JP2020045543A - Recovery method of copper from chalcopyrite and solvent system for recovery method - Google Patents

Abstract

To provide: a simple and economical recovery method for exuding, refining, and recovering copper from chalcopyrite; and a solvent system used for the recovery method.SOLUTION: Provided is a recovery method of copper from chalcopyrite, comprising: a step for dissolving chalcopyrite in a solvent system containing copper halide and an aprotic polar organic solvent; and a step for precipitating copper from the solvent system in which the chalcopyrite is dissolved by electrolytic extraction. Also provided is a solvent system to be used for dissolving chalcopyrite and recovering copper, which contains copper halide and an aprotic polar organic solvent.SELECTED DRAWING: None

Description

  The present invention relates to a method for recovering metal from ore, particularly to a method for recovering copper from chalcopyrite, and a solvent system used for the method.

  Copper is the third largest metal material in the world. Copper ores are classified into three types: primary sulfide ores (such as chalcopyrite (CuFeS2)), secondary sulfide ores (such as chalcopyrite (Cu2S)), and oxide ores (such as chalcopyrite (Cu2O)). Most of the world's copper is obtained from chalcopyrite (CuFeS2).

  Methods for producing copper from ore are generally classified into a dry smelting method and a hydrometallurgical method. The dry smelting method is a method of producing electrolytic copper through an electrolytic refining process after removing impurities such as iron and sulfur by a chemical reaction by heat treatment. Although the dry smelting method is an effective method for copper sulfide ores such as chalcopyrite (CuFeS2) which is a primary sulfide ore, it is not economically viable unless high-grade ore is used.

  On the other hand, the wet refining method is a method in which copper is leached from an oxidized ore (such as Cu2O) with a sulfuric acid solution, only copper ions are extracted by two-layer separation, and finally electrolytic copper is produced by an electrolytic extraction process. It has been established as Extraction-Electro-Winning (SX-EW method).

  Copper ore is a non-renewable resource, and in recent years, its crude ore grade has been significantly reduced. Therefore, as a method for producing copper from low-grade ore, dry smelting has become economically infeasible. On the other hand, the above SX-EW method cannot be applied to chalcopyrite (CuFeS2), which accounts for the majority of copper ore, and the process of wet-treating low-grade chalcopyrite (CuFeS2) is still It is currently not commercialized. The leaching rate of copper from chalcopyrite (CuFeS2) is very low in the sulfuric acid solution used in the SX-EW method because the surface of the chalcopyrite is passivated, and 10-40% even after 10-20 years This is because there are drawbacks such as leaching only to a degree.

  In recent years, a bioleaching technique for chalcopyrite using bacteria has been studied, but generally, bioleaching has a disadvantage that the leaching rate of metal is low.

  Further, Patent Document 1 filed by the applicant himself discloses that gold, palladium, silver, and platinum can be dissolved in a copper bromide-containing dimethyl sulfoxide solvent, but nothing is described with respect to dissolution of chalcopyrite. .

International Publication No. 2014/156300

  In view of the above background, an object of the present invention is to provide a simple and economical recovery method for recovering copper from chalcopyrite and a solvent system used for the recovery method.

  The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by using an organic solvent system containing copper halide, it is possible to dissolve and precipitate the target copper in a relatively short time. And completed the present invention.

  According to one aspect of the present invention, in order to solve the above-mentioned problems, a step (A) of dissolving chalcopyrite in a solvent system containing a copper halide and an aprotic polar organic solvent; The method includes a step (B) of precipitating copper by electrolytic sampling from the dissolved solvent system.

  It is further preferred that the copper halide is selected from copper (I) bromide, copper (II) bromide, copper (I) chloride or copper (II) chloride.

  Further, it is desirable that the aprotic polar organic solvent be selected from dimethylsulfoxide, dimethylformamide, acetone, acetonitrile, tetrahydrofuran, propylene carbonate or a mixture thereof.

  Further, it is desirable that the solvent system further comprises a sodium or potassium halide.

  According to another aspect of the present invention, there is provided a solvent system containing copper halide and an aprotic polar organic solvent, which is used for dissolving chalcopyrite to recover copper.

  It is further preferred that the copper halide is selected from copper (I) bromide, copper (II) bromide, copper (I) chloride or copper (II) chloride.

  Further, it is desirable that the aprotic polar organic solvent be selected from dimethylsulfoxide, dimethylformamide, acetone, acetonitrile, tetrahydrofuran, propylene carbonate or a mixture thereof.

  Further, it is desirable to further include sodium halide or potassium halide.

  To date, there has been no commercially applicable hydrometallurgical process for chalcopyrite (CuFeS2), which is the most consumed copper ore, but in the future the crude ore grade of copper ore will decline. According to the present invention, copper can be leached and refined from chalcopyrite (CuFeS2) with a simple procedure in a short time and with extremely high efficiency. It makes a great contribution to sustainable production.

  Further, generally, in an aqueous solution, copper ions are stably present as divalent, so that two moles of electrons e are required to produce one mole of copper. However, in an aprotic polar organic solvent, copper ions are stably present as monovalent, so that one mole of the electron e is sufficient to produce one mole of copper, which is a half. Therefore, according to the present invention, the amount of electric power at the time of electrowinning can be halved, and there is also an advantage that the energy saving effect is remarkably large.

It is a figure which shows the crystal | crystallization of the extracted sulfur.

  Hereinafter, embodiments of the present invention will be described. The scope of the present invention is not limited by these descriptions, and can be appropriately modified and implemented in a range that does not impair the gist of the present invention, other than the following examples.

  The method for recovering copper from chalcopyrite in the present invention comprises: A) a step of dissolving a target chalcopyrite in a solvent system containing an organic solvent such as a copper halide and an aprotic polar organic solvent; A step of precipitating copper by electrolytic extraction from a solvent system in which chalcopyrite is dissolved.

  The solvent system used in the above step A) is for dissolving chalcopyrite, and is typically an organic solvent containing copper halide. Hereinafter, the configuration of the solvent system will be described.

  The organic solvent is not particularly limited as long as it can dissolve copper ions generated by an oxidation-reduction reaction with a copper halide, but is preferably a polar aprotic organic solvent. Examples of such aprotic polar organic solvents include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetone, acetonitrile, tetrahydrofuran (THF), dimethylacetamide, methyl acetate, ethyl acetate, butyl acetate, propyl acetate And propylene carbonate. A mixed solvent containing two or more of these can also be used. Among these, a structure having a sulfoxide group such as DMSO is particularly preferable.

  The copper halide used in the present invention is copper fluoride, copper chloride, copper bromide, or copper iodide, and can be a monovalent or divalent salt, respectively. Preferably, it is copper (I) bromide (CuBr), copper (II) bromide (CuBr2), copper (I) chloride (CuCl) or copper (II) chloride (CuCl2).

  It is thought that the larger the content of the copper halide in the solvent system, the higher the amount of copper dissolved, but typically, the amount of copper halide is 100 mmol / L or more, preferably 200 mmol / L or more, more preferably 400 mmol / L or more. It is.

  The solvent system used in the present invention may further contain an alkali metal halide as an auxiliary component for the purpose of further increasing the dissolution rate and the amount of copper dissolved. Preferably, it is sodium halide or potassium halide. The type of halogen is preferably one that dissociates in a solvent to generate the same halogen anion as the above-mentioned copper halide (that is, in the case of copper bromide, sodium bromide or potassium bromide).

  The content of these further components in the solvent system is not particularly limited, but is used in the range of 0.5 to 10 times, preferably 1 to 2 times the concentration of the copper bromide in the solution. be able to.

  The electrowinning in the step B) in the recovery method of the present invention has a configuration in which the copper ions dissolved in the solution in the step A) are precipitated and recovered at the cathode electrode (negative electrode).

  Generally, in an aqueous solution, copper ions are stably present as divalent, so that 2 moles of electron e are required to produce 1 mole of copper. However, in an aprotic polar organic solvent, copper ions are stably present as monovalent, so that one mole of the electron e is sufficient to produce one mole of copper, which is a half. Therefore, according to the present invention, the amount of electric power at the time of the electrowinning in the step B) can be halved, and the energy saving effect is remarkably large.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

  For example, in a copper bromide-containing dimethylsulfoxide solvent, it is known that copper ions act as a strong oxidizing agent and dissolve noble metals, but there are no reports examining chalcopyrite.

Therefore, chalcopyrite was dissolved using this solvent (copper bromide-containing dimethyl sulfoxide solvent). When a dissolution experiment of chalcopyrite was conducted using temperature conditions and the like as parameters, it was confirmed that copper Cu and sulfur S contained in chalcopyrite were completely dissolved after about 4 hours at 100 ° C. It was also found that iron Fe remained as a residue and was separated. Table 1 below shows the compositions of copper Cu, sulfur S, and iron Fe in chalcopyrite that were subjected to the leaching experiment. Table 2 below shows the mass of the sample used in the leaching experiment, the mass of the residue, and the ratio of residual Cu in the residue. Since the residual Cu in the residue is 0%, it is clear that the copper Cu contained in the chalcopyrite was completely dissolved. In Table 2, although the mass ratio of the residue is large, it is considered that the mass ratio of the residue is increased because components other than copper Cu, sulfur S, and iron Fe are also included.

  Furthermore, it was discovered that by cooling a solvent in which copper and sulfur were completely dissolved, sulfur was precipitated as a single crystal. FIG. 1 shows the state of the precipitated sulfur crystals. This has made it possible to separate sulfur. Then, the copper ions dissolved in the solvent after the sulfur has been separated can be precipitated at the cathode electrode (negative electrode) by electrolytic sampling to produce (recover) copper.

  With the above configuration, it was confirmed that iron, sulfur, and copper could be completely separated from chalcopyrite (CuFeS2) by a simple procedure in a short time and with very high efficiency.

  In addition, by including the alkali metal halide as an auxiliary component in the solvent, the dissolution rate and amount of copper can be increased, so that the copper recovery process from chalcopyrite can be operated even more efficiently. Becomes

The effects of the present embodiment are as follows.
(1) There was no commercially applicable hydrometallurgical refining method for chalcopyrite (CuFeS2), but in the future, as the grade of copper ore is deteriorating, the use of this example will There is an advantage that copper can be leached and refined from copper ore (CuFeS2) by a simple procedure in a short time and with very high efficiency.
(2) Generally, in an aqueous solution, copper ions are stably present as divalent, so that two moles of electrons e are required to produce one mole of copper. However, in an aprotic polar organic solvent, copper ions are stably present as monovalent, so that one mole of the electron e is sufficient to produce one mole of copper, which is a half. Therefore, according to the present embodiment, since the amount of electric power during electrowinning can be reduced by half, there is also an advantage that the energy saving effect is remarkably large.

  In the embodiments and examples of the present invention, a method for recovering copper from chalcopyrite has been described. However, the present recovery method is a method for recovering zinc (Zn) from sphalerite (ZnS), and also includes nickel pyrite ((Fe, Ni) 9S8) and nickel pyrrhotite ((Fe, Ni) 1 -xS) is also applicable as a method for recovering nickel (Ni).

  INDUSTRIAL APPLICABILITY The present invention can be industrially used as a method for recovering metal from ore, particularly a simple and economical method for recovering copper from chalcopyrite, and a solvent system used for the method.

Claims (8)

  Step (A) of dissolving chalcopyrite in a solvent system containing a copper halide and an aprotic polar organic solvent, and step (B) of depositing copper from the solvent system in which the chalcopyrite is dissolved by electrowinning A method for recovering copper from chalcopyrite, comprising:   The method for recovering copper from chalcopyrite according to claim 1, wherein the copper halide is selected from copper (I) bromide, copper (II) bromide, copper (I) chloride or copper (II) chloride. .   The method for recovering copper from chalcopyrite according to claim 1 or 2, wherein the aprotic polar organic solvent is selected from dimethyl sulfoxide, dimethylformamide, acetone, acetonitrile, tetrahydrofuran, propylene carbonate or a mixture thereof.   The method for recovering copper from chalcopyrite according to any one of claims 1 to 3, wherein the solvent system further comprises sodium halide or potassium halide.   A solvent system comprising copper halide and an aprotic polar organic solvent used to dissolve chalcopyrite to recover copper.   The solvent system according to claim 5, wherein the copper halide is selected from copper (I) bromide, copper (II) bromide, copper (I) chloride or copper (II) chloride.   The solvent system according to claim 5 or 6, wherein the aprotic polar organic solvent is selected from dimethyl sulfoxide, dimethylformamide, acetone, acetonitrile, tetrahydrofuran, propylene carbonate or a mixture thereof.   The solvent system according to any one of claims 5 to 7, further comprising a sodium halide or a potassium halide.