Method for selectively recovering arsenic-containing copper mineral

Abstract

Provided is a method for selectively recovering arsenic-containing copper minerals from a mixture containing the arsenic-containing copper minerals and arsenic-free copper minerals to decrease arsenic, which is a harmful substance in a copper concentrate.　The present invention provides a method for selectively recovering arsenic-containing copper minerals from a mixture containing the arsenic-containing copper minerals and arsenic-free copper minerals, the method comprising: a pretreatment step for exposing the mixture to an oxygen-containing gas; a repulping step for adding water to the mixture that has been subjected to the pretreatment step and repulping the mixture to form a slurry; and a flotation step for adding a flotation agent containing a collector represented by formula (1) R1–S–R2 (in formula (1), R1 is a C5-10 alkyl group, and R2 is a C1-10 alkyl group) to the slurry, selectively causing the arsenic-containing copper minerals to float, and performing beneficiation thereof.

Description

Method for selectively recovering arsenic-containing copper minerals

[0001] The present invention relates to a method for selectively recovering arsenic-containing copper minerals from a mixture containing arsenic-containing copper minerals and arsenic-free copper minerals.

[0002] In Japan, copper concentrate is imported from foreign countries (for example, South American countries such as Chile and Peru) that are known as mining countries, and is smelted domestically to produce copper bullion. Copper ore mined overseas generally contains copper minerals that contain arsenic (for example, enargite and tetrahedrite) and copper minerals that do not contain arsenic (for example, chalcopyrite, bornite, covellite, and chalcocite), but in recent years the arsenic content in copper concentrate has tended to increase.

[0003] The arsenic contained in copper concentrate is distributed to slag, dust, etc. during the smelting process, and although these are fixed in a stable form and processed at the smelter, there are concerns about increased processing costs due to the increased content and problems with storage space inside and outside the smelter. Therefore, there is a need for a technology that can selectively recover arsenic-containing copper minerals in the process preceding the copper smelting process. Flotation is known as one such ore-benefiting method.

[0004] Non-Patent Document 1 discloses the results of a study investigating flotation pretreatment parameters for efficiently separating enargite and chalcopyrite from a mixed ore of mineral specimens. Specifically, Non-Patent Document 1 describes that the effects of varying the slurry pH, flotation time, and the amount of PAX (potassium amyl xanthate) added as a collector on the recovery rate and separation efficiency of each mineral were investigated.

[0005] Materials Transactions, Vol. 53, No. 4 (2012) pp. 707-715

[0006] However, according to the investigations of the present inventors, the flotation separation method described in Non-Patent Document 1 focuses only on the separation of enargite and chalcopyrite, and it has been found that there is room for further improvement from the viewpoint of selective recovery.

[0007] The present invention aims to provide a method for selectively recovering arsenic-containing copper minerals from a mixture containing arsenic-containing copper minerals and arsenic-free copper minerals in order to reduce the amount of arsenic, a harmful substance, in copper concentrate. In particular, the present invention aims to provide a method for selectively recovering arsenic-containing copper minerals with high separation efficiency from a high-arsenic-containing copper concentrate after bulk flotation, which contains arsenic-containing copper minerals and arsenic-free copper minerals.

[0008] The present inventors have conducted extensive experiments and intensive studies to solve the above problems, and as a result have completed the present invention.

[0009] That is, the gist of the present invention is as follows: [1] A method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral, comprising: a pretreatment step of exposing the mixture to an oxygen-containing gas; a repulping step of adding water to the mixture after the pretreatment step to repulp it into a slurry; and a reaction mixture satisfying the following formula (1): R １ -S-R ２ ... (1) (In the above formula (1), R １ is an alkyl group having 5 to 10 carbon atoms, and R ２ and a flotation step of adding a flotation agent containing a collector represented by the formula (I) (wherein R is an alkyl group having 1 to 10 carbon atoms) to the slurry to selectively float and beneficiate the arsenic-containing copper mineral. [2] The recovery method according to [1], wherein the pretreatment step is a step of exposing the mixture to the oxygen-containing gas at 0°C to 80°C. [3] The recovery method according to [1], wherein the mixture is a dehydrated product obtained by dehydrating a mineral liquor. [4] The recovery method according to [1], wherein the mixture is a bulk concentrate obtained by bulk flotation of a raw ore. [5] The recovery method according to [1], wherein the arsenic-containing copper mineral comprises enargite, arsenictetrahedrite, or a combination thereof. [6] The recovery method according to [1], wherein the arsenic-free copper mineral comprises chalcopyrite, bornite, covellite, or chalcocite, or a combination thereof.

[0010] The present invention provides a method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral, thereby reducing the arsenic content in copper concentrate to be subjected to a copper smelting process.

[0011] 1 is a flow diagram showing an example of the steps of the recovery method of the present embodiment. It is a diagram plotting separation efficiency against flotation time (minutes) in Example 1, Comparative Example 1, and Reference Example 1. It is a diagram plotting separation efficiency against flotation time (minutes) in Examples 2-1 to 2-3 and Comparative Example 2. It is a diagram showing a comparison of experimental results for Examples 2-1 to 2-3 and Comparative Example 2 when the flotation time is 2 minutes. That is, it is a diagram showing a comparison of the effects of differences in drying temperature in the pretreatment step (Example 2-1: 25°C, Example 2-2: 60°C, Example 2-3: 105°C, Comparative Example 2: no drying) on ​​the recovery rate of arsenic-containing copper ore, the recovery rate of arsenic-free copper ore, and separation efficiency. It is a diagram plotting separation efficiency against flotation time (minutes) in Examples 2-1 and 3-2.

[0012] An example of a preferred embodiment of the present invention will be described below. However, the following embodiment is an example for explaining the present invention, and the present invention is not limited to the following embodiment.

[0013] The recovery method of this embodiment is a method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral. An example of the steps of the recovery method of this embodiment is shown in a flow diagram in Figure 1. As shown in Figure 1, the recovery method of this embodiment includes the steps of dehydrating a pulp slurry of a mixture of an arsenic-containing copper mineral and an arsenic-free copper mineral and exposing it to an oxygen-containing gas (pretreatment step: S1), adding water to the pretreatment step and repulping the pulp (repulping step: S2), adding a modifier to the repulped slurry (modifier addition step: S3), adjusting the pH of the slurry (pH adjustment step: S4), adding a flotation agent containing a collector to the slurry (addition step: S5), and selectively floating and beneficiating the arsenic-containing copper mineral (flotation step: S6).

[0014] The recovery method of this embodiment is characterized in that in the pretreatment step S1, a mixture of an arsenic-containing copper mineral and an arsenic-free copper mineral is exposed to an oxygen-containing gas. The pulp slurry containing the mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral may be exposed to the oxygen-containing gas after dehydration. The dehydration method is not particularly limited, but examples include filtration through a filter and solid-liquid separation using a thickener. Furthermore, the drying method is not particularly limited, but examples include leaving the pulp at room temperature and drying using a dryer, oven, and / or kiln. Such treatments are expected to dehydrate and dry the pulp slurry and to provide a suitable surface treatment for the mixture in the pulp slurry. Examples of the oxygen-containing gas used in the pretreatment step include oxygen and air. Among these, air is preferred in terms of oxygen content, and oxygen is particularly preferred. In the pretreatment step, the temperature at which the oxygen-containing gas is exposed to the mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral (e.g., a dehydrated product of a pulp slurry) may be 0°C or higher, 10°C or higher, or 20°C or higher, or 80°C or lower, 60°C or lower, or 45°C or lower, from the viewpoint of separation efficiency and the like. Since treatment at high temperatures tends to decrease the recovery rate of the arsenic-containing copper ore, it is preferable to perform the pretreatment step at 80°C or lower. In the pretreatment step, the lower limit of the time for which the oxygen-containing gas is exposed to the mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral (e.g., a dehydrated product of a pulp slurry) at the above temperature is not particularly limited, from the viewpoint of separation efficiency and the like, and may be, for example, less than 10 minutes, 10 minutes or higher, 30 minutes or higher, or 1 hour or higher. Furthermore, the upper limit of the time is not particularly limited, and may be, for example, 2 hours or less, 12 hours or less, 24 hours or less, or more than 24 hours. For example, it may be 20 to 100 hours. By using a modifier such as hydrogen peroxide in combination with a collector such as di-n-octyl sulfide (hereinafter, sometimes referred to as "DOS"), it is possible to selectively increase the recovery rate of the arsenic-containing copper mineral and improve the separation efficiency even when a flotation step is performed for a relatively short time, as shown in the examples described below.Furthermore, for example, in the treatment of high-arsenic copper concentrate that remains after bulk flotation with xanthate salts and the like attached thereto, arsenic-containing copper minerals and arsenic-free copper minerals can be separated extremely efficiently by using a modifier such as hydrogen peroxide and a collector such as DOS in combination in each step of the recovery method.

[0015] In the recovery method of this embodiment, after the pretreatment step S1, water is added in the repulping step S2 for repulping. Examples of water used in the repulping step include distilled water, tap water, natural water, industrial water, process water, and RO water. Among these, RO water and distilled water are preferred in terms of impurities.

[0016] The arsenic-containing copper mineral is a copper mineral containing arsenic. More specifically, it refers to a copper mineral containing arsenic (As) as a chemical composition, such as enargite (Cu ３ AsS ４ ), Tennantite (Cu ６ [Cu ４ (Fe, Zn) ２ ]As ４ S １３ ), Giraudite (Cu ６ [Cu ４ (Fe, Zn) ２ ]As ４ Se １３ ), Goldfieldite (Cu ６ Cu ４ Te ２ (Sb, As) ４ S １３ ), Argentotennantite, Ag ６ [Cu ４ (Fe, Zn) ２ ]As ４ S １３ ) etc.

[0017] Arsenic-free copper minerals are copper minerals that do not contain arsenic. More specifically, they are copper minerals that do not contain arsenic element in their chemical composition. For example, chalcopyrite (CuFeS ２ ), Bornite, Cu ５FeS ４ ), Cobellite, CuS, Chalcocite, Cu ２ S) and the like.

[0018] The arsenic-containing copper mineral may contain single-edged particles with the arsenic-free copper mineral. The arsenic-free copper mineral may also contain a trace amount (e.g., 0.1 wt % or less) of single-edged particles with the arsenic-containing copper mineral. The arsenic-free copper mineral may also contain a trace amount (e.g., 0.1 wt % or less) of arsenic as an impurity.

[0019] The slurry (after repulping) of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral may be a mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral. For example, it may be a mixture of fine particles of the arsenic-containing copper mineral and fine particles of the arsenic-free copper mineral that have been pulverized and atomized. It may also be a copper concentrate containing the arsenic-containing copper mineral and the arsenic-free copper mineral, or a copper ore containing the arsenic-containing copper mineral and the arsenic-free copper mineral.

[0020] The mixing ratio of the arsenic-containing copper mineral and the arsenic-free copper mineral in the slurry of the mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral is not particularly limited as long as the arsenic-containing copper mineral can be selectively recovered. For example, the arsenic-containing copper mineral and the arsenic-free copper mineral may be mixed in the same ratio, or the arsenic-containing copper mineral may be mixed in a larger amount than the arsenic-free copper mineral, or vice versa.

[0021] In this embodiment, the term "slurry" refers to a fluid in which mineral particles (arsenic-containing copper mineral particles and arsenic-free copper mineral particles) are suspended in an aqueous solution. The water contained in the slurry of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral is not particularly limited and may be, for example, distilled water, tap water, natural water, industrial water, or process water (water recycled from the flotation process). It may also be water (RO water) obtained by filtering tap water or natural water through an ultrafine reverse osmosis membrane filter known as an RO membrane. The water content of the slurry of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral is not particularly limited as long as a slurry is formed, and may be, for example, 500 mL to 30,000 mL per 310 g of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral.

[0022] In the recovery method of this embodiment, a modifier is added to the slurry in a modifier adding step S3 (modifier adding step).

[0023] Examples of the modifier used in the modifier addition step include hydrogen peroxide, sodium percarbonate, sodium peroxide, and sodium hypochlorite. Among these, hydrogen peroxide and sodium percarbonate are preferred, with hydrogen peroxide being particularly preferred, from the standpoints of separation efficiency and the arsenic (As) content in the sink. When hydrogen peroxide is used as the modifier, the amount of hydrogen peroxide added is preferably 1 to 5 kg / t or more based on the weight of the high-arsenic copper concentrate, from the standpoints of separation efficiency and flotation time. By using hydrogen peroxide in combination with a collector such as di-n-octyl sulfide (hereinafter sometimes referred to as "DOS"), the recovery rate of arsenic-containing copper mineral can be selectively increased and separation efficiency can also be improved, as shown in the examples described below. Furthermore, for example, in the treatment of high-arsenic-containing copper concentrate that has xanthate salts and the like remaining after bulk flotation, arsenic-containing copper minerals and arsenic-free copper minerals can be separated extremely efficiently by using hydrogen peroxide and a collector such as DOS in combination in each step of the recovery method.

[0024] In the modifier addition step, the modifier is preferably added to the slurry and mixed for a predetermined time. The mixing method is not particularly limited, but mechanical stirring using an impeller or the like can be used.

[0025] From the viewpoint of separation efficiency, the time required for the modifier addition step is preferably 10 minutes or less, more preferably 5 minutes or less, and even more preferably 1 minute or less.

[0026] In the recovery method of this embodiment, the pH of the slurry obtained in the modifier addition step S3 is adjusted (pH adjustment step S4).

[0027] In the pH adjustment step S4, the pH of the slurry adjusted is preferably equal to or higher than 7. In this embodiment, the arsenic-containing copper mineral tends to float in a slurry in the neutral to alkaline range.

[0028] The temperature of the slurry is not particularly limited as long as it is a temperature at which the arsenic-containing copper mineral can be floated, and may be, for example, a normal temperature of 20 to 25°C.

[0029] In the recovery method of the present embodiment, a flotation agent containing a collector is added to the slurry adjusted in the pH adjustment step S4 (addition step S5).

[0030] The flotation agent used in the addition step S5 is not particularly limited as long as it contains a collector represented by the following formula (1): １ -S-R ２ ... (1) (In the above formula (1), R １ is an alkyl group having 5 to 10 carbon atoms, and R ２ is an alkyl group having 1 to 10 carbon atoms)

[0031] Collector R １ may be a linear alkyl group. １ The linear alkyl group R improves hydrophobicity and tends to make it easier to float the arsenic-containing copper mineral. １ may be a linear alkyl group having 7 to 9 carbon atoms.

[0032] Collector R １ and R ２ may be alkyl groups of the same structure. １ and R ２By using alkyl groups having the same structure, the efficiency of separating arsenic-containing copper minerals from arsenic-free copper minerals tends to improve, for example, in the case of di-n-octyl sulfide (DOS).

[0033] Collector R ２ may be a linear alkyl group. ２ When the alkyl group is a straight chain alkyl group, the efficiency of separating arsenic-containing copper minerals from arsenic-free copper minerals tends to improve, for example, as in methyl n-octyl sulfide and the above-mentioned DOS.

[0034] Examples of the collector of formula (1) include methyl n-octyl sulfide, di-n-octyl sulfide (DOS), methyl n-amyl sulfide, di-n-amyl sulfide, di-n-hexyl sulfide, methyl n-heptyl sulfide, di-n-heptyl sulfide, di-n-nonyl sulfide, di-n-decyl sulfide, methyl n-decyl sulfide, etc. Among these, from the viewpoints of separation efficiency and the arsenic (As) content in the sinking ore, methyl n-octyl sulfide and di-n-octyl sulfide are preferred, with methyl n-octyl sulfide being particularly preferred.

[0035] The amount of collector added may be 5 g to 500 g, 20 g to 300 g, or 50 g to 150 g per ton of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral. If the amount of collector added is less than 5 g per ton of the mixture containing the arsenic-containing copper mineral and the arsenic-free copper mineral, the recovery rate of the arsenic-containing copper mineral tends to decrease, and if the amount is more than 200 g, the recovery rate does not improve significantly and instead selectivity tends to decrease.

[0036] The flotation agent may contain, in addition to the collector, an activator, a depressant, a foaming agent, etc. Alternatively, the flotation agent may be the collector itself without containing any other substances than the collector.

[0037] As described above, the flotation reagent of the present embodiment is a flotation reagent containing a collector represented by the following formula (1), which is used in a method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral. １ -S-R ２... (1) (In the above formula (1), R １ is an alkyl group having 5 to 10 carbon atoms, and R ２ is an alkyl group having 1 to 10 carbon atoms)

[0038] In the recovery method of this embodiment, the arsenic-containing copper mineral is selectively floated and beneficiated from the slurry to which the flotation agent containing the collector has been added in the adding step S5 (flotation step S6).

[0039] In this embodiment, selectively recovering the arsenic-containing copper mineral means ore-benefiting by floating the arsenic-containing copper mineral to the surface of the slurry in a flotation step, including selectively separating the arsenic-containing copper mineral from the arsenic-free copper mineral, and the floating float (froth) contains the arsenic-containing copper mineral. Here, the floating float may contain not only the arsenic-containing copper mineral but also the arsenic-free copper mineral, other minerals, impurities, and the like. In this embodiment, selectively recovering the arsenic-containing copper mineral also means efficiently removing the arsenic-containing copper mineral from a mixture of the arsenic-containing copper mineral and the arsenic-free copper mineral, and copper can be obtained by removing arsenic from the selectively recovered arsenic-containing copper mineral in a subsequent smelting step.

[0040] In the recovery method of this embodiment in which the arsenic-containing copper mineral is floated and beneficiated, the arsenic-free copper mineral can also be recovered by allowing it to settle to the bottom of the slurry. That is, by a so-called reverse flotation process, a concentrate containing arsenic-free copper mineral and having a low arsenic content can be efficiently obtained from a mixture of arsenic-containing copper mineral and arsenic-free copper mineral.

[0041] Flotation (flotation separation) is a separation method that utilizes the phenomenon in which air is blown into a slurry (after repulping) in which mineral particles are suspended in water. Hydrophobic particles among the mineral particles adhere to the air bubbles and float to the surface, while hydrophilic particles among the mineral particles cannot adhere to the air bubbles and remain in the slurry. The collector comprises a moiety that selectively adsorbs to the target mineral particles and a hydrophobic group that easily adheres to the air bubbles. In this embodiment, reverse flotation is a method of increasing the concentration of desired mineral particles in the slurry by attaching air bubbles to unwanted mineral particles and floating them up for separation. The collector of this embodiment has a hydrophobic group and a moiety that selectively adsorbs to arsenic-containing copper minerals but does not adsorb to arsenic-free copper minerals. Therefore, only arsenic-containing copper minerals (particles) adhere to the air bubbles and selectively float to the top of the slurry, resulting in a froth that becomes a high-arsenic copper concentrate with concentrated arsenic. Furthermore, efficient separation is possible by performing a reverse flotation process that increases the concentration of arsenic-free copper minerals (particles) in the slurry. As a result, the arsenic-free copper minerals are concentrated in the sink (tailings), and the sink becomes a low-arsenic copper concentrate with reduced arsenic. That is, the recovery method of this embodiment can also be described as a method for selectively recovering arsenic-containing copper minerals from a mixture containing arsenic-containing copper minerals and arsenic-free copper minerals, and includes a reverse flotation step in which a flotation agent containing a collector is added to the slurry, the arsenic-containing copper minerals are selectively floated and beneficiated, and the arsenic-free copper minerals are concentrated in the slurry.

[0042] In this embodiment, the recovery rate and separation efficiency can be determined as follows: Note that some of the formulas have been described using the case where the arsenic-containing copper mineral is enargite as an example.

[0043]

[0044]

[0045]

[0046] In this embodiment, the recovery rate and separation efficiency of the arsenic-containing copper mineral are preferably high. In addition, a high recovery rate of the arsenic-containing copper mineral is also preferable in that the arsenic-free copper mineral (particles) in the slurry is concentrated, and the resulting ore becomes a low-arsenic copper concentrate with a reduced arsenic content.

[0047] The copper-bearing mineral targeted by this embodiment is not limited to arsenic-rich copper concentrate, but may also be copper ore, copper concentrate, copper flotation tailings, or a mixture containing arsenic-containing copper minerals and arsenic-free copper minerals.

[0048] When flotation (flotation separation) is performed, the ore can be separated more effectively if the arsenic-containing copper mineral and the arsenic-free copper mineral exist as single particles, so it is desirable to perform pretreatment such as crushing so that most of the arsenic-containing copper mineral and the arsenic-free copper mineral are separated into single particles. The average particle size of the mixture of the finely powdered arsenic-containing copper mineral and the arsenic-free copper mineral is preferably 10 μm or more, as this tends to make the mineral particles more likely to be adsorbed by air bubbles.

[0049] As described above, according to the recovery method of this embodiment, it is possible to efficiently recover an arsenic-containing copper mineral selectively from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral. Furthermore, the present invention can provide a method for selectively recovering an arsenic-containing copper mineral with high separation efficiency from a flotation-prepared arsenic-rich copper concentrate containing an arsenic-containing copper mineral and an arsenic-free copper mineral. As a result, it is possible to efficiently reduce the arsenic in the copper concentrate to be subjected to a copper smelting process.

[0050] The effects of the present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. [Example 1] A high-arsenic copper concentrate slurry (slurry slurry, pulp pulp) obtained at a mineral processing plant was used as a sample. The elemental quality of the sample was determined using the following analytical flow. First, the slurry slurry was dehydrated by filtration and dried at 105°C for 24 hours. The dried sample was weighed, then microwave-heated and dissolved in acid, and the solution was filled up to a constant volume to prepare an analytical sample solution. Each analytical sample solution was subjected to ICP analysis using an ICP-OES 5110 manufactured by Agilent Technologies, and the elemental concentration in the solution was quantitatively analyzed. Specifically, the volume of the solution after filling up was multiplied by the solution concentration of each component element analyzed by ICP, and the result was divided by the weight of the acid-dissolved sample to obtain the elemental quality (wt%). The results are shown below. As 2.17 wt% Cu 19.21 wt% Fe 26.13 wt% Next, the mineral composition (mineral content) of the sample was determined using the following flow. First, the sample was embedded in resin, and the surface was polished to prepare an analytical sample. Each of these analytical samples was subjected to quality analysis using an MLA (Quanta 650) manufactured by FEI. MLA stands for Mineral Liberation Analyzer, and is an automatic mineral analysis device in which mineral analysis software is incorporated into SEM-EDS. Using the MLA, the mineral content (modal mineralogy) was measured as a quantitative analysis, and the composition ratio of the mineral composition was determined. The chemical formula of each composition is arsenopyrite (Cu ３ AsS ４ ), tetrahedrite ((Cu, Fe, Zn) １２ As ４ S １３ ), chalcopyrite (CuFeS ２ ), bornite (Cu ５ FeS ４ ), chalcocite (Cu ２ S), pyrite (FeS ２) The results are shown below. Arsenocite 9.02 wt% Arsenite 9.91 wt% Chalcopyrite 9.09 wt% Bornite 2.59 wt% Chalcocite 8.32 wt% Pyrite 50.46 wt% A separation evaluation test was carried out using an Agitair type flotation tester according to the following flow. First, a pulp slurry containing 310 g of high-arsenic copper concentrate was filtered and dehydrated, and then pretreated by exposing it to air at 25°C for 24 hours to dry. Next, RO water was added to this slurry to repulp it, and the resulting slurry was placed in a 1 L cell for the Agitair type flotation tester. Next, hydrogen peroxide H ２ O ２ was added at a rate of 5 kg / t, followed by 0.05 M H in an amount to set the pH to 7. ２ SO ４ The pH was adjusted over 1 minute. Next, di-n-octyl sulfide (DOS) was added as a collector (flotation agent) at a dosage of 127.7 g / t (0.49 mol / t). After mixing in the cell for 30 seconds, 10 g / t of a foaming agent was added and the mixture was further mixed for 30 seconds. Mixing was then continued, and air was blown in at a flow rate of 2 liters / minute (LPM), and separation by flotation was performed for 8 minutes. The recovery rate and separation efficiency of the float and sink ores obtained in the flotation process for each flotation time interval (1, 2, 4, and 8 minutes) were calculated according to the procedures described in [Equation 1] to [Equation 4] in the detailed description of the invention. The recovery rate and separation efficiency of arsenic-containing copper minerals and arsenic-free copper minerals are shown in Table 1, and the separation efficiency is shown in Figure 2.

[0051] In Comparative Example 1, a separation evaluation test was carried out in the same manner as in Example 1, except that the slurry containing process water was directly placed in a 1 L cell for Agitair-type flotation tests without the pretreatment of dehydrating and drying by exposing it to air at 25° C. for 24 hours as in Example 1. The results are shown in Table 1 and Figure 2.

[0052] [Reference Example 1] In Reference Example 1, the hydrogen peroxide H ２ O ２ The separation evaluation test was carried out in the same manner as in Comparative Example 1, except that no was added. The results are shown in Table 1 and FIG.

[0053]

[0054] (Results and Discussion) As shown in Table 1, by carrying out pretreatment of dehydration by filtration and drying by exposure to air at 25°C for 24 hours, followed by repulping with RO water (Example 1), the recovery rate of arsenic-containing copper minerals in the float ore was improved compared to the case where pretreatment of dehydration and drying was not carried out (Comparative Example 1), and the separation efficiency was also improved as shown in Figure 2. Furthermore, as is clear from the comparison of Example 1, Comparative Example 1, and Reference Example 1, the recovery rate of arsenic-containing copper minerals in the float ore was improved, and the separation efficiency was also improved as shown in Figure 2. ２ O ２ By using these in each process and then pre-treating the pulp by dehydrating and drying, the separation efficiency was significantly improved. ２ O ２ This is thought to be because the addition of the above modified the surface condition of the raw copper concentrate so that the collector DOS could function and act efficiently.

[0055] [Example 2] In Example 2-1, a separation evaluation test was conducted in the same manner as in Example 1, except that the flow rate of air blown in during flotation was 4 liters per minute (LPM). In Examples 2-2 and 2-3, a separation evaluation test was conducted in the same manner as in Example 2-1, except that the drying temperatures were changed from 25°C to 60°C and 105°C, respectively. These results are shown in Table 2 and Figure 3. In addition, Figure 4 compares the experimental results for Examples 2-1 to 2-3, where the flotation time was 2 minutes, i.e., the effects of different drying temperatures in the pretreatment step (Example 2-1: 25°C, Example 2-2: 60°C, Example 2-3: 105°C) on the recovery rate of arsenic-containing copper ore, the recovery rate of arsenic-free copper ore, and the separation efficiency.

[0056] Comparative Example 2 In Comparative Example 2, a separation evaluation test was carried out in the same manner as in Example 2-1, except that the pretreatments of dehydration by filtration and drying by exposure to air at 25°C for 24 hours, which were performed in Example 2-1, were not performed, and process water was used for repulping instead of RO water. The results are shown in Table 2 and Figure 3. In addition, Figure 4 shows a comparison of experimental results for a flotation time of 2 minutes, which compares the effects on the recovery rate of arsenic-containing copper ore, the recovery rate of arsenic-free copper ore, and the separation efficiency when the pretreatments of dehydration by filtration and drying by exposure to air at 25°C for 24 hours were not performed.

[0057]

[0058] (Results and Discussion) As shown in Table 2, by carrying out pretreatment of dehydration by filtration and drying by exposure to air at 25°C to 105°C for 24 hours, followed by repulping with RO water (Examples 2-1 to 2-3), the recovery rate of arsenic-containing copper minerals in the float improved compared to the case where pretreatment of dehydration and drying was not carried out (Comparative Example 2), and the separation efficiency was also improved as shown in Figure 3. This is because pretreatment of dehydration and drying, repulping, and further H ２ O ２ This is thought to be because the addition of the compound modified the surface condition of the raw copper concentrate so that the collector DOS could function and act efficiently. Furthermore, as shown in Table 2, when the flotation time was 2 minutes, a comparison was made of the effects of different drying temperatures in the pretreatment step (Example 2-1: 25°C, Example 2-2: 60°C, Example 2-3: 105°C, Comparative Example 2: no drying) on ​​the recovery rate of arsenic-containing copper ore, the recovery rate of arsenic-free copper ore, and the separation efficiency. As shown in Figure 4, the recovery rate of arsenic-containing copper ore was improved at drying temperatures of 25°C to 60°C, but the recovery rate of arsenic-free copper ore decreased as the drying temperature increased within the range of 25°C to 105°C, and the separation efficiency was slightly higher at a drying temperature of 60°C than at a drying temperature of 105°C.

[0059] Example 3 Example 3-1 is the same as Example 2-1, and a separation evaluation test was carried out in the same manner as in Example 1, except that the flow rate of air blown in during flotation was 4 liters per minute (LPM). In Example 3-2, a separation evaluation test was carried out in the same manner as in Example 3-1, except that the drying time in the pretreatment, in which the material was dehydrated and dried by exposure to air at 25°C for 24 hours, was changed from 24 hours to 96 hours. These results are shown in Table 3 and FIG. 5.

[0060]

[0061] (Results and Discussion) As shown in Table 3, even when the drying time was changed from 24 hours to 96 hours, there was no significant difference in the recovery rate of arsenic-containing copper minerals, but the recovery rate of arsenic-free copper minerals tended to decrease as the drying time increased. Also, as shown in Figure 5, by increasing the drying time from 24 hours to 96 hours, the separation efficiency was further improved. Thus, the recovery rate of arsenic-free copper minerals was significantly improved by increasing the drying time from 24 hours to 96 hours. ２ O ２ When these processes are used in combination, by ensuring a sufficiently long drying time, the flotation process can be performed efficiently in a shorter time, and the separation efficiency is also improved. This is because proper pretreatment of dewatering and drying, repulping, and further H ２ O ２ This is thought to be because the addition of the above modified the surface condition of the raw copper concentrate so that the collector DOS could function and act efficiently.

[0062] INDUSTRIAL APPLICABILITY The present invention provides a method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral, and as a result, the arsenic content in copper concentrate to be subjected to a copper smelting process can be reduced, and therefore the method has industrial applicability.

Claims

1. A method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral, comprising: a pretreatment step of exposing the mixture to an oxygen-containing gas; a repulping step of adding water to the mixture that has been pretreated to repulp it into a slurry; and a method for selectively recovering an arsenic-containing copper mineral from a mixture containing an arsenic-containing copper mineral and an arsenic-free copper mineral, the method comprising: １ -S-R ２ ... (1) (In the above formula (1), R １ is an alkyl group having 5 to 10 carbon atoms, and R ２ and a flotation step of adding a flotation agent containing a collector represented by the formula (I) to the slurry, and selectively floating and beneficiating the arsenic-containing copper mineral.

2. The recovery method according to claim 1, wherein the pretreatment step is a step of exposing the mixture to the oxygen-containing gas at 0°C to 80°C.

3. The recovery method according to claim 1, wherein the mixture is a dehydrated product obtained by dehydrating a mineral pulp.

4. The recovery method of claim 1, wherein the mixture is a bulk concentrate obtained by bulk flotation of raw ore.

5. The method of claim 1, wherein the arsenic-containing copper mineral comprises enargite, arsenite, or a combination thereof.

6. The recovery method of claim 1, wherein the arsenic-free copper mineral comprises any one or combination of chalcopyrite, bornite, covellite, or chalcocite.

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