material into the copper smelting furnace.

13. 13. The method of operating a copper smelting furnace according to claim 12, wherein the sulfur-containing material is copper concentrate.

14. 13. The method for operating a copper smelting furnace according to claim 12, wherein the granules are introduced into the copper smelting furnace when a metal phase coexists in the matte produced in the copper smelting furnace.

15. 13. The copper smelting operation method according to claim 12, wherein the granules are added when the smelting raw materials charged into the copper smelting furnace contain a metallic component in an amount exceeding the solubility in matte produced in the copper smelting furnace.

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