JP2017119623A - Method for recovering tellurium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering tellurium from a copper electrolytic slime capable of achieving enhancement of recovery efficiency of tellurium as whole treatment process.SOLUTION: There is provided a method for recovering tellurium from a copper electrolytic slime including supplying an alkali leach residue containing tellurium after leaching copper telluride to a copper removal leach treatment tank containing the copper electrolyte and copper electrolytic slime in a copper removal leach process for removing copper from the copper electrolytic slime by dissolving the copper electrolytic slime into the copper electrolyte and leaching impurities containing copper and tellurium into the electrolyte.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for recovering tellurium, and more specifically, a method for recovering tellurium from a copper electrolytic deposit.

  In the electrolytic refining of copper, the crude copper from the converter is refined to about 99.5% in the refining furnace, and the cast anode (anode) and the seed plate or stainless steel plate as the cathode are alternately placed in the electrolytic cell. Hang in one set. Copper electrodeposited on a seed plate or stainless steel plate is called electrolytic copper. Impurities contained in the anode deposit in a muddy state at the bottom of the electrolytic cell. This deposit is called copper electrolytic deposit (anode slime). In the copper electrolyte, various precious metals in the raw material including gold are concentrated in addition to copper, and are used as a main raw material for precious metal recovery.

  In the treatment of copper electrolytic deposits, both dry methods and wet methods have been put into practical use, but it has been considered that the wet method is highly useful in terms of equipment cost, treatment flow, etc. . In the wet method, copper electrolytic porcelain is repulped with an electrolytic solution, copper, tellurium, arsenic and other soluble impurities remaining in the porcelain are dissolved, and insoluble matter mainly composed of noble metals, selenium, etc. And solid-liquid separation and concentration and purification of precious metals. The main components of the insoluble material are silver, selenium, gold, platinum group, tellurium, lead and the like.

  An example of the processing flow of the copper electrolytic deposit is shown in FIG. First, in the copper removal leaching step, the electrolytic deposit is dissolved using a copper electrolyte, and impurities such as copper, tellurium, arsenic, etc. are leached. The leaching residue is dissolved using a hydrochloric acid solution and an oxidizing agent, and then solid-liquid separated with silver or the like as a chloride (chlorinated leaching step). Gold is separated from the leached solution after separation by solvent extraction using dibutyl carbitol (DBC) or the like (gold extraction step), and gold reduction treatment is performed to obtain product gold.

On the other hand, from the gold-extracted solution, selenium reduction is performed by blowing in sulfurous acid gas (SO ₂ ) until the selenium concentration in the solution becomes 2.5 to 4 g / L to obtain selenium soot, followed by vacuum distillation. Remove selenium. On the other hand, since valuable metals such as tellurium and selenium are still contained in the liquid after reducing selenium after recovering selenium soot, after further reducing the selenium concentration to 1 mg / L or less by blowing in sulfurous acid gas, tellurium Get reduced soot. Tellurium reduced soot is sent to an alkaline leaching process in which tellurium is leached with caustic soda.

  On the other hand, the post-leaching solution obtained in the decopper leaching step is subjected to detellation treatment, and copper telluride is taken out. In order to recover tellurium from copper telluride, tellurium is leached with caustic soda in the alkaline leaching step. The post-leaching solution after filtration is obtained by isolating tellurium by adding sulfuric acid to obtain tellurium dioxide (neutralization step).

Sulfurous acid gas (SO ₂ ) is blown into the post-neutralization solution to perform reduction treatment, thereby extracting selenium (de-selenium step). The post-reduction liquid and reduction residue after deselenization are sent to a separate process for precious metal recovery. On the other hand, the alkali leaching residue produced in the tellurium alkali leaching treatment is repeated for smelting again.

  In order to increase the recovery efficiency of selenium and tellurium in copper electrolytic treatment, various studies have been made to extract tellurium dioxide, selenium, and the like (see, for example, Patent Document 1). However, in view of the overall process for treating copper electrolytic deposits, there are processes in which tellurium-containing materials are still repeated for waste liquid treatment or smelting, etc., and tellurium recovery rate when judged from the overall treatment process There is still room for consideration to achieve improvement.

  Therefore, as a measure to improve the recovery rate of tellurium when considering the entire treatment process, attention was paid to the alkali leaching residue after alkali leaching of copper telluride, which had been merely repeated for smelting in the past, and this residue was treated. An attempt was made to return it to the system. For example, in Patent Document 2, an alkaline leaching residue is mixed with a solution after a selenium reduction step, and tellurium contained in the mixture is acid leached, and then the leached solution after acid leaching is reduced with sulfurous acid gas. It has been proposed to recover tellurium.

  However, if the method described in Patent Document 2 is continuously adopted in a copper electrolytic processing plant, tellurium that should be reduced without any problem in theory is not actually reduced, and as a result, the entire treatment process is performed. As a result, it has been found that the recovery efficiency of tellurium may not be improved.

JP 2005-126800 A JP 2012-211027 A

  In view of the above problems, the present invention provides a method for recovering tellurium from a copper electrolytic product capable of improving the recovery efficiency of tellurium as a whole treatment process.

  In order to solve the above problems, the present inventor tried to return the alkali leaching residue containing tellurium after alkali leaching of copper telluride to the copper electrolysis residue decopper leaching process. It was found that the tellurium recovery efficiency as a whole treatment process can be improved without adversely affecting the process.

  The present invention completed on the basis of the above knowledge is, in one aspect, a method for recovering tellurium from a copper electrolyte, wherein the copper electrolyte is dissolved in the copper electrolyte, and copper and copper are dissolved in the copper electrolyte. After leaching copper telluride into a decopper leaching treatment bath containing a copper electrolyte and a copper electrolytic deposit in a copper leaching step of removing copper from the copper electrolytic deposit by leaching impurities containing tellurium A method is provided for recovering tellurium from a copper electrolysate comprising supplying an alkaline leaching residue containing no tellurium.

  In one embodiment, the method for recovering tellurium from a copper electrolytic product according to the present invention includes supplying an alkali leaching residue at a slurry concentration of 10 to 40 g / L.

  In another embodiment of the method for recovering tellurium from the copper electrolytic product according to the present invention, the alkali leaching residue is a caustic soda leaching residue containing 5 to 20% by mass of tellurium.

  In another embodiment of the method for recovering tellurium from the copper electrolytic product according to the present invention, the copper electrolyte has a copper concentration of 90 to 120 g / L and a sulfuric acid concentration of 350 to 400 g / L.

  In another aspect of the present invention, an alkaline leaching residue containing tellurium is supplied into a treatment tank containing a copper electrolyte and a copper electrolyte, and impurities containing copper and tellurium are leached in the copper electrolyte. A method for recovering tellurium is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the recovery method of the tellurium from the copper electrolytic deposit which can aim at the improvement of the recovery efficiency of the tellurium as the whole processing process can be provided.

It is a processing flow figure showing an example of the recovery method of tellurium from the copper electrolysis thing concerning an embodiment of the invention. It is a processing flow figure showing the processing method of the conventional copper electrolytic deposit.

  As shown in FIG. 1, the tellurium recovery method according to the embodiment of the present invention includes returning the alkali leaching residue containing tellurium to the decopper leaching step which is the first step of the copper electrolytic residue treatment. .

<Alkali leaching residue containing tellurium>
The “alkaline leaching residue containing tellurium” used in the tellurium recovery method according to the embodiment of the present invention is an alkali leaching residue obtained in the copper electrolyzing residue treatment step, and more specifically, for example, FIG. Desulfurization leaching, chloride leaching, gold extraction, sulfurous acid gas reduction treatment (selenium reduction treatment) for the alkali leaching residue and / or copper electrolytic deposit after the copper telluride after detellurization treatment shown in 1 It is possible to use the alkali leaching residue after alkali leaching of the tellurium-reduced soot after having been carried out with caustic soda.

  In this alkali leaching residue, for example, 5 to 20% by mass of tellurium (Te) is contained. The alkali leaching residue after alkali leaching of the copper telluride after the detellurization treatment contains, for example, 50 to 70% by mass of copper (Cu) and a trace amount of lead (Pb) in addition to tellurium. In addition, tellurium-reduced soot after copper leaching, chloride leaching, gold extraction, and selenium reduction treatment for copper electrolytic deposits are added to tellurium in the alkaline leaching residue after alkaline leaching with caustic soda. Furthermore, 0-2 mass% selenium (Se), 0.01-0.02 mass% rhodium (Rh), 0.05-0.2 mass% ruthenium (Ru), copper, etc. are contained.

<Decopper leaching process>
In addition to 25 to 35% by mass of copper, the copper electrolytic product to be treated is 1 to 5% by mass of tellurium (Te), 2 to 5% by mass of arsenic (As), and 1 to 3% by mass of copper. Gold (Au), 5 to 15% by mass of selenium (Se), 0.02 to 0.08% by mass of platinum (Pt), 0.002 to 0.01% by mass of rhodium (Rh), 0.05 to 0.25 mass% ruthenium (Ru), 1-5 mass% lead (Pb), 15-25 mass% silver (Ag), etc. are contained.

  In the copper removal leaching process, the copper electrolytic product is dissolved in a copper electrolytic solution in a treatment tank (decopper leaching treatment tank), and impurities such as copper, tellurium and arsenic are leached into the copper electrolytic solution. To remove copper from the copper electrolyte.

  As a composition of the copper electrolyte solution used for the treatment, for example, a copper electrolyte solution having a copper concentration of 90 to 120 g / L and a sulfuric acid concentration of 350 to 400 g / L can be used.

  The method for supplying the alkali leaching residue containing tellurium to the copper removal leaching treatment tank may be batch supply or continuous supply. However, if a large amount of alkali leaching residue is supplied too much into the treatment tank at one time, it may adversely affect each treatment step of the copper electrolytic product performed thereafter.

  For example, if the supply amount of the alkali leaching residue is too large, there may be a problem that the copper telluride obtained after the detellurization treatment shown in FIG. Furthermore, in the selenium reduction treatment shown in FIG. 1 after copper leaching, the reducing soot is solidified in the tank, causing clogging of the tank and reducing the recovery efficiency of various metals recovered from the copper electrolytic deposit. There is a case. Moreover, when the amount of alkali leaching residue input is increased, the filter cloth may be clogged when the liquid after decopper leaching is filtered with a filtration facility (filter press).

  Therefore, in the tellurium recovery method according to the embodiment of the present invention, the copper leaching is carried out at a slurry concentration of 10 to 40 g / L, more preferably 10 to 20 g / L, and still more preferably 10 to 15 g / L. It is preferable to supply to a processing tank. That is, the alkali leaching residue is supplied at a rate of 10 to 40 g / L, more preferably 10 to 20 g / L, and still more preferably 10 to 15 g / L with respect to a copper electrolyte having a slurry concentration of 350 to 400 g / L. Thereby, even if it supplies an alkali leaching residue to a copper removal leaching processing tank, the influence which it has on each metal recovery process after a copper removal leaching can be made small. In addition, the liquid temperature of the copper electrolyte solution in a copper removal leaching process can be suitably performed at about 78 to 82 ° C.

  The alkali leaching residue containing tellurium after leaching copper telluride contains a higher concentration of tellurium than the tellurium reduced soot shown in FIG. Conventionally, in order to effectively use the tellurium in the obtained alkali leaching residue, it has been studied to repeat to selenium reduction soot, and was not repeated in the decopper leaching step as in the present invention. . This is because the alkali leaching residue containing tellurium after leaching copper telluride from the copper electrolytic deposit contains tellurium and copper, so that copper may not be completely removed in the copper removal process, This is because there was a possibility that the tellurium quality of the future would rise. Moreover, it is because repeating to a copper removal leaching process had a bad influence on each process after a copper removal leaching process, and it was thought that collection | recovery efficiency of each metal, such as gold | metal | money, selenium, and tellurium, falls. Alternatively, there is a concern that troubles such as clogging may increase in each process by introducing impurities.

  According to the tellurium recovery method according to the embodiment of the present invention, an alkaline leaching residue containing tellurium after leaching copper telluride is introduced into a copper removal leaching process that has not been conventionally performed. As a result, tellurium in the alkaline leaching residue can be effectively used, and it is possible to improve the recovery efficiency of tellurium as a whole treatment process without adversely affecting each metal recovery flow after the copper removal leaching process. Become. Moreover, since the alkaline leaching residue containing tellurium is not repeated for smelting, impurities in the alkaline leaching residue are not mixed into the smelting process, and the impurity quality in the copper anode produced by the smelting process is lowered. be able to.

  Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. For example, in the above method, as the alkali leaching residue, the alkali leaching residue after the copper telluride after the detellation treatment of FIG. 1 is leached with alkali, and / or the copper electrolytic deposit, leaching copper leaching, chloride leaching, Although an example using an alkali leaching residue after leaching alkali with caustic soda after selenium reduction after gold extraction and selenium reduction treatment is shown, it is not limited to the above example, and FIG. The present invention is applicable to any alkali leaching residue containing tellurium obtained in a treatment process other than the electrolytic deposit treatment process shown.

  EXAMPLES Examples of the present invention will be described below, but these are provided for better understanding of the present invention and are not intended to limit the present invention.

  In the copper electrolytic process flow shown in FIG. 1, the balance of the quantity of when the alkali leaching residue is introduced into the decopper leaching treatment tank in the decopper leaching process is compared with the case where the alkali leaching residue is not added. The influence on the treatment process after the copper leaching process was evaluated.

(Test conditions)
The conditions in the copper removal leaching process of FIG.
Condition A: Alkali leaching residue is not charged: Total amount of copper electrolytic residue treated is 4304 dry-kg
Condition B: Alkali leaching residue introduced: Total amount of copper electrolytic residue treated 4238 dry-kg
Condition C: Alkali leaching residue input: Total amount of copper electrolytic deposit processed 4323 dry-kg

  In condition B, a total amount of caustic soda leaching residue (copper hydroxide) after de-tellurium treatment of the copper electrolytic deposit was 149 dry− as an alkaline leaching residue containing tellurium with respect to the copper electrolytic deposit total amount (dry amount) of 4238 dry-kg. kg (tellurium content: 18.3 kg, tellurium quality: 12.3% by mass) was supplied to a decopper leaching treatment tank.

  Under condition C, the total amount of caustic soda leaching residue (copper hydroxide) after detellurization of the copper electrolytic deposit was 171 dry-kg (tellurium-containing) as the alkaline leaching residue containing tellurium with respect to the total amount of copper electrolytic deposit 4323 dry-kg. A quantity of 21.0 kg, tellurium grade 12.3% by mass) was supplied to a decopper leaching treatment tank.

(Processing flow)
Since the processing steps of the copper electrolytic deposit are diverse as shown in FIG. 1, paying attention to each leaching residue and each leaching solution after decopper leaching, chloride leaching, detellurization treatment, and their concentrations, The influence of trouble on each process was evaluated. The details of the copper removal leaching process, the chloride leaching process, and the detellurization treatment process are as follows.

-Decopper leaching process-
A copper electrolytic deposit is dissolved in a copper removal leaching treatment tank containing a copper electrolytic solution having a copper concentration of 90 to 120 g / L and a sulfuric acid concentration of 350 to 400 g / L, and impurities such as copper, tellurium and arsenic are leached. A leaching residue and a liquid after leaching were obtained. In Condition B, an alkali leaching residue containing tellurium was supplied into the copper removal leaching treatment tank at a slurry concentration of 15 g / L, and the tellurium contained in the alkali leaching residue was further leached. Under condition C, an alkali leaching residue containing tellurium was supplied into the decopper leaching treatment tank at a slurry concentration of 17 g / L, and tellurium contained in the alkali leaching residue was further leached. Table 1 shows the composition of the obtained decopper leaching residue and the liquid after decopper leaching.

-Chloride leaching process-
(Chloride leaching treatment)
The decopper leaching residue obtained in the decopper leaching step is dissolved in a 35% by mass hydrochloric acid solution using hydrogen peroxide, and is subjected to solid-liquid separation at a reaction temperature of 70 to 74 ° C. as silver chloride. A chloride leaching residue and a solution after chloride leaching were obtained. Table 2 shows the composition of the obtained leaching residue and the solution after leaching.

(Chlorine cooling treatment)
The solution after leaching with chloride obtained by the leaching treatment was cooled to precipitate lead chloride and antimony trioxide to obtain a chloride cooling residue and a solution after cooling with chloride. Table 3 shows the composition of the obtained chloride cooling residue and the solution after chloride cooling.

-Detellurization treatment-
The post-decopper leaching solution obtained in the decopper leaching step was detellurized by cementation with a copper plate to obtain copper telluride and post-detellurium solution. Table 4 shows the composition of the obtained copper telluride and post-de tellurium solution.

(result)
Evaluation of the tellurium recovery rate based on the tellurium concentration before treatment with reference to the tellurium concentration contained in the post-cooling solution obtained by the chloride cooling treatment, the chloride cooling residue and the copper telluride obtained in the detellurization step , By introducing an alkaline leaching residue containing tellurium into the copper removal leaching process (conditions B and C), the tellurium recovery rate is improved by about 3% compared to when no alkaline leaching residue is added (condition A). did. Thus, it was found that tellurium can be recovered without any problem without reducing the tellurium recovery rate in each step by repeating the alkaline leaching residue containing tellurium in the copper removal leaching step. Further, when viewed as a whole treatment process, the total amount of tellurium recovered can be increased by repeating alkali residue containing tellurium in the system, so that the tellurium recovery efficiency as a whole treatment process can be improved. I understood that.

  Under the conditions B and C in which the alkali leaching residue was put into the copper removal leaching treatment tank, no adverse effects such as an increase in the tellurium quality in gold and silver and clogging of piping were observed due to the introduction of impurities in the copper removal leaching process. That is, even when the alkaline leaching residue containing tellurium after treating copper telluride is put into the treatment tank in the decopper leaching process, recovery of tellurium as a whole treatment process without adversely affecting the decopper leaching process. It was found that the efficiency can be improved.

  In condition B where the amount of alkali leaching residue supplied was within an appropriate range, discoloration of the copper telluride obtained after the detellurization treatment in FIG. 1 was not observed, and process troubles such as tank clogging due to the selenium reduction process were also observed. There wasn't. Under condition C, copper telluride sometimes turned blue-green rather than normal. In addition, the tank was clogged in the selenium reduction process.

Claims (5)

A method for recovering tellurium from a copper electrolytic deposit,
In a decopper leaching step of removing copper from the copper electrolyte by dissolving the copper electrolyte in the copper electrolyte and leaching impurities containing copper and tellurium in the copper electrolyte,
Tellurium from a copper electrolytic deposit characterized by supplying an alkaline leaching residue containing tellurium after leaching copper telluride into a decopper leaching treatment bath containing a copper electrolyte and a copper electrolytic deposit. Recovery method.   The method for recovering tellurium from a copper electrolytic deposit according to claim 1, comprising supplying the alkali leaching residue at a slurry concentration of 10 to 40 g / L.   The method for recovering tellurium from a copper electrolytic deposit according to claim 1 or 2, wherein the alkaline leaching residue is a caustic soda leaching residue containing 5 to 20% by mass of tellurium.   The method for recovering tellurium from a copper electrolyte according to any one of claims 1 to 3, wherein the copper electrolyte has a copper concentration of 90 to 120 g / L and a sulfuric acid concentration of 350 to 400 g / L.   The tellurium is characterized by comprising supplying an alkaline leaching residue containing tellurium into a treatment tank containing a copper electrolyte and a copper electrolyte, and leaching impurities containing copper and tellurium into the copper electrolyte. Recovery method.

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