JP7134658B2 - Sb removal method and valuable metal recovery method - Google Patents

Description

The present invention relates to a method for removing Sb and a method for recovering valuable metals.

Matte produced in a melting furnace for melting recycled raw materials contains a large amount of Cu (copper), so it is repeatedly used in flash smelting furnaces and converters for copper smelting. Dust produced in the melting furnace is neutralized after acid leaching. The neutralization slag from the neutralization contains a small amount of Cu and is therefore repeated in the melting furnace. Since this neutralized slag also contains Sb (antimony), Sb is included in the repeated materials repeated in the flash smelting furnace. Therefore, it is preferable to remove as much Sb as possible from the acidic solution produced by acid-leaching the dust in the melting furnace. For example, a technique for removing Sb by bringing an acidic solution containing Sb into contact with a chelate resin has been disclosed (see, for example, Patent Document 1).

JP 2012-062551 A

However, removal of Sb using a chelate resin is costly.

In view of the above problems, it is an object of the present invention to provide a method for removing Sb and a method for recovering valuable metals capable of removing Sb from an Sb-containing acidic solution while suppressing costs.

The method for removing Sb according to the present invention includes adding Sn ²⁺ to an acidic solution containing Sb and Cu , and adjusting the pH of the acidic solution to 2.0 or more and 4.5 or less to coprecipitate Sb. characterized by

When the pH of the acidic solution is not in the range of 2.0 to 4.5, the pH of the acidic solution may be adjusted to 2.0 to 4.5. The acidic solution may be a sulfuric acid solution. Sn ²⁺ may be added to the acidic solution so that the molar ratio of Sn/Sb in the acidic solution is 0.1 or more and 20 or less . The acidic solution may be a solution obtained by acid leaching dust from a melting furnace that processes recycled raw materials containing Sb. The precipitate obtained by the coprecipitation of Sb may be put into an electric furnace for melting raw materials containing Pb. The acidic solution may contain Zn .

The method for recovering valuable metals according to the present invention comprises neutralizing the acidic solution after removing Sb by the method for removing Sb described above to obtain a neutralized slag containing Cu and a neutralized slag containing Zn. characterized by

According to the present invention, Sb can be removed from an Sb-containing acidic solution while suppressing costs.

FIG. 4 is a diagram illustrating a flow representing a method for removing Sb;

Embodiments for carrying out the present invention will be described below.

First, in the following embodiments, Sb is removed from an acidic solution. The acidic solution is not particularly limited as long as it is an acidic solution containing Sb. Sb is in equilibrium with Sb ³⁺ and Sb ⁵⁺ in an acidic solution. Therefore, Sb exists in the form of Sb ⁵⁺ and Sb ³⁺ in acidic solutions. Acidic solutions include sulfuric acid solutions, hydrochloric acid solutions, and the like. The acidic solution containing Sb also includes slurry. However, if Fe ³⁺ , Sn ²⁺ , Al ³⁺ are added and the amount of liquid is insufficient for coprecipitation, the amount of liquid can be adjusted by adding an aqueous solution containing water, acidic liquids, ions, etc. You may In the present embodiment, as an example of the acidic solution containing Sb, an acidic solution obtained by acid leaching dust from a melting furnace that processes recycled raw materials is used.

(First embodiment)
FIG. 1 is a diagram illustrating a flow representing a method for removing Sb. As exemplified in FIG. 1, the recycled raw material is melt processed in a melting furnace. The matte produced in melting furnaces is Cu-rich and is replicated in flash smelting furnaces and converters in copper smelting. Thereby, Cu can be recovered. The slag produced in the melting furnace is treated externally. Dust generated in melting furnaces is leached with an acid such as sulfuric acid. As a result, Cu (copper), Sb (antimony), Zn, (zinc), Fe (iron), As (arsenic), etc. contained in the dust are leached out. The pH of the acidic solution, which is the post-leaching solution, is less than 4, for example, about 1.3.

The leaching residue may be separated from the acidic solution by subjecting the acidic solution after the leaching solution to solid-liquid separation. Alternatively, solid-liquid separation may not be performed on the acidic solution.

Next, Fe ³⁺ is added by adding iron sulfate or the like to the acidic solution that has undergone solid-liquid separation or the acidic solution that has not undergone solid-liquid separation. Furthermore, if the pH of the acidic solution is not between 2.0 and 4.5, the pH is adjusted to between 2.0 and 4.5 by adding NaOH or the like to the acidic solution. In this case, Fe ³⁺ becomes precipitated. When Fe ³⁺ precipitates, the surface vicinity of Fe(OH) ₃ becomes positively charged in the acidic region. In this case, the anion antimonic acid is attracted and locally increases the concentration of Sb ⁵⁺ . As a result, Sb and Fe co-precipitate due to the action of Sb ⁵⁺ . As a result, Sb can be removed from the acidic solution. However, the theory of coprecipitation of Sb and Fe is not limited to this. In addition, if the pH of the acidic solution is 2.0 or more and 4.5 or less before the addition of Fe ³⁺ , it is not necessary to adjust the pH. The temperature of the acidic solution may be room temperature, but from the viewpoint of promoting coprecipitation, it is preferably adjusted to 40°C or higher, more preferably about 60°C, by heating. From the viewpoint of promoting coprecipitation, the amount of Fe ³⁺ added is preferably such that the molar ratio of (Fe/Sb) in the acidic solution becomes 3 or more and 9 or less after Fe ³⁺ is added. When Sb is present as Sb ³⁺ in a large amount, it is preferable to add an oxidizing agent such as hydrogen peroxide to increase the abundance ratio of Sb ⁵⁺ to Sb ³⁺ . Moreover, from the viewpoint of promoting coprecipitation, it is preferable to adjust the pH of the acidic solution to 3.0 or more and 4.5 or less. If the pH is too low, the coprecipitation will not occur sufficiently, while if the pH is too high, the copper will precipitate, which may lead to less copper being cycled through the flash smelting furnace of copper smelting. .

Precipitates containing Sb can then be removed from the acidic solution by filtering the acidic solution. A precipitate containing Sb is subjected to a step of recovering Sb. For example, the precipitate containing Sb may be put into a Pb electric furnace that melts raw materials containing Pb. The Sb-bearing precipitate can be treated in a common Pb smelting process and recovered as Sb ₂ O ₃ .

Next, a primary neutralization treatment is performed by adding NaOH or the like to the acidic solution after removing Sb. Thereby, a primary neutralization slag containing Cu is obtained. The primary neutralization residue can be removed by filtering the liquid after the primary neutralization treatment. The primary slag is cycled through the melting furnace.

Next, a secondary neutralization treatment is performed by adding NaOH or the like to the liquid after filtration. Thereby, a second neutralized slag containing Zn is obtained. The secondary neutralization residue can be removed by filtering the liquid after the secondary neutralization treatment. The secondary neutralized slag is subjected to a Zn recovery step. Thereby, Zn can be recovered.

According to the present embodiment, Fe ³⁺ is added to an acidic solution containing Sb, at least a portion of which exists in the form of Sb ⁵⁺ , and the pH of the acidic solution is adjusted to 2.0 or more and 4.5 or less, so that Fe and Sb can be coprecipitated. Since there is no need to use a chelate resin or the like, costs can be suppressed. That is, Sb can be removed from the Sb-containing acidic solution while suppressing costs. Since Sb is removed from the Sb-containing acidic solution, the amount of Sb contained in the primary neutralized slag that is repeated to the melting furnace is reduced. As a result, the amount of Sb contained in the matte repeated in flash smelting furnaces and converters in copper smelting is also reduced.

(Second embodiment)
In the second embodiment, Sn ²⁺ is added instead of Fe ³⁺ to the acidic solution. Furthermore, if the pH of the acidic solution is not between 2.0 and 4.5, the pH is adjusted to between 2.0 and 4.5 by adding NaOH or the like to the acidic solution. As a result, Sb and Sn are coprecipitated by the action of Sb ⁵⁺ . As a result, Sb can be removed from the acidic solution. In addition, if the pH of the acidic solution is 2.0 or more and 4.5 or less before the addition of Sn ²⁺ , it is not necessary to adjust the pH. The temperature of the acidic solution may be room temperature, but from the viewpoint of promoting coprecipitation, it is preferably adjusted to 40°C or higher, more preferably about 60°C, by heating. In addition, from the viewpoint of promoting coprecipitation, the amount of Sn ²⁺ added is preferably such that the molar ratio of (Sn/Sb) in the acidic solution is 0.1 or more and 20 or less after the addition of Sn ²⁺ . It is more preferable to make it 3 or more and 9 or less. When Sb is present as Sb ³⁺ in a large amount, it is preferable to add an oxidizing agent such as hydrogen peroxide to increase the abundance ratio of Sb ⁵⁺ to Sb ³⁺ . Moreover, from the viewpoint of promoting coprecipitation, it is preferable to adjust the pH of the acidic solution to 3.0 or more and 4.5 or less.

According to the present embodiment, Sn ²⁺ is added to an acidic solution containing Sb, at least a portion of which exists in the form of Sb ⁵⁺ , and the pH of the acidic solution is adjusted to 2.0 or more and 4.5 or less, whereby Sn and Sb can be coprecipitated. Since there is no need to use a chelate resin or the like, costs can be suppressed. That is, Sb can be removed from the Sb-containing acidic solution while suppressing costs. In the second embodiment, since the precipitate containing Sb obtained by coprecipitation has a low Fe grade, the amount of spice generated can be suppressed when the precipitate is treated in a Pb electric furnace.

(Third Embodiment)
In a third embodiment, Al ³⁺ is added instead of Fe ³⁺ or Sn ²⁺ to the acidic solution. Furthermore, if the pH of the acidic solution is not between 2.0 and 4.5, the pH is adjusted to between 2.0 and 4.5 by adding NaOH or the like to the acidic solution. As a result, Sb and Al are coprecipitated by the action of Sb ⁵⁺ . As a result, Sb can be removed from the acidic solution. In addition, if the pH of the acidic solution is 2.0 or more and 4.5 or less before the addition of Al ³⁺ , it is not necessary to adjust the pH. The temperature of the acidic solution may be room temperature, but from the viewpoint of promoting coprecipitation, it is preferably adjusted to 40°C or higher, more preferably about 60°C, by heating. In addition, from the viewpoint of promoting coprecipitation, the amount of Al ³⁺ added is preferably such that the molar ratio of (Al / Sb) in the acidic solution is 0.1 or more and 20 or less after the addition of Al ³⁺ . It is more preferable to make it 1.5 or more and 6 or less. When Sb is present as Sb ³⁺ in a large amount, it is preferable to add an oxidizing agent such as hydrogen peroxide to increase the abundance ratio of Sb ⁵⁺ to Sb ³⁺ .

According to the present embodiment, Al ³⁺ is added to an acidic solution containing Sb, at least part of which exists in the form of Sb ⁵⁺ , and the pH of the acidic solution is adjusted to 2.0 or more and 4.5 or less, so that Al and Sb can be coprecipitated. Since there is no need to use a chelate resin or the like, costs can be suppressed. That is, Sb can be removed from the Sb-containing acidic solution while suppressing costs. In the third embodiment, since the Fe grade of the precipitate containing Sb obtained by coprecipitation is low, the amount of spice generated can be suppressed when the precipitate is treated in a Pb electric furnace.

In addition, although Fe ³⁺ is added in the first embodiment, Sn ²⁺ is added in the second embodiment, and Al ³⁺ is added in the third embodiment, a plurality of these elements may be added in combination.

(Example 1)
Fe ³⁺ was added to the Sb-containing acidic solution according to the first embodiment. An acidic solution containing Sb, Cu, As, Zn and Fe was used as the acidic solution. This acid solution is a solution obtained by acid leaching dust obtained from a melting furnace for recycled raw materials. The concentration of each component is shown in Table 1.

Fe ³⁺ was added in the form of iron sulfate (trivalent) and the pH was adjusted to 4.0 by adding NaOH while warming to 60°C. In this state, the concentration of Fe ³⁺ was set to 1.1 g/L and the molar ratio of Fe/Sb was set to 6. As a result, Fe and Sb coprecipitated. The Sb precipitation rate was 77%.

(Comparative example 1)
In Comparative Example 1, the conditions were the same as in Example 1, except that iron sulfate (trivalent) was not added to the acidic solution. In Comparative Example 1, the Sb precipitation rate was 12%.

Thus, while the Sb precipitation rate was 12% in Comparative Example 1, the Sb precipitation rate in Example 1 was greatly increased to 77%. This is probably because the addition of Fe ³⁺ coprecipitated Sb and Fe due to the action of Sb ⁵⁺ . In addition, in Example 1, the Sb precipitation rate further increased to 88% by stirring the acidic solution.

(Examples 2-4)
Sn ²⁺ was added to the Sb-containing acidic solution according to the second embodiment. An acidic solution containing Sb, Cu, As, Zn and Fe was prepared as an acidic solution. The concentration of each component is the same as Table 1.

Sn ²⁺ was added in the form of tin chloride (divalent) and the pH was adjusted to 4.0 by adding NaOH while warming to 60°C. In this state, in Example 2, the Sn ²⁺ concentration was 1.1 g/L (molar ratio of Sn/Sb=3), and in Example 3, the Sn ²⁺ concentration was 2.2 g/L (molar ratio of Sn/Sb). ratio=6), and in Example 4, the concentration of Sn ²⁺ was set to 3.4 g/L (molar ratio of Sn/Sb=9). As a result, Sn and Sb coprecipitated. In Example 2, the Sb precipitation rate was 22%. In Example 3, the Sb precipitation rate was 89%. In Example 4, the Sb precipitation rate was 94%.

As described above, while the Sb precipitation rate was 12% in Comparative Example 1, the precipitation rate increased in all of Examples 2 to 4. This is probably because the addition of Sn ²⁺ caused Sb to co-precipitate with Sn due to the action of Sb ⁵⁺ . In addition, it was found that the precipitation rate of Sb is increased by setting the molar ratio of Sn/Sb to 3 or more and 9 or less.

(Examples 5-7)
Al ³⁺ was added to the Sb-containing acidic solution according to the third embodiment. An acidic solution containing Sb, Cu, As, Zn and Fe was prepared as an acidic solution. The concentration of each component is the same as Table 1.

Al ³⁺ was added in the form of aluminum sulfate, and the pH was adjusted to 4.0 by adding NaOH while heating to 60°C. In this state, in Example 5, the concentration of Al ³⁺ was 0.5 g/L (molar ratio of Al/Sb=6), and in Example 6, the concentration of Al ³⁺ was 0.3 g/L (molar ratio of Al/Sb). ratio=3), and in Example 7, the concentration of Al ³⁺ was set to 0.1 g/L (molar ratio of Al/Sb=1.5). As a result, Al and Sb coprecipitated. In Example 5, the Sb precipitation rate was 95%. In Example 6, the Sb precipitation rate was 95%. In Example 7, the Sb precipitation rate was 87%.

As described above, while the Sb precipitation rate was 12% in Comparative Example 1, the precipitation rate was increased in all of Examples 5 to 7. It is considered that this is because Sb co-precipitated with Al due to the action of Sb ⁵⁺ due to the addition of Al ³⁺ . In addition, it was found that the precipitation rate of Sb is increased by setting the Al/Sb molar ratio to 1.5 or more and 6 or less.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

Claims (8)

A method for removing Sb, comprising adding Sn ²⁺ to an acidic solution containing Sb and Cu and adjusting the pH of the acidic solution to 2.0 or more and 4.5 or less to coprecipitate Sb. 2. The pH of the acidic solution is adjusted to 2.0 or more and 4.5 or less when the pH of the acidic solution is not in the range of 2.0 or more and 4.5 or less. removal method. 3. The method for removing Sb according to claim 1, wherein said acidic solution is a sulfuric acid solution. Sn ²⁺ is added to the acidic solution so that the Sn/Sb molar ratio of the acidic solution is 0.1 or more and 20 or less . removal method. The method for removing Sb according to any one of claims 1 to 4, wherein the acidic solution is a solution obtained by leaching dust from a melting furnace for processing recycled raw materials containing Sb with an acid. . The method for removing Sb according to any one of claims 1 to 5, wherein the precipitate obtained by coprecipitation of the Sb is put into an electric furnace for melting a raw material containing Pb. The method for removing Sb according to any one of claims 1 to 6, wherein the acidic solution contains Zn . A method for recovering valuable metals, comprising the step of neutralizing the acidic solution after removing Sb by the method of claim 7 to obtain a neutralized slag containing Cu and a neutralized slag containing Zn.

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