Copper smelting operational method

Abstract

To provide a copper smelting operational method that enables the inhibition of metallic Cu phase production while reducing the number of steps.SOLUTION: A copper smelting operational method supplies, within a smelting furnace, metallic Cu to the matte produced from copper concentrate under conditions where the addition amount is below the solubility of metallic Cu in the matte; and extracts the matte from the smelting furnace within 30 minutes.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 fed from a concentrate burner together with smelting raw materials such as copper concentrate and solvent. The copper concentrate undergoes an oxidation reaction due to 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] JP 2002-363659 A [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 ratio of recycled raw materials as smelting raw materials has been increasing. However, recycled raw materials may contain metallic Cu. As the amount of recycled raw materials processed increases, the ratio of metallic Cu supplied to smelting furnaces such as flash smelting furnaces increases. When the amount of metallic Cu supplied to a smelting furnace increases and exceeds the solubility of metallic Cu in matte, three phases, slag, matte, and metal, coexist in the furnace. When metal accumulates at the bottom of a smelting furnace, it promotes the concentration of impurity elements in the metal phase, the penetration of low-melting-point metal into the joints of the hearth bricks, and the impregnation of the bricks themselves, increasing the risk of molten metal leaking from the bottom of the hearth. In addition, when the amount of metal exceeds a certain amount and reaches the matte tap hole level, metal is suddenly discharged from the matte hole, which may cause the risk of melting the metal matte trough, and may also cause operations to be disrupted by the supply of high-impurity metal to the converter.

[0005] One possible solution to this problem is to perform a pretreatment such as pulverizing metallic Cu to suppress the formation of the metal phase. However, this pretreatment increases the number of steps and requires energy for pulverization.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a copper smelting operation method that can suppress the formation of metallic Cu phase while reducing the number of steps. [Means for solving the problem]

[0007] The copper smelting operation method according to the present invention is characterized in that metallic Cu is supplied to matte produced from copper concentrate in a smelting furnace in an amount equal to or less than the solubility of metallic Cu in the matte, and the matte is discharged from the smelting furnace within 30 minutes.

[0008] Another operating method of copper smelting according to the present invention involves calculating the time required to melt each piece of metallic Cu to be charged into a smelting furnace by dividing the weight of each piece of metallic Cu by a melting rate, assuming a melting rate of 0.05 to 0.3 g / min, under the condition that the amount of metallic Cu added is equal to or less than the solubility of the metallic Cu in matte produced from copper concentrate, and calculating the meltable time as the time from when the metallic Cu is charged into the molten metal of the smelting furnace to when it is discharged out of the furnace, and adjusting the weight of each piece of metallic Cu so that the meltable time exceeds the required melting time.

[0009] Another copper smelting operation method according to the present invention is characterized in that metallic Cu is supplied to matte generated from copper concentrate in a smelting furnace in an amount equal to or less than the solubility of metallic Cu in the matte, and the metallic Cu is contained in recycled raw materials, and includes sieved raw materials sieved to a predetermined particle size after incineration treatment.

[0010] Another copper smelting operation method according to the present invention is characterized in that metallic Cu is supplied to a matte generated from copper concentrate in a smelting furnace under the condition that the amount of metallic Cu added is equal to or less than the solubility of metallic Cu in the matte, the metallic Cu is contained in a recycled material, and the recycled material includes particles having a particle size of 20 mm or more. The recycled material may be supplied to the matte without sorting a plurality of raw material solids by particle size. A plurality of raw material solids may be sorted by particle size, and the sieved material may be supplied to the matte as the recycled material. The recycled material may be supplied to the matte without at least one of crushing, cutting, and incineration. The recycled material may include sieved material sieved to a predetermined particle size after incineration. The recycled material may be used as a raw material for a smelting furnace without sorting by particle size after incineration.

[0011] In the copper smelting operation method, the amount of metallic Cu supplied to the matte may be equal to or less than 98 mass% of the solubility of the metallic Cu in the matte. The amount of metallic Cu supplied to the matte may be equal to or more than 70 mass% of the solubility of the metallic Cu in the matte. Effect of the Invention

[0012] According to the present invention, it is possible to provide a copper smelting operation method capable of suppressing the formation of a metallic Cu phase while reducing the number of steps. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a flash furnace for copper smelting according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating the details of a concentrate burner 4. [Diagram 3] FIG. 2 is a phase diagram showing the solubility of Cu in the matte. [Figure 4] FIG. 2 is a diagram illustrating an injection nozzle. [Diagram 5] FIG. 1 illustrates an experimental setup. [Figure 6] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] (Embodiment) FIG. 1 is a diagram showing 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 reaction main blast gas, a reaction auxiliary gas, and a dispersion gas (which also contributes to the reaction) into the reaction shaft 1 together with copper concentrate, solvent, recycled raw materials, etc. (hereinafter, these solid raw materials are referred to as smelting raw materials). For example, the reaction main blast gas and the reaction auxiliary gas are oxygen-enriched air, and the dispersion gas is air or oxygen-enriched air.

[0015] FIG. 2 is a diagram illustrating the details of the concentrate burner 4, and is an explanatory diagram showing the input section 10 that inputs the smelting raw material, the main reaction blast gas, the auxiliary reaction gas, and the dispersion gas into the reaction shaft 1.

[0016] The input section 10 of the concentrate burner 4 is provided with a lance 16, and a first passage 11 through which the dispersion gas passes and a fourth passage 14 through which the reaction auxiliary gas passes are formed in the lance 16. 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 is also provided with a second passage 12 as a raw material flow path provided on the outside of the lance 16, more specifically on the outer periphery of the lance 16. The input section 10 further includes a third passage 13 provided on the outside of the second passage 12, more specifically on the outer periphery of the second passage 12, through which the reaction main blast gas passes. The third passage 13 is formed by a tubular portion provided so as 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.

[0017] 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 blast 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.

[0018] 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 side portion 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 provided so that the gas is discharged in the normal direction to the bottom circle of the dispersion cone 15.

[0019] When the 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 separates into matte 5 and 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 matte 5, and FeO·SiO2 corresponds to the main component of slag 6. Silica ore is used as the solvent. CuFeS2+SiO2+O2→Cu2S·FeS+FeO·SiO2+SO2+ Reaction heat (1)

[0020] The recycled raw material may contain metallic Cu. If the amount of metallic Cu is small, the metallic Cu is sulfidized and becomes matte 5 during the process of falling from the concentrate burner 4. Therefore, no metal phase is generated.

[0021] However, as the amount of recycled raw materials processed increases, the proportion of metallic Cu in the smelting raw materials tends to increase. In recent years, the proportion of metallic Cu in the Cu component of the smelting raw materials may be 5 mass% or more and 16 mass% or less, or 5 mass% or more and 13 mass% or less, or 5 mass% or more and 8 mass% or less.

[0022] When the ratio of metallic Cu in the smelting raw material becomes high, metallic Cu is not completely sulfidized during the process of falling from the concentrate burner 4 and falls as metallic Cu. Although 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 the matte. "matte(l)+Cu(l)" indicates the range in which metallic Cu cannot dissolve in the matte and a metal phase is generated. The phase diagram in Figure 3 is based on "Takazaietsu, Yazawa Akira, 1983 Selection Research Report".

[0023] Therefore, it is considered that the metallic Cu particle size can be reduced by, for example, pulverizing the recycled raw material as a pretreatment, to promote matting of the metallic Cu in the process of dropping from the concentrate burner 4, and reduce the generation of the metal phase in the settler 2. However, matting is affected by the passing atmosphere in the process of dropping from the concentrate burner 4, and even if the metallic Cu is pulverized, the reaction does not necessarily proceed. In addition, when the pretreatment is performed, the number of steps is increased and energy required for pulverization is required. According to the intensive research of the present inventors, it has been found that when the supply amount of metallic Cu is equal to or less than the solubility in the matte 5, the generation of the metal phase is suppressed even if metallic Cu with a large particle size is used, and metallic Cu can be dissolved in the matte 5.

[0024] Specifically, it has been found that, when the supply amount of metallic Cu is equal to or less than the solubility in matte 5, even if the particle size of metallic Cu is large, metallic Cu can be dissolved in matte 5 within 30 minutes after metallic Cu is supplied to matte 5. Therefore, in this embodiment, the matte 5 is extracted to the outside from the flash smelting furnace 100 within 30 minutes after metallic Cu is supplied to the matte 5, and is subjected to the next process.

[0025] From the viewpoint of sufficiently dissolving the metallic Cu in the matte 5, it is preferable to allow the metallic Cu to remain sufficiently in the matte 5. In this embodiment, it is preferable to discharge the matte 5 from the flash smelting furnace 100 to the outside after 10 minutes or more have elapsed since the metallic Cu was supplied to the matte 5, and it is more preferable to discharge the matte 5 from the flash smelting furnace 100 to the outside after 20 minutes or more have elapsed.

[0026] From the viewpoint of sufficiently dissolving metallic Cu in mat 5, it is preferable to pay attention to the dissolution rate. Specifically, under the condition that the supply amount of metallic Cu is equal to or less than the solubility in mat 5, the time required to dissolve each piece of metallic Cu charged into mat 5 is calculated by dividing the weight of each piece of metallic Cu by the dissolution rate assuming that the dissolution rate is 0.05 to 0.3 g / min, and the time from when the metallic Cu is charged into mat 5 until it is discharged out of the furnace is calculated as the dissolvable time, and it is preferable to adjust the weight of each piece of metallic Cu so that the dissolvable time exceeds the required dissolution time. In this way, metallic Cu can be sufficiently dissolved in mat 5.

[0027] Even if the particle size of metallic Cu is large, as long as the supply amount of metallic Cu is equal to or less than the solubility in mat 5, metallic Cu can be sufficiently dissolved in mat 5. Therefore, under the condition that the supply amount of metallic Cu is equal to or less than the solubility in mat 5, metallic Cu is contained in the recycled raw material, and the recycled raw material is preferably supplied to mat 5 in a state including particles having a particle size of 20 mm or more. Note that the particle size here means the major axis of the triaxial diameter. The recycled raw material may be supplied to mat 5 without sorting the multiple raw material solids by particle size. Alternatively, multiple raw material solids may be sorted by particle size, and the raw material on the sieve may be supplied to the mat as the recycled raw material.

[0028] For example, when the supply amount of metallic Cu is less than the solubility in matte 5, the specific surface area is 452 mm 2 / g or less to the mat 5, the generation of the metal phase can be suppressed. In this case, pretreatment such as pulverization of the recycled raw material can be omitted, so that the number of steps can be reduced.

[0029] The smaller the specific surface area of ​​metallic Cu, the wider the permissible range of the particle size of metallic Cu becomes, and the less need there is for fine pulverization of the recycled raw material. 2 / g or less is more preferable, and 300 mm 2 It is more preferable that the molecular weight is not more than 1 / g.

[0030] On the other hand, if the specific surface area of ​​the metallic Cu is too small, the particle size of the metallic Cu becomes large, and there is a risk that the metallic Cu cannot be dissolved in the mat 5. Therefore, it is preferable to set a lower limit for the specific surface area of ​​the metallic Cu. In this embodiment, the specific surface area of ​​the metallic Cu is 133 mm 2 / g or more, and 150 mm 2 / g or more is more preferable, and 200 mm 2 It is more preferable that the molecular weight is 1 / g or more.

[0031] From the viewpoint of suppressing the generation of a metal phase, it is preferable to set the supply amount of metallic Cu to be less than the solubility limit in the mat 5. In this embodiment, the supply amount of metallic Cu to the mat 5 is preferably set to be equal to or less than an amount equivalent to 100 mass% of the solubility of metallic Cu in the mat 5, more preferably equal to or less than an amount equivalent to 98 mass%, and even more preferably equal to or less than an amount equivalent to 90 mass%.

[0032] On the other hand, if the supply amount of metallic Cu is too small, the processing amount of the recycled raw material will be reduced. Therefore, it is preferable to set a lower limit on the supply amount of metallic Cu. In this embodiment, the supply amount of metallic Cu to the mat 5 is preferably equal to or more than an amount corresponding to 70 mass% of the solubility of metallic Cu in the mat 5, more preferably equal to or more than an amount corresponding to 90 mass%, and even more preferably equal to or more than an amount corresponding to 95 mass%.

[0033] The method of supplying metallic Cu to the mat 5 is not particularly limited. For example, as described above, recycled raw materials may be mixed with the smelting raw materials. In this case, the recycled raw materials are trapped by droplets generated by the reaction of the copper concentrate with the reactive gas. Therefore, even if the specific gravity of the recycled raw materials is small, 5.0 or less, metallic Cu can reach the mat 5.

[0034] Alternatively, as shown in FIG. 4, an injection nozzle 40 may be provided on the reaction shaft 1, and the recycled raw material may be injected into the reaction shaft 1 from the injection nozzle 40. In this case, even if the specific gravity of the recycled raw material is small, such as 5.0 or less, the metallic Cu can reach the matte 5. For example, in order to allow the recycled raw material to penetrate the slag 6 and reach the matte 5, it is preferable to set a lower limit on the injection speed.

[0035] The matte 5 is fed to a copper smelting furnace in the next process. If the generation of metal phases in the matte 5 is suppressed, there is no need to make any particular adjustments to the operating conditions in the copper smelting furnace.

[0036] Whether or not the supply amount of metallic Cu is equal to or less than the solubility in matte 5 can be determined by sampling the smelting raw material and measuring the composition ratio. Alternatively, it may be determined that the supply amount of metallic Cu is equal to or less than the solubility in matte 5 when sampling the matte 5 of the reaction shaft 1 and no metal phase is confirmed.

[0037] In the above embodiment, a flash smelting furnace has been described as an example of a smelting furnace, but the present invention is not limited thereto. As long as the smelting furnace produces matte mainly composed of copper sulfides from a smelting raw material containing copper concentrate and a raw material containing metallic Cu, the metallic Cu can be dissolved in the matte within 30 minutes after the metallic Cu is supplied to the matte, even if the particle size of the metallic Cu is large, and the metallic Cu can be dissolved in the matte when the amount of metallic Cu supplied is equal to or less than the solubility of the matte, and the generation of a metal phase can be suppressed. EXAMPLES

[0038] Example 1 First, the solubility limit (solubility) of metallic Cu in matte based on the matte composition on the phase diagram was calculated in advance as the weight ratio of matte / metallic Cu. Next, as shown in Fig. 5, matte 52 was filled into a quartz Tammann tube 51, and the quartz Tammann tube 51 was fixed to an alumina crucible. Next, the alumina crucible was set in an electric furnace, and the temperature was raised to a molten metal temperature of 1250°C.

[0039] Next, metallic Cu53 was added to the molten matte at a concentration of 90 mass% or 80 mass% of the limit of Cu solubility on the phase diagram. 2 0.59 g of spherical Cu with a molecular weight of 1 / g was used. The amount of matte was adjusted so that the amount of metallic copper added was 90 mass% or 80 mass% of the solubility limit of Cu. At this time, the solution in the quartz Tammann tube 51 had a uniform matte composition on the boundary line where two liquid phases coexist.

[0040] After being held in the electric furnace for a predetermined time, in order to avoid Cu precipitation during the cooling process, the alumina crucible was removed from the electric furnace and immersed in ice water together with the quartz Tammann tube 51 for rapid cooling. Three holding times in the electric furnace were set: 2 minutes, 5 minutes, and 10 minutes.

[0041] The compositions of the matte 52 and metallic Cu 53 used in the test are shown in Table 1. [Table 1]

[0042] Example 2 In Example 2, metallic Cu53 was used with a purity of 100 mass% and a specific surface area of ​​451 mm 2 The other conditions were the same as in Example 1.

[0043] In Example 2, the retention time in the electric furnace was set to two times: 2 minutes and 10 minutes.

[0044] (analysis) The presence or absence of residual Cu phase (metallic Cu) in the sample after quenching was confirmed for the sample of the embodiment. The residual Cu phase was evaluated by CT scanning and microscopic observation of the sample cross section. The sample cross section was observed by polishing the sample with a diameter of 17.0 mm in 0.5 mm increments and repeating the observation to confirm the presence or absence of Cu phase. The evaluation accuracy was improved by using CT in combination.

[0045] The results are shown in FIG. 6 and Table 2. In Table 2, the residual metallic Cu is the weight of the metallic Cu 53 confirmed in the cross section of the quenched sample. The weight of the residual metallic Cu was obtained by dividing the quenched sample into small pieces, taking out the part with the metal component, removing the excess matte, and measuring the weight. The dissolved amount is the weight of the metallic Cu 53 supplied to the quartz Tammann tube 51 that was dissolved in the matte. As shown in FIG. 6 and Table 2, in Examples 1 and 2, it was confirmed that metallic Cu was dissolved in the matte and the generation of the metal phase was suppressed. In particular, it was confirmed that metallic Cu was dissolved in the matte to such an extent that the metal phase was not confirmed by setting the holding time in the electric furnace to 10 minutes or more. It can be seen from FIG. 6 that the dissolution rate of metallic Cu was high in the initial stage of dissolution, and then, as the dissolution progresses and the dissolution rate approaches the dissolution limit, the dissolution rate becomes smaller. In other words, it is suggested that the dissolution rate of metallic Cu changes depending on the margin for the matte dissolution limit. In Example 2, the amount of metallic Cu dissolved after 2 minutes was 0.40 g. In other words, if a test was performed using 0.40 g of metallic Cu, all of the metallic Cu would have dissolved in 2 minutes. In this case, the dissolution rate of metallic Cu would be 0.2 g / min. On the other hand, if the dissolution rate is calculated in the same manner using the results in which all of the metallic Cu has dissolved after a holding time of 10 minutes, the result is 0.059 g / min. [Table 2]

[0046] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this embodiment and can be modified in various ways without departing from the scope of the present invention. [Explanation of symbols]

[0047] 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 51 Quartz Tammann tube 52 Matt 53 Metallic Cu 100 Flash furnace

Claims

1. A method for operating a copper smelting process, comprising: supplying metallic Cu to matte produced from copper concentrate in a smelting furnace in an amount equal to or less than the solubility of metallic Cu in the matte; and withdrawing the matte from the smelting furnace within 30 minutes.

2. In a smelting furnace, the amount of metallic Cu added is equal to or less than the solubility of metallic Cu in matte produced from copper concentrate. The time required to melt one piece of metallic Cu charged into the smelting furnace is calculated by dividing the weight of one piece of metallic Cu by the melting rate, assuming that the melting rate is 0.05 to 0.3 g / min; The time from when the metallic Cu is charged into the molten metal of the smelting furnace until when it is discharged out of the furnace is calculated as the melting time, A copper smelting operation method, comprising adjusting a weight per piece of the metallic Cu so that the meltable time exceeds the required melting time.

3. In a smelting furnace, metallic Cu is supplied to matte produced from copper concentrate in an amount equal to or less than the solubility of metallic Cu in the matte; The metallic Cu is contained in recycled materials, The method for operating a copper smelter is characterized in that the recycled raw material contains particles having a particle size of 20 mm or more.

4. 4. The copper smelting method according to claim 3, wherein the recycled raw material is supplied to the matte without separating the raw material pieces according to particle size.

5. 4. The copper smelting method according to claim 3, further comprising the steps of: separating a plurality of raw material solids according to particle size; and supplying the raw material on the sieve to the matte as the recycled raw material.

6. 4. The copper smelting method according to claim 3, wherein the recycled raw material is supplied to the matte without being subjected to at least one of crushing, cutting and incineration.

7. 6. The copper smelting operation method according to claim 5, wherein the recycled raw material includes sieved raw material that has been incinerated and then sieved to a predetermined particle size.

8. 5. The copper smelting method according to claim 4, wherein the recycled raw materials are used as raw materials for a smelting furnace without being screened according to particle size after incineration.

9. 4. The copper smelting operation method according to claim 1, wherein the amount of metallic Cu supplied to the matte is equal to or less than an amount corresponding to a solubility of metallic Cu in the matte of 98 mass %.

10. 4. The copper smelting operation method according to claim 1, wherein the amount of metallic Cu supplied to the matte is equal to or greater than 70 mass% of the solubility of the metallic Cu in the matte.

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