CA2908364C - Method of recovering gold from sulfide ore - Google Patents
Method of recovering gold from sulfide ore Download PDFInfo
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- CA2908364C CA2908364C CA2908364A CA2908364A CA2908364C CA 2908364 C CA2908364 C CA 2908364C CA 2908364 A CA2908364 A CA 2908364A CA 2908364 A CA2908364 A CA 2908364A CA 2908364 C CA2908364 C CA 2908364C
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/22—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition
- C22B3/24—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition by adsorption on solid substances, e.g. by extraction with solid resins
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B11/00—Obtaining noble metals
- C22B11/04—Obtaining noble metals by wet processes
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
Disclosed is A method of recovering gold from sulfide ores comprising: Step 1 for contacting sulfide ores or a leaching residue obtained after sulfide ores are leached with a acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the leaching residue; Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 40 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 500 mV
or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
Description
METHOD OF RECOVERING GOLD FROM SULFIDE ORE
TECHNICAL FIELD
[0001]
The present invention relates to a method of recovering gold from sulfide ore.
RELATED ART
TECHNICAL FIELD
[0001]
The present invention relates to a method of recovering gold from sulfide ore.
RELATED ART
[0002]
Recently, the technique in which copper is recovered from sulfide ores by a wet process instead of the conventional dry process has. been focused. Since sulfide ores often contain noble metals such as gold even slightly, a method for recovering such noble metals in addition to copper economically is demanded.
Recently, the technique in which copper is recovered from sulfide ores by a wet process instead of the conventional dry process has. been focused. Since sulfide ores often contain noble metals such as gold even slightly, a method for recovering such noble metals in addition to copper economically is demanded.
[0003]
With respect to a technique for working through such problem, a method is known to conduct a gold leaching step on the residue from a copper leaching step in which chlorides and bromides of an alkaline metal or an alkaline earth metal, and chlorides and bromides of copper and iron are used (referred to JP-A-2009-235519). In accordance with such method, copper and gold in the sulfide ores could be leached and recovered at high leaching rate merely by use of air, without using a special oxidation agent.
With respect to a technique for working through such problem, a method is known to conduct a gold leaching step on the residue from a copper leaching step in which chlorides and bromides of an alkaline metal or an alkaline earth metal, and chlorides and bromides of copper and iron are used (referred to JP-A-2009-235519). In accordance with such method, copper and gold in the sulfide ores could be leached and recovered at high leaching rate merely by use of air, without using a special oxidation agent.
[0004]
With respect to the technique as mentioned above, JP-A-2009-235525 describes "in order to leach gold existing in a copper concentrate, appropriate oxidizing agent and a stabilizer for preventing the leached gold from being reduced again to precipitate as a metal gold are needed. In the invention, chlorine ions are used to form gold chloride, so that gold may be eluted stably. When bromine ions is used together with chlorine ions, gold bromide may be formed, so that the gold leaching may be more easily conducted." (paragraph 0014). It is also described, in paragraph 0017, that Bromine ions are necessary for generating gold bromide and forming a complex with gold which is eluted, and that the concentration of the bromine ions for use of the leaching reaction for gold depends on the concentration of gold to be eluted, and that it is assumed that there should also be the upper limit of the solubility because of influence by the concentration of coexisting sodium chloride, and that taking such solubility into consideration the concentration should be 1 to 80 g/L, more desirably about 10 to 26 g/L from the viewpoint of the economical usage of the chemicals. The publication describes that bromine ions in the leaching liquid is added in a form of sodium bromide or the like, and that although the higher concentration thereof should be better, the practical concentration in terms of bromine ion should be 1 to 50 g/L, preferably 10 to 26 g/L since the solubility may be varied by the influence of the concentration of chlorine ions which are added together, and by the influence of the temperature (paragraph 0025).
With respect to the technique as mentioned above, JP-A-2009-235525 describes "in order to leach gold existing in a copper concentrate, appropriate oxidizing agent and a stabilizer for preventing the leached gold from being reduced again to precipitate as a metal gold are needed. In the invention, chlorine ions are used to form gold chloride, so that gold may be eluted stably. When bromine ions is used together with chlorine ions, gold bromide may be formed, so that the gold leaching may be more easily conducted." (paragraph 0014). It is also described, in paragraph 0017, that Bromine ions are necessary for generating gold bromide and forming a complex with gold which is eluted, and that the concentration of the bromine ions for use of the leaching reaction for gold depends on the concentration of gold to be eluted, and that it is assumed that there should also be the upper limit of the solubility because of influence by the concentration of coexisting sodium chloride, and that taking such solubility into consideration the concentration should be 1 to 80 g/L, more desirably about 10 to 26 g/L from the viewpoint of the economical usage of the chemicals. The publication describes that bromine ions in the leaching liquid is added in a form of sodium bromide or the like, and that although the higher concentration thereof should be better, the practical concentration in terms of bromine ion should be 1 to 50 g/L, preferably 10 to 26 g/L since the solubility may be varied by the influence of the concentration of chlorine ions which are added together, and by the influence of the temperature (paragraph 0025).
[0005]
Further, JP-A-2009-526912 proposes that alkaline bromide in the leaching liquid would be 0.5 to 30 g/L in order to promote the leaching when recovering gold from the intermediate product or the leaching residue obtained after the primary material of copper sulfide is leached with chlorides under atmospheric air.
PRIOR ART
PATENT LITERATURE
Further, JP-A-2009-526912 proposes that alkaline bromide in the leaching liquid would be 0.5 to 30 g/L in order to promote the leaching when recovering gold from the intermediate product or the leaching residue obtained after the primary material of copper sulfide is leached with chlorides under atmospheric air.
PRIOR ART
PATENT LITERATURE
[0006]
Patent Document 1: JP-A-2009-235519 Patent Document 2: JP-A-2009-235525 Patent Document 3: JP-A-2009-526912 SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
Patent Document 1: JP-A-2009-235519 Patent Document 2: JP-A-2009-235525 Patent Document 3: JP-A-2009-526912 SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0007]
The technique as mentioned in the above documents proposes a commercially practicable technique related to a method of recovering gold based on the wet process for copper sulfide wherein chlorine ions is a main part in a gold-leaching liquid, and wherein bromine ions is added supplementarily thereto.
Further, the post-gold-leaching solution contains gold at high concentration right after conducting gold-leaching by use of the conventional technique. However, in the conventional technique, there is a problem that the concentration of gold in the post-gold-leaching solution decreases rapidly with the passage of time.
The technique as mentioned in the above documents proposes a commercially practicable technique related to a method of recovering gold based on the wet process for copper sulfide wherein chlorine ions is a main part in a gold-leaching liquid, and wherein bromine ions is added supplementarily thereto.
Further, the post-gold-leaching solution contains gold at high concentration right after conducting gold-leaching by use of the conventional technique. However, in the conventional technique, there is a problem that the concentration of gold in the post-gold-leaching solution decreases rapidly with the passage of time.
[0008]
In actual operation for recovering gold from copper ore, after the gold leaching step, gold recovery step is not necessarily performed immediately, and based on the schedule of the solid-liquid separation operations and operations to gold leaching, the gold recovering step may be conducted after the post-gold-leaching solution is stored for about 1 to 3 days.
Therefore, while storing the post-gold-leaching solution, a method is desired, which is possible to keep the concentration of gold, being dissloved, as much as possible.
In actual operation for recovering gold from copper ore, after the gold leaching step, gold recovery step is not necessarily performed immediately, and based on the schedule of the solid-liquid separation operations and operations to gold leaching, the gold recovering step may be conducted after the post-gold-leaching solution is stored for about 1 to 3 days.
Therefore, while storing the post-gold-leaching solution, a method is desired, which is possible to keep the concentration of gold, being dissloved, as much as possible.
[0009]
In recovering gold, it is conducted that gold complex included in the post-leaching solution after the gold leaching step is adsorbed to activated carbon. When the adsorption amount is larger, and then the yield should be also larger. In particular, in the case of incineration of activated carbon, the adsorption amount per unit weight of activated carbon have a great influence directly to production costs. Therefore, although the development of a method for increasing the unit adsorption is desired, none of the Patent Documents 1 and 2 even make a consideration on increasing the adsorption amount of gold to the activated carbon. Further, an appropriate method has been still unknown in general since there are too many matter to be considered on such as the type of the activated carbon and the contaminant of the post leaching solution.
In recovering gold, it is conducted that gold complex included in the post-leaching solution after the gold leaching step is adsorbed to activated carbon. When the adsorption amount is larger, and then the yield should be also larger. In particular, in the case of incineration of activated carbon, the adsorption amount per unit weight of activated carbon have a great influence directly to production costs. Therefore, although the development of a method for increasing the unit adsorption is desired, none of the Patent Documents 1 and 2 even make a consideration on increasing the adsorption amount of gold to the activated carbon. Further, an appropriate method has been still unknown in general since there are too many matter to be considered on such as the type of the activated carbon and the contaminant of the post leaching solution.
[0010]
The present invention provides a method for recovering gold from the sulfide ores, in which inhibiting a decrease in the concentration of gold in the post-gold leaching solution over time, and which can improve the adsorption amount of gold to activated carbon.
MEANS FOR SOLVING THE PROBLEM
The present invention provides a method for recovering gold from the sulfide ores, in which inhibiting a decrease in the concentration of gold in the post-gold leaching solution over time, and which can improve the adsorption amount of gold to activated carbon.
MEANS FOR SOLVING THE PROBLEM
[0011]
The present inventors have conducted intensive studies, and found that the state in which gold is dissolved in the post-leaching solution can be held stably, by setting extremely high concentration of bromine ions in the gold leaching liquid based on alkaline chloride aqueous solution. Further, it was also found that the concentration of monovalent copper ions in the post-leaching solution, which would be competitive adsorption in adsorbing gold complex to the activated carbon, may be reduced beforehand to significantly improve the adsorption amount of gold to the activated carbon.
The present inventors have conducted intensive studies, and found that the state in which gold is dissolved in the post-leaching solution can be held stably, by setting extremely high concentration of bromine ions in the gold leaching liquid based on alkaline chloride aqueous solution. Further, it was also found that the concentration of monovalent copper ions in the post-leaching solution, which would be competitive adsorption in adsorbing gold complex to the activated carbon, may be reduced beforehand to significantly improve the adsorption amount of gold to the activated carbon.
[0012]
In one aspect, the present invention is a method of recovering gold from sulfide ores comprising: Step 1 for contacting sulfide ores or a leaching residue obtained after sulfide ores are leached with a acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the leaching residue; Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 40 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 500 mV or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
In one aspect, the present invention is a method of recovering gold from sulfide ores comprising: Step 1 for contacting sulfide ores or a leaching residue obtained after sulfide ores are leached with a acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the leaching residue; Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 40 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 500 mV or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
[0013]
In another aspect, the present invention is a method of recovering gold from sulfide ores comprising: Step 1 for contacting sulfide ores or a leaching residue obtained after sulfide ores are leached with a acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the leaching residue; Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 80 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 480 mV or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
In another aspect, the present invention is a method of recovering gold from sulfide ores comprising: Step 1 for contacting sulfide ores or a leaching residue obtained after sulfide ores are leached with a acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the leaching residue; Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 80 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 480 mV or greater; Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
[0014]
In another embodiment of the method of recovering gold from sulfide ores according to the present invention, the Step 3 comprises adjusting the oxidation-reduction potential (reference electrode: silver/silver chloride) to 520 mV to 570 mV.
In another embodiment of the method of recovering gold from sulfide ores according to the present invention, the Step 3 comprises adjusting the oxidation-reduction potential (reference electrode: silver/silver chloride) to 520 mV to 570 mV.
[0015]
In another embodiment of the method of recovering gold from sulfide ores according to the prensent invention, the Step 3 comprises the oxidation-reduction potential is adjusted by blowing air.
EFFECT OF THE INVENTION
In another embodiment of the method of recovering gold from sulfide ores according to the prensent invention, the Step 3 comprises the oxidation-reduction potential is adjusted by blowing air.
EFFECT OF THE INVENTION
[0016]
The present invention may provide a method for recovering gold from the sulfide ores, in which inhibiting a decrease in the concentration of gold in the post-gold leaching solution over time, and which can improve the adsorption amount of gold to activated carbon.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may provide a method for recovering gold from the sulfide ores, in which inhibiting a decrease in the concentration of gold in the post-gold leaching solution over time, and which can improve the adsorption amount of gold to activated carbon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
FIG. 1 is a graph illustrating a change in the concentration of gold which is dissolved in the post-leaching solution;
FIG. 2 is a graph illustrating a relationship between the oxidation-reduction potential of the post-gold-leaching solution and the concentration of gold in the post-adsorption solution; and FIG. 3 is a graph illustrating a relationship between changes in the oxidation-reduction potential and the concentration of gold, provided that the post-gold-leaching solution is continuously fed into a column filled with an activated carbon and that adding CuCl and flowing air is conducted.
MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a graph illustrating a change in the concentration of gold which is dissolved in the post-leaching solution;
FIG. 2 is a graph illustrating a relationship between the oxidation-reduction potential of the post-gold-leaching solution and the concentration of gold in the post-adsorption solution; and FIG. 3 is a graph illustrating a relationship between changes in the oxidation-reduction potential and the concentration of gold, provided that the post-gold-leaching solution is continuously fed into a column filled with an activated carbon and that adding CuCl and flowing air is conducted.
MODE FOR CARRYING OUT THE INVENTION
[0018]
(Step 1) In the gold leaching step, an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions (gold leaching liquid) is brought into contact with a raw material with supplying an oxidizing agent to leach the gold content in the raw material. It is preferable to adjust the concentration of chlorine ions in the acidic aqueous solution to 40 to 200 g/L, the concentration of bromine ions to 20 to 100 g/L, the concentration of copper ions to 5 to 25 g/L, and the concentration of iron ions to 0.01 to 10 g/L. Such raw material which is subjected to the treatment of the present invention would include sulfide ores, and leaching residue obtained after sulfide ores are leached. Sulfide ores includes, without special limitation, typically a primary copper sulfide ore containing gold (for example, copper pyrite), a copper sulfide ore containing silicate ores with gold, a pyrite containing gold. Further, intermediate product generated at a variety of process for treating sulfide ores should be also treated as sulfide ores.
(Step 1) In the gold leaching step, an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions (gold leaching liquid) is brought into contact with a raw material with supplying an oxidizing agent to leach the gold content in the raw material. It is preferable to adjust the concentration of chlorine ions in the acidic aqueous solution to 40 to 200 g/L, the concentration of bromine ions to 20 to 100 g/L, the concentration of copper ions to 5 to 25 g/L, and the concentration of iron ions to 0.01 to 10 g/L. Such raw material which is subjected to the treatment of the present invention would include sulfide ores, and leaching residue obtained after sulfide ores are leached. Sulfide ores includes, without special limitation, typically a primary copper sulfide ore containing gold (for example, copper pyrite), a copper sulfide ore containing silicate ores with gold, a pyrite containing gold. Further, intermediate product generated at a variety of process for treating sulfide ores should be also treated as sulfide ores.
[0019]
Leaching gold would make progress by reacting eluted gold with chlorine ions or bromine ions to form a chloride complex of gold or a bromide complex of gold. Using bromine ions together, the complex may be formed in the state of lower voltage, so that leaching time may be reduced, and that it is ensured to improve the gold leaching efficiency, that is, to raise the concentration of gold in the post-gold-leaching solution. In the present invention, the concentration of bromine ions in the gold leaching liquid is remarkably high, so that the leached gold may exist in a dissolved state stably for a long period of time.
Leaching gold would make progress by reacting eluted gold with chlorine ions or bromine ions to form a chloride complex of gold or a bromide complex of gold. Using bromine ions together, the complex may be formed in the state of lower voltage, so that leaching time may be reduced, and that it is ensured to improve the gold leaching efficiency, that is, to raise the concentration of gold in the post-gold-leaching solution. In the present invention, the concentration of bromine ions in the gold leaching liquid is remarkably high, so that the leached gold may exist in a dissolved state stably for a long period of time.
[0020]
The oxidation-reduction potential of the leaching liquid depends also on the temperature, so that the liquid temperature decreases by roughly 10 degrees C, and then the oxidation-reduction potential would also decease by about 10 mV.
Accordingly, allowing the leaching liquid from about 80 degrees C, which is the general leaching temperature, the temperature of the leaching liquid decreases, and the oxidation-reduction potential decreases, so that it becomes hard to maintain the state that gold is dissolved.
The oxidation-reduction potential of the leaching liquid depends also on the temperature, so that the liquid temperature decreases by roughly 10 degrees C, and then the oxidation-reduction potential would also decease by about 10 mV.
Accordingly, allowing the leaching liquid from about 80 degrees C, which is the general leaching temperature, the temperature of the leaching liquid decreases, and the oxidation-reduction potential decreases, so that it becomes hard to maintain the state that gold is dissolved.
[0021]
The concentration of bromine ions in the gold leaching liquid, from the viewpoint of reaction rate and solubility, may be about 5 g/L enough. However, when it is desired to maintain the state that gold may be stably dissolved for several days at the concentration of gold in the post-leaching solution of 2 mg/L or higher, of to maintain the state that gold may be dissolved even if the liquid temperature of the post-leaching solution drops from 80 degrees C, which is the general leaching temperature, to room temperature, it is necessary that the concentration of bromine ions in the gold leaching liquid should be 40 g/L or higher, preferably 80 g/L or higher, more preferably 100 g/L or higher, still more preferably 120 g/L or higher. However, the concentration of bromine ions in the post-gold-leaching solution should generally be low from the viewpoint of the cost, so that the concentration should be preferably 80 to 100 g/L.
The concentration of bromine ions in the gold leaching liquid, from the viewpoint of reaction rate and solubility, may be about 5 g/L enough. However, when it is desired to maintain the state that gold may be stably dissolved for several days at the concentration of gold in the post-leaching solution of 2 mg/L or higher, of to maintain the state that gold may be dissolved even if the liquid temperature of the post-leaching solution drops from 80 degrees C, which is the general leaching temperature, to room temperature, it is necessary that the concentration of bromine ions in the gold leaching liquid should be 40 g/L or higher, preferably 80 g/L or higher, more preferably 100 g/L or higher, still more preferably 120 g/L or higher. However, the concentration of bromine ions in the post-gold-leaching solution should generally be low from the viewpoint of the cost, so that the concentration should be preferably 80 to 100 g/L.
[0022]
The concentration of chlorine ions in the gold leaching liquid, from the viewpoint of generating Cu(I), may be preferably g/L or higher, more preferably 15 g/L or higher. However, when the concentration of chlorine ions is extremely high, the problem that the precipitation may be generated would raise, so that the concentration of chlorine ions should be 200 g/L or less, preferably 20 to 40 g/L.
The concentration of chlorine ions in the gold leaching liquid, from the viewpoint of generating Cu(I), may be preferably g/L or higher, more preferably 15 g/L or higher. However, when the concentration of chlorine ions is extremely high, the problem that the precipitation may be generated would raise, so that the concentration of chlorine ions should be 200 g/L or less, preferably 20 to 40 g/L.
[0023]
Iron ions is presented as trivalent iron ions by oxidation with supplying an oxidizing agent, or originally trivalent iron ions, so that they take role for oxidizing gold. The concentration of iron ions in the gold leaching liquid may be preferably 0.01 g/L or higher, more preferably 3 g/L or higher.
Iron ions is presented as trivalent iron ions by oxidation with supplying an oxidizing agent, or originally trivalent iron ions, so that they take role for oxidizing gold. The concentration of iron ions in the gold leaching liquid may be preferably 0.01 g/L or higher, more preferably 3 g/L or higher.
[0024]
Copper ions do not directly involve the reaction, and however by existing copper ions the oxidizing rate by iron ions may become larger. With respect to copper ions, a divalent copper ions would take role for oxidation. The concentration of copper ions in the leaching liquid may be preferably 5 g/L or higher, more preferably 20 g/L or higher.
Copper ions do not directly involve the reaction, and however by existing copper ions the oxidizing rate by iron ions may become larger. With respect to copper ions, a divalent copper ions would take role for oxidation. The concentration of copper ions in the leaching liquid may be preferably 5 g/L or higher, more preferably 20 g/L or higher.
[0025]
A source of supply for chlorine ions includes, without special limitation, hydrogen chloride, hydrochloric acid, metal chloride and chlorine gas. From the viewpoint of economy and safety, chlorine ions is preferably supplied in a form of metal chloride. Such metal chloride includes, for instance, copper chloride (copper(I) chloride, copper(II) chloride), and iron chloride (iron(I) chloride, iron(II) chloride), and a chloride of alkaline metal such as lithium, sodium, potassium, rubidium, cesium, francium, and a chloride of alkaline earth metal such as beryllium, magnesium, calcium, strontium, barium, radium. From the viewpoint of economy and availability, sodium chloride is preferable. Copper chloride and iron chloride are also preferable since those chlorides may be used as a source of supply for copper ions and iron ions.
A source of supply for chlorine ions includes, without special limitation, hydrogen chloride, hydrochloric acid, metal chloride and chlorine gas. From the viewpoint of economy and safety, chlorine ions is preferably supplied in a form of metal chloride. Such metal chloride includes, for instance, copper chloride (copper(I) chloride, copper(II) chloride), and iron chloride (iron(I) chloride, iron(II) chloride), and a chloride of alkaline metal such as lithium, sodium, potassium, rubidium, cesium, francium, and a chloride of alkaline earth metal such as beryllium, magnesium, calcium, strontium, barium, radium. From the viewpoint of economy and availability, sodium chloride is preferable. Copper chloride and iron chloride are also preferable since those chlorides may be used as a source of supply for copper ions and iron ions.
[0026]
A source of supply for bromine ions includes, without special limitation, hydrogen bromide, hydrobromic acid, metal bromide and bromine gas. From the viewpoint of economy and safety, bromine ions is preferably supplied in a form of metal bromide.
Such metal bromide includes, for instance, copper bromide (copper(I) bromide, copper(II) bromide), and iron bromide (iron(I) bromide, iron(II) bromide), and a bromide of alkaline metal such as lithium, sodium, potassium, rubidium, cesium, francium, and a bromide of alkaline earth metal such as beryllium, magnesium, calcium, strontium, barium, radium. From the viewpoint of economy and availability, sodium bromide is preferable. Copper bromide and iron bromide are also preferable since those bromides may be used as a source of supply for copper ions and iron ions.
A source of supply for bromine ions includes, without special limitation, hydrogen bromide, hydrobromic acid, metal bromide and bromine gas. From the viewpoint of economy and safety, bromine ions is preferably supplied in a form of metal bromide.
Such metal bromide includes, for instance, copper bromide (copper(I) bromide, copper(II) bromide), and iron bromide (iron(I) bromide, iron(II) bromide), and a bromide of alkaline metal such as lithium, sodium, potassium, rubidium, cesium, francium, and a bromide of alkaline earth metal such as beryllium, magnesium, calcium, strontium, barium, radium. From the viewpoint of economy and availability, sodium bromide is preferable. Copper bromide and iron bromide are also preferable since those bromides may be used as a source of supply for copper ions and iron ions.
[0027]
A source of copper ions and iron ions is usually in a form of salt, and for example may be supplied in a form of a halogenated salt. Copper ions is preferably supplied in a form of copper chloride and/or copper bromide, and iron ions is preferably supplied in a form of iron chloride and/or iron bromide, from the viewpoint which they also could be used as a source of supply for chloride ions and/or bromide ions. It is preferable to use copper(II) chloride (CuC12) and iron(II) chloride (FeC13) as such a copper chloride and iron chloride, respectively, from the viewpoint of oxidizability. However, it does not make much difference to use copper(I) chloride (CuCl) and iron(I) chloride (FeCl2), since those chlorides may be oxidized to copper(II) chloride (CuC12) and iron(II) chloride (FeCl3), respectively, with supplying an oxidizing agent to the leaching liquid.
A source of copper ions and iron ions is usually in a form of salt, and for example may be supplied in a form of a halogenated salt. Copper ions is preferably supplied in a form of copper chloride and/or copper bromide, and iron ions is preferably supplied in a form of iron chloride and/or iron bromide, from the viewpoint which they also could be used as a source of supply for chloride ions and/or bromide ions. It is preferable to use copper(II) chloride (CuC12) and iron(II) chloride (FeC13) as such a copper chloride and iron chloride, respectively, from the viewpoint of oxidizability. However, it does not make much difference to use copper(I) chloride (CuCl) and iron(I) chloride (FeCl2), since those chlorides may be oxidized to copper(II) chloride (CuC12) and iron(II) chloride (FeCl3), respectively, with supplying an oxidizing agent to the leaching liquid.
[0028]
Accordingly, in a suitable embodiment of the gold leaching step, a mixture of at least one of hydrochloric acid and hydrobromic acid, and at least one of copper(II) chloride and copper(II) bromide, and at least one of iron(II) chloride and iron(II) bromide, and at least one of sodium chloride and sodium bromide may be used as a leaching liquid, as far as both of chloride ions and bromide ions are included therein.
Accordingly, in a suitable embodiment of the gold leaching step, a mixture of at least one of hydrochloric acid and hydrobromic acid, and at least one of copper(II) chloride and copper(II) bromide, and at least one of iron(II) chloride and iron(II) bromide, and at least one of sodium chloride and sodium bromide may be used as a leaching liquid, as far as both of chloride ions and bromide ions are included therein.
[0029]
For the reason of ensuring the dissolution of the trivalent iron ions, the pH of the gold leaching liquid is preferably about 0 to 3, and more preferably about 0.5 to 2Ø The oxidation-reduction potential (reference electrode:
silver/silver chloride) of the gold leaching liquid at starting of the gold leaching step may be affected by bromine ions and preferably 500 mV or greater, more preferably 550 mV or greater.
The temperature of the gold leaching liquid is preferably 60 degrees C or higher from the viewpoint of the leaching efficiency and the materials of the apparatus, more preferably 70 to 90 degrees C from the viewpoint of the leaching rate.
For the reason of ensuring the dissolution of the trivalent iron ions, the pH of the gold leaching liquid is preferably about 0 to 3, and more preferably about 0.5 to 2Ø The oxidation-reduction potential (reference electrode:
silver/silver chloride) of the gold leaching liquid at starting of the gold leaching step may be affected by bromine ions and preferably 500 mV or greater, more preferably 550 mV or greater.
The temperature of the gold leaching liquid is preferably 60 degrees C or higher from the viewpoint of the leaching efficiency and the materials of the apparatus, more preferably 70 to 90 degrees C from the viewpoint of the leaching rate.
[0030]
The gold leaching step is conducted with supplying an oxidizing agent to manage the oxidation-reduction potential.
Such oxidizing agent includes, without special limitation, oxygen, air, chlorine, bromine and hydrogen peroxide. An oxidizing agent having the extremely high oxidation-reduction potential is not needed, and air should be sufficient. Further, even air is preferable from the viewpoint of economy and safety.
The gold leaching step is conducted with supplying an oxidizing agent to manage the oxidation-reduction potential.
Such oxidizing agent includes, without special limitation, oxygen, air, chlorine, bromine and hydrogen peroxide. An oxidizing agent having the extremely high oxidation-reduction potential is not needed, and air should be sufficient. Further, even air is preferable from the viewpoint of economy and safety.
[0031]
A manner of contacting the gold leaching solution with the raw material includes, without special limitation, spraying and dipping. From the viewpoint of the reaction efficiency, it is preferable to dip raw materials in the leaching liquid and to stir it.
A manner of contacting the gold leaching solution with the raw material includes, without special limitation, spraying and dipping. From the viewpoint of the reaction efficiency, it is preferable to dip raw materials in the leaching liquid and to stir it.
[0032]
(Step 2) In order to maintain the state that gold is stably dissolved in the post-gold-leaching solution after terminating the gold leaching step, the concentration of bromine ions in the post-gold-leaching solution should have been managed, so that the concentration may be in a specific range during storing.
Specifically, when the concentration of bromine ions in the acidic aqueous solution being subjected to the gold leaching is 40 g/L or higher, it may be maintained that gold is dissolved by managing the oxidation-reduction potential (reference electrode:
silver/silver chloride) of the post-gold-leaching-solution at 500 mV or greater at room temperature or higher (25 degrees C or higher). This is smaller by 40 mV or greater than the oxidation-reduction potential right after the leaching. When the concentration of bromine ions in the acidic aqueous solution being subjected to the gold leaching is 80 g/L or higher, it may be maintained that gold is dissolved by managing the oxidation-reduction potential (reference electrode: silver/silver chloride) of the post-gold-leaching-solution at 480 mV or greater at room temperature or higher (25 degrees C or higher). Further, the higher the temperature to be managed is higher, the higher solubility gold should exhibit, and however on the other hand the cost for maintaining the temperature should take higher, and accordingly it is preferable to store the post-gold-leaching solution at room temperature (20 to 60 degrees C, more typically 25 to 40 degrees C).
(Step 2) In order to maintain the state that gold is stably dissolved in the post-gold-leaching solution after terminating the gold leaching step, the concentration of bromine ions in the post-gold-leaching solution should have been managed, so that the concentration may be in a specific range during storing.
Specifically, when the concentration of bromine ions in the acidic aqueous solution being subjected to the gold leaching is 40 g/L or higher, it may be maintained that gold is dissolved by managing the oxidation-reduction potential (reference electrode:
silver/silver chloride) of the post-gold-leaching-solution at 500 mV or greater at room temperature or higher (25 degrees C or higher). This is smaller by 40 mV or greater than the oxidation-reduction potential right after the leaching. When the concentration of bromine ions in the acidic aqueous solution being subjected to the gold leaching is 80 g/L or higher, it may be maintained that gold is dissolved by managing the oxidation-reduction potential (reference electrode: silver/silver chloride) of the post-gold-leaching-solution at 480 mV or greater at room temperature or higher (25 degrees C or higher). Further, the higher the temperature to be managed is higher, the higher solubility gold should exhibit, and however on the other hand the cost for maintaining the temperature should take higher, and accordingly it is preferable to store the post-gold-leaching solution at room temperature (20 to 60 degrees C, more typically 25 to 40 degrees C).
[0033]
According to the present invention, the stability of gold which dissolved in the post-leaching solution after gold leaching may be high, so that it is possible to take a long period of time for storing the post-leaching solution from terminating the gold leaching step to starting recovering step for gold.
For example, the storage period may be 5 day or longer, and also 1 week or longer. However, since there is few advantages for storing for a long period, it is preferably within 2 days.
According to the present invention, the stability of gold which dissolved in the post-leaching solution after gold leaching may be high, so that it is possible to take a long period of time for storing the post-leaching solution from terminating the gold leaching step to starting recovering step for gold.
For example, the storage period may be 5 day or longer, and also 1 week or longer. However, since there is few advantages for storing for a long period, it is preferably within 2 days.
[0034]
A source of supply for bromine ions may be added to the post-leaching solution within one day, more preferably within half a day, further more preferably within six hours, still further preferably within one hour, after terminating the gold leaching step. Such source of supply for bromine ions includes the previously mentioned compounds. From the viewpoint of economy and availability, sodium bromide is preferable.
A source of supply for bromine ions may be added to the post-leaching solution within one day, more preferably within half a day, further more preferably within six hours, still further preferably within one hour, after terminating the gold leaching step. Such source of supply for bromine ions includes the previously mentioned compounds. From the viewpoint of economy and availability, sodium bromide is preferable.
[0035]
(Step 3) CuCl is added to the post-gold-leaching solution after storing step and stir it to reduce the oxidation-reduction potential to 520 mV or less, preferably 500 mV or less, and then an oxidizing agent is added to re-adjust the OPR to 520 mV or greater. As a result, monovalent copper ions in the post-gold-leaching solution, which inhibits the adsorption of gold to the activated carbon, is oxidized to divalent copper ions to reduce the amount of monovalent copper, so that the amount of competitive adsorption to the activated carbon in the post-gold-leaching solution is reduced. Accordingly, the adsorption rate of gold on the activated carbon is improved.
(Step 3) CuCl is added to the post-gold-leaching solution after storing step and stir it to reduce the oxidation-reduction potential to 520 mV or less, preferably 500 mV or less, and then an oxidizing agent is added to re-adjust the OPR to 520 mV or greater. As a result, monovalent copper ions in the post-gold-leaching solution, which inhibits the adsorption of gold to the activated carbon, is oxidized to divalent copper ions to reduce the amount of monovalent copper, so that the amount of competitive adsorption to the activated carbon in the post-gold-leaching solution is reduced. Accordingly, the adsorption rate of gold on the activated carbon is improved.
[0036]
For the oxidizing agent, without special limitation, air is used from the viewpoint of cost. Further, for the solution temperature, without special limitation, from the viewpoint that the gold leaching is a heat-leaching, and the viewpoint of the oxidation efficiency, it is preferable to keep the solution temperature of the post-gold-leaching solution at 45 degrees C or higher, more preferable 50 degrees C or higher.
For the oxidizing agent, without special limitation, air is used from the viewpoint of cost. Further, for the solution temperature, without special limitation, from the viewpoint that the gold leaching is a heat-leaching, and the viewpoint of the oxidation efficiency, it is preferable to keep the solution temperature of the post-gold-leaching solution at 45 degrees C or higher, more preferable 50 degrees C or higher.
[0037]
The increase of the ORP indicates reducing the amount of monovalent copper in the post-gold-leaching solution. Monovalent copper is known as a quite soft element, so that it has high affinity for the activated carbon, and then compete against a gold complex in the adsorption to the activated carbon. By redusing the amount of the monovalent copper, the activated sites for the adsorption in the activated carbon will open to gold, so that the selectivity by gold increases, and the effective recovery of gold is achieved.
The increase of the ORP indicates reducing the amount of monovalent copper in the post-gold-leaching solution. Monovalent copper is known as a quite soft element, so that it has high affinity for the activated carbon, and then compete against a gold complex in the adsorption to the activated carbon. By redusing the amount of the monovalent copper, the activated sites for the adsorption in the activated carbon will open to gold, so that the selectivity by gold increases, and the effective recovery of gold is achieved.
[0038]
By adjusting the ORP to 520 mV or greater, the concetration of the monovalent copper in the solution is reduced, so that the adsorption rate of gold to the actiated carbon may be improved.
For the upper limit of the ORP, without special limitation, from the viewpoint of a period requried to adjust the ORP and reduction efficiency of the amount of monovalent copper, the ORP is adjusted preferably to 570 mV or less, more preferably to 530 to 560 mV.
By adjusting the ORP to 520 mV or greater, the concetration of the monovalent copper in the solution is reduced, so that the adsorption rate of gold to the actiated carbon may be improved.
For the upper limit of the ORP, without special limitation, from the viewpoint of a period requried to adjust the ORP and reduction efficiency of the amount of monovalent copper, the ORP is adjusted preferably to 570 mV or less, more preferably to 530 to 560 mV.
[0039]
Gold recovery (Step 4) Step 4 is conducted for recovering gold by adsorption to the activated carbon from the gold solution obtained by the solid-liquid separation after the gold leaching reaction. The contact of gold to the activated carbon may be conducted by batchwise manner, or continuous eluting the acidic leaching solution on the adsorption column filled with the activated carbon.
Gold recovery (Step 4) Step 4 is conducted for recovering gold by adsorption to the activated carbon from the gold solution obtained by the solid-liquid separation after the gold leaching reaction. The contact of gold to the activated carbon may be conducted by batchwise manner, or continuous eluting the acidic leaching solution on the adsorption column filled with the activated carbon.
[0040]
In case of batchwise manner, the stirring rate is not designed. The activated carbon is filled to the amount of 50 times to 10000 times of the mass amount of gold.
In case of batchwise manner, the stirring rate is not designed. The activated carbon is filled to the amount of 50 times to 10000 times of the mass amount of gold.
[0041]
In case of continuous eluting, elution rate is not limited (in general, SV 1 to 25). On the other hand, when the amount of gold adsorption at a unit mass of the activated carbon reaches 20000 to 30000 g/t, such activated carbon does not meet the required capability. Therefore, strip of gold from the activated carbon or recovering is conducted based on the above mentioned amount of gold adsorption. Recovering the activated carbon is conducted by, without special limitation, well know method with sulfur compound, nitrogen compound or oxygen.
In case of continuous eluting, elution rate is not limited (in general, SV 1 to 25). On the other hand, when the amount of gold adsorption at a unit mass of the activated carbon reaches 20000 to 30000 g/t, such activated carbon does not meet the required capability. Therefore, strip of gold from the activated carbon or recovering is conducted based on the above mentioned amount of gold adsorption. Recovering the activated carbon is conducted by, without special limitation, well know method with sulfur compound, nitrogen compound or oxygen.
[0042]
<Other step>
(Recovering copper) Since the post-leaching solution from the copper leaching step contains copper content in a large amount, copper may be recovered from such post-leaching solution. A manner for recovering copper includes, without special limitation, solvent extraction, ion exchange, displacement deposition with base metals and electrowinning. The post-leaching solution contains copper as mixture of a form of both of monovalent and divalent, so that oxidation may be preferably conducted, and then all should be divalent copper ions in order to facilitate the solvent extraction and the ion exchange. For a manner for oxidation, without special limitation, a manner that air or oxygen is blown into the post-leaching solution is easy-to-use.
EXAMPLES
<Other step>
(Recovering copper) Since the post-leaching solution from the copper leaching step contains copper content in a large amount, copper may be recovered from such post-leaching solution. A manner for recovering copper includes, without special limitation, solvent extraction, ion exchange, displacement deposition with base metals and electrowinning. The post-leaching solution contains copper as mixture of a form of both of monovalent and divalent, so that oxidation may be preferably conducted, and then all should be divalent copper ions in order to facilitate the solvent extraction and the ion exchange. For a manner for oxidation, without special limitation, a manner that air or oxygen is blown into the post-leaching solution is easy-to-use.
EXAMPLES
[0043]
<Example 1>
In the test, gold was leached from the residue which was obtained by leaching copper from sulfide copper concentrate containing gold. In the residue, the gold content was 26 g/t, and the copper content was 1.2 %. The gold leaching was conducted at the liquid temperature of 80 degrees C by use of a leaching liquid in which the concentration of Cl ions was adjusted to 40 g/L, the concentration of Cu ions to 20 g/L, the concentration of Fe ions to 2 g/L, and the concentration of Br ions to 20 to 120 g/L, while blowing air. The oxidation-reduction potential at 80 degrees C was 537 to 557 mV (reference electrode: silver/silver chloride).
<Example 1>
In the test, gold was leached from the residue which was obtained by leaching copper from sulfide copper concentrate containing gold. In the residue, the gold content was 26 g/t, and the copper content was 1.2 %. The gold leaching was conducted at the liquid temperature of 80 degrees C by use of a leaching liquid in which the concentration of Cl ions was adjusted to 40 g/L, the concentration of Cu ions to 20 g/L, the concentration of Fe ions to 2 g/L, and the concentration of Br ions to 20 to 120 g/L, while blowing air. The oxidation-reduction potential at 80 degrees C was 537 to 557 mV (reference electrode: silver/silver chloride).
[0044]
The post-leaching solution was allowed at room temperature (15 to 25 degrees C), and the concentration of gold which was dissolved in the solution was determined after the lapse of 1 to 7 days. For excluding any influence of the fine precipitation, the sampled solution was subjected to filtration with membrane filter of 0.1 pm, and to ICP analysis. The oxidation-reduction potential during the storage period was measured after the liquid temperature of the post-leaching solution dropped to 25 degrees C.
The post-leaching solution was allowed at room temperature (15 to 25 degrees C), and the concentration of gold which was dissolved in the solution was determined after the lapse of 1 to 7 days. For excluding any influence of the fine precipitation, the sampled solution was subjected to filtration with membrane filter of 0.1 pm, and to ICP analysis. The oxidation-reduction potential during the storage period was measured after the liquid temperature of the post-leaching solution dropped to 25 degrees C.
[0045]
The results of the analysis was shown in FIG. 1. When the leaching liquid had the concentration of Br of 20 g/L and the oxidation-reduction potential of 500mV, the gold concentration decreased to 1 mg/L or less after one day. On the other hand, when the leaching liquid had the Br concentration of 40 g/L or higher and the oxidation-reduction potential of 500 mV, the gold concentration was maintained the initial gold concentration over 7 days.
Further, when the oxidation-reduction potential was 480 mV, the gold concentration in the solution having 60 g/L of the Br concentration decreased to half or less after one day, and on the other hand the gold concentration in the solution having 80 g/L of the Br concentration maintained the initial gold concentration even after five days.
The results of the analysis was shown in FIG. 1. When the leaching liquid had the concentration of Br of 20 g/L and the oxidation-reduction potential of 500mV, the gold concentration decreased to 1 mg/L or less after one day. On the other hand, when the leaching liquid had the Br concentration of 40 g/L or higher and the oxidation-reduction potential of 500 mV, the gold concentration was maintained the initial gold concentration over 7 days.
Further, when the oxidation-reduction potential was 480 mV, the gold concentration in the solution having 60 g/L of the Br concentration decreased to half or less after one day, and on the other hand the gold concentration in the solution having 80 g/L of the Br concentration maintained the initial gold concentration even after five days.
[0046]
<Example 2>
Gold was recovered from the post-gold-leaching solution obtained after the gold leaching step by use of a gold leaching liquid containing 50 g/L of chloride ions, 80 g/L of bromide ions, 18 g/L of copper and 0.2 g/L of iron. The post-gold leaching solution contained 84 g/L of NaC1, 103 g/L of NaBr, 20 g/L of Cu, 2 g/L of Fe and 8 mg/L of Au, and had pH of 1.2. Thereto was added CuCl to adjust the ORP of 510 mV. The post-leaching solution was heated to 55 degrees C, and air was blown by 0.4 L a minute with stirring. The resulting post-gold-leaching solution was passed through a glass column filled with about 14 ml of the activated carbon derived from coconut shell (Yashicoal MC, manufactured by Taihei Chemical Industrial Co., Ltd.), to adsorb gold to the activated carbon. The column had the size of 11 mm of diameter and 150 mm of height. The feeding rate of the liquid was 11.9 ml/minute, and the space velocity thereof was 50 (l/h). The eluted gold in the post-adsorption solution was diluted by hydrochloric acid to be determined the quantity thereof by ICP-AES. FIG. 2 shows the relationship between the ORP and the concentration of gold in the post-adsorption solution.
<Example 2>
Gold was recovered from the post-gold-leaching solution obtained after the gold leaching step by use of a gold leaching liquid containing 50 g/L of chloride ions, 80 g/L of bromide ions, 18 g/L of copper and 0.2 g/L of iron. The post-gold leaching solution contained 84 g/L of NaC1, 103 g/L of NaBr, 20 g/L of Cu, 2 g/L of Fe and 8 mg/L of Au, and had pH of 1.2. Thereto was added CuCl to adjust the ORP of 510 mV. The post-leaching solution was heated to 55 degrees C, and air was blown by 0.4 L a minute with stirring. The resulting post-gold-leaching solution was passed through a glass column filled with about 14 ml of the activated carbon derived from coconut shell (Yashicoal MC, manufactured by Taihei Chemical Industrial Co., Ltd.), to adsorb gold to the activated carbon. The column had the size of 11 mm of diameter and 150 mm of height. The feeding rate of the liquid was 11.9 ml/minute, and the space velocity thereof was 50 (l/h). The eluted gold in the post-adsorption solution was diluted by hydrochloric acid to be determined the quantity thereof by ICP-AES. FIG. 2 shows the relationship between the ORP and the concentration of gold in the post-adsorption solution.
[0047]
It is recognized that the concentration of gold contained in the post-adsorption solution remarkably decreased in case of adjusting the ORP of 520 mV or greater. It is also recognized that although the upper limit of the ORP should not be provided, the concentration of gold in the post-adsorption solution should not dramatically decrease when extremely raising the voltage, and that it is enough to oxidize the solution to at least 520 mV, and however it should not be prohibited to extremely oxidize it.
It is recognized that the concentration of gold contained in the post-adsorption solution remarkably decreased in case of adjusting the ORP of 520 mV or greater. It is also recognized that although the upper limit of the ORP should not be provided, the concentration of gold in the post-adsorption solution should not dramatically decrease when extremely raising the voltage, and that it is enough to oxidize the solution to at least 520 mV, and however it should not be prohibited to extremely oxidize it.
[0048]
<Example 3>
While continuously supplying liquid by used of the column filled with the activated carbon and the post-leaching solution as used in Example 2, the concentration of gold in the post-adsorption solution was determined by varying the ORP by the addition of CuCl and blowing air. The result is shown in FIG. 3.
<Example 3>
While continuously supplying liquid by used of the column filled with the activated carbon and the post-leaching solution as used in Example 2, the concentration of gold in the post-adsorption solution was determined by varying the ORP by the addition of CuCl and blowing air. The result is shown in FIG. 3.
[0049]
It is also clear based on FIG. 3 that there is a certain relationship between the ORP and the adsorption of gold to the activated carbon. It is possible to favorably recover gold by contacting the post-gold-leaching solution with the activated carbon at the ORP of 520 mV or greater. Further, it is understood that what has an influence on the ORP should be Cu(I).
It is also clear based on FIG. 3 that there is a certain relationship between the ORP and the adsorption of gold to the activated carbon. It is possible to favorably recover gold by contacting the post-gold-leaching solution with the activated carbon at the ORP of 520 mV or greater. Further, it is understood that what has an influence on the ORP should be Cu(I).
[0050]
Although Cu(I) is easily oxidized in an aqueous solution to become Cu(II), in an aqueous solution containing halide at high concentration as in a system of the invention, it may be exist in a considerably stable state. Therefore, although it is estimated to obtain the same effect by oxidizing Cu(I) with an oxidizing agent such as hydrogen peroxide and hypochlorous acid other than by blowing air, blowing air may be preferable from the viewpoint of the cost and the convenience of handling.
Although Cu(I) is easily oxidized in an aqueous solution to become Cu(II), in an aqueous solution containing halide at high concentration as in a system of the invention, it may be exist in a considerably stable state. Therefore, although it is estimated to obtain the same effect by oxidizing Cu(I) with an oxidizing agent such as hydrogen peroxide and hypochlorous acid other than by blowing air, blowing air may be preferable from the viewpoint of the cost and the convenience of handling.
Claims (4)
1. A method of recovering gold from sulfide ores comprising:
Step 1 for contacting raw materials which are a leaching residue obtained after sulfide ores are leached or sulfide ores with an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the raw materials;
Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 40 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 500 mV or greater;
Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce the amount of monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
Step 1 for contacting raw materials which are a leaching residue obtained after sulfide ores are leached or sulfide ores with an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the raw materials;
Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 40 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 500 mV or greater;
Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce the amount of monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
2. A method of recovering gold from sulfide ores comprising:
Step 1 for contacting raw materials which are a leaching residue obtained after sulfide ores are leached or sulfide ores with an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the raw materials;
Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 80 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 480 mV or greater;
Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce the amount of monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
Step 1 for contacting raw materials which are a leaching residue obtained after sulfide ores are leached or sulfide ores with an acidic aqueous solution containing chlorine ions, bromine ions, copper ions and iron ions with supplying an oxidizing agent to leach the gold content in the raw materials;
Step 2 for storing the post-gold-leaching solution obtained by leaching the gold content and keeping a concentration of bromine ions in the post-gold-leaching solution at 80 g/L or higher, and the oxidation-reduction potential (reference electrode: silver/silver chloride) at 480 mV or greater;
Step 3 for adding copper(I) chloride to the post-gold-leaching solution thus obtained in Step 2, and then adding an oxidizing agent to adjust the oxidation-reduction potential to 520 mV or greater, to thereby reduce the amount of monovalent copper ions in the post-gold-leaching solution; and Step 4 for adsorbing gold in the post-gold-leaching solution thus obtained in Step 3 to activated carbon.
3. The method of recovering gold from sulfide ores according to claim 1 or 2, wherein said Step 3 comprises adjusting the oxidation-reduction potential (reference electrode: silver/silver chloride) to 520 mV to 570 mV.
4. The method of recovering gold from sulfide ores according to any one of claims 1 to 3, wherein said Step 3 comprises the oxidation-reduction potential is adjusted by blowing air.
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| JP2013-075230 | 2013-03-29 | ||
| JP2013075230A JP5840643B2 (en) | 2013-03-29 | 2013-03-29 | Method for recovering gold from sulfide minerals |
| PCT/JP2014/053193 WO2014156350A1 (en) | 2013-03-29 | 2014-02-12 | Method for recovering gold from sulfide ore |
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| CA2908364C true CA2908364C (en) | 2017-11-21 |
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| JP6849482B2 (en) * | 2016-03-31 | 2021-03-24 | Ｊｘ金属株式会社 | How to recover gold from ores containing gold or refining intermediates |
| JP6899672B2 (en) * | 2017-03-14 | 2021-07-07 | Ｊｘ金属株式会社 | How to recover gold from ore or refining intermediates |
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| JP5319718B2 (en) * | 2011-03-04 | 2013-10-16 | Ｊｘ日鉱日石金属株式会社 | Methods for leaching copper and gold from sulfide ores |
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- 2013-03-29 JP JP2013075230A patent/JP5840643B2/en active Active
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2014
- 2014-02-12 WO PCT/JP2014/053193 patent/WO2014156350A1/en active Application Filing
- 2014-02-12 PE PE2015002097A patent/PE20151820A1/en active IP Right Grant
- 2014-02-12 CA CA2908364A patent/CA2908364C/en active Active
-
2015
- 2015-09-29 CL CL2015002902A patent/CL2015002902A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| PE20151820A1 (en) | 2015-12-16 |
| CA2908364A1 (en) | 2014-10-02 |
| JP5840643B2 (en) | 2016-01-06 |
| CL2015002902A1 (en) | 2016-06-10 |
| JP2014198888A (en) | 2014-10-23 |
| WO2014156350A1 (en) | 2014-10-02 |
| AU2014245390A1 (en) | 2015-10-22 |
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