JP5983443B2 - Copper smelting dust treatment method and copper smelting operation method - Google Patents

Description

  The present invention relates to a method for treating copper smelting dust, and a method for operating copper smelting, and more specifically, from impurities discharged from a copper smelting furnace, impurities components such as zinc, lead, bismuth, and tin that are unnecessary for copper smelting. It is related with the processing method to isolate | separate, and the operation method of the copper smelting to which the method is applied.

  In copper smelting, copper ore is put in a furnace and melted at high temperature. At this time, dust (smoke ash) is generated from the furnace together with waste gas such as sulfur oxide. Dust generated by copper smelting contains impurity components contained in ores such as lead, bismuth, and zinc, and is collected by a dust collector. Further, since dust contains fine copper, it is economically undesirable to dispose of it as it is, and it is common to repeat the dust again in the smelting process to recover copper. .

  However, when the total amount of generated dust is repeatedly processed in the copper smelting system, impurities such as lead, bismuth, and zinc are concentrated and accumulated in the system, and there is a concern that the purity of the product may be finally affected. Therefore, it is desirable that some dust is separated from copper outside the system, and then only copper is returned to the system, and valuable metals are separately collected.

  In particular, for lead and bismuth, for example, as shown in Patent Document 1, dust is leached with water or dilute sulfuric acid to recover soluble salts such as copper and zinc as leachate, while lead that forms insoluble sulfates. And bismuth is fixed as a leaching residue and used as a raw material for lead smelting. By using this method, bismuth and lead can be discharged out of the system, and the impurity load in the copper smelting system can be reduced.

  Further, in order to further reduce the amount of undissolved copper remaining in the above-described leaching residue, for example, as disclosed in Patent Document 2 and Patent Document 3, the leaching residue is subjected to a wet classification process, and the undissolved copper particles There is a case where processing aiming at coarse grain side recovery is performed.

  However, even when the above-described prior art is used, most of the copper in the dust is leached and distributed to the liquid phase when the leaching process is performed, so that the copper in the liquid phase is precipitated by some method and recovered. However, it is necessary to re-enter the copper smelting system after sufficiently drying.

  In the above-described method, the recovered copper needs to be sufficiently dried before being reintroduced into the copper smelting system. The inside of the smelting furnace is hot, and there is a risk of a steam explosion etc. if dust with moisture is put into the furnace carelessly. Further, when the dust becomes irregularly lumped by moisture, there is a possibility of handling and blockage in the process, which is not preferable. For this reason, the apparatus and energy for a drying process are required, and there exists a subject that cost increases very much.

  As described above, no method has been found for dust generated in a copper smelting system that can efficiently discharge impurity components at low cost and effectively reduce copper load to copper smelting by reducing the load of impurities. .

JP-A-4-285136 JP 2006-124828 A JP 2012-71283 A

  Therefore, the present invention provides a copper smelting dust treatment method capable of efficiently separating impurity components such as zinc, lead, bismuth and tin contained in dust generated in copper smelting, and a copper smelting using the treatment method. The purpose is to provide a method of operation.

  The inventors of the present invention have made extensive studies to achieve the above-described object. When the particle size distribution of the copper smelting dust was measured, it had a total of two peak tops, one in the region with a particle size of several tens to several hundreds of μm and one in a region with a particle size of less than 1 μm, and the most particles between the peaks. The inventors found that the point where the number is reduced is present in a region having a particle diameter of 1 to 5 μm and completed the present invention.

That is, in the method for treating copper smelting dust according to the present invention, the dust (copper smelting dust) generated when copper-containing ore is introduced into a smelting furnace and copper is smelted, the classification point is 1 μm in particle size. Using the dry physical separation means set in the range of 5 μm or less, the coarse particles obtained by separating the fine particles below the classification point and the coarse particles exceeding the classification point and separating the fine particles are separated. It is characterized by being repeatedly put into the smelting furnace .

  Here, in the copper smelting dust treatment method described above, the coarse particles obtained by separation can be charged into the smelting furnace.

  Moreover, it is preferable to wash | clean the said fine particle obtained by isolate | separating into a water-soluble substance and a washing | cleaning fine particle.

  Moreover, the said ore can use what contains one or more elements among zinc, lead, bismuth, and tin other than copper.

  Furthermore, the copper smelting operation method according to the present invention is a copper smelting operation method in which an ore containing copper is introduced into a smelting furnace to smelt copper, and dust generated in copper smelting (copper smelting dust) Using a dry physical separation means in which the classification point is set to a particle size in the range of 1 μm to 5 μm, the fine particles below the classification point and the coarse particles exceeding the classification point are separated and obtained by separation. The obtained coarse particles are repeated in the smelting furnace.

  According to the present invention, impurity components in copper smelting such as zinc, lead, bismuth and tin contained in copper smelting dust can be efficiently separated and recovered at low cost without using water. And the copper contained in the dust can be effectively smelted by repeating the dust from which these impurity components are separated and removed in the copper smelting furnace.

It is a photograph figure which shows the surface analysis result by the electron beam microanalyzer (EPMA) of a dust particle cross section. It is a schematic diagram of the EPMA analysis photograph about Cu in FIG. It is a particle size distribution map of copper smelting dust. It is a figure which shows the flow of the processing method of copper smelting dust. It is a figure which shows the processing flow with respect to the impurity concentrate distributed to the fine grain side.

  Hereinafter, a specific embodiment (hereinafter, referred to as “this embodiment”) of a method for treating copper smelting dust (hereinafter, also simply referred to as “dust”) according to the present invention will be described in detail with reference to the drawings. explain. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.

  The method for treating copper smelting dust according to the present embodiment is a method for treating dust (smoke ash) generated in copper smelting by putting copper-containing ore into a smelting furnace and smelting copper. This is a method for separating impurity components in copper smelting such as zinc, lead, bismuth and tin contained in dust.

  Specifically, this copper smelting dust treatment method is a method of dry-classifying dust generated during copper smelting (copper smelting dust) at a predetermined classification point using dry physical separation means, and fine and coarse particles. It is characterized by being separated into

  This treatment method is suitably used for copper smelting dust generated when copper smelting is performed using ore containing one or more elements of zinc, lead, bismuth and tin in addition to copper. be able to. Such copper smelting dust contains impurity components such as zinc, lead, bismuth and tin in addition to copper. The composition of the copper smelting dust is not particularly limited.

  Here, the copper smelting dust will be described from the viewpoint of the generation mechanism. Copper smelting dust generated in copper smelting is caused by volatilization of metals and sulfides having a low vapor pressure, and by splattering of the melt in the smelting furnace. In copper smelting, these copper smelting dust is collected by a dust collector.

Specifically, a component such as zinc, lead, bismuth, or tin that exists in a form having a vapor pressure of a certain level or more is volatilized and then reacts with oxygen or sulfurous acid gas (SO ₂ ) in the exhaust gas. It is cooled and finely granulated, sent to the dust collector as it is, and collected as dust. On the other hand, a part of the melt splash scattered by the air stream blown into the smelting furnace reaches the dust collector by the exhaust gas flow and is recovered as dust. The substrate of the molten droplets is copper metal or copper sulfide (Cu ₂ S), and the surface of the metal particles reacts with sulfurous acid gas in the exhaust gas to change into the form of copper sulfate (CuSO ₄ ). it is conceivable that.

The present inventors observed the surface of the copper particles present in the dust particles by plane analysis using a cross-sectional electron beam microanalyzer (EPMA). FIG. 1 is a photograph of the EPMA analysis result, and FIG. 2 is a schematic diagram of an EPMA analysis photograph of Cu. As shown in FIGS. 1 and 2, most of the dust particles are in the form of metal (copper (Cu) metal) or sulfide (Cu ₂ S) particles, and the surface of the copper metal particles. Was found to change to the form of copper sulfate (CuSO ₄ ). Furthermore, as shown in FIG. 1, it was found that bismuth, lead, and zinc are thinly attached to the surface of the copper particles.

  The generation mechanism of the existence form of the copper particles is not clear, but may be caused, for example, as follows. That is, the copper smelting dust may be generated as simple dust accompanying the charging of the ore into the smelting furnace, or may be generated by being diffused as fine particles after being once melted in the furnace. In particular, in the latter case, since the reaction has passed, the particles are likely to have a uniform shape, and the surface is directly exposed to a high-temperature reaction atmosphere, so it is easy to take the sulfate form under the influence of sulfur oxides. Furthermore, it is considered that impurities such as bismuth, lead and zinc are likely to precipitate around the copper particles.

  Regarding such copper smelting dust, the present inventors investigated the particle size distribution of dust generated under various copper smelting process conditions. FIG. 3 is a particle size distribution diagram obtained by measuring copper smelting dust with a Microtrac particle size distribution meter. As a result, as shown in FIG. 3, the particle size distribution of the copper smelting dust has a total of two peak tops, one in the region of several tens to several hundred μm and one in the region of less than 1 μm. It was found that the boundary between these two peaks, that is, the point where the number of particles between the peaks is the smallest is present in the region having a particle diameter of 1 to 5 μm. Note that the frequency (%) on the vertical axis in the particle size distribution graph of FIG. 3 indicates the frequency of the volume fraction.

  This is because particles of components distributed to dust due to volatilization of zinc, lead, bismuth, tin, etc. have a distribution with a peak top of less than 1 μm, while copper particles distributed to dust as a molten droplet have a peak top of several tens to This is considered to be a distribution of several hundred μm.

  From this, in the copper smelting dust processing method according to the present embodiment, the copper smelting dust collected by the dust collector is set as the processing target, and the dry physical separation is performed by setting the classification point in the range of 1 μm to 5 μm. .

  Specifically, FIG. 4 shows an example of a flow of a method for treating copper smelting dust according to the present embodiment. As shown in FIG. 4, this copper smelting dust treatment method separates copper smelting dust using dry physical separation means set in a range of a classification point of 1 μm to 5 μm. Then, from the relationship of the particle size distribution in FIG. 3 described above, an impurity concentrate in which impurity elements such as zinc, lead, bismuth and tin are concentrated at a high density is distributed on the fine particle side below the classification point, and the coarse particle exceeding the classification point is distributed. The copper particle concentrate containing copper particles is distributed on the grain side.

  When the classification point is less than 1 μm, as described above, since the particle size region has peaks derived from impurity components such as zinc, lead, bismuth, and tin, the distribution of the copper particles to the fine particle side is reduced. The distribution of impurity elements to the coarse grain side increases, and repeated use in a copper smelting furnace concentrates and accumulates in the system, affecting the purity of the product. On the other hand, when the classification point is larger than 5 μm, as described above, it approximates the peak derived from the copper particles distributed to the dust as a melt droplet, so that the distribution of the impurity element to the coarse particle side is reduced. However, the distribution of copper particles to the fine grain side increases, and the amount of copper discarded increases.

  The dry physical separation means is not particularly limited as long as the classification point can be set in the range of 1 μm or more and 5 μm or less and the dry classification can be performed. Specifically, for example, a dry physical classifier using a classification system such as centrifugal force or inertial force can be used.

  According to such a copper smelting dust treatment method, elements such as zinc, lead, bismuth, tin and the like which are impurity components in copper smelting are effectively and easily separated from copper from the copper smelting dust to be treated. be able to. And the copper particle concentrate obtained by separating the coarse particles in this way can be repeated without treatment in a copper smelting furnace, effectively smelting the copper contained in the dust. It can be recovered. That is, unlike the conventional method in which copper is distributed to the liquid phase by a wet process, it is not necessary to perform a drying process, and the equipment cost and the extra energy cost for drying are also unnecessary.

  On the other hand, the impurity concentrate on the fine grain side obtained by separation can be used as a raw material for smelting zinc or lead by separately treating each composition.

  By the way, a part of copper sulfate may be finely granulated and mixed in the impurity concentrate on the fine grain side obtained by separation by dry classification. Therefore, by further separating the copper and the impurity component from the impurity concentrate on the fine grain side, the impurity component can be further concentrated and the mixed copper can also be recovered.

  Therefore, it is preferable that the impurity concentrate on the fine grain side is further subjected to a water washing treatment. Specifically, FIG. 5 shows a processing flow for the impurity concentrate distributed on the fine particle side. The flow of FIG. 5 shows a series of flow from the dry classification process for the copper smelting dust described above, and the flow of the water washing process and the like for the impurity concentrate on the fine grain side is shown in a dotted line encircled portion in FIG. .

  As shown in FIG. 5, the fine particle side impurity concentrate obtained by dry classification of smelting dust is subjected to a water washing treatment. Then, copper sulfate, which is a water-soluble sulfate, dissolves in the aqueous solution, while lead, bismuth, tin and the like remain on the washing residue side. Then, by separating this from solid and liquid, it is possible to separate lead, bismuth, tin, and the like, which are further concentrated impurity elements, and to separate copper into the aqueous solution.

  The method for the water washing treatment is not particularly limited, but it is preferable to carry out the impurity concentrate and water for washing (pure water) into the treatment tank while stirring using a stirrer or the like. Further, the method of solid-liquid separation after the water washing treatment is not particularly limited, and it can be performed by filtration such as suction filtration or centrifugation.

  In addition, the filtrate (waste liquid) containing copper sulfate is introduced into the existing wastewater treatment process together with the wastewater from the copper smelting process, so that copper can be removed from the wastewater using known methods such as neutralization and sulfidation. It collect | recovers as a containing solid substance and can repeat to copper smelting by dehydrating and drying. In addition, zinc contained in the fine particle side impurity concentrate obtained by dry classification is concentrated to the aqueous solution side (filtrate side) by this water washing treatment. Therefore, by separately treating the filtrate, it is possible to effectively separate zinc.

  Specific examples and comparative examples to which the present invention is applied will be described below, but the present invention is not limited to these examples and comparative examples.

  Here, the distribution ratio of each element shown in the examples and comparative examples indicates the ratio of the element contained in the dust before treatment to the solid content and filtrate obtained by the treatment, and before the treatment. It calculated from the chemical analysis value of the solid content obtained by dust and processing, and a filtrate. In addition, this element distribution rate shows distribution when the amount of each element contained in the copper smelting converter dust A to be treated is 100%. Further, the chemical analysis value was analyzed by ICP emission spectrometry after performing necessary pretreatment on the analysis sample.

[Example 1]
Using 10 kg of copper smelting converter dust A, dry classification was performed using a dry classifier with a classification point set to 5 μm. In addition, the dust A used what was generate | occur | produced and collect | recovered when smelting the copper concentrate of Peru using the well-known flash smelting method.

  By the classification, 6.1 kg of impurity concentrate B on the fine powder side and 3.9 kg of copper particle concentrate on the coarse particle side were separated and recovered. Table 1 below shows the distribution ratio of zinc, lead, bismuth, tin, and copper to the impurity concentrate B.

  As shown in Table 1, it can be seen that zinc, lead, bismuth and tin, which are impurity components in copper smelting, can be effectively concentrated and separated.

[Example 2]
In Example 2, water-soluble copper was separated from the impurity concentrate B obtained in Example 1.

  Specifically, 500 g of the impurity concentrate B was put into a 2 liter beaker together with 1 liter of water, and stirred for 15 minutes using a stirrer whose rotational speed was set to 300 rpm. Thereafter, suction filtration was performed using a hard filter paper (4A) to obtain 1.95 liter of filtrate E, and the solid content obtained at the same time was vacuum-dried to obtain 245 g of impurity concentrate C. Table 1 below shows the distribution ratios of zinc, lead, bismuth, tin, and copper to the impurity concentrate C, and Table 2 below shows the distribution ratios to the filtrate E.

  As shown in Table 1, it can be seen that an impurity concentrate of lead, bismuth, and tin with less copper contamination was obtained. In addition, it turned out that zinc in the impurity concentrate B is concentrated in the filtrate obtained in this Example 2, and can be collect | recovered by processing this separately.

[Comparative Example 1]
A wet classification test using a test sieve having a mesh size of 10 μm was conducted on 1 kg of copper smelting converter dust A.

  After the wet classification treatment, the slurry under the sieve is suction filtered using a hard filter paper (4A) to obtain 8.4 liters of filtrate F. At the same time, the obtained solid is vacuum-dried to concentrate 364 g of impurities. Product D was obtained.

  Table 1 below shows the distribution ratios of zinc, lead, bismuth, tin, and copper to the impurity concentrate D, and Table 2 below shows the distribution ratios to the filtrate F.

  As shown in Table 1, in Comparative Example 1, it can be seen that the copper contamination into the impurity concentrate D is 8 times higher than the concentrate C in Example 2 above. Moreover, it turns out that the distribution amount of the copper to the filtrate F is 4 times or more of the filtrate.

  As described above, the copper smelting dust can be effectively separated from the impurity components in the copper smelting such as zinc, lead, bismuth and tin contained in the dust by dry separation at a predetermined classification point. I understood. Furthermore, it was found that a concentrate having a further reduced amount of copper contamination can be obtained by washing and dehydrating the concentrate of these impurity components.

Claims (4)

Using dry physical separation means in which dust (copper smelting dust) generated when smelting copper containing ore containing copper into a smelting furnace is set to a particle size range of 1 μm to 5 μm Separating into fine particles below the classification point and coarse particles exceeding the classification point ,
A method for treating copper smelting dust, wherein the coarse particles obtained by separation are repeatedly charged into the smelting furnace . The method for treating copper smelting dust according to claim 1, wherein the fine particles obtained by separation are washed with water to separate into water-soluble materials and washed fine particles. The said ore contains one or more elements of zinc, lead, bismuth, tin other than copper, The processing method of the copper smelting dust of Claim 1 or 2 characterized by the above-mentioned. In a copper smelting operation method in which an ore containing copper is put into a smelting furnace to smelt copper,
Dust generated in copper smelting (copper smelting dust) using a dry physical separation means in which the classification point is set to a particle size in the range of 1 μm or more and 5 μm or less, and fine particles below the classification point and exceeding the classification point A method for operating copper smelting, characterized in that it is separated into coarse particles and the coarse particles obtained by separation are repeated in the smelting furnace.