JP2007113084A - Method for reducing cupric chloride ion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reducing cupric chloride ions by which cupric chloride ions can efficiently be reduced into cuprous chloride ions in order to obtain a reduced product liquid, in which cuprous chloride ions exist at high ratio, by a method utilizing a copper concentrate as a reducing agent, regardless of the difference in the mineral composition of the copper concentrate in a wet type copper refining process. <P>SOLUTION: In the wet type copper refining process, when a process where cupric chloride ions are reduced into cuprous chloride ions is performed, (i) reaction temperature is set to 90 to 120°C, (ii) copper concentrate comprising at least one copper sulfide mineral selected from chalcopyrite, chalcocite and bornite is used as the reducing agent, and (iii) the amount of the reducing agent to be added is decided based on the containing ratio of the copper sulfide mineral(s) in the copper concentrate for controlling the final oxidation-reduction potential after completion of the reduction reaction to desired value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for reducing cupric chloride ions, and more specifically, a step of leaching a copper raw material containing a copper sulfide mineral to form cupric chloride ions, and leaching the cupric chloride ions. In a wet copper smelting process including a step of reducing to cuprous chloride ions by a reducing agent and a step of electrolytically collecting the reduced cuprous chloride ions, the cupric chloride ions are reduced to cuprous chloride ions. In order to obtain a reduction product liquid containing cupric chloride ions in a high ratio in a manner using copper concentrate as a reducing agent, regardless of the difference in the mineral composition of copper concentrate, The present invention relates to a method for reducing cupric chloride ions that can be efficiently reduced.

Currently, most of the world's copper is produced by the dry smelting method using copper sulfide concentrate as a raw material. Copper smelting by dry smelting is a method in which copper sulfide concentrate is subjected to a series of dry smelting processes such as a smelting furnace, converter and refining furnace, and then the resulting crude copper is electrolytically purified. Although it is a method suitable for efficient processing, the reaction efficiency is poor in small equipment, but on the other hand, enormous capital investment is required for large equipment, and a large amount of SO ₂ gas is recovered. There are issues such as being indispensable.

  Under such circumstances, in recent years, a smelting method using a wet method has been studied. Conventionally, as copper refining by a wet method, using copper ore containing copper oxide minerals, sulfuric acid is sprayed on the piled ore to leach copper, and solvent extraction method to increase the copper concentration of the leaching product liquid After the treatment with, the method of electrolytic collection is widely used industrially. However, when the above method is applied to sulfide ore occupying most of copper ore, the mineral composition of sulfide ore is generally a natural mineral, so there is no single mineral composition, and various copper sulfide minerals are a mixture. It is processed in the state. Here, chalcocite and porphyry are easily soluble in sulfuric acid leaching, while chalcopyrite, which has the highest abundance as a contained mineral, has a problem that the leaching rate with sulfuric acid is slow and the copper leaching rate is low. was there. Therefore, it has been difficult to obtain productivity comparable to dry smelting by a smelting method using a wet method.

  Therefore, in the hydrometallurgical process for copper concentrates containing copper sulfide minerals such as chalcopyrite, there is a hydrometallurgical process in which copper concentrate is leached with an aqueous chloride solution or chlorine gas and electrowinned to obtain metallic copper. Proposed. For example, a wet copper refining process (for example, a step of leaching a copper raw material containing copper sulfide minerals, a step of reducing a copper ion by adding a reducing agent to the leaching product solution, and a step of electrowinning the copper ion) In addition to many basic problems of the above-mentioned dry smelting method, many problems as a wet smelting method, for example, suppression of sulfur oxidation, high leaching rate of copper from chalcopyrite And the recovery of the accompanying valuable metals is solved.

By the way, conventionally, the electrolytic extraction method in a sulfuric acid bath which is industrially performed is to reduce cupric sulfate (divalent) ions by electrolysis and deposit as a metal. Unlike a sulfuric acid bath, copper ions can exist in a monovalent or divalent form in a chloride bath using an aqueous chloride solution. Therefore, when the electrolytic collection is performed from the cuprous chloride ion, the amount of electricity that is half of that obtained by the electrolytic collection from the cupric chloride ion is sufficient, and the power cost can be greatly reduced.
That is, the purpose of the step of reducing the copper ions is to obtain cupric chloride (2) in the leaching product obtained in the step of leaching a copper raw material containing a copper sulfide mineral prior to the step of electrolytically collecting copper ions. (Reduced) ions are previously reduced to cuprous chloride (monovalent) ions. Here, when iron coexists in the leaching solution, iron is simultaneously reduced from ferric chloride (trivalent) ions to ferrous chloride (divalent) ions.

  In general, the simplest method for reducing copper and iron in an aqueous chloride solution to cuprous ions and ferrous ions is to use metallic copper or a base metal rather than copper such as iron as the reducing agent. However, there are problems in economic efficiency such as a decrease in the direct yield of copper and an increase in the iron concentration of the electrolyte. Moreover, the method using sulfite gas, sulfite, etc. has practical problems such as an increase in the sulfate ion concentration in the liquid and an increase in the cost for removing it.

Further, in a method of corroding a chlorine leaching product liquid with a copper raw material such as chalcopyrite (CuFeS ₂ ) under high pressure and high temperature (see, for example, Patent Document 2), the second copper ion in the leaching product liquid is a first. Although it can be effectively reduced to copper ions, there are problems such as an increase in the cost of equipment such as an autoclave, and complicated control and handling of the reaction.

  As a solution to this, a wet copper smelting process including a step of leaching a copper raw material containing a copper sulfide mineral, a step of reducing a copper ion by adding a reducing agent to the leaching solution, and a step of electrolytically collecting the copper ion In the process, in the step of reducing the copper ions, copper concentrate containing chalcopyrite as a main mineral as a reducing agent is added to a leaching product solution at a temperature of 100 to 120 ° C. under atmospheric pressure to form a slurry, Thereafter, a reduction method of cupric chloride ion that performs a reduction reaction (for example, see Patent Document 3) has been proposed. According to this proposal, it is possible to reduce the cupric ion using copper concentrate with chalcopyrite as the main mineral as a reducing agent, and obtain a reduction product liquid in which the cuprous ion is present in a high ratio. It has been shown that there are differences in the efficiency of the reduction reaction due to changes in the production area and deposits of the copper concentrates that affect the operating conditions such as the required amount of addition to the leaching solution.

  From the above situation, copper concentrate is used as a reducing agent in the process of reducing copper ions in a wet smelting method in which copper concentrate is leached with an aqueous chloride solution or chlorine gas to obtain metal copper by electrowinning. Regardless of the difference in the mineral composition of copper concentrate, a method for stably and efficiently reducing cupric chloride ions in the leaching solution to cuprous chloride ions is required.

JP 2005-60813 A (first page, second page) JP-A-2004-244663 (first page, second page) JP-A-2005-232594 (first page, second page)

  In view of the above-mentioned problems of the prior art, an object of the present invention is to form a cupric chloride ion by leaching a copper raw material containing a copper sulfide mineral to form a cupric chloride ion, and to reduce the extracted cupric chloride ion to a reducing agent. A step of reducing the cupric chloride ion to cuprous chloride ion in a wet copper smelting process including a step of reducing to cuprous chloride ion by electrolysis and a step of electrolytically collecting the reduced cuprous chloride ion. In order to obtain a reduction product liquid containing cupric chloride ions in a high ratio by using copper concentrate as a reducing agent, it is efficient regardless of the difference in the mineral composition of copper concentrate. An object of the present invention is to provide a method for reducing cupric chloride ions that can be reduced to a low level.

  In order to achieve the above object, the present inventors have conducted extensive research on the method of reducing cupric chloride ions in the wet copper smelting process, and as a result, in the step of reducing the copper ions, After setting the reaction temperature within a specific temperature range, copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite, chalcocite or porphyry is used as the reducing agent, and the amount of the reducing agent added is In order to control the final redox potential after the reduction reaction to a desired value, it was determined based on the copper sulfide mineral content in the copper concentrate regardless of the difference in the mineral composition of the copper concentrate. The present inventors have found that the reduction can be performed stably and efficiently with a reducing power without deficiency.

That is, according to the first invention of the present invention, the step of leaching a copper raw material containing a copper sulfide mineral to form cupric chloride ions and the leached cupric chloride ions with a reducing agent are chlorinated. In a wet copper smelting process including a step of reducing to one copper ion and a step of electrolytically collecting the reduced cuprous chloride ion,
In carrying out the step of reducing the cupric chloride ion to cuprous chloride ion,
B) The reaction temperature is set to 90 to 120 ° C,
B) The reducing agent is a copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite, chalcocite or porphyry,
C) The amount of the reducing agent added is determined based on the content ratio of the copper sulfide mineral in the copper concentrate in order to control the final redox potential after completion of the reduction reaction to a desired value. A method for reducing cupric chloride ions is provided.

According to the second invention of the present invention, in the first invention, the amount of the reducing agent added is adjusted to a value equal to or higher than the slurry concentration (C) satisfying the following formula (1): A method for reducing cupric chloride ions is provided.
C = (A−B) / (a × D / 100 + b × E / 100 + c × F / 100) (1)
(In the formula, A represents the oxidation-reduction potential of the leaching solution (Ag / AgCl electrode standard), and the unit is mV. B is the final oxidation-reduction potential after the desired reduction reaction (Ag / AgCl electrode standard). The unit is mV, C is the slurry concentration, and the unit is g / L. D, E, and F are the contents of chalcopyrite, chalcopyrite, and chalcopyrite, respectively, in the copper concentrate ( A, b, and c represent a unit concentration (1 g / L) of copper sulfide mineral by controlling the leaching product liquid having a desired composition after reduction using copper concentrate to a desired temperature. (Denotes the reduction value of the oxidation-reduction potential (Ag / AgCl electrode standard) obtained when added alone.)

  According to the third invention of the present invention, in the second invention, in the formula (1), a is 1.49, b is 1.58, and c is 0.56. A method for reducing cupric chloride ions is provided.

  According to the fourth invention of the present invention, in the second or third invention, B is 380 in the formula (1), wherein the cupric chloride ion is reduced. Is provided.

  According to a fifth invention of the present invention, in any one of the first to fourth inventions, the particle size of the copper concentrate is adjusted to an average particle size (D50) of 0.5 to 60 μm. A method for reducing cupric chloride ions is provided.

  According to the method for reducing cupric chloride ions of the present invention, according to the first aspect, a step of leaching a copper raw material containing a copper sulfide mineral to form cupric chloride ions and leached second chloride chloride. In the process of reducing the cupric chloride ion in a wet copper smelting process, including a step of reducing copper ion to cuprous chloride ion by a reducing agent and a step of electrolytically collecting the reduced cuprous chloride ion. In order to obtain cuprous chloride ions by reducing cupric chloride ions using copper concentrate as a reducing agent, regardless of the difference in the mineral composition of copper concentrate, the amount added to the leaching product liquid is determined, Since the reduction can be performed stably and efficiently with a reducing power without deficiency, its industrial value is extremely large.

  In addition, in the second invention, the amount of copper concentrate added to the leaching product liquid is such that the slurry concentration to be formed, the redox potential of the leaching product liquid, the final redox potential after the desired reduction reaction, the reduction of the copper sulfide mineral The relationship between the reduction value of the oxidation-reduction potential when a unit concentration (1 g / L) of copper sulfide mineral is added to the leaching product liquid, and the composition ratio of the copper sulfide mineral in the copper concentrate. Since it can be calculated | required using, it is simple and is more advantageous. In the third invention, a representative value of 1.49, b of 1.58, and c of 0.56 can be used as representative values. In the fourth aspect of the invention, a reduction product liquid in which cuprous chloride ions are present in a high ratio can be obtained. Furthermore, the fifth invention is more advantageous because the reduction reaction can be performed more efficiently by optimizing the particle size of the copper concentrate.

Hereinafter, the cupric chloride ion reduction method of the present invention will be described in detail.
The method for reducing cupric chloride ion according to the present invention includes a step of leaching a copper raw material containing a copper sulfide mineral to form cupric chloride ions, and leaching the leached cupric chloride ions with a reducing agent. In the wet copper smelting process including the step of reducing to 1 copper ion and the step of electrolytically collecting the reduced cuprous chloride ion, the step of reducing the cupric chloride ion to cuprous chloride ion is performed. In the above, a) the reaction temperature is set at a temperature of 90 to 120 ° C., and b) the reducing agent is a copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite, chalcopyrite or porphyry, Furthermore, the amount of addition of the reducing agent is determined based on the content ratio of the copper sulfide mineral in the copper concentrate in order to control the final oxidation-reduction potential after the reduction reaction to a desired value. And

In the reduction method of the present invention, the reactivity of the copper sulfide mineral, which is a reducing agent, with the cupric ions and ferric ions in the leaching product solution is a reduction in the redox potential of the reduction product solution, that is, the reduction reaction. It is important for the degree of progress.
Here, a reduction reaction when the copper sulfide mineral is chalcopyrite is shown as an example. The reduction reaction is a reaction in which cupric ions and ferric ions are reduced to cuprous ions and ferrous ions and elemental sulfur is generated, and is represented by the following chemical reaction formulas 1 and 2. It is a leaching reaction of chalcopyrite with cupric ions and ferric ions.

Chemical reaction formula 1: Cu ²⁺ + 1 / 3CuFeS ₂ → 4 / 3Cu ⁺ + 1 / 3Fe ²⁺ + 2 / 3S,
Chemical reaction formula 2: Fe ³⁺ + 1 / 3CuFeS ₂ → 1 / 3Cu ⁺ + 4 / 3Fe ²⁺ + 2 / 3S

  In the above reaction, the reactivity of the cupric and ferric ions in the leaching solution and the chalcopyrite, which is the reducing agent, depends on the concentration of each ion in the leaching solution, the oxidation-reduction potential, etc. It is controlled by conditions such as particle size, reduction temperature, and slurry concentration.

In the reduction method of the present invention, the copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite, chalcopyrite, or porphyry as a reducing agent is used to reduce the leaching product liquid. It is important to determine the amount of copper concentrate to be added to the leaching solution based on the content of each copper sulfide mineral and form a slurry with the amount of addition and perform a reduction reaction at a temperature of 90 to 120 ° C. . Thereby, it can reduce stably and efficiently with the reducing power without deficiency irrespective of the difference in the content composition of copper concentrate.
That is, when reducing the leaching solution, the reducing power for the leaching solution varies depending on the copper sulfide mineral contained in the copper concentrate. Therefore, it is important to form a slurry using the addition amount considering the content ratio of each copper sulfide mineral or copper concentrate in order to efficiently reduce with a reducing power without deficiency. .

  As one embodiment of the above reduction method, the amount of copper concentrate added is preferably a value equal to or higher than the slurry concentration (C) that satisfies the following formula (1).

  C = (A−B) / (a × D / 100 + b × E / 100 + c × F / 100) (1)

  Here, in the formula, A represents the oxidation-reduction potential (Ag / AgCl electrode standard) of the leaching solution, and the unit is mV. B represents the final oxidation-reduction potential (Ag / AgCl electrode standard) after the desired reduction reaction, and the unit is mV. D, E, and F represent the content ratio (% by weight) of chalcopyrite, chalcocite and chalcopyrite, respectively, in the copper concentrate. a, b, and c are obtained when a leaching product liquid having a desired composition after reduction using copper concentrate is controlled at a desired temperature and a copper sulfide mineral having a unit concentration (1 g / L) is added alone. The reduction value of the oxidation-reduction potential (Ag / AgCl electrode standard) is expressed, and the unit is mV / (g / L).

  That is, in the formula (1), the slurry concentration (C) is the redox potential (AB) that should be reduced by reduction, when the copper sulfide mineral having a unit concentration (1 g / L) is added to the leaching product liquid alone. It is obtained as the sum of the reduced values of the obtained oxidation-reduction potential (Ag / AgCl electrode standard) by the composition ratio, that is, divided by the reducing power of copper concentrate.

  In addition, the values of a, b, and c are determined by controlling the leaching product liquid having a desired composition (copper and iron concentration) after reduction using copper concentrate to a desired temperature to obtain a predetermined amount of copper sulfide mineral. It is determined from the decreased value of the oxidation-reduction potential (Ag / AgCl electrode standard) when added. For example, the values of a, b and c obtained by controlling a leaching solution having a typical liquid composition (liquid composition: copper 20 g / L, iron 100 g / L, chlorine 200 g / L) at 103 to 105 ° C. Are 1.49, 1.58, and 0.56, respectively. However, the oxidation-reduction potential is 90 ° C. standard.

  Therefore, when the values of a, b and c are used, from the above equation (1), the slurry concentration (C), the oxidation-reduction potential (A) of the leaching product liquid, and the final oxidation-reduction after the desired reduction reaction The following formula (2) representing the relationship between the potential (B) and the content ratios (D, E, F) of chalcopyrite, chalcocite and porphyry in the copper concentrate is obtained. However, the oxidation-reduction potential is 90 ° C. standard.

  C = (A−B) / (1.49 × D / 100 + 1.58 × E / 100 + 0.56 × F / 100) (2)

The copper concentrate used in the reduction method is a copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite (CuFeS ₂ ), chalcocite (Cu ₂ S), or chalcopyrite (Cu ₅ FeS ₄ ). For example, copper concentrate obtained by concentrating sulfide minerals by physical separation means such as flotation is used for ores containing copper sulfide minerals such as chalcopyrite, chalcopyrite, and chalcopyrite. For example, in the above-mentioned wet copper refining process, when copper concentrate containing chalcopyrite as a main mineral is used as a copper raw material containing copper sulfide mineral, this can be used as a reducing agent. This is efficient because the copper concentrate can be partially leached prior to the chlorine leaching step.

  The particle size of the copper concentrate is not particularly limited, and a particle size usually obtained by a flotation method, for example, an average particle size (D50) of 100 μm or less is used, but an average particle size (D50) of the copper concentrate is used. Since the reduction reaction is more likely to proceed as the particle size becomes finer, the average particle size (D50) is preferably 0.5 to 60 μm, and more preferably 5 to 15 μm in view of the required reaction time and filterability in the next step. Adjusted to In addition, the average particle diameter (D50) of copper concentrate corresponds to 50 volume% of volume frequency accumulation, and was measured with the micro track particle size distribution meter.

  The leaching product used in the reduction method is not particularly limited, and an aqueous chloride solution containing cupric ions and ferric ions and having a boiling point of 100 ° C. or higher is used. A chloride aqueous solution containing copper and iron obtained in the step of leaching a copper raw material containing copper mineral is preferred. In the case of the above-mentioned wet copper refining process, when the chlorine leaching process is performed under preferable operating conditions, this chloride aqueous solution usually has a redox potential (Ag / AgCl electrode standard) of 480 to 600 mV depending on the leaching conditions, and the chlorine ion concentration is 200. -400 g / L. That is, the boiling point of this liquid is 100 ° C. or higher in this chlorine ion concentration range.

It does not specifically limit as temperature used for the said reduction reaction, 90-120 degreeC is preferable. That is, when the temperature exceeds 120 ° C., the treatment under atmospheric pressure cannot be performed. On the other hand, when the temperature is lower than 90 ° C., the reaction is slow even if the copper concentrate is refined, and the efficiency is low because a long time treatment is required. Furthermore, 100-104 degreeC is more preferable from the surface of promotion of reaction and heat energy supply. Further, the temperature is maintained in the temperature range for the time required for the completion of the reduction reaction.
By the way, in the above-mentioned wet copper refining process, when the preferred operating conditions of the chlorine leaching process are used, chlorine leaching is usually performed at 100 to 110 ° C. under atmospheric pressure with a leaching solution having a chloride ion concentration of 6 mol / L or more. By boiling the liquid, the boiling point of the leaching product liquid can be raised to about 120 ° C. If the concentration is further advanced, the dissolved substance in the leaching product liquid starts to be precipitated as crystals, so that the liquid state cannot be maintained. Here, when there is a drop in the liquid temperature in handling the leaching product liquid, temperature adjustment such as heating can be performed.

  The time used for the reduction reaction is not particularly limited, and a reaction time for obtaining a desired oxidation-reduction potential, for example, 400 mV (Ag / AgCl electrode standard, 90 ° C.) or less is used. The reaction rate varies depending on the particle size of the ore, the water content, etc., and the reduction reaction conditions such as temperature and chloride ion concentration. Therefore, from the economical aspect, 1 to 5 hours are used, and in particular, 3 to 5 hours in which the reduction reaction sufficiently proceeds is more preferable.

  In the step of reducing the copper ions by the above reduction reaction, the oxidation-reduction potential (Ag / AgCl electrode standard, 90 ° C.) measured at 90 ° C. is used as the desired oxidation-reduction potential, that is, copper sulfide concentrate. Then, the second copper ions can be reduced to 400 mV or less, preferably 380 mV or less, in which the first copper ions are present in a high ratio. That is, a reduction product solution in which cupric ions are efficiently reduced to cuprous ions by treatment under atmospheric pressure, and an oxidation-reduction potential (Ag / AgCl electrode standard, 90 ° C.) is 400 mV or less, preferably 380 mV or less. Means you can get

  By the way, although it is difficult to accurately analyze the form of the cuprous and cupric copper in the leaching product liquid in which iron ions and the like coexist, for example, in the knowledge of the synthetic test liquid, the oxidation-reduction potential (Ag / AgCl When the electrode standard (90 ° C.) exceeds 400 mV, it is estimated that cupric ions are present in the liquid. That is, when a solution in which cuprous chloride and ferric chloride are mixed at a constant concentration is heated to 90 ° C., the oxidation-reduction potential (Ag / AgCl electrode standard, 90 ° C.) shows 380 to 400 mV. Therefore, in order for copper ions and iron ions to exist as cuprous ions and ferrous ions, the oxidation-reduction potential (Ag / AgCl electrode standard, 90 ° C.) is 400 mV or less, and completely the first copper ions and the second ions. It is presumed that it is required to be 380 mV or less in order to obtain 1 iron ion.

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 of the metal used by the Example and the comparative example and the average particle diameter (D50) of a copper concentrate are as follows.
(1) Metal analysis: ICP emission analysis was performed.
(2) Measurement of average particle diameter (D50) of copper concentrate: It was measured with a Microtrac particle size distribution meter.

Example 1
As a reducing agent, copper concentrate A (particle size: D50 = 22.0 μm, composition: copper 30.2 wt%, iron 29.1 wt%, sulfur 31.5 wt%) was used as a raw material. The mineral composition of this copper concentrate is obtained by converting the mineral ratio by observation with a reflection microscope to weight conversion, 87.9% of chalcopyrite, 0.05% of chalcopyrite, 0.0% of chalcopyrite, 5.6% of pyrite, pulse The stone content was 6.3%. In addition, a leaching product liquid of liquid composition: copper 20 g / L, iron 100 g / L, chlorine 200 g / L) was used. The oxidation reduction potential (Ag / AgCl electrode standard, 90 ° C.) of this leaching product solution was 517 mV.
First, after the said leaching product liquid was heated to 105 degreeC in reaction container, the said copper concentrate was thrown in so that a slurry density | concentration might be 110 g / L, and the copper ion in a liquid was reduce | restored, stirring.
Note that the slurry concentration is A = 517 (C = (A−B) / (1.49 × D / 100 + 1.58 × E / 100 + 0.56 × F / 100) using the following formula (2): mV), B = 380 (mV), D = 87.9 (% by weight) and E = 0.05 (% by weight) were calculated to be 104 g / L.
Thereafter, the redox potential decreases with time, and the final redox potential becomes 380 mV or less. At that time, the cupric ions in the liquid are changed to cuprous ions, and the ferric ions are converted to ferrous ions. Was.

(Example 2)
Copper concentrate B (particle size: D50 = 14.94 μm, composition: copper 32.2 wt%, iron 17.4 wt%, sulfur 23.7 wt%) was used as a reducing agent, and the slurry concentration was Except that it was 145 g / L, it was carried out in the same manner as in Example 1. As a result, the final oxidation-reduction potential became 380 mV or less, and the second copper ion in the liquid at that time was changed to the first copper ion, and the second iron ion was The reduction reaction to ferrous ions was complete.
In addition, the mineral composition of this copper concentrate is obtained by converting the mineral ratio obtained by observation with a reflection microscope into a weight conversion, 50.6% of chalcopyrite, 10.9% of chalcopyrite, 9.8% of chalcopyrite, and 4.8% of pyrite. The gangue component was 23.7%. At this time, the slurry concentration calculated from the equation (2) is A = 517 (mV), B = 380 (mV), D = 50.6 (wt%), E = 10.9 (wt%), Using F = 9.8 (wt%), it was 140 g / L.

(Comparative Example 1)
Except that the slurry concentration was 85 g / L, it was carried out in the same manner as in Example 1. As a result, the final oxidation-reduction potential was 405 mV, and the reduction reaction of the cupric ions in the liquid to the first copper ions was sufficiently performed. It was not progressing.

(Comparative Example 2)
When the same procedure as in Example 2 was performed except that the slurry concentration was 90 g / L, the final oxidation-reduction potential was 429 mV, and the reduction reaction of the second copper ions in the liquid to the first copper ions was sufficiently performed. It was not progressing.

  As mentioned above, in Example 1 or 2, in order to control the final oxidation-reduction potential after completion of the reduction reaction to a desired value, based on the content ratio of the copper sulfide mineral in the copper concentrate, Since the amount of addition was determined, a slurry was formed with the amount of addition, and the process was performed according to the method of the present invention, the final oxidation-reduction potential was lowered to 380 mV or less, and a reduction product solution containing cuprous chloride ions in a high ratio. It can be seen that On the other hand, in Comparative Example 1 or 2, since the addition amount of copper concentrate does not meet these conditions, it can be seen that satisfactory results cannot be obtained in the reduction reaction of the cupric ion.

  As is clear from the above, the cupric chloride ion reduction method of the present invention reduces the cupric chloride ion using copper concentrate as a reducing agent to obtain cuprous chloride ion. The amount of addition to the leaching solution is determined based on the mineral composition of the ore, and regardless of the difference in the mineral composition of the copper concentrate, it can be efficiently reduced with a sufficient reducing power. In the above, it is suitably used in the step of reducing copper ions.

Claims (5)

A step of leaching a copper raw material containing copper sulfide minerals to form cupric chloride ions; a step of reducing the leached cupric chloride ions to cuprous chloride ions by a reducing agent; and reduced chloride In a wet copper smelting process including a step of electrolytically collecting cuprous ions,
In carrying out the step of reducing the cupric chloride ion to cuprous chloride ion,
B) The reaction temperature is set to 90 to 120 ° C,
B) The reducing agent is a copper concentrate containing at least one copper sulfide mineral selected from chalcopyrite, chalcocite or porphyry,
C) The amount of the reducing agent added is determined based on the content ratio of the copper sulfide mineral in the copper concentrate in order to control the final redox potential after completion of the reduction reaction to a desired value. Reduction method of cupric chloride ion. 2. The cupric chloride ion reduction method according to claim 1, wherein the addition amount of the reducing agent is adjusted to a value equal to or higher than a slurry concentration (C) satisfying the following formula (1).
C = (A−B) / (a × D / 100 + b × E / 100 + c × F / 100) (1)
(In the formula, A represents the oxidation-reduction potential of the leaching solution (Ag / AgCl electrode standard), and the unit is mV. B is the final oxidation-reduction potential after the desired reduction reaction (Ag / AgCl electrode standard). The unit is mV, C is the slurry concentration, and the unit is g / L. D, E, and F are the contents of chalcopyrite, chalcopyrite, and chalcopyrite, respectively, in the copper concentrate ( A, b, and c represent a unit concentration (1 g / L) of copper sulfide mineral by controlling the leaching product liquid having a desired composition after reduction using copper concentrate to a desired temperature. (Denotes the reduction value of the oxidation-reduction potential (Ag / AgCl electrode standard) obtained when added alone.)   3. The method for reducing cupric chloride ions according to claim 2, wherein a is 1.49, b is 1.58, and c is 0.56 in the formula (1).   The method for reducing cupric chloride ions according to claim 2 or 3, wherein B is 380 in the formula (1).   The method for reducing cupric chloride ions according to any one of claims 1 to 4, wherein a particle size of the copper concentrate is adjusted to an average particle size (D50) of 0.5 to 60 µm.