JP2006057133A - Method for recovering gold concentrate from residue of leached copper concentrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering a gold concentrate, which reduces an environmental load in a post-process with the use of the obtained gold concentrate, improves economical efficiency as well, and at the same time separate gold from simple sulfur at a high recovery rate, when commercializing gold and simple sulfur from a residue containing gold and simple sulfur, which is produced after having leached the copper concentrate in a wet-refining process. <P>SOLUTION: The method for recovering the gold concentrate from the residue containing gold and simple sulfur, which is produced after having leached the copper concentrate in a wet-refining process includes centrifuging the residue while heating it to a sufficiently high temperature for melting simple sulfur, to obtain the gold concentrate and simple sulfur. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for recovering a gold concentrate from a copper concentrate leaching residue, and more specifically, commercializing gold and simple sulfur from a leaching residue containing gold and simple sulfur produced by a wet refining method of copper concentrate. Of the gold concentrate that can be separated from the elemental sulfur at a high gold recovery rate while improving the environmental impact of the subsequent process and improving the economic efficiency using the obtained gold concentrate. Regarding the method.

  Conventionally, in copper smelting, recovery of gold contained in copper ore has been an unavoidable problem due to its economic value. Therefore, in the copper refining method, various gold recovery methods have been performed depending on the raw material form and processing method.

Currently, copper smelting by the dry smelting method, where most of the world's copper is produced, is made from copper concentrate as a raw material, and this is a series of dry smelting using a smelting furnace, converter, refining furnace, etc. The crude copper obtained by treating the concentrate is electrolytically purified to produce high-purity electrolytic copper.
The copper concentrate is obtained by sulfidizing ores containing copper sulfide minerals such as chalcopyrite (CuFeS ₂ ), chalcocite (Cu ₂ S), and chalcopyrite (Cu ₅ FeS ₄ ) by physical separation means such as a flotation method. Obtained by concentrating minerals. In general, copper concentrate contains the above-mentioned copper sulfide mineral, iron sulfide minerals such as pyrite and pyrrhotite, gangue such as quartz and silicate minerals, and noble metals such as gold and silver.
In the dry smelting method, noble metals such as gold and silver are concentrated in a starch produced by copper electrolysis, and gold is recovered using various methods using the starch as a raw material.

  By the way, in recent years, researches on wet refining methods using copper concentrate as a raw material have been actively conducted. This wet refining method uses an acidic aqueous solution containing sulfuric acid or hydrochloric acid to leach copper sulfide minerals in the presence of an oxidizing agent such as ferric ion, cupric ion, oxygen, chlorine, etc. It is a process to collect. As one of the processes, a method has been developed in which gold is leached at the same time by increasing the oxidation-reduction potential of the solution (hereinafter sometimes referred to as ORP) during copper leaching. Low leaching rate and recovery rate and low economic efficiency.

  Therefore, a method has been developed in which gold is intentionally left in the leach residue and recovered therefrom. Such a leaching residue contains a large amount of sulfur that remains without being intentionally oxidized together with a noble metal such as gold. In addition, the gold content is usually as low as several tens of g / ton, and since leaching is performed at a high ORP in order to obtain a high leaching rate of copper, the oxidization is strong.

  As a method for recovering gold in the starch in the dry smelting method and leaching residue in the wet smelting method, for example, in the chlorine leaching-activated carbon adsorption method, gold is leached with chlorine gas, Gold is adsorbed and recovered by activated carbon. Thereafter, the gold adsorbed on the activated carbon is recovered in a metallic state by a method of roasting activated carbon or the like. In this method, sulfur in the leaching residue in the hydrometallurgical process is oxidized, and sulfuric acid is generated in the liquid, resulting in impurities that cannot be reused, and activated carbon cannot be reused, resulting in high activated carbon costs. There is. In addition, since chlorine gas is used, there is a problem that the equipment cost increases due to the use of a corrosion-resistant material in the production equipment and the installation of an abatement equipment as an environmental measure.

  Further, a cyan leaching method in which gold is leached as a complex with a cyanide compound is performed. The cyan leaching method is most commonly employed as a method for leaching gold from silicate ore, and this method is characterized by a relatively high gold leaching rate. However, since a toxic cyanide compound is used, there are many problems such as special considerations for handling and treatment of cyanate-containing waste liquid, and environmental considerations are indispensable.

  As another method, a method using a thiourea method has also been proposed. The leaching of gold with thiourea is based on the complexation of thiourea with gold in an ionic state. As the thiourea method, a gold or silver-containing ore is treated with an aqueous solution containing thiourea and iron ions, and gold is recovered from this aqueous solution by a neutralization precipitation method (see, for example, Patent Document 1). Further, a method of recovering gold by adding a metal reducing agent such as iron to an aqueous solution obtained by leaching gold as a thiourea compound from a gold-containing material such as gold plating, gold-plated, or gold-containing ore (see, for example, Patent Document 2). ) Has been proposed. However, thiourea is oxidized in the presence of an oxidizing agent and loses its leaching capacity, so its application on an industrial scale is limited. Especially, application to a large amount of raw material with low gold content such as ore is costly. There is a problem above.

In addition, it is conceivable to volatilize and remove elemental sulfur contained as a method of concentrating gold from the leach residue in the wet refining method, but a large amount of energy is required to volatilize, resulting in high cost. End up.
From the above situation, there is a need for a method for recovering gold concentrate that can reduce the environmental load and facility capacity due to leaching agent and exhaust gas, using leaching residue produced by wet refining of copper concentrate as a raw material. Yes.

JP-A-60-103138 (pages 1 to 3) JP-A-9-13127 (first page, second page)

  The object of the present invention is obtained in the case of commercializing gold and simple sulfur from a leaching residue containing gold and simple sulfur produced by the copper concentrate wet refining method in view of the above-mentioned problems of the prior art. To improve the environmental impact of the post-process using the gold concentrate and improve the economic efficiency, and to provide a method for recovering the gold concentrate that can be separated from the elemental sulfur at a high gold recovery rate. is there.

  In order to achieve the above object, the present inventors have conducted extensive research on a method for recovering a gold concentrate from a leaching residue produced by a wet refining method of copper concentrate. By centrifuging under the conditions, the simple sulfur contained in the leaching residue is separated, while gold is concentrated to the leaching residue, and a high-grade gold concentrate is obtained with a high recovery rate. Completed the invention.

That is, according to the first invention of the present invention, a method for recovering a gold concentrate from a leaching residue containing gold and simple sulfur produced by a wet refining method of copper concentrate,
A method for recovering a gold concentrate from a copper concentrate leaching residue is provided, wherein the leaching residue is subjected to centrifugation while heating to a degree sufficient to melt the elemental sulfur to obtain a gold concentrate and elemental sulfur. Is done.

  According to a second aspect of the present invention, there is provided a method for recovering a gold concentrate from a copper concentrate leaching residue, characterized in that in the first aspect, the heating is performed in a non-oxidizing atmosphere. The

  According to a third invention of the present invention, there is provided a method for recovering a gold concentrate from a copper concentrate leaching residue, wherein the heating temperature is 110 to 150 ° C. in the first or second invention. Is done.

  According to a fourth invention of the present invention, in any one of the first to third inventions, the leaching residue is subjected to flotation prior to the centrifugation, and then the copper concentrate leaching residue is changed to gold. A method for recovering the concentrate is provided.

  The method for recovering a gold concentrate from a copper concentrate leach residue according to the present invention is obtained when commercializing gold and simple sulfur from a leach residue containing gold and simple sulfur produced by a wet refining method of copper concentrate. By using the obtained gold concentrate, it is possible to improve the environmental impact of the post-process and improve the economic efficiency. Further, since it can be separated from simple sulfur with a high gold recovery rate, its industrial value is extremely large.

In the centrifugal separation, if the heating atmosphere and the heating temperature are preferably controlled, the effect can be increased, which is more advantageous. Furthermore, if a floating substance obtained by a flotation process of a wet residue is used as a raw material for centrifugation, a higher-grade gold concentrate can be obtained.
Moreover, since simple sulfur with few impurities can be obtained by centrifugation, it is easy to produce a product.

Hereinafter, the method for recovering the gold concentrate from the copper concentrate leaching residue of the present invention will be described in detail.
A method for recovering a gold concentrate from a copper concentrate leaching residue according to the present invention is a method for recovering a gold concentrate from a leaching residue containing gold and simple sulfur produced by a wet refining method of copper concentrate, The leaching residue is subjected to centrifugal separation while heating to a degree sufficient for melting of simple sulfur, thereby obtaining a gold concentrate and simple sulfur.

In the recovery method of the present invention, it is important to subject the copper concentrate leaching residue to centrifugation while heating the copper concentrate leaching residue to a degree sufficient to melt the elemental sulfur. As a result, when gold is commercialized, the resulting gold concentrate can be used to improve the environmental impact of the post-process and improve the economic efficiency, while separating it from single sulfur with a high gold recovery rate. Can do.
That is, by heating the copper concentrate leaching residue, the single sulfur is melted to form a melt with good fluidity. On the other hand, since the components contained in the leaching residue such as gold remain in a solid state, the melt of the simple sulfur and the solid can be separated by filtration using a centrifugal separation method.

  The method for wet refining of copper concentrate is not particularly limited, and an acidic aqueous solution containing sulfuric acid or hydrochloric acid is used in the coexistence of an oxidizing agent such as ferric ion, cupric ion, oxygen or chlorine. When the copper sulfide mineral is oxidatively leached, the method is preferably performed under the condition that suppresses gold leaching. In particular, in the chlorine leaching method using chlorine gas as the oxidizing agent, the above conditions are suitably performed by appropriately controlling the ORP. This allows gold to remain in the leaching residue.

The copper concentrate leaching residue used in the recovery method is not particularly limited, and a leaching residue containing gold and simple sulfur produced by a copper smelting method is used. In particular, a residue containing a large amount of simple sulfur can be used.
The composition and components of the leaching residue vary depending on the composition and components of the copper concentrate as a raw material, the type of wet refining method, and the like. For example, the residue produced by the sulfuric acid leaching method generally contains undissolved iron sulfide minerals, gangue minerals such as quartz, and iron hydroxides or oxides in addition to noble metals such as gold and elemental sulfur. Moreover, the residue by the chlorine leaching method generally contains undissolved iron sulfide minerals and gangue minerals such as quartz in addition to noble metals such as gold and simple sulfur. Here, most of gold exists as gold particles and gold alloy particles.

  The embodiment of the recovery method is not particularly limited. For example, the leaching residue is charged into a centrifuge and heated. Prior to charging, the leaching residue may be heated in advance. Here, the centrifugal separation operation is performed in a state where the single sulfur is melted by heating and a desired melt having good fluidity is formed.

  The heating used in the above recovery method is not particularly limited, and it is preferably performed in a non-oxidizing atmosphere in which the oxidation of simple sulfur hardly occurs. In addition, it is preferable that the said heating atmosphere is maintained consistently from heating of a leaching residue to centrifugation operation. The non-oxidizing atmosphere can be formed, for example, by flowing a low oxygen concentration heating gas such as a low oxygen concentration combustion gas, nitrogen gas or inert gas into a centrifuge. .

  The heating temperature used in the above recovery method is not particularly limited, and a temperature exceeding the melting point of sulfur is used, but it is preferably 100 to 300 ° C., and 110 to 150 ° C. from both sides of sulfur evaporation suppression and oxidation suppression. More preferred. That is, in the temperature range of 110 to 150 ° C., the viscosity of the sulfur melt can be maintained at the lowest state and the separability is improved. On the other hand, when the temperature exceeds 300 ° C., the evaporation of sulfur becomes intense. In addition, it is preferable that the said heating temperature is maintained consistently from heating of a leaching residue to centrifugation operation.

  By performing the centrifugal separation operation under the above heating atmosphere and heating temperature, a high gold concentration ratio can be obtained, and sulfur volatilization and oxidation can be suppressed.

  Centrifugation used in the above recovery method is not particularly limited, and means for filtering and separating the sulfur melt from the solid can be used, and can be carried out using a commercially available centrifuge. However, commercially available centrifuges may be cooled by wind power during operation, and are equipped with a device for heating the introduced inert gas, or have a heating device on the outer periphery to keep the centrifuge basket warm. Those that do are preferred.

  In the above recovery method, if necessary, prior to centrifugation, the leach residue can be subjected to flotation, and the resulting suspended matter can be subjected to centrifugation. This gives a higher quality gold concentrate. In other words, gold and gold alloy particles and elemental sulfur are floated by the flotation treatment of the leach residue, and most of the iron sulfide minerals and gangue minerals are distributed as sediments. Separation from stone minerals takes place.

  The conditions for the flotation beneficiation are not particularly limited, and conditions are selected in which the elemental sulfur, gold and gold alloy particles are separated as floating substances. For example, the leaching residue slurry is adjusted to a predetermined pH. It is done.

  The gold concentrate obtained by the above recovery method can be processed by various existing separation and purification methods for gold recovery. For example, if gold concentrate is put into the converter process etc. using the existing dry smelting method, gold can be recovered as a starch in the current copper anode electrolytic purification process. At this time, the amount of sulfurous acid gas generated is small compared to the case where the leaching residue is directly processed in the dry smelting process, which is advantageous in terms of environmental load.

  Moreover, it can process by wet methods, such as a chlorine leaching method, a cyan leaching method, and a thiourea method, using gold concentrate as a raw material. At that time, sulfur is removed from the leaching residue and the amount is reduced, and the removal of sulfur improves the hydrophilicity of the residue and allows the leaching agent to permeate easily. Thus, the economics such as the processing capacity of the wet method can be improved.

  EXAMPLES The present invention will be described in more detail below with reference to examples of the present invention, but the present invention is not limited to these examples. In addition, the analysis method of the metal used in the Example was performed by ICP emission spectrometry.

Example 1
As a copper concentrate leaching residue, a leaching residue obtained by a chlorine leaching method comprising a composition of Cu: 0.6% by weight, Fe: 9.5% by weight, S: 49.3% by weight, and Au: 61 g / t. used.
First, 10 kg of the leaching residue was charged into a centrifuge (filter cloth: made of polypropylene). Next, nitrogen gas heated to 140 ° C. was introduced into the centrifuge, and the sulfur contained in the leaching residue was brought into a molten state.
The centrifuge was then started and a centrifugal force of about 1000 G was separated over 5 minutes into molten sulfur and residue (gold concentrate). Subsequently, the gold concentrate was removed from the centrifuge. Thereafter, the obtained gold concentrate and elemental sulfur were analyzed. In addition, the weight of the obtained gold concentrate and simple substance sulfur was 5.0 kg and 4.9 kg, respectively.

As a result, the quality of the gold concentrate was Cu: 1.2 wt%, Fe: 19 wt%, and Au: 120 g / t, and it was found that gold was concentrated twice. Further, it was found that Cu, Fe, and Au were all below the lower limit of detection in the separated simple sulfur.
As is apparent from the above, in Example 1, since the separation of elemental sulfur was performed according to the method of the present invention, it can be seen that a high-quality gold concentrate can be obtained with a high gold recovery rate. In addition, simple sulfur having a purity that is easy to produce was obtained.

(Example 2)
As the copper concentrate leaching residue, a chlorine leaching residue having a composition of Cu: 0.53% by weight, Fe: 8.3% by weight, S: 52% by weight and Au: 54 g / t was used.
First, 20 kg of the leaching residue was made into a slurry with water, and the pH of the slurry was adjusted to 11. Next, the slurry whose pH was adjusted was subjected to flotation using a flotation machine. In addition, in the case of flotation, a stirrer type flotation machine is used and, as a foaming agent, Pine Oil No. 7 (manufactured by Nippon Fragrance Chemicals Co., Ltd.) is used to obtain a suspended matter and a sediment. analyzed. The weight of suspended matter and sediment was almost the same. As a result, the obtained sediment was mainly composed of pyrite and gangue minerals, and the Au quality was as low as 11 g / t. The obtained suspended matter is mainly a concentrate of simple sulfur, and has a composition of Cu: 0.91% by weight, Fe: 6.2% by weight, S: 84% by weight, and Au: 80 g / t. It was.

Next, 10 kg of the suspended matter was placed in a centrifuge (filter cloth: made of polypropylene). Next, nitrogen gas heated to 140 ° C. was introduced into the centrifuge, and the sulfur contained in the suspended matter was brought into a molten state.
Subsequently, the centrifuge was started and a centrifugal force of about 1000 G was separated into molten sulfur and residue (gold concentrate) over 5 minutes. Subsequently, the gold concentrate was removed from the centrifuge. Thereafter, the obtained gold concentrate and elemental sulfur were analyzed. In addition, the weights of the obtained gold concentrate and simple substance sulfur were 2.6 kg and 7.3 kg, respectively.

As a result, the quality of the gold concentrate was Fe: 20% by weight, Au: 310 g / t, and it was found that gold was concentrated 3.9 times. Further, it was found that Cu, Fe, and Au were all below the lower limit of detection in the separated simple sulfur.
As is apparent from the above, in Example 2, since the separation of gangue minerals and elemental sulfur was performed according to the method of the present invention, it can be seen that a high-quality gold concentrate can be obtained with a high gold recovery rate. . In addition, simple sulfur having a purity that is easy to produce was obtained.

  As is clear from the above, the method for recovering a gold concentrate from a copper concentrate leaching residue according to the present invention is a copper hydrometallurgical field in which copper concentrate is leached with chlorine gas or sulfuric acid to recover copper. It is suitable as a method for separating the elemental sulfur and obtaining a gold concentrate with a high recovery rate.

Claims (4)

A method for recovering a gold concentrate from a leaching residue containing gold and elemental sulfur produced by a wet refining method of copper concentrate,
A method for recovering a gold concentrate from a copper concentrate leaching residue, wherein the leaching residue is subjected to centrifugation while heating to a degree sufficient for melting the simple sulfur to obtain a gold concentrate and simple sulfur.   The method for recovering a gold concentrate from a copper concentrate leaching residue according to claim 1, wherein the heating is performed in a non-oxidizing atmosphere.   The method for recovering a gold concentrate from a copper concentrate leaching residue according to claim 1 or 2, wherein the heating temperature is 110 to 150 ° C.   The method for recovering a gold concentrate from a copper concentrate leaching residue according to any one of claims 1 to 3, further comprising subjecting the leaching residue to flotation prior to centrifugation.