JP2011144437A - Method for separating and recovering copper from copper-containing iron sulfide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for separating and recovering copper from a copper-containing iron sulfide which contains copper and iron, by which the amount of sulfuric acid consumed in the whole steps from leaching to electrowinning is reduced, and the use of a neutralizing agent in extraction and back extraction steps is eliminated, thus allowing substantial cost reduction. <P>SOLUTION: The method includes the steps of: leaching a copper-containing iron sulfide with a sulfuric acid solution; mixing the leaching solution with an organic extractant to extract copper; back-extracting copper from the resulting organic extractant containing copper; and electrowinning copper from a solution after back extraction. The temperature in the leaching step is maintained in the range of 102 to 112°C. An aldoxime extractant essentially comprising 5-alkyl salicylaldoxime and containing less than 5 wt.% of alcohols or phenols is used as the organic extractant in the extraction step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a method for separating and recovering copper by a wet method from copper-containing iron sulfide containing impurities such as iron together with copper, and in particular, the amount of sulfuric acid and neutralizing agent used in the entire process can be reduced. Regarding the method.

  The wet copper smelting process that smelts copper by a wet method from copper sulfide minerals such as copper concentrate and copper ore, or sulfides containing copper and iron as intermediate raw materials in the copper smelting process, Depending on the type of liquid used when leaching into the solution, it can be broadly divided into two processes, chlorinated and sulfuric.

  That is, the chlorinated process uses a solution containing chloride and other halogen compounds, and leaches copper into the solution in combination with an oxidizing agent such as chlorine gas. On the other hand, the sulfuric acid-based process uses a sulfuric acid or sulfate solution and leaches copper into the solution in combination with an oxidizing agent such as oxygen or air. In any of the processes, the copper in the obtained leachate is separated by removing impurities such as iron and arsenic in the leachate in the solvent extraction step, and after back extraction, Copper is recovered as electrolytic copper using a method such as electrowinning.

  The sulfuric acid process can be further classified into two methods from the viewpoint of the mechanism of the leaching reaction. The first method is a method in which oxygen or air is introduced in an aqueous solution containing sulfuric acid and copper in the sulfide is oxidized and leached with sulfuric acid, as described in Patent Document 1, for example. Specifically, in Patent Document 1, copper sulfide is pressure-oxidized at 115 ° C. to 175 ° C. and copper is leached using a sulfuric acid solution, and the pH of the obtained copper sulfate solution is adjusted to 1.5 to 3. A method of recovering copper by adjusting to a range of 0.0, extracting with a solvent, and finally collecting by electrolysis is shown.

In this method, for example, when oxidizing and leaching chalcopyrite, as shown in the following chemical formula 1, 2 mol of sulfuric acid is added and leached with respect to 1 mol of copper contained in chalcopyrite. By leaching, copper in chalcopyrite dissolves in the sulfuric acid solution in the form of copper sulfate, ie, divalent copper ions.
[Chemical Formula 1]
CuFeS ₂ + O ₂ + 2H ₂ SO ₄ → CuSO ₄ + FeSO ₄ + 2H ₂ O + 2S

In addition, iron in chalcopyrite is also dissolved in the sulfuric acid solution in the form of iron sulfate, that is, divalent and partly trivalent iron ions. Most of the divalent iron ions are represented by the following chemical formula 2. In addition, it undergoes hydrolysis to produce hardly soluble ferric trioxide (hematite) and by-produce sulfuric acid. That is, considering the entire leaching reaction of Chemical Formulas 1 and 2, 1 mol of sulfuric acid is required to leach 1 mol of chalcopyrite.
“Chemical Formula 2”
FeSO ₄ + 1 / 4O ₂ + 2H ₂ O → 1 / 2Fe ₂ O ₃ + H ₂ SO ₄

  The sulfuric acid solution (leaching solution) containing divalent copper ions obtained by the above oxidative leaching is obtained by diluting hardly soluble ferric trioxide by solid-liquid separation and then diluting copper by solvent extraction using an organic extractant. The ions are separated from the impurities by extraction into an organic extractant. The organic extractant containing copper (extracted organic) is subjected to a process such as back extraction in order to obtain a liquid having a high copper concentration suitable for electrolytic collection.

  In general, organic extractants have the property that elements with lower basicity are easier to extract. Therefore, in the case where a leachate in which divalent copper ions and divalent and trivalent iron ions coexist, such as when leaching the chalcopyrite with sulfuric acid, is targeted, Trivalent iron ions are preferentially extracted over copper ions, and the copper ions tend to be separated.

Therefore, when copper ions are preferentially leached from a leachate obtained by leaching chalcopyrite with sulfuric acid, copper ions are preferentially given over trivalent iron ions by forming a stable chelate with divalent copper ions. In many cases, an acidic extractant such as an oxime type that can extract sucrose is used. In the case of an oxime-based acidic extractant, copper is extracted by the reaction shown in Chemical Formula 3 below.
[Chemical formula 3]
CuSO ₄ + 2HA → CuA ₂ + H ₂ SO ₄
(However, HA means a state in which hydrogen H is added to the oxime-based extractant A.)

  As shown in the above chemical formula 3, with the oxime-based extractant, 1 mol of sulfuric acid is by-produced as copper is extracted. If this sulfuric acid is repeated for the leaching of the above chemical formulas 1 and 2, copper can be leached without adding new sulfuric acid. However, the extraction behavior in solvent extraction is affected by the pH of the solution, and in particular, the extraction performance of the oxime-based extractant is better on the high pH side. Therefore, during extraction, the pH is raised by adding alkali or the like to the leachate in advance. In addition, it is necessary to neutralize by-product sulfuric acid.

In the case of an oxime-based extractant, when copper ions are separated from the extractant (extracted organic) after extraction by back extraction, the lower pH side is more advantageous than the above extraction. For example, when a sulfuric acid solution is added to and mixed with an organic extractant (extracted organic) after extraction, the copper ions in the oxime-based extractant are back-extracted into the sulfuric acid solution as shown in the following chemical formula 4, and the solution after back-extraction Is obtained.
[Chemical formula 4]
CuA ₂ + H ₂ SO ₄ → CuSO ₄ + 2HA

Copper is recovered by electrowinning using the solution after back extraction as an electrolytic solution. In the electrolytic collection, as shown in the following chemical formula 5, when 1 mol of copper is electrodeposited on the cathode, 1 mol of sulfuric acid is by-produced in the electrolytic solution. The by-produced sulfuric acid can be used again in the back extraction of Chemical Formula 4.
[Chemical formula 5]
CuSO ₄ + 2e + 2H ⁺ → Cu + H ₂ SO ₄

  That is, when 1 mol of chalcopyrite is processed by the method of Patent Document 1, 1 mol of sulfuric acid is consumed according to the chemical formulas 1-2 in the leaching process, and the solvent extraction reaction shown in the chemical formula 3 is performed in the extraction process. Causes a 1 molar excess of sulfuric acid. Therefore, the addition of sulfuric acid in the leaching process and the neutralization treatment of sulfuric acid in the extraction process are necessary.

As another method in the sulfuric acid process, Patent Document 2 discloses that copper sulfide is added to a copper sulfide mineral as a reaction catalyst, and oxygen or air is blown in a temperature range of 200 ° C. to 220 ° C. to oxidize. The leaching method in which sulfur contained in the sulfide mineral is oxidized to produce sulfuric acid, and copper is dissolved in the following chemical formula 6 and iron is dissolved in the sulfuric acid solution by the same reaction as the above chemical formula 2 is shown. Has been.
[Chemical formula 6]
CuFeS ₂ + 4O ₂ → CuSO ₄ + FeSO ₄

  According to this method, as shown in the chemical formula 6, addition of sulfuric acid in the leaching process is unnecessary. However, as shown in Chemical Formula 2, sulfuric acid is by-produced when iron oxide is produced from iron sulfate in the leachate. Further, since it is necessary to separate copper and impurities from the obtained leachate by solvent extraction, sulfuric acid is by-produced in the extraction process as shown in the above chemical formula 3, and 1 mol is obtained from leaching to electrowinning. As the copper is processed, 2 moles of sulfuric acid are by-produced.

  As can be seen from the sulfuric acid-based process described above, in both methods of Patent Document 1 and Patent Document 2, in the copper solvent extraction step, as shown in Chemical Formula 3, 1 mole of copper is extracted per 1 mole of extraction. Of sulfuric acid is by-produced. Therefore, in order to neutralize this sulfuric acid and maintain high extraction performance, a neutralizing agent was required during copper extraction.

  In general, as a copper extractant, an oxime-based weakly acidic ketoxime type extractant has often been selected with emphasis on obtaining good copper back-extraction characteristics. However, the weakly acidic ketoxime-type extractant has problems such as the back extraction reaction proceeds with the sulfuric acid generated by the reaction of Chemical Formula 3 as the extraction reaction proceeds, and the copper extraction rate is significantly reduced.

  Therefore, the addition of a ketoxime type extractant or higher alcohols or higher phenols is used for the purpose of weakening acidity against the strongly acidic aldoxime type extractant, which is also a kind of oxime, An extractant for this purpose is also commercially available. However, it is easy to back-extract copper even when such an aldoxime type extractant with weak acidity is used. However, in the solvent extraction process, a neutralizer is added to neutralize excess sulfuric acid. It was necessary to prevent the back extraction reaction from proceeding.

  As a neutralizing agent in that case, for example, a copper oxide ore may be substituted. When oxide ore is added, sulfuric acid becomes copper sulfate, and the same effect as neutralization is obtained. At the same time, copper in the oxide ore is also leached. However, oxide ore is not always available, and when it cannot be used, it is necessary to use an alkali such as sodium hydroxide or slaked lime as a neutralizing agent.

  For this reason, when copper sulfide is treated by a sulfuric acid-based process, a large amount of sulfuric acid is used in the copper leaching process from the copper sulfide, and the sulfuric acid produced in the copper extraction process from the leached liquid is used. Since a large amount of the neutralizing agent used for neutralization is required, sulfuric acid is wasted and a large amount of cost is required, resulting in a decrease in cost competitiveness.

  In Patent Document 3, when a sulfuric acid process is used, copper sulfide minerals are leached with sulfuric acid at 170 ° C. to 235 ° C., and then excess acid is diluted with water to adjust the pH of the leachate to 1.2 to 2. A method for adjusting to the range of 0.0 is disclosed. However, in order to adjust the pH by lowering the acid concentration by diluting the leachate, it is necessary to add a large amount of dilution water, so considering the capacity of the equipment, water balance, labor and cost of wastewater treatment, etc. It is hard to say that it is a practical method.

Japanese National Patent Publication No. 10-510585 Japanese National Patent Publication No. 11-506166 JP 2007-297717 A

  The present invention has been made in view of the problems in the method for separating and recovering copper from sulfides by the sulfuric acid-based process described above, and the amount of sulfuric acid consumed in all steps from sulfide leaching to copper electrowinning. It is an object of the present invention to provide a method for separating and recovering copper, which can reduce the cost and can greatly reduce the cost as compared with the conventional method without using a neutralizing agent in the extraction and back-extraction steps.

  In order to achieve the above object, the present inventors have conducted detailed studies on conditions for separating and recovering copper from sulfides by a sulfuric acid-based process. As a result, when the temperature during leaching is maintained within a specific range, It was found that not only the oxidation of iron was suppressed, but also iron ions and free sulfuric acid formed and precipitated H-type iron alunite. In addition, when extracting copper from the leachate, by optimizing the composition of the aldoxime-type extractant, which is one of the oxime-based extractants, it can be seen that excellent back-extraction performance as well as excellent extraction performance can be obtained. The present invention has been completed based on these findings.

That is, in the method for separating and recovering copper from copper-containing iron sulfide provided by the present invention, a slurry obtained by mixing the sulfide and sulfuric acid solution is placed in a reaction vessel, and copper and iron are leached while blowing oxygen or air. A leaching step, an extraction step in which the obtained leachate is mixed with an organic extractant to extract copper, and a reverse extraction in which the obtained extracted organic is mixed with a back-extraction starting solution and copper is back-extracted into the solution after back-extraction. A step and an electrolysis step of electrolytically collecting electrolytic copper using the obtained back-extracted post-extraction solution as an electrolysis start solution,
The temperature in the leaching step is maintained in the range of 102 ° C. or higher and 112 ° C. or lower, and an aldoxime type extractant is used as the organic extractant in the extraction step, and the aldoxime type extractant is mainly 5-alkylsalicylaldoxime. It is a component, and the content of alcohols or phenols is less than 5% by weight.

  In the method for separating and recovering copper from copper-containing iron sulfide according to the present invention, it is preferable that the concentration of 5-alkylsalicylaldoxime in the aldoxime type extractant is 25 wt% or more and 35 wt% or less. The extraction residual liquid in the extraction step can be used as a sulfuric acid solution for leaching copper and iron by repeating the leaching step.

  According to the present invention, the extraction step and the back extraction step can be operated without using any neutralizing agent. Moreover, since the extraction residual liquid in the extraction process can be reused in the leaching process, the amount of sulfuric acid added can be reduced throughout the entire process. Therefore, by using the method for separating and recovering copper from the copper-containing iron sulfide of the present invention, the cost can be greatly reduced as compared with the conventional method.

It is a flowchart which shows each process in the separation-and-recovery method of copper from the copper-containing iron sulfide of this invention.

  In the present invention, as shown in FIG. 1, first, in the leaching step, a slurry in which copper-containing iron sulfide and a sulfuric acid solution (leaching start solution) are mixed is put into a reaction vessel, and oxygen or air is blown into it. Leach copper, iron, lead, etc. from the iron sulfide into the leachate. The obtained leachate is separated from the leach residue and sent to the next extraction step.

  However, when copper and iron are extracted from a copper-containing iron sulfide with a sulfuric acid solution, as described above, sulfuric acid is generated by the above chemical formula 2 in the conventional leaching method. In the next extraction step, sulfuric acid is by-produced by the above chemical formula 3 by using an oxime-based extractant. Since the extraction performance of the oxime-based extractant is lowered by these excessive sulfuric acids, it has been performed to neutralize the sulfuric acid by adding an alkali or the like for the purpose of suppressing the performance drop.

In order to solve this problem of excessive sulfuric acid, in the present invention, by maintaining the temperature in the range of 102 ° C. or higher and 112 ° C. or lower during leaching, sulfur oxidation can be suppressed, and free sulfuric acid in the leachate can be reduced. It can be precipitated as H-type iron aurite by reacting with iron ions (Jarosite-Hydronium; HFe ₃ (SO ₄ ) ₂ (OH) ₆ ). Also, when the free sulfuric acid concentration becomes low, for example, as low as 20 g / l or less, and the sulfuric acid / iron molar ratio exceeds two-thirds of the theoretical required amount, iron ions become goethite (Goethite; It has been found that free sulfuric acid is not affected because it produces (FeOOH).

  When leaching copper from iron-containing copper sulfide in the leaching step and simultaneously hydrolyzing and fixing iron, the leaching time becomes very slow at a temperature below 102 ° C. On the other hand, when the temperature at the time of leaching exceeds 112 ° C., oxidation of the coexisting iron sulfide ore proceeds preferentially, and free sulfuric acid exceeding the level that can be suppressed is generated. Therefore, the leaching temperature range needs to be 102 ° C. or higher and 112 ° C. or lower.

  Thus, in the leaching process of the present invention, the leaching temperature is controlled in the range of 102 ° C. or higher and 112 ° C. or lower, that is, by operating under conditions that generate H-type iron alunite, the coexisting iron ions are used. Excess sulfuric acid can be separated from the leachate. As a result, excess sulfuric acid does not accumulate in the leachate as in the case of leaching with a conventional sulfuric acid solution, and the sulfuric acid concentration can be kept constant from the leaching step to the extraction step as will be described later.

  In the next extraction process, copper is extracted by mixing the leachate obtained in the above leaching process with an organic extractant, and an aldoxime type extractant, which is a kind of oxime-based extractant, is used as the organic extractant. To do. Aldoxime type extractants have the property of easily extracting copper into the extractant, but it is known that back extraction of copper from the extractant (extracted organic) after extraction tends to be incomplete.

  Therefore, many of the aldoxime type extractants currently on the market improve the back extraction performance by reducing the acidity by containing alcohols or phenols in addition to 5-alkylsalicylaldoxime as the main component. Yes. However, if the acidity is weakened by adding alcohols or phenols, as described above, the back extraction reaction proceeds due to the sulfuric acid generated as the extraction reaction proceeds, and the copper extraction rate is significantly reduced. It was.

  In order to solve the problem of such an aldoxime type extractant, the present invention is excellent by optimizing the composition of the aldoxime type extractant, that is, by suppressing the concentration of alcohols or phenols to less than 5% by weight. It was possible to obtain good back extraction performance at the same time while maintaining the extraction performance. In order to optimize the composition so that the concentration of alcohols or phenols falls within the above range, for example, a commercially available aldoxime type extractant may be diluted with a diluent.

  Moreover, when optimizing the composition of the aldoxime type extractant, it is preferable that the concentration of 5-alkylsalicylaldoxime is 25% by weight or more and 35% by weight or less, for example, by diluting with a diluent. When the concentration of 5-alkylsalicylaldoxime exceeds 35% by weight, the viscosity increases and the phase separation time increases remarkably, which is not preferable. On the other hand, when the concentration of 5-alkylsalicylaldoxime is less than 25% by weight, the extraction capacity is insufficient, which is not preferable.

  As an aldoxime type extractant used in the present invention, for example, there is LIX860N-IC (trade name) manufactured by Cognis, and the composition may be optimized by dilution. Further, as a diluent used for optimizing the composition of the aldoxime type extractant, a hydrocarbon solvent having a high solubility and boiling point of the extractant, a high flash point, and a low solubility in water is preferable. Teclean N-20 (trade name, manufactured by Nippon Oil Corporation) or the like can be used.

  When copper is extracted from the leachate using the aldoxium-type extractant whose composition has been optimized by dilution as described above, excess sulfuric acid can be removed during the extraction, coupled with the ability to remove excess sulfuric acid by temperature control in the leaching step. No need to neutralize the sulfuric acid. Therefore, as shown in FIG. 1, the extraction residual liquid can be used again as a leaching start liquid (sulfuric acid solution) for leaching copper-containing iron sulfide by repeating the leaching step.

  The extracted organic obtained in the extraction step (the organic extractant after extraction) is mixed with the back extraction starting solution in the next back extraction step to obtain a back-extracted solution from which copper ions are back-extracted. The aldoxime-type extractant after the copper ions are back-extracted (organic after back-extraction) is repeated in the extraction step and can be reused for extracting copper from the leachate.

  In the actual operation, the extraction step is performed by mixing the aldoxium-type extractant whose composition is optimized by dilution and the leachate so that the volume ratio of the aldoxium-type extractant: exudate is 4: 1. It is preferable to extract copper through a stage or a three-stage mixing tank. On the other hand, in the back extraction step, the extracted organic and the back extraction start solution (sulfuric acid concentration 200 to 250 g / l) are mixed so that the volume ratio of the extract organic: back extraction start solution is 2: 1. It is preferable to back-extract copper in the extracted organic using a stage or three-stage mixing tank.

  The back-extracted solution containing copper obtained in the back extraction step is sent to the electrolysis step, and copper is recovered as electrolytic copper using a method such as electrowinning as in the prior art. Since the obtained electrolytic waste liquid is a sulfuric acid solution, it can be reused as the back extraction start liquid by repeating the back extraction step.

  As described above, according to the present invention, it is possible to carry out the cycle of the extraction step and the back extraction step without using a neutralizing agent. Further, since the extraction residual liquid can be repeated as the leaching start liquid in the leaching process and the electrolytic waste liquid can be repeated as the back extraction start liquid in the back extraction process, the amount of sulfuric acid added can be reduced throughout the entire process. In addition, this invention is not limited to copper sulfide minerals, such as copper concentrate and chalcopyrite, but can be applied if it is a sulfide containing copper and iron.

[Example 1]
As the copper-containing iron sulfide, a copper concentrate comprising a mixture of chalcopyrite and pyrite and containing 20.6% by weight of copper, 25.7% by weight of iron and 24.6% by weight of sulfur was used. This copper concentrate was wet pulverized, and the particle size was adjusted so that particles having a particle size of 10 μm or less occupied 80% or more of the total. The pulverized copper concentrate was fractionated so as to be equivalent to 200 g in terms of dry weight.

  200 g of the separated copper concentrate is suspended in 1000 ml of an aqueous sulfuric acid solution having a copper concentration of 1.3 g / l, a divalent iron concentration of 45.3 g / l, a sulfur concentration of 64.2 g / l, and a free sulfuric acid concentration of 95 g / l. Further, sodium lignin sulfonate as a surfactant was added to a concentration of 0.5 g / l to obtain a slurry.

  The slurry was charged in a pressure vessel, sealed, and heated to 105 ° C. while mixing. The internal pressure after the temperature increase was 0.1 MPa. Next, oxygen gas was blown into the pressure vessel, and the internal pressure was increased to 1.5 MPa. Further, stirring was continued for 2 hours while maintaining a temperature of 105 ° C., and oxygen gas was blown in to maintain a constant pressure for the time during which the pressure decreased.

  The slurry after the reaction was filtered using Nutsche and a filter bottle, and separated into a leachate and a leach residue. The concentrations of copper, iron and sulfur in the leachate and leach residue were each analyzed using ICP. The concentration of free sulfuric acid in the leachate was determined by neutralization titration. As a result, the copper concentration in the leaching solution was 48.3 g / l, and the leaching rate of copper was 81.0%. Moreover, the free sulfuric acid concentration was 2 g / l, and the oxidation rate of sulfur (the ratio of the sulfur contained in the copper concentrate eluted in the leachate) was 7.6%.

  Next, the obtained leachate was mixed with an organic extractant to extract copper. The organic extractant used was an aldoxime type organic extractant LIX860N-IC (trade name; manufactured by Cognis) consisting of 85% by weight of 5-nonylsalicylaldoxime and 5% by weight of 2-nonylphenol. N-20 (trade name; manufactured by Nippon Oil Corporation) is mixed at a volume ratio of 3: 7, and the content of 2-nonylphenol is adjusted to 1.5% by weight.

  In addition, the density | concentration of 5-nonyl salicyl aldoxime in the organic extractant which adjusted said composition is 26 weight%. Also, prior to the extraction operation, assuming a state in which the process is circulated and maintained in an equilibrium state, the organic extractant and the copper sulfate solution are mixed, so that the copper ion concentration in the organic extractant is 23 g / l in advance. Adjusted.

  The ratio of the leachate 1 to the organic extractant 4, that is, the volume ratio (O / A ratio) of the amount of the organic extractant and the leachate was 4: 1. The number of extraction stages was three, and the organic extractant and the leachate were passed and mixed so that the countercurrent flowed countercurrently, and the copper contained in the leachate was extracted into the organic extractant.

  When the extracted leachate (extracted residual liquid) was analyzed in the same manner as described above, the copper concentration in the extracted residual liquid was reduced to 8.3 g / l, and 83% of the copper ions contained in the extracted liquid were contained in the organic extractant. Could be extracted. On the other hand, the free sulfuric acid concentration in the extracted residue was 78 g / l due to the by-product of sulfuric acid. Moreover, when the mixed solution of the organic extractant and the leachate was sampled from the extraction tank and allowed to stand to measure the phase separation time until the extractant and the leachate were separated, it was 25 seconds.

  In addition, using the extraction residual liquid obtained by the above extraction, the same copper concentrate was leached again with the other conditions set to the same without adding new sulfuric acid. As a result, the copper concentration in the obtained leachate was 48 g / l as in the above case, while the free sulfuric acid concentration decreased to 2 g / l. From this, it was confirmed that the extraction residual liquid can be used as a leaching start liquid by repeating it to the next leaching step.

  Next, copper was back-extracted from the extracted organic extractant (extracted organic). As a back extraction starting solution, a solution prepared in advance using a reagent copper sulfate and sulfuric acid to a copper concentration of 36 g / l and a free sulfuric acid concentration of 231 g / l was used. The O / A ratio was set to 2 and the number of extraction stages was 4, and the mixture was passed through the mixer settler in a countercurrent manner and mixed, and copper was back-extracted from the extracted organic into a sulfuric acid solution to obtain a liquid after back extraction.

  When the obtained solution after back extraction was analyzed in the same manner as described above, the copper concentration was 56 g / l and the free sulfuric acid concentration was 200 g / l. Moreover, the copper concentration in the organic extractant after back extraction (organic after back extraction) was 23 g / l, which was reduced to the copper concentration contained in the organic extractant before extraction. Therefore, the back extraction rate was almost 100% with respect to the extracted copper, and it was confirmed that the organic after back extraction was regenerated as an organic extractant and could be used repeatedly in the extraction process.

The back-extracted solution obtained by the above-described back extraction is used as an electrolytic starting solution, and the current density is 300 A / m ^{2 using} a lead anode and a stainless steel cathode as electrodes while maintaining the solution temperature in the range of 57 ° C. to 62 ° C. Then, copper was electrodeposited on the cathode. When the copper concentration in the electrolyte reached 36 g / l, the current supply was stopped, the cathode was lifted, and the electrodeposited copper was peeled off and washed.

  As a result of analyzing the electrolytic solution after completion of the electrolysis in the same manner as described above, the concentration of free sulfuric acid in the electrolytic solution was 231 g / l, which is the same as the back extraction starting solution used for the back extraction. From this result, it was confirmed that the solution after back extraction was regenerated by electrowinning and can be used as a back extraction starting solution by repeating the back extraction step.

[Comparative Example 1]
Although it carried out similarly to the said Example 1, it leached on the same conditions as the above except having changed the leaching temperature of the copper concentrate to 100 degreeC, 120 degreeC, and 140 degreeC, respectively, and sulfur was carried out similarly to the above. The oxidation rate was determined. The resulting sulfur oxidation rate was 2% at a leaching temperature of 100 ° C, 39% at a leaching temperature of 120 ° C, and 46% at a leaching temperature of 140 ° C. The higher the leaching temperature, the higher the oxidation rate of sulfur. Byproduct increased. When the leaching temperature was 100 ° C., the leaching time was extremely slow.

  When the leachate at each leaching temperature is extracted under the same conditions as in Example 1 and the extraction liquid is circulated three times to the leaching step, sulfate ions generated under the leaching temperature of 100 ° C. Insufficient sulfuric acid was required. On the other hand, under the conditions where the leaching temperatures were 120 ° C. and 140 ° C., sulfate ions became excessive, and it was necessary to add a neutralizing agent.

[Comparative Example 2]
Although it implemented similarly to the said Example 1, as an organic extractant, aldoxime type organic extractant LIX984 (commodity) which consists of 50 weight% 5-dodecyl salicyl aldoxime and 50 weight% 2-hydroxy-5-nonyl acetophenone oxime Extraction was performed under the same conditions as described above except that the product (name: Cognis) was used without dilution. As a result, the copper extraction rate in the extraction process was 45%, and only a result much lower than that of Example 1 was obtained.

[Reference Example 1]
Although it implemented similarly to the said Example 1, when the density | concentration of 5-nonyl salicyl aldoxime in the organic extractant which adjusted the composition was increased to 40 weight%, the extraction rate of copper was about 80%, and said Example Although not different from 1, the phase separation time increased to 234 seconds. Moreover, when the said density | concentration was increased to 50 weight%, phase-separation time increased to 343 seconds, and it was confirmed that phase-separability deteriorates remarkably.

  On the other hand, when the concentration of the organic extractant was reduced to 20% by weight, the phase separation time was shortened to 23 seconds, but the copper extraction rate was reduced to 55%.

[Reference Example 2]
Although it carried out similarly to the said Example 1, when the phase ratio was set to O / A = 2/1 in the extraction process and five steps of extraction was performed by multistage countercurrent, the extraction rate of copper was 46% and was impractical Only a low extraction rate was obtained.

  Moreover, although implemented similarly to the said Example 1, about the copper extraction organic produced | generated at the extraction process, it is multistage with O / A = 4/1 in the aqueous solution of a composition with a copper concentration of 36 g / l and a free sulfuric acid density | concentration of 231 g / l. When three stages of back extraction were performed in countercurrent, the back extraction rate for the extracted copper was only up to 48%, which was incomplete.

Claims (3)

A method of separating and recovering copper from a copper-containing iron sulfide containing copper and iron by a wet method, wherein a slurry in which the sulfide and a sulfuric acid solution are mixed is put into a reaction vessel, and copper or The leaching step of leaching iron, the extraction step of extracting the copper by mixing the obtained leachate with an organic extractant, and mixing the obtained extracted organic with the back extraction starting solution, and reverse the copper to the solution after back extraction A back extraction step for extraction, and an electrolysis step for electrolytically collecting electrolytic copper using the obtained back-extraction solution as an electrolysis start solution,
The temperature in the leaching step is maintained in the range of 102 ° C. or higher and 112 ° C. or lower, and an aldoxime type extractant is used as the organic extractant in the extraction step, and the aldoxime type extractant is mainly 5-alkylsalicylaldoxime. A method for separating and recovering copper from a copper-containing iron sulfide, characterized in that the content of the alcohol or phenol is less than 5% by weight as a component.   The method for separating and recovering copper from copper-containing iron sulfide according to claim 1, wherein the concentration of 5-alkylsalicylaldoxime in the aldoxime-type extractant is 25 wt% or more and 35 wt% or less.   The copper from the copper-containing iron sulfide according to claim 1 or 2, wherein the extraction residual liquid in the extraction step is repeated in the leaching step and used as a sulfuric acid solution for leaching copper and iron. Separation and recovery method.

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