JP5641952B2 - Copper concentrate processing method - Google Patents

Description

  The present invention relates to a method for treating copper concentrate.

Copper ore produced in copper mines is mainly sulfide ore. Roughly categorizing sulfide ores, relatively high copper grade secondary sulfide ores, mainly composed of minerals such as chalcocite (Cu ₂ S) and copper indigo (CuS), and the first generation mainly composed of chalcopyrite (CuFeS ₂ ) Divided into sulfide ores. In recent years, copper ores collected at copper mines are mainly the latter. As a result, impurities such as iron and sulfur increase, and the copper quality tends to decrease. This causes factors such as a decline in the copper quality of copper concentrate produced for copper smelting in the mine and an increase in iron and sulfur content.

  In general, after refining copper concentrate, copper is recovered as product electrolytic copper, iron is recovered as slag, and sulfur is recovered as sulfuric acid. The recent reduction in the quality of copper concentrate causes an increase in production costs in the copper smelting process. Furthermore, in the domestic copper smelting industry, the supply and demand of slag and sulfuric acid generated by copper smelting has been affected, and many are directed to unprofitable exports, putting pressure on business profits. If the copper grade of copper concentrate further declines in the future, these slag and sulfuric acid problems will become prominent, and it is thought that this will affect the business continuity.

One means for solving these problems is the application of a copper concentrate pretreatment method. In the pretreatment method, copper concentrate particles mainly composed of chalcopyrite (CuFeS ₂ ) are reacted with sulfur (S) at a predetermined temperature, and refined composed of copper indigo (CuS) and pyrite (FeS ₂ ). It is a process of sulfidizing into mineral particles. This sulfide conversion reaction is known as a pretreatment method for wet smelting in the sense that chalcopyrite, which is difficult to be leached, becomes a relatively easy leaching form. This is a process that is not widely used from the viewpoint.

  As another means for solving the above problem, there is a method of selecting copper indigo and pyrite after sulfur conversion reaction with sulfur and subjecting them to dry smelting as a high copper grade concentrate mainly composed of copper indigo (for example, Patent Document 1). reference). In Patent Document 1, selection of copper indigo and pyrite can be performed by an electrostatic method, a gravitational method, a magnetic method, a wind method, a particle size method, a hydrocyclone method, a flotation process, or a combination thereof. It is disclosed.

International Publication No. 2008/074805

  However, Patent Document 1 does not describe a specific method for selecting copper indigo and pyrite.

  An object of this invention is to provide the processing method of the copper concentrate which can collect | recover copper concentrate with low Fe quality efficiently and economically in view of said subject.

Method of processing copper concentrate according to the present invention, to concentrate particles mainly composed of chalcopyrite (CuFeS _2), from 1.0 sulfur (S) with respect to copper in the concentrate particles 1.2 was added at a molar ratio, by reaction with the sulfur (S), the concentrate particles, sulfide conversion step of converting covellite the (CuS) and pyrite (FeS ₂₎ sulfide concentrate particles mainly , A milling process in which the 50% particle diameter is 30 μm to 50 μm, and a difference in particle diameter and specific gravity with respect to the milled concentrate particles obtained in the milling process. And a separation step of separating into fine grains with high Cu quality and coarse grains with high Fe quality. In the copper concentrate processing method according to the present invention, a copper concentrate having a low Fe quality can be efficiently and economically recovered.

  The sulfur conversion step may be performed at 400 ° C to 450 ° C. In the separation step, the fine particles having a 50% particle diameter of 5 μm to 15 μm and the coarse particles having a 50% particle diameter of 35 μm to 55 μm may be separated. In the grinding process, a wet pulverizer or a dry pulverizer may be used. In the grinding process, a ball mill, a jet mill, an attrition mill, a tube mill, or a combination thereof may be used.

  In the sorting process, a table sorter, a centrifugal classifier, an inertia classifier, a gravity classifier, or a combination thereof may be used. The grinding step and the separation step may be performed again on the coarse particles obtained in the separation step. The fine grains and coarse grains obtained in the separation step may be subjected to floating beneficiation as they are or after grinding and grinding.

  ADVANTAGE OF THE INVENTION According to this invention, the processing method of the copper concentrate which can collect | recover copper concentrate with low Fe quality efficiently and economically can be provided.

It is process drawing which shows an example of the processing method of the copper concentrate which concerns on embodiment. It is a concentrate particle obtained by mapping copper indigo and pyrite identified by electron beam microanalyzer. It is a schematic diagram which shows an example of a table sorter. It is process drawing which shows the processing method of the copper concentrate which concerns on Example 1. FIG. It is a figure which shows the analysis result by XRD. It is a figure which shows the particle size distribution after a grinding process. It is a figure which shows the particle size distribution measurement result of a fine grain with high Cu quality. It is a figure which shows the particle size distribution measurement result of the coarse grain with high Fe quality. It is a figure which shows the XRD analysis result of a fine grain with high Cu quality. It is a figure which shows the XRD analysis result of the coarse grain with high Fe quality. It is process drawing which shows the processing method of the copper concentrate which concerns on Example 2. FIG. It is a figure which shows the particle size distribution after a grinding process. It is process drawing which shows the processing method of the copper concentrate which concerns on a comparative example. It is a figure which shows the particle size distribution after a grinding process.

  Hereinafter, an embodiment for carrying out the present invention will be described.

(Embodiment)
This embodiment separates copper indigo and pyrite by milling the copper concentrate particles that have undergone sulfidation conversion, and collects copper concentrate mainly composed of low-quality Fe indigo to contain copper concentrate. The amount of iron and sulfur produced is reduced, the cost of the copper smelting process is reduced, and the business profitability is improved by reducing the generation of slag and sulfuric acid.

The target processed product according to the present embodiment is copper concentrate. In particular, it is a copper concentrate mainly composed of chalcopyrite (CuFeS ₂ ). Copper concentrate mainly composed of chalcopyrite contains 25 wt% to 40 wt% copper and 20 wt% to 35 wt% iron. Such chalcopyrite contains a large amount of iron and thus generates a large amount of slag in the smelting process.

  FIG. 1 is a process diagram showing an example of a copper concentrate processing method according to this embodiment. With reference to FIG. 1, first, a sulfidation conversion step is performed on copper concentrate. For example, sulfur (S) is added at a molar ratio of 1.0 to 1.2 with respect to copper (Cu) in the copper concentrate. As an example, sulfur is added in the form of elemental sulfur and mixed well. The mixed processed material is subjected to heat treatment at a predetermined temperature and a predetermined time in an inert atmosphere. This heat treatment can be performed using, for example, a rotary kiln. For example, nitrogen gas can be used as the inert atmosphere. Moreover, it is preferable that heat processing time shall be 30 minutes-60 minutes. This is because the remaining amount of unreacted chalcopyrite can be reduced.

The heat treatment temperature is preferably 400 ° C to 450 ° C. For example, when the sulfide conversion process is performed at 350 ° C. or 375 ° C. below 400 ° C., the remaining amount of chalcopyrite (CuFeS ₂ ), which is the main compound contained in the copper concentrate before the sulfide conversion, increases, so It is not suitable for this process of separating Cu and Fe as pyrite. Further, when the treatment is performed at a temperature higher than 450 ° C., the state of copper indigo becomes unstable, and Bornite (Cu ₅ FeS ₄ ), Nukundamite ((Cu, Fe) ₄ S ₄ ), and the like are generated, so that Cu and Fe Is difficult to separate. Therefore, the heat treatment temperature is preferably 400 ° C to 450 ° C.

  As a result of the heat treatment, sulfide concentrate particles composed of copper indigo and pyrite are obtained. This sulfide concentrate particle has pyrite as an inner shell, and is composed of pyrite covered with copper indigo as an outer shell. FIG. 2 shows sulfide concentrate particles obtained by mapping copper indigo and pyrite identified by an electron beam microanalyzer (EPMA). Referring to FIG. 2, light gray pyrite covers dark gray copper indigo. In order to mainly recover copper indigo from such sulfide concentrate particles, it is necessary to separate each sulfide concentrate particle into copper indigo and pyrite.

  Therefore, referring to FIG. 1 again, the grinding process is performed on the concentrate particles that have undergone the sulfide conversion process. In order to select copper indigo and pyrite on the basis of the difference in specific gravity and particle size, it is desirable to leave the inner shell pyrite without breaking while peeling off the outer shell copper indigo. Excessive milling will refine pyrite, so there is an optimum range of milling conditions.

  In milling conditions where the outer shell copper indigo can be peeled off while leaving the inner shell pyrite intact, the copper indigo is stripped with a particle size of about 2 μm to 20 μm. The particle diameter is about 30 μm to 70 μm. As a result of intensive studies and investigations by the present inventors, in order to realize the above particle size range, the particle size suitable for separating copper indigo existing in the outer shell by grinding and sorting with a table sorter is 50 % Particle size was found to be 30-50 μm.

  In the milling process, a wet pulverizer or a dry pulverizer can be used. As a pulverizer, for example, a ball mill, a jet mill, an attrition mill, a tube mill or the like can be used. Any type can be used as long as it can be pulverized to a 50% particle size of about 30 μm to 50 μm. However, a pulverizer capable of scraping copper indigo present in the outer shell and preserving pyrite existing inside in a coarse state is preferable.

  Next, the concentrate particles obtained in the milling process are subjected to a sorting process based on the difference in particle diameter and specific gravity, and separated into fine grains having high Cu quality and coarse grains having high Fe quality. In the sorting process, a table sorter, a centrifugal classifier, an inertia classifier, a gravity classifier, or a combination thereof can be used. Since the table sorter has a mechanically simple structure and low wear, it is advantageous compared to other sorters in terms of maintenance and operation costs, and provides good sorting results. Can be easily obtained. Therefore, it is preferable to use a table sorter.

  FIG. 3 is a schematic top view showing an example of a table sorter. A table sorter is an apparatus that separates an object based on a particle size difference and a specific gravity difference. The slurry of concentrate particles after milling put on the table surface is sorted into large and small particles by the rocking motion of the table surface, and sorted into large and small specific gravity by the shower water flow. Is done. In the example of FIG. 3, those having a small specific gravity and a large particle diameter are collected at the collection position 1, and those having a large specific gravity and a large particle diameter and those having a small specific gravity and a small particle diameter are collected at the collection position 2. In general, an object having an intermediate characteristic between the collection position 1 and the collection position 3 is collected. However, the characteristics of the particles collected at the collection position vary depending on the particle diameter of the particles forming the slurry, the conditions of the shower water flow, and the like. For example, particles having a particle diameter of several μm are often collected at the collection position 1 regardless of the specific gravity difference because they easily accompany the water flow.

  Since the pyrite particles cover the pyrite particles in the sulfide concentrate particles obtained in the sulfide conversion step, the particle size of the copper indigo obtained in the grinding step is relatively small, and the particle size of the pyrite is relatively large. Moreover, the specific gravity of copper indigo is relatively small and the specific gravity of pyrite is relatively large. Therefore, by separating into fine grains and coarse grains through a sorting process using a sorter, fine grains with high Cu quality (particles with a high copper indigo ratio and low Fe grade) and coarse grains with high Fe grade ( Particles with a high pyrite ratio). For example, the 50% particle diameter of fine grains with high Cu quality to be separated and recovered is preferably 5 μm to 15 μm, and the 50% particle diameter of coarse grains with high Fe quality is preferably 35 μm to 55 μm.

  Next, fine grains with high Cu quality are recovered as a selected concentrate. By using this selected concentrate as a copper smelting raw material, copper smelting with a small amount of slag generation can be performed. On the other hand, coarse grains with high Fe quality are recovered as a selected tailing. It should be noted that fine grains having high Cu quality can be recovered by performing the grinding process, the sorting process and the separation process again on the sorted tailings.

  In addition, Cu and Fe are concentrated to the selected concentrate and the selected tailings respectively by using the fine grains having high Cu quality and the coarse grains having high Fe quality as they are or after grinding and pulverizing them, and then subjecting them to floatation. Can do.

  According to this embodiment, copper concentrate with low Fe quality can be recovered efficiently and economically.

  Examples based on the above embodiment will be described below.

(Example 1)
FIG. 4 is a process diagram illustrating the copper concentrate processing method according to the first embodiment. Copper concentrate mainly composed of chalcopyrite (Cu grade = 34 wt%, Fe grade = 24 wt%) and elemental sulfur are mixed at a molar ratio of Cu: sulfur = 1.0: 1.2 in a copper concentrate, and in a nitrogen atmosphere The pyrite was converted to copper indigo and pyrite by heat treatment at 425 ° C. for 60 minutes. As can be seen from the results of XRD analysis in FIG. 5, copper indigo and pyrite are formed after sulfidation conversion.

  Next, the copper concentrate (Cu grade = 30 wt%, Fe grade = 21 wt%) converted to copper indigo and pyrite was milled by a wet ball mill to obtain a mill concentrate showing the particle size distribution of FIG. . The slurry concentration at this time was 30 wt%, the grinding time was 30 minutes, and the 50% particle size was 42 μm.

  This fine ore concentrate was screened by a table sorter (first time) and sorted into fine grains and coarse grains, and then the sorted coarse grains were sorted again by a table sorter (second time). The coarse particles recovered by the second sorting were ground again by a wet ball mill, and the third sorting was performed by a table sorter. Sorting was carried out with the stroke of the sorter being 15 mm and the rotational speed of the transmission being 357 rpm.

  7 and FIG. 8 show the results of particle size distribution measurement of fine grains with high Cu quality (collected at collection position 1 in FIG. 3) obtained by sorting and separation, and coarse grains with high Fe quality (collection position in FIG. 3). 3 is a particle size distribution measurement result. FIG. 9 and FIG. 10 show the XRD analysis results of fine grains with high Cu quality obtained by selective separation and the XRD analysis results of coarse grains with high quality of Fe, respectively.

  Next, each sample collected and collected by the above table sorter is divided into three groups: high Cu grade sample (sorted concentrate), high Fe grade sample (sorted tailings), and other (intermediate concentrate). The weight ratio (wt%), Cu recovery rate (wt%), Cu quality (wt%), and Fe quality (wt%) of each group when divided and mixed were investigated. Table 1 shows the results.

  The selected concentrate was higher in Cu quality and lower in Fe quality compared to the original concentrate after sulfidation conversion (Cu quality = 30 wt%, Fe quality = 21 wt%). Further, compared to the original concentrate before sulfidation conversion (Cu grade = 34 wt%, Fe grade = 24 wt%), the selected concentrate has a Fe grade lower by 5.8 wt%. For this reason, the concentrate before sulfidation contains Fe: 0.71 with respect to Cu: 1.00 by weight, whereas the sorted concentrate has Cu: 1.00 with respect to weight. Fe is reduced to 0.53, and the amount of slag generated at the smelter can be reduced. The selected tailings have the lowest Cu grade at 16.2% and the highest Fe grade at 33.8%.

  Sorting conditions can be arbitrarily changed according to sorting results, that is, Cu recovery rate and sorted concentrate Cu quality, or processing costs. The intermediate concentrate and the selected tailing can be directly subjected to flotation, or by repeating grinding and multistage selection again, it is possible to concentrate Cu and Fe into concentrate and tailing, respectively.

(Example 2)
FIG. 11 is a process diagram illustrating the copper concentrate processing method according to the second embodiment. The sulfide conversion treatment of the copper concentrate mainly composed of chalcopyrite is the same as that in Example 1. Copper sulfide concentrate (Cu grade = 30 wt%, Fe grade = 21 wt%) converted to copper indigo and pyrite was milled by a wet ball mill to obtain a mill concentrate showing the particle size distribution of FIG. The slurry concentration at this time was 30 wt%, the grinding time was 30 minutes, and the 50% particle size was 45 μm.

  After this ore concentrate is sorted by a table sorter (first time) and sorted into fine and coarse grains, the sorted coarse grains are ground again by a wet ball mill, and the second sort by a table sorter. Carried out. Sorting was carried out with the stroke of the sorter being 15 mm and the rotational speed of the transmission being 357 rpm. The sample quality collected at the time of each sorting is shown in FIG.

  Next, the samples sorted and recovered by the table sorter are samples with high Cu grade (sorted concentrate), samples with high Fe grade (sorted tailings), other 1 (intermediate concentrate 1), and other 2 Investigate the weight ratio (wt%), Cu recovery rate (wt%), Cu grade (wt%), and Fe grade (wt%) of each group when mixed into 4 groups of (Intermediate concentrate 2) did. Table 2 shows the results.

  The selected concentrate was higher in Cu quality and lower in Fe quality compared to the original concentrate after sulfidation conversion (Cu quality = 30 wt%, Fe quality = 21 wt%). Further, the Fe grade is reduced by 5.8 wt% with respect to the original concentrate (Cu grade = 34 wt%, Fe grade = 24 wt%) before sulfidation conversion. From this, the concentrate before conversion contains Fe: 0.71 with respect to Cu: 1.00 by weight ratio, while the selected concentrate contains Fe with respect to Cu: 1.00 by weight ratio. : It is reduced to 0.57, and the amount of slag generated at the smelter can be reduced. Further, the selected tailings have the lowest Cu grade at 15.0% and the highest Fe grade at 36.0%.

(Comparative example)
FIG. 13 is a process diagram showing a copper concentrate treatment method according to a comparative example. The conversion process of the copper concentrate mainly composed of chalcopyrite is the same as in the first and second embodiments. Copper sulfide concentrate (Cu grade = 30 wt%, Fe grade = 20 wt%) converted to copper indigo and pyrite was ground by a jet mill which is a milling machine different from Examples 1 and 2, and the particle size shown in FIG. The ore concentrate showing the distribution was obtained.

  The crushing pressure at this time was 0.5 MPa, and the 50% particle size of the obtained fine ore concentrate particles was 8.0 μm. In the comparative example, grinding was performed under conditions that were smaller than the 50% particle diameter of 40 μm of the milled concentrate particles in Examples 1 and 2. This mill concentrate was sorted (first time) with a table sorter and sorted into fine and coarse grains. Sorting was performed with a table sorter stroke of 15 mm and a transmission speed of 357 rpm. The sample quality collected at the time of each sorting is shown in FIG.

  Next, each sample selected and collected by the table sorter is divided into two groups, a sample with high Cu quality (screened concentrate) and a sample with high Fe quality (screened tailings). The weight ratio (wt%), Cu recovery rate (wt%), Cu quality (wt%), and Fe quality (wt%) were investigated. Table 3 shows the results.

  Compared with the original concentrate (Cu quality = 30 wt%, Fe quality = 21 wt%), the selected concentrate was slightly higher in both Cu quality and Fe quality. As shown in Table 3, the copper recovery rate was as high as 85 wt%. However, compared to the original concentrate before sulfidation conversion (Cu grade = 34 wt%, Fe grade = 24 wt%), the Fe grade is only reduced by 1.9 wt%. In the same manner that Fe: 0.71 is contained with respect to Cu: 1.00, the concentrated concentrate also contains Fe: 0.71 with respect to Cu: 1.00 by weight ratio. , Not very high value. Under this screening condition, it is difficult to further reduce the amount of slag generated at the smelter. The sorted tailings were the lowest in both Cu and Fe grades.

(analysis)
In Examples 1 and 2, the flow shown in FIG. 4 and FIG. 11 (Example 1 after sulfidation conversion, mill 1 → selection 1 → selection 2 → milling 2 → selection 3, and Example 2 shows mill 1 → Although the sorting process was carried out by sorting 1 → milling 2 → sorting 2), almost the same results were obtained with respect to the Cu quality and Cu recovery rate of the final sorted concentrate. In addition, the inventors also performed a screening test in a combined flow of other grinding conditions and screening conditions, but the 50% particle size of the grinding concentrate particles obtained in the first grinding is approximately 30 μm to 50 μm. Thus, it was confirmed that the same sorting result was obtained.

On the other hand, in the comparative example, the 50% particle size of the mill concentrate particles was reduced to about 8.0 μm, so that a good sorting result could not be obtained. This is because the FeS ₂ produced in the inner shell at the time of sulfidation conversion was destroyed due to excessive grinding conditions, and the sorting effect of the table sorter, which is mainly based on the particle size difference, was not obtained. Show.

The 50% particle size of the milling concentrate particles in Examples 1 and 2 is 42 μm and 45 μm, respectively, and the 50% particle size is in the range of 30 μm to 50 μm, but 50% of the milling concentrate particles of the comparative example. The particle diameter is 8 μm, and FeS ₂ in the inner shell is out of the proper range of 30 μm to 50 μm that can remain in a coarse state, and the selection effect cannot be obtained because FeS ₂ is broken down to fine particles It was. When the fine ore concentrate particles exceed the appropriate range of 30% to 50 μm of the 50% particle diameter, for example, in the grinding state where the 50% particle diameter is about 80 μm to 100 μm, the outer shell CuS is not sufficiently peeled off (In a state where no single substance is separated), and the sorting effect is small.

  However, the appropriate range of the 50% particle size of the fine ore concentrate is appropriate in the screening test for conversion particles with a 50% particle size of about 80μm to 150μm after sulfidation conversion of the copper concentrate mainly composed of chalcopyrite. It is a range.

Claims (8)

To the concentrate particles mainly composed of chalcopyrite (CuFeS ₂ ) , sulfur (S) is added at a molar ratio of 1.0 to 1.2 with respect to the copper in the concentrate particles, and the sulfur (S) by reacting, the concentrate particles, sulfide conversion step of converting covellite the (CuS) and pyrite (FeS ₂₎ sulfide concentrate particles mainly,
A milling step of milling the sulfide concentrate particles so that the 50% particle size is 30 μm to 50 μm;
Separation process of separating fine particles with high Cu quality and coarse particles with high Fe quality by sorting the fine concentrate particles obtained in the grinding process based on the difference in particle diameter and specific gravity. And a method for treating a copper concentrate.   The method for treating copper concentrate according to claim 1, wherein the sulfidation conversion step is performed at 400 ° C to 450 ° C.   3. The copper concentrate treatment according to claim 1, wherein in the separation step, the copper concentrate is separated into fine particles having a 50% particle diameter of 5 μm to 15 μm and coarse particles having a 50% particle diameter of 35 μm to 55 μm. Method.   The processing method of copper concentrate according to any one of claims 1 to 3, wherein a wet pulverizer or a dry pulverizer is used in the milling step.   5. The copper concentrate treatment method according to claim 4, wherein a ball mill, a jet mill, an attrition mill, a tube mill, or a combination thereof is used in the grinding step.   In the sorting process, a table sorter, a centrifugal classifier, an inertia classifier, a gravity classifier, or a combination thereof is used. Processing method.   The method for treating copper concentrate according to any one of claims 1 to 6, wherein the grinding step and the separation step are performed again on the coarse particles obtained in the separation step.   The processing of the copper concentrate according to any one of claims 1 to 7, wherein the fine and coarse particles obtained in the separation step are subjected to floatation as they are or after grinding and grinding. Method.

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