JP4525372B2 - Leaching method of copper sulfide ores containing chalcopyrite - Google Patents

Description

  The present invention relates to a method for leaching copper sulfide ore containing chalcopyrite, and more particularly to an efficient method for leaching copper from copper sulfide ore containing chalcopyrite at a high leaching rate with a high leaching rate.

  Conventionally, as one of the methods for recovering copper from copper ore, a method has been used in which copper is leached with sulfuric acid or the like, and the leached copper is concentrated by solvent extraction and recovered as a copper cathode by electrowinning. ing. In this method, when the copper contained in the copper ore is in the form of oxide or carbonate, 40 to 90% of the copper contained by simple acid leaching can be easily leached, and the copper can be obtained in a high yield. Can be recovered.

Further, when the copper mineral in the copper ore is a secondary sulfide mineral such as chalcocite (Cu ₂ S), porphyry (Cu ₅ FeS ₄ ), a bacterial leaching method is used. In this method, copper can be efficiently leached by using a leaching solution containing iron sulfate as an oxidizing agent under the conditions in which microorganisms such as iron-oxidizing bacteria coexist. All of the above methods can recover copper economically and efficiently, and are widely used in large-scale copper mines in North and South America.

However, when the copper mineral contained in the copper ore is chalcopyrite (CuFeS ₂ ), the leaching rate of copper becomes extremely slow. Therefore, in general bacterial leaching, it is about several to 20%. There was a problem that the copper leaching rate was remarkably impaired. This cause is related to the redox potential of the leachate. That is, Fe ³⁺ ions contained in the leachate act as an oxidant and promote the dissolution of sulfide minerals. At this time, they are reduced to Fe ²⁺ ions, so that the redox potential of the leachate decreases as the leaching reaction proceeds. At this time, the Fe ²⁺ ions are oxidized into Fe ³⁺ ions by air oxidation, but the reaction rate is dramatically increased when microorganisms such as iron-oxidizing bacteria naturally inhabiting the deposited ore dump are involved.

For example, when the copper mineral contained in the copper sulfide ore is a secondary sulfide mineral such as chalcocite (Cu ₂ S) or porphyry (Cu ₅ FeS ₄ ), these are more easily dissolved as the redox potential is higher. Therefore, the more copper is eluted as the bacteria are actively activated and the Fe ³⁺ ions in the leachate increase. On the other hand, when the copper mineral is chalcopyrite (CuFeS ₂ ), which is a primary sulfide mineral, leaching is extremely slow in a redox potential region of 500 to 700 mV (Ag / AgCl electrode standard) where bacteria are actively active. And hardly leached under conditions suitable for leaching of the secondary sulfide mineral. Further, leaching can be accelerated by making the potential higher than this, but it is difficult to maintain the high potential only by the oxidizing action of bacteria.

  By the way, generally, copper contained in the low-grade copper ore, for example, the primary enrichment zone below the porphyry type ore is chalcopyrite. Moreover, copper ores including chalcopyrite are widely distributed throughout the world. However, since these ores are not suitable for copper recovery by the above leaching method, the copper concentrate must be recovered by an economically disadvantageous flotation method or disposed as waste ore.

  As a solution to this, as a method of leaching chalcopyrite, a method of adding pressure sulfuric acid and an oxidizing agent and leaching under pressure, a method of heating using hydrochloric acid, etc. have been proposed. Not economical. For example, a technique using a carbonaceous additive as a reaction accelerator at the time of oxidative pressure leaching with a sulfuric acid solution of copper concentrate (for example, see Patent Document 1) has been proposed. This method is an effective method for hardly leaching copper minerals such as chalcopyrite, but oxidative pressure leaching is performed under severe conditions of leaching reaction temperature of 90 to 220 ° C. and pressure of 100 to 3000 kPa. It is. Therefore, the leaching method under mild conditions such as bacterial leaching is fundamentally different in the expected leaching rate.

From the above situation, there is a demand for an economical method capable of leaching copper from copper sulfide ores containing chalcopyrite at a high leaching rate and at a high leaching rate.
US Pat. No. 5,730,776

  An object of the present invention is to provide an efficient method of leaching copper from a copper sulfide ore containing chalcopyrite at a high leaching rate while increasing the leaching rate.

  In order to achieve the above object, the present inventors have conducted extensive research on a method of leaching copper from chalcopyrite containing copper ore. As a result, an aqueous iron sulfate solution was added as a leaching solution to the deposited layer of copper sulfide ore. In addition, when air is charged and the oxygen concentration in the air in the deposited layer is adjusted to a specific condition, copper can be leached at a high leaching rate with a high leaching rate. The headline and the present invention were completed.

That is, according to the first invention of the present invention, a method of leaching copper using a leachate from a copper sulfide ore containing chalcopyrite while charging air,
By adding an iron sulfate aqueous solution as a leachate to the copper sulfide ore deposit and circulating low-oxygen-concentrated air discharged from the deposit as charge air to the deposit , except immediately after the start of leaching. Provided is a copper sulfide ore leaching method characterized by adjusting the oxygen concentration in the air supplied into the deposition layer to 10% by weight or less until the end of leaching.

  According to a second aspect of the present invention, in the first aspect, the aqueous iron sulfate solution has an iron concentration of 1 to 10 g / L and a pH of 1.0 to 2.5. A method of leaching copper sulfide ore is provided.

  According to a third aspect of the present invention, there is provided the copper sulfide ore leaching method according to the second aspect, wherein the iron sulfate aqueous solution has a copper concentration of 0.1 to 5 g / L. The

  According to a fourth aspect of the present invention, there is provided the copper sulfide ore leaching method according to the first aspect, wherein the leaching is performed by any one of heap leaching, butt leaching or column leaching. Provided.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the redox potential (Ag / AgCl electrode reference) of the leachate in the deposited layer is adjusted to 350 to 450 mV. A method of leaching copper sulfide ore is provided.

  The leaching method of copper sulfide ore containing chalcopyrite of the present invention can increase the leaching rate of copper from copper sulfide ore containing chalcopyrite and can leach copper at a high leaching rate, so its industrial value is extremely large. .

Hereinafter, the leaching method of copper sulfide ore containing chalcopyrite according to the present invention will be described in detail.
The method for leaching copper sulfide ore containing chalcopyrite according to the present invention is a method of leaching copper from a copper sulfide ore containing chalcopyrite using leachate while charging air, and is used as a leachate in the deposited layer made of copper sulfide ore. While adding an aqueous iron sulfate solution and circulating and using low oxygen concentration air discharged from the deposition layer as the charge air to the deposition layer , the deposition is performed until the end of leaching except immediately after the start of leaching. The oxygen concentration in the air supplied into the layer is adjusted to 10% by weight or less.

  In the leaching method of the present invention, it is important to adjust so that the oxygen concentration in the air in the deposition layer is maintained at 10% by weight or less until the end of leaching except for the period of high oxygen concentration immediately after the start of leaching. It is. As a result, chalcopyrite reacts in a specific oxidation-reduction potential region in a sulfuric acid aqueous solution and is leached at a high speed. Here, the chalcopyrite in the sulfuric acid aqueous solution is leached according to a two-step reaction shown in the following reaction formulas (1) and (2) in a certain oxidation-reduction potential region.

^{_{CuFeS 2 + 3Cu 2+ + 3Fe 2+}} = 2Cu 2 S + 4Fe 3+ (1)
Cu ₂ S + 4Fe ³⁺ = 2Cu ²⁺ + S + 4Fe ²⁺ (2)

  That is, first, based on the formula (1), chalcopyrite is reduced in a low redox potential region, and chalcopyrite having a higher oxidation elution rate is generated as a reaction intermediate. Thereafter, based on the formula (2), the chalcocite is oxidized and copper is eluted. In order to establish such a reaction mechanism, it is an essential condition that the oxidation-reduction potential E of the solution satisfies the following formula (3).

Eox <E <Ec (3)
(In the formula, Ec represents the redox potential of formula (1), and Eox represents the redox potential of formula (2).)

Moreover, the whole reaction in which chalcopyrite dissolves is represented by the following formula (4), which is a sum of formula (1) and formula (2), and the overall reaction in which chalcopyrite dissolves is an oxidation reaction with Fe ^3+. I understand that.

_{^{CuFeS 2 + 4Fe 3+ = Cu 2+}} + 2S + 5Fe 2+ (4)

Further, Fe ³⁺ consumed in the reaction of the formula (4) is regenerated by being oxidized by oxygen in the air in which the generated Fe ²⁺ is charged, and further, due to the involvement of microorganisms such as iron-oxidizing bacteria. The reaction is accelerated. This reaction is represented by the following formula (5).

Fe ²⁺ + e ⁻ = Fe ³⁺ (5)

Regarding the reaction mechanism, the relationship between the reaction rate and the oxidation-reduction potential (hereinafter sometimes abbreviated as potential) will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing the relationship between the dissolution rate of chalcopyrite and the potential.
In FIG. 1, when the condition of the formula (3) is satisfied, the chalcopyrite is reduced, and a chalcopyrite having a higher oxidation elution rate is generated as a reaction intermediate, and the chalcopyrite is leached at high speed because it is oxidized and eluted. That is, in the vicinity of Ec, the chalcopyrite reduction reaction (Cu ₂ S formation reaction: R) and the Cu ₂ S oxidation reaction (O), the reduction reaction of chalcopyrite controls the entire process, so the copper elution rate K Increases with decreasing potential. On the other hand, in the vicinity of Eox, the Cu ₂ S oxidation reaction becomes a rate-limiting step, and the elution rate K of copper increases as the potential increases. Therefore, the elution rate of copper is maximized at the potential (Eop) at which the chalcopyrite reduction reaction (R) and the Cu ₂ S oxidation reaction (O) intersect. Moreover, in the case of Ec <E, since copper elutes directly from chalcopyrite by the chalcopyrite oxidation reaction (D) (formula (4)), the elution rate of copper becomes low.

By the way, in the normal leaching condition of copper sulfide ore, the regeneration of Fe ³⁺ by the reaction of Formula (5) is more dominant than the consumption of Fe ³⁺ by the reaction of Formula (4), and the Nernst formula (Formula (6) The potential of the leachate expressed by) tends to increase beyond the optimum potential range for the chalcopyrite leaching described in FIG.

E = 0.670 + 0.059 log ([Fe ³⁺ ] / [Fe ²⁺ ]) (6)

For this reason, as a method of suppressing the regeneration of Fe ³⁺ according to the formula (5) and maintaining the potential within a desired range, it is conceivable to introduce a reducing agent or sterilize iron-oxidizing bacteria. Even in the method, the cost of the medicine increases, which causes a problem in economy.

  As a countermeasure, the oxygen concentration in the air in the deposited layer is 10% by weight in the method of the present invention, that is, at least during most of the leaching period, for example, until the leaching end except for immediately after the start of leaching. In the following, it is effective to adjust so that it is preferably maintained at 0.1 to 10% by weight, more preferably 0.1 to 5% by weight. Thereby, the oxidation-reduction potential in the solution is maintained within a desired specific range that satisfies the requirement of the formula (3), and copper is rapidly leached from chalcopyrite in a two-step reaction.

  On the other hand, in the oxidation leaching of chalcopyrite with an aqueous iron sulfate solution under normal air charging conditions, the oxygen concentration in the air in the sedimentary layer is the period of high oxygen concentration due to the charging air immediately after the leaching starts. After that, since oxygen is consumed by the reducing power of the copper sulfide ore, it decreases. Thereafter, when the charging of air is continued, the oxygen concentration in the air in the deposition layer rises again. At this time, when the period in which the oxygen concentration in the air in the deposited layer exceeds 10% by weight extends to the end of the leaching except for the period immediately after the start of leaching, the redox of the solution in the deposited layer Since the potential rises above the desired upper limit, direct leaching of chalcopyrite proceeds slowly.

  The copper sulfide ore containing chalcopyrite used for the raw material of the present invention is not particularly limited, and copper sulfide ore in which part or most of the contained copper mineral is chalcopyrite, or flotation from the copper sulfide ore, etc. A copper concentrate enriched with copper is used.

  The copper sulfide ore is crushed and used in order to expose most of the copper mineral. As the crushing method, blasting during mining or various crushers are used. Here, the particle size of the crushed product is not particularly limited, and an optimum pulverized particle size may be selected by comprehensively judging the properties and profitability of the raw ore. When the target is copper concentrate, it is already fine and does not need to be crushed.

  The leaching method of the present invention is not particularly limited, and a method of adding an aqueous iron sulfate solution to the deposited layer made of copper sulfide ore and allowing the charged air to pass therethrough, for example, heap leaching, bat leaching or column Of these, leaching is used. Among these, bat leaching or column leaching is preferable from the viewpoint of controllability of oxygen concentration.

The means for adjusting the oxygen concentration in the air in the deposition layer used in the present invention is not particularly limited, but may be a leaching method (butt leaching or column leaching) in which a deposition layer is formed in the column or bat. For example, the opening of the leaching container can be closed and the amount of air charged into the container can be adjusted with a pump or the like, or the oxygen concentration in the charging air can be adjusted. In the case of heap leaching, the amount of air blown from the drain pipe or aeration pipe embedded in the heap may be adjusted.
For example, as a means of adjusting the oxygen concentration in the charge air, it is effective to circulate and use exhaust air that has become a low oxygen concentration due to iron oxidation reaction in the deposit layer as the charge air to the deposit layer. To be done.

  In the case of bat leaching or column leaching, the oxygen concentration of the air in the deposited layer is measured by introducing air discharged from the leaching vessel into a sealed vessel and installing an oxygen concentration meter in the vessel. In the case of heap leaching, a pipe is inserted to an appropriate depth in the heap, the internal air is sucked out by a pump, and the oxygen concentration is measured.

The iron sulfate aqueous solution used in the present invention is not particularly limited, but preferably has an iron concentration of 1 to 10 g / L and a pH of 1.0 to 2.5. Here, the iron concentration and pH in the iron sulfate aqueous solution are adjusted and used.
Furthermore, the iron sulfate aqueous solution used in the present invention is not particularly limited, but the iron concentration is 1 to 10 g / L, the copper concentration is 0.1 to 5 g / L, and the pH is 1.0 to 2. 5 is more preferable. Here, as the leachate, the solution discharged through the deposition layer is repeatedly used after adjusting the components as necessary. In order to obtain an iron sulfate aqueous solution within this range of conditions, there is no particular limitation, but the conditions of the solvent extraction step performed as a post-leaching step are adjusted, and the extraction residual liquid obtained from that step is again reused. Can be used with adjustment.

  The Fe concentration of the iron sulfate aqueous solution is preferably adjusted to 1 to 10 g / L, more preferably around 5 g / L. That is, the higher the iron concentration, the higher the copper leaching rate, but if it is less than 1 g / L, the copper leaching rate decreases and the recovery efficiency decreases. On the other hand, if it exceeds 10 g / L, the viscosity of the liquid increases and precipitation of insoluble iron compounds increases, which hinders leaching.

  The method for adjusting the Fe concentration of the aqueous iron sulfate solution is not particularly limited. Usually, iron eluted from the ore in the leaching noble liquid is not recovered by solvent extraction, so that the extraction residual liquid containing iron is used as the leaching liquid as it is. The concentration can be maintained by repeating. If the iron concentration becomes too high, part of the extraction residue is discharged out of the system and diluted by replenishing with fresh water. When it is insufficient, it is preferable to add ferrous sulfate and / or ferric sulfate to a new aqueous solution or leaching circulating liquid. Here, since the form of the iron sulfate to be added is greatly related to the potential of the aqueous iron sulfate solution, the one that allows easy adjustment of the potential is appropriately selected.

  The pH of the iron sulfate aqueous solution is preferably adjusted to 1.0 to 2.5, more preferably 1.5 to 2.0. That is, if the pH is less than 1.0, the acid consumption is increased, which is economically disadvantageous, and causes a decrease in extraction rate in solvent extraction generally performed in the downstream process of the leaching process. Problems arise. On the other hand, when the pH exceeds 2.5, there arises a problem that the leaching rate of copper is lowered and the insoluble iron compound is precipitated to prevent the leaching reaction. The method for adjusting the pH is not particularly limited, and a mineral acid such as sulfuric acid or hydrochloric acid is added to the aqueous solution or the leaching circulating solution. In particular, it is preferable to use inexpensive sulfuric acid from the viewpoint of economy.

  Moreover, Cu concentration of the said iron sulfate aqueous solution becomes like this. Preferably it is 0.1-5 g / L, More preferably, it adjusts to 0.5-1 g / L. That is, the higher the copper concentration, the higher the copper leaching rate. However, when the concentration is less than 0.1 g / L, the copper leaching rate decreases. On the other hand, when the concentration exceeds 5 g / L, the copper leaching rate is included in the leachate remaining in the deposited layer. The amount of copper produced increases and the recovery rate decreases.

  The addition amount of the iron sulfate aqueous solution is not particularly limited, and at least an amount that can be sufficiently distributed over the entire copper sulfide ore is added. However, depending on the shape of the reaction vessel to be used, the situation of downstream processes after leaching, etc. Adjust accordingly. Among these, if the amount of the iron sulfate aqueous solution added as the leaching solution is too large, the concentration of the leaching noble solution (leaching product solution) becomes too thin and the efficiency in the solvent extraction in the downstream process is lowered. 20 times or less is preferable.

  In the leaching method of the present invention, in order to control the leaching reaction, the pH and potential of the leachate obtained from the deposited layer are measured at regular intervals. Here, in general, the potential of the leachate in the deposited layer gradually decreases due to the reducing power of the copper mineral itself, but is normally balanced by the oxidizing power of oxygen dissolved from the air present in the gaps in the deposited layer. It is kept constant.

  The oxidation-reduction potential (Ag / AgCl electrode standard) of the leachate in the deposition layer is not particularly limited, and preferably 350 to 450 mV by adjusting the oxygen concentration of air in the deposition layer by the above method. More preferably, it is adjusted to 380 to 420 mV.

As a method of taking out the noble liquid containing copper obtained by the leaching method of the present invention from the process, a method of intermittently recovering the leachate in the reaction tank by a replenishment operation, a method of continuously recovering a small amount of the leachate, A method of collecting all the noble liquids at once is performed, and a method suitable for the form and capacity of the downstream process can be appropriately selected.
In addition, as a method for recovering copper from the noble liquid, a method of producing electrolytic copper by solvent extraction and electrowinning is generally performed, but the noble liquid recovered by the method of the present invention is used in this method. It is suitable for application.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples of the present invention, but the present invention is not limited to these examples. In addition, the analysis method of the metal used in an Example and a comparative example, a mineral ratio, and fixed carbon is as follows.
(1) Metal analysis: ICP emission analysis was performed.
(2) Analysis of mineral ratio: Determined by microscopic observation.

  In addition, the copper sulfide ores used in the examples and comparative examples were crushed meteorites not containing sulfide minerals to 12.5 mm or less, and mixed with Chilean copper concentrate so that the total Cu quality would be 1% by weight. And formulated. The mixing ratio at this time was 360 g of copper concentrate with respect to 10 kg of meteorite. Table 1 shows chemical analysis values and mineral ratios of the Chilean copper concentrate.

  From Table 1, it can be seen that almost all of the copper mineral contained in the copper concentrate is chalcopyrite.

The structure of the column leaching device used in the examples and comparative examples is as follows.
FIG. 2 shows the structure of the column leaching device. In FIG. 2, the upper end of the column 1, the leachate pipe 2, the leachate noble liquid pipe 3, the leachate tank 4, and other openings are sealed or water-sealed to prevent excess contact with the outside air. Here, the leachate can be repeatedly added to the column 1 by the feed roller pump 5 via the leachate tank 4.
In addition, air is introduced from the vent pipe 6 provided at the lower end of the column 1 by the aeration roller pump 8, and the air discharged from the upper exhaust pipe 7 to the outside of the column is connected to the roller pump suction pipe 9 and circulated. The oxygen concentration can be measured with an oxygen concentration meter 10 installed in the middle of the pipe. Further, the roller pump suction pipe 9 is provided with a three-way cock 11 so that outside air can be introduced as required.

Example 1
First, 10 kg of the copper sulfide ore was kneaded on a polyethylene sheet while adding a predetermined amount of water and concentrated sulfuric acid little by little to prepare an ingot for leaching. Here, the addition amount of water was 200 mL, and the addition amount of concentrated sulfuric acid (concentration 98 wt%) was 5.2 g. The amount of water to be added is the minimum amount in which ore does not adhere to the polyethylene sheet after kneading, and the amount of concentrated sulfuric acid added is a preliminary test so that the effluent pH at the start of leaching is around 2.0. We used what was found by

Next, the obtained agglomerated material was leached as follows using the column leaching device. The column leaching apparatus is installed in a temperature-controlled room controlled at 30 ° C.
The agglomerated material was packed in a vinyl chloride column having a diameter of 10 cm and a height of 1 m, and a leachate was dropped from the top of the column with a roller metering pump at a rate of 5 L / h per square meter of the upper surface area. Here, as an initial leaching solution, a solution prepared by dissolving ferrous sulfate in pure water so as to have an iron concentration of 5 g / L and adding sulfuric acid to adjust the pH to 1.5 was used.
The liquid flowing out from the lower end of the column was collected in a 10 L polyethylene bottle, supplied to a roller-type metering pump, and repeated as a leachate. Thereafter, when the leaching operation progressed and the copper concentration of the leaching precious liquid exceeded 5 g / L, half of the leaching liquid to be charged was replaced with a solution having the same composition as the initial leaching liquid, and the leaching operation was further continued. Here, air was introduced into the column at a flow rate of 60 mL / h, and then the air discharged from the upper end of the column was circulated and used throughout the leaching period.

During this time, the oxygen concentration in the circulating air and the oxidation-reduction potential of the leachate discharged from the column (leaching noble liquid) were measured throughout the leaching operation.
The measurement result of the obtained oxygen concentration in the circulating air is shown in FIG. FIG. 3 shows that the oxygen concentration in the circulating air gradually decreases because oxygen is consumed in the leaching reaction, and is less than 10% by weight 20 days after the start of leaching. Furthermore, after that, it decreases to 5% by weight or less, but it can be seen that the decrease becomes moderate. This seems to be because outside air enters through the gaps in the pipe joints because the inside of the apparatus has a negative pressure.
Moreover, the measurement result of the oxidation-reduction potential (ORP, Ag / AgCl electrode standard) of the obtained leaching noble liquid is shown in FIG. FIG. 4 shows that the redox potential (Ag / AgCl electrode standard) of the leaching noble liquid is maintained in the range of 350 to 450 mV over the entire leaching period.
In the above leaching operation, the Cu leaching rate was measured over the entire leaching period. In addition, the measurement of the Cu leaching rate was obtained by analyzing the copper concentration of the leaching noble liquid every predetermined number of days. The results are shown in FIG.

(Comparative Example 1)
Except that outside air was introduced from the lower end of the column at a flow rate of 1.0 mL / min and the air discharged from the column was not circulated, the same operation as in Example 1 was performed. During this time, the column was discharged from the column during the entire leaching operation. The oxygen concentration in the air and the redox potential of the leachate discharged from the column (leaching noble liquid) were measured. The results are shown in FIGS. 3 and 4, respectively.
FIG. 3 shows that the oxygen concentration in the air exhausted from the column at this time once decreases at the initial stage of the leaching reaction, but then increases to an oxygen concentration of 10% by weight or more. Further, from FIG. 4, the oxidation-reduction potential (Ag / AgCl electrode standard) of the leaching noble solution at this time is in the range of a high potential exceeding 450 mV over the entire leaching period except for a short period at the beginning of leaching. I understand that. For this reason, since the oxidation-reduction potential of the leaching solution is not maintained in a desired range, the leaching of chalcopyrite proceeds slowly.
Moreover, Cu leaching rate was measured over the whole leaching period. The results are shown in FIG.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the air exhausted from the column was not circulated and the column was not sealed and the outside air was allowed to freely enter and exit the column. The redox potential of the discharged leachate (leached noble liquid) was measured. The results are shown in FIG. From FIG. 4, the oxidation-reduction potential (Ag / AgCl electrode standard) of the leaching noble solution at this time is in a high potential range exceeding 450 mV over the entire leaching period except for a short period at the beginning of leaching. I understand. Note that the air in the column at this time is in a state where it can freely enter and exit, so the oxygen concentration can be regarded as 21% by weight, which is the same as air.
Moreover, Cu leaching rate was measured over the whole leaching period. The results are shown in FIG.

  As is clear from FIG. 1, in Example 1, the oxygen concentration in the air in the deposited layer is adjusted according to the method of the present invention, and the redox potential of the leachate obtained from the deposited layer (Ag / AgCl electrode standard). Is maintained in the range of 350 to 450 mV throughout the leaching period, it can be seen that the chalcopyrite is leached by a two-stage reaction, the copper leaching rate is increased, and leaching is performed at a high leaching rate. On the other hand, in Comparative Example 1 or 2, since the adjustment of the oxygen concentration in the air in the deposition layer does not meet these conditions, the oxidation-reduction potential of the leaching solution is not maintained in a desired range. It can be seen that satisfactory results are not obtained.

  As is clear from the above, the leaching method of copper sulfide ore containing chalcopyrite of the present invention is suitable as a leaching method of copper mineral used in the copper refining field. In particular, it is useful as a method for eluting copper at a high leaching rate from hardly leachable copper ore, which is mainly copper mineral.

It is a conceptual diagram showing the relationship between the elution rate of chalcopyrite and electric potential. It is a figure showing the structure of the column leaching apparatus used by the Example and the comparative example. It is a figure showing the change of the oxygen concentration in the air discharged | emitted from the column obtained by the Example and the comparative example. It is a figure showing the change of the oxidation reduction potential of the leachate discharged | emitted from the column obtained by the Example and the comparative example. It is a figure showing transition of Cu leaching rate obtained by the Example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Column 2 Leachate piping 3 Leached noble liquid piping 4 Leachate tank 5 Liquid supply roller pump 6 Vent pipe 7 Exhaust pipe 8 Ventilation roller pump 9 Roller pump suction pipe 10 Oxygen meter 11 Three-way cock

Claims (5)

A method of leaching copper using a leachate from a copper sulfide ore containing chalcopyrite while charging air,
By adding an iron sulfate aqueous solution as a leachate to the copper sulfide ore deposit and circulating low-oxygen-concentrated air discharged from the deposit as charge air to the deposit , except immediately after the start of leaching. A copper sulfide ore leaching method characterized by adjusting the oxygen concentration in the air supplied into the deposition layer to 10% by weight or less until the end of leaching.   2. The copper sulfide ore leaching method according to claim 1, wherein the iron sulfate aqueous solution has an iron concentration of 1 to 10 g / L and a pH of 1.0 to 2.5.   The copper sulfide ore leaching method according to claim 2, wherein the iron sulfate aqueous solution has a copper concentration of 0.1 to 5 g / L.   2. The copper sulfide ore leaching method according to claim 1, wherein the leaching is performed by any one of heap leaching, butt leaching, and column leaching. Leaching method of copper sulfide ore according to any one of claims 1 to 4, characterized in that adjusting the redox potential of the leaching solution of the deposited layer within the (Ag / AgCl electrode standard) to 350～450MV.

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