JP2013237920A - Treatment method of copper smelting flue cinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of increasing a leaching rate of copper in flue cinder, improving a recovery percentage, effectively separating lead and bismuth in the flue cinder as leach residues, and improving economical efficiency, in the treatment of leaching the flue cinder, which is generated and discharged in copper smelting process, under sulfuric acidity.SOLUTION: In a method, flue cinder generated in copper smelting process is added to a sulfuric acid solution whose pH is adjusted to be 1.0 or higher, and while oxidizing it using a ferric compound, copper in the flue cinder is leached.

Description

  The present invention relates to a method for treating copper smelting ash, and more particularly to a method for leaching and recovering copper from smoke ash generated and discharged from a copper smelting converter.

  The smoke ash generated in the converter process of copper smelting contains copper, lead, bismuth, zinc, etc., and is collected by a dust collector. If this smoke ash is repeatedly processed in the copper smelting system, lead, bismuth, zinc, etc. are concentrated and accumulated in the system as impurities, affecting the purity of the product. It is desirable to collect.

  In particular, for lead and bismuth, as shown in Patent Document 1, copper converter smoke ash is leached with water or dilute sulfuric acid, and copper is recovered along with soluble salts such as zinc to the leachate, and insoluble on the leach residue side. There is a method of reducing the impurity load in the copper smelting system by supplying lead and bismuth concentrated almost as sulfate as raw materials for lead recovery processing by dry processing.

  However, in the leaching residue, a part of copper remains without eluting, and the residue is not recovered as copper. Even if the acid concentration in the leaching process is increased so as to reduce the residual amount of copper, the copper recovery rate is not improved so much and elution of bismuth is promoted.

  Copper that does not dissolve by dilute sulfuric acid leaching is presumed to be present in the residue in the form of metal or sulfide, and leaching is considered possible by adding a strong oxidizing agent such as chlorine gas or hypochlorous acid. However, it is difficult to say that the processing method is economically efficient because a processing facility for materials that can withstand strong oxidation is required and the cost of reagents increases.

JP-A-4-285136

  Therefore, the present invention can improve the recovery rate by increasing the leaching rate of copper in the smoke ash in the process of leaching the smoke ash generated and discharged in the copper smelting process under sulfuric acid acidity, An object is to provide an economically efficient method that can effectively separate bismuth as a leach residue.

  As a result of intensive investigations to achieve the above-mentioned object, the present inventors have leached the smoke ash recovered from copper smelting by adding an iron agent containing a trivalent iron compound under a predetermined pH condition. The present inventors have found that copper can be selectively recovered and can be effectively separated as a leaching residue by suppressing the elution of lead and bismuth.

  That is, the copper smelting ash treatment method according to the present invention adds the smoke ash generated in copper smelting to a sulfuric acid acidic solution whose pH is adjusted to 1.0 or more, and oxidizes using a trivalent iron compound, It is characterized by leaching copper in the smoke ash.

  Here, it is preferable to adjust the pH of the sulfuric acid acidic solution to 1.0 to 2.0.

  Moreover, it is preferable to add the said iron compound so that it may become the range of 10-35g as a trivalent iron amount per kg of said smoke ash.

  ADVANTAGE OF THE INVENTION According to this invention, the copper leaching rate in smoke ash can be raised, the amount of copper remaining in the leaching residue can be reduced, and the copper recovery rate can be improved. Moreover, the elution of lead and bismuth in the smoke ash can be suppressed, and the leaching residue can be effectively separated.

  Hereinafter, specific embodiments of a method for treating smoke ash generated from copper smelting (hereinafter, also referred to as “copper smelted smoke ash” or simply “smoke ash”) according to the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.

  The method for treating copper smelter ash according to the present embodiment is a method for leaching copper smelter ash and recovering copper contained in the smoke ash. Specifically, the smoke ash generated by copper smelting is added to a sulfuric acid acidic solution whose pH is adjusted to 1.0 or more, and the copper in the smoke ash is leached while being oxidized using a trivalent iron compound. It is characterized by.

  Here, the composition of the smoke ash to be treated is not particularly limited, and can be suitably applied to smoke ash having any composition generated from copper smelting and collected by a dust collector. Specifically, as a metal element in the copper smelting ash, lead, bismuth are contained together with copper, and zinc, cadmium, antimony, arsenic, selenium, iron, tin, sulfur and the like are also included.

  According to such a treatment method, copper in smoke ash can be selectively leached at a high leaching rate and the residual to the leaching residue can be suppressed, so that the copper recovery rate can be improved, Elution of lead and bismuth contained in the smoke ash can be suppressed and effectively separated as a leaching residue. Moreover, since a strong oxidizing agent or the like is not used as in the prior art, equipment costs and reagent costs can be suppressed, and economically efficient processing can be performed.

  When leaching treatment is performed on the smoke ash under sulfuric acid acid, impurities such as zinc, cadmium, and arsenic are dissolved and contained in the leachate together with copper. Since these impurity components dissolved and contained in the leachate are not different from the impurity components in the copper waste liquid discharged from other processes of copper smelting, a process for removing these impurities in the existing waste liquid treatment process should be performed Only copper can be recovered.

  Further, iron added to the sulfuric acid solution is also dissolved on the leaching solution side, but can be treated without any problem in the waste liquid treatment.

  Hereinafter, the processing method of copper smelting smoke ash is demonstrated in detail.

  In the copper smelting ash treatment method, the pH condition when leaching the smoke ash with a sulfuric acid acidic solution is 1.0 or more, preferably 1.0 to 2.0. The pH adjustment of the sulfuric acid acidic solution may be performed by adjusting the concentration of sulfuric acid used.

  When the pH of the sulfuric acid acidic solution is less than 1.0, that is, when the acid concentration is high, elution of bismuth contained in the smoke ash is promoted and mixed in the leachate, but the dissolution of copper is not improved. Moreover, regarding the upper limit of pH, when pH is larger than 2.0, the dissolution (leaching) efficiency of copper may be gradually lowered. Therefore, by leaching with a sulfuric acid acidic solution adjusted to pH 1.0 or more, preferably in the range of pH 1.0 to 2.0, elution of bismuth can be suppressed and copper can be selectively leached.

  Further, the leaching treatment for the copper smelting smoke ash is characterized by leaching using a trivalent iron compound. In the copper smelting ash treatment method according to the present embodiment, the trivalent iron ions added to the sulfuric acid solution are not dissolved by simple sulfuric acid leaching by leaching using the trivalent iron compound. It acts as an oxidation catalyst for copper metal and copper sulfide, and can effectively promote the dissolution of copper in smoke ash. The added trivalent iron ions themselves are reduced to divalent iron ions along with the oxidation catalytic action on copper.

The trivalent iron compound is not particularly limited as long as it is a compound that has solubility under sulfuric acid acidity and can supply trivalent iron ions into the solution. Specific examples include ferric sulfate, ferric chloride, iron oxide hydroxide, iron agate (KFe (SO ₄ ) ₂ · 12H ₂ O), and iron starch containing trivalent iron.

  Moreover, it is not restricted to adding a trivalent iron compound, For example, by adding a divalent iron compound in a solution and blowing and stirring air as an oxidizing agent, for example, You may make it contain in a solution by oxidizing to trivalent iron ion.

  The method for adding the iron compound is not particularly limited, and it is possible to add a solution obtained by dissolving the above-described iron compound or to add it as a solid slurry.

  Moreover, it does not specifically limit as addition amount of an iron compound, However It is preferable to add so that it may become the range of 15g-35g as trivalent iron amount per kg of smoke ash. Further, as described above, even when a part or all of the trivalent iron compound is added as a trivalent iron compound, the trivalent iron amount is oxidized with an oxidizing agent so as to be within the above range, and the trivalent iron is added to the sulfuric acid solution. Contains iron ions.

  If the amount of trivalent iron added to the solution is less than 15 g, the effect of promoting the dissolution of copper in the smoke ash may not be sufficiently obtained. On the other hand, if the amount of trivalent iron to be added exceeds 35 g, no further effect of promoting dissolution is obtained, and the amount of iron that will be contained in the leachate and leach residue increases, and the leachate is treated as a waste solution. And the load of the process of separating and refining other metal elements from the leach residue is increased.

  The temperature condition at the time of leaching can be room temperature, but it is preferable to heat in order to increase the reaction rate. For example, the solution is heated to 60 ° C. or higher, preferably 80 ° C. or higher. However, in order to prevent equipment deterioration, it is preferable to carry out at 90 degrees C or less.

  The leaching treatment is preferably performed while stirring the sulfuric acid solution using a known stirring device. Thereby, the leaching efficiency of copper in the smoke ash can be further increased.

  After completion of the leaching process, the liquid after the leaching process is subjected to a solid-liquid separation process to separate into a leaching liquid in which copper is dissolved and a leaching residue containing lead, bismuth and the like. The solid-liquid separation method is not particularly limited, and a known method such as suction filtration or centrifugation can be used.

  As described above, in the method for treating copper smelting smoke ash according to the present embodiment, the smoke ash generated by copper smelting is added to a sulfuric acid acidic solution having a pH of 1.0 or more and oxidized using a trivalent iron compound. While leaching the copper in the smoke ash. According to this method, the leaching rate of copper in the smoke ash can be increased to suppress the residue in the leaching residue, and the copper recovery rate can be effectively improved. In addition, since the leaching treatment is performed by controlling the pH of the sulfuric acid solution to 1.0 or more, the elution of lead and bismuth contained in the smoke ash into the leachate is suppressed and effectively separated from copper as a leach residue. can do.

  In addition, this method can increase the dissolution (leaching) efficiency of copper without using a strong oxidizing agent, etc., so there is no need to take equipment measures such as improving the durability against the oxidizing agent, and the oxidizing agent reagent. Costs can be suppressed, and economically efficient processing can be performed.

  In addition, in the processing method of the copper smelting ash mentioned above, since the leaching process is performed by adding an iron compound, it is considered that the iron quality in the leaching residue increases. Thus, when the iron quality in the leaching residue increases, for example, in the process of recovering lead from the leaching residue, a method that can effectively recover lead even if the amount of iron in the residue is large, such as the above-mentioned patent document Processing may be performed using the method disclosed in FIG.

  Specific examples and comparative examples to which the present invention is applied will be described below, but the present invention is not limited to these examples and comparative examples.

  The liquid and solid chemical analysis values shown in the examples were analyzed by ICP emission spectrometry after an appropriate pretreatment was performed on the analysis sample. The quantification of divalent iron was performed according to the iron ore acid-soluble iron (II) quantification method (JIS-M8213). The quantitative value of trivalent iron was obtained by subtracting the concentration of divalent iron measured by the above method from the total iron concentration measured using ICP emission spectrometry.

[Example 1]
As an iron amount, ferric sulfate for 35 g and 5 liters of water were put into a stainless 10 liter container, and the temperature was raised to 80 ° C. while stirring using a Teflon (registered trademark) stirring blade. Next, this was made into the sulfuric acid acidic solution adjusted to pH1.0 using 64% sulfuric acid, 1 kg of copper smelting smoke ash A was thrown into this sulfuric acid acidic solution, and the leaching process for 3 hours was performed.

  After the leaching treatment, solid-liquid separation by suction filtration was performed using a Buchner funnel and a filter bottle. Thereafter, water was applied to the precipitate on the Buchner funnel, and the washed liquid dropped from the funnel was washed until there was no coloration of copper sulfate. After washing, the residue was dried, and the amount of copper, lead and bismuth remaining in the residue was quantitatively analyzed.

[Example 2]
As an iron amount, 35 g of iron oxide starch and 5 liters of water were placed in a stainless 10 liter container, and the temperature was raised to 80 ° C. while stirring using a Teflon stirring blade. Next, this was made into the sulfuric acid acidic solution adjusted to pH1.2 using 64% sulfuric acid. When divalent iron in the sulfuric acid acidic solution (slurry) was quantitatively analyzed, it was found that 22 g of the added iron 35 g was divalent iron and the remaining 13 g was trivalent iron.

  Next, 1 kg of copper smelting ash A was introduced into this sulfuric acid acidic solution, and a leaching treatment was performed for 3 hours. The leaching residue after the leaching treatment was subjected to the same solid-liquid separation treatment as in Example 1 and washed with water, dried, and quantitatively analyzed for the amounts of copper, lead, and bismuth remaining in the residue.

[Comparative Example 1]
5 liters of water was placed in a stainless 10 liter container, and the mixture was stirred and heated in the same manner as in Example 1 to obtain a sulfuric acid acidic solution adjusted to pH 0.7 using 64% sulfuric acid.

  Next, 1 kg of copper smelting ash A was introduced into this sulfuric acid acidic solution, and a leaching treatment was performed for 3 hours. The leaching residue after the leaching treatment was subjected to the same solid-liquid separation treatment as in Example 1 and washed with water, dried, and quantitatively analyzed for the amounts of copper, lead, and bismuth remaining in the residue.

[Comparative Example 2]
As an iron amount, ferrous sulfate for 35 g and 5 liters of water were put into a stainless 10 liter container, and the temperature was raised to 80 ° C. while stirring using a Teflon stirring blade. Next, this was made into the sulfuric acid acidic solution adjusted to pH1.0 using 64% sulfuric acid.

  Next, 1 kg of copper smelting ash A was introduced into this sulfuric acid acidic solution, and a leaching treatment was performed for 3 hours. The leaching residue after the leaching treatment was subjected to the same solid-liquid separation treatment as in Example 1 and washed with water, dried, and quantitatively analyzed for the amounts of copper, lead, and bismuth remaining in the residue.

  Table 1 below shows the quantitative analysis results of the above-described Examples and Comparative Examples.

  As shown in Table 1, Example 1 and Example in which a ferric sulfate or iron starch slurry containing trivalent iron was added to a sulfuric acid acidic solution having a pH of 1.0 or more as an iron agent to perform leaching treatment for smoke ash. In Example 2, it can be seen that the leaching rate of copper was greatly improved and the amount of copper remaining in the leaching residue was reduced compared to the case where leaching was simply performed with a sulfuric acid solution as in the prior art (for example, Comparative Example 1). .

  In Comparative Example 1 in which leaching was simply performed with a sulfuric acid solution, a large amount of copper was not dissolved but remained in the leaching residue, resulting in a copper recovery loss. Moreover, in this comparative example 1, it turns out that the weight in the leaching residue of bismuth fell and it eluted in the leaching solution. This elution of bismuth is considered to be due to the leaching treatment performed under the condition of pH 0.7 and less than pH 1.0.

  Moreover, even if it is an iron compound, the comparative example 2 which added the bivalent iron compound and was made to coexist in the state of a trivalent iron ion has little improvement effect of the copper leaching rate, and is the same as the comparative example 1. A large amount of copper remained in the leaching residue, resulting in a copper recovery loss.

Claims (3)

  The smoke ash generated by copper smelting is added to a sulfuric acid acidic solution whose pH is adjusted to 1.0 or more, and the copper in the smoke ash is leached while being oxidized using a trivalent iron compound. Processing method of smelting ash.   The copper smelting ash treatment method according to claim 1, wherein the pH of the sulfuric acid acidic solution is adjusted to 1.0 to 2.0.   The method for treating copper smelting ash according to claim 1 or 2, wherein the iron compound is added in an amount of 10 to 35 g as the amount of trivalent iron per 1 kg of the smoke ash.