JP6480358B2 - Sb recovery method - Google Patents

Description

  The present invention relates to a method for recovering Sb.

  Sb (antimony) is one of valuable metals recovered from copper electrolytic starch. For example, Sb is contained in the lead chloride leaching residue generated as an intermediate product in the recovery process of valuable metals from copper electrolytic starch. Many are included. The lead chloride leaching residue is a leaching residue obtained by removing silver chloride obtained by wet treatment of a copper electrolytic starch (see Patent Document 1). This residue is reduced to obtain metallic Sb. However, metal-like Sb contains a large amount of impurities, and it is necessary to remove the impurities.

  As a method for removing impurities, there is known a method in which Sb is volatilized as antimony oxide and Sb is recovered from the volatiles. However, for volatilization, a melt of about 1000 ° C. is required by heating and melting. (See Patent Document 2)

JP 2011-68528 A JP 2000-302443 A

  However, the fact that a high temperature such as 1000 ° C. is required means that energy loss occurs and equipment for high temperature is required. Further, the crude Sb containing impurities may contain a highly volatile metal. In this case, if the temperature is high, the recovered Sb oxide may contain the impurities as impurities. Therefore, it is desirable to volatilize at a lower temperature if possible.

  In view of the above problems, an object of the present invention is to provide a Sb recovery method that can recover Sb from impurities containing Sb at a relatively low temperature.

The method for recovering Sb according to the present invention includes a step of obtaining Sb containing impurities by dissolving and reducing Sb-containing residues with coke, and a molten Sb containing impurities having a temperature of 660 ° C. or higher and 700 ° C. or lower. A step of recovering Sb by introducing a raw material having a concentration of 40 mass% or less to set the Sb concentration in the molten metal to 50 mass% or less and volatilizing Sb containing the impurities as Sb ₂ O _3. It is a feature. The impurity is at least Pb, may be any one of Ag, and Bi. The main component in the raw material may be Bi. Sb containing the impurities, after dissolving the reducing the Sb-containing residues may be those obtained by soda process. The volatile soot obtained by the volatilization may be put into a furnace for reducing the Sb-containing residue.

  According to the Sb recovery method of the present invention, Sb can be recovered from Sb containing impurities at a relatively low temperature.

It is process drawing showing the processing method of a lead chloride leaching residue.

  “Sb containing impurities”, which is the subject of the present invention, is a metallic Sb containing impurities. Sb is one of various valuable materials in the copper electrolytic starch. Sb is also concentrated while various valuables in the copper electrolytic starch are separated and recovered. In this specification, although it concentrated as "Sb containing an impurity", it is Sb of a state which still contains many impurities, and it is aimed at the intermediate state in a concentration collection process. Hereinafter, as an example of “Sb containing impurities”, a copper electrolytic starch will be described with an example of a treatment method from a lead chloride leaching residue containing a large amount of Sb generated in the process of concentrating various valuable materials. However, the present invention is not limited to this.

  Various valuable materials are concentrated in the copper electrolytic starch. The copper electrolytic starch is depulped by repulping the copper electrolytic starch into a sulfuric acid bath, blowing air and oxidizing and leaching. Sb in the copper electrolytic starch becomes an oxide and remains in the decoppered starch. Chlorinated leaching is performed on the decoppered starch. Lead and antimony can be precipitated by cooling the solution after leaching of chloride from which the resulting silver chloride has been separated. Antimony can be concentrated in the leaching residue by performing alkaline leaching on the deposited lead and antimony precipitate to remove impurities. This leaching residue is a lead chloride leaching residue. The lead chloride leaching residue is an example of an Sb-containing residue.

  FIG. 1 is a process diagram showing a method for treating a lead chloride leaching residue. As illustrated in FIG. 1, the starting material is lead chloride leaching residue. In this lead chloride leaching residue, impurities such as Sb are concentrated together with lead chloride. The components of the lead chloride leaching residue are, for example, Sb, Pb (lead), Se (selenium), Te (tellurium), Cu (copper), Fe (iron), Sn (tin), Ag (silver), and the like. . For example, each grade of the lead chloride leaching residue is Sb: 50 mass% or less, Pb: 30 mass% or less, Se: 1 mass% or less, Te: 5 mass% or less, and Cu: 7 mass% or less.

(Drying process)
Since the lead chloride leaching residue contains moisture, the moisture content is reduced by drying. For example, the lead chloride leaching residue is put in a corrugated can and dried with a drying facility using steam heat.

(Input process)
Next, the lead chloride leaching residue after drying is put into a melting furnace together with soda ash (anhydrous sodium carbonate) and the like, and 0 to 10% by weight of coke with respect to the lead chloride leaching residue is put into the melting furnace. . The temperature of the melting furnace is preferably 1000 ° C. ± 100 ° C. In this case, the inside of the melting furnace is a weak reducing atmosphere. In a weak reducing atmosphere, it is estimated that sodium antimonate (NaSbO ₃ ) contained in the lead chloride leaching residue is decomposed into sodium oxide and antimony oxide (Sb ₂ O ₃ , Sb ₂ O ₅ ). The melting point of sodium antimonate (NaSbO ₃ ) is 1427 ° C., whereas the melting point of Sb ₂ O ₃ is 656 ° C. and the melting point of Sb ₂ O ₅ is 380 ° C. The melting points of Sb ₂ O ₃ and Sb ₂ O ₅ are lower than the temperature of the melting furnace. Therefore, dissolution of the lead chloride leaching residue can be promoted.

(Dissolution reduction process)
Moreover, the lead chloride leaching residue can be reduced by the addition of the coke. By the reduction, chlorine is removed from the chloride component in the lead chloride leaching residue and separated into molten metal and molten slag. The molten metal includes Sb, Pb, Ag, and the like. The molten slag contains Se, Te, etc., as well as Na, O, etc., contained in soda ash. Since dust generated from the melting furnace contains Sb, Pb, etc., the dust is again fed into the melting furnace together with the lead chloride leaching residue.

  Note that coke exists in a solid state in the temperature range of the melting furnace. If the lead chloride leaching residue does not dissolve, the above reduction proceeds by a solid-solid reaction. In this case, since a good reactivity cannot be obtained, the reduction rate decreases. On the other hand, if the lead chloride leaching residue is dissolved, the above reduction proceeds by a solid-liquid reaction. In this case, good reactivity can be obtained, so that the reduction rate is improved.

  If the amount of coke input is too small, the reduction reaction of Sb becomes insufficient, so that Sb may remain in the slag. On the other hand, if the input amount of coke is too large, the reduction rate of Sb may be reduced. Therefore, there is an optimum range for the amount of coke input. As a result of diligent research by the present inventors, it has been found that the amount of coke to be added to the amount of lead chloride leaching residue in the melting furnace is preferably 5% to 30% by weight. In this range, the distribution ratio of Sb to the molten metal is particularly high.

  Therefore, in order to improve the reduction rate, it is preferable to add coke to the melting furnace as needed. In this case, the coke is introduced so that the total amount (weight ratio) of coke with respect to the lead chloride leaching residue introduced into the melting furnace is 5% to 30%. More preferably, the total amount (weight ratio) of coke relative to the lead chloride leaching residue introduced into the melting furnace is 10% or more and 15% or less. Moreover, it is preferable that the amount of coke input in the input step is equal to or less than the amount of coke input in the dissolution reduction step. The metal-like Sb obtained in this step can be “Sb containing impurities” targeted by the present embodiment. Furthermore, it is possible to bring it into the volatilization process in the form of molten metal.

(Soda treatment process)
However, depending on the impurities and the amount of impurities, it may not be preferable to bring the molten metal directly into the volatilization process. For example, it includes a large amount of Se, Te, As and the like. In this case, it is necessary to soda the molten metal with a caustic soda solution. By soda treatment, Se, Te, As, etc. can be separated from the molten metal as scum. Since one or more of Pb, Ag, and Bi are contained as impurities in the molten metal, the metal after the soda treatment process is brought into the volatilization process as “Sb containing impurities” targeted by the present embodiment. It is also possible to bring it into the volatilization process in the form of molten metal.

(Volatile process)
The metal obtained by the smelting reduction and the metal obtained by the soda treatment are put into a volatilization furnace as “Sb containing impurities” and melted by heat. Further, by oxidizing the molten metal, Sb is oxidized to generate volatile Sb ₂ O ₃ . For example, Sb can be oxidized by blowing oxygen to the molten metal, blowing it, or adding an oxidizing agent. Since Sb ₂ O ₃ has high volatility, it volatilizes from the molten metal. Thereby, Sb can be recovered. For example, the molten metal temperature is preferably 660 ° C. to 700 ° C., and the amount of air blown onto the molten metal is preferably 51 to 56 Nm ³ / h per 1 m ² of the molten metal surface. More preferably, the molten metal temperature is 680 ° C to 700 ° C. Moreover, the production of nonvolatile Sb ₂ O ₄ , Sb ₆ O _13, etc. is suppressed and Sb ₂ O ₃ is produced by setting the Sb concentration in the molten metal to 50 mass% or less, preferably 40 mass% or less. Can do. In addition, when diluting Sb density | concentration in a molten metal, a raw material with low Sb quality (40 mass% or less) can be used. For example, it is preferable to use a raw material whose main component is a low melting point metal such as Pb or Bi. However, it is more preferable to use Bi because Pb has volatility. The volatile soot obtained by volatilization is preferably returned to the melting furnace and used for reduction.

According to the present embodiment, the temperature of the molten metal (Sb including impurities) is set to 660 ° C. or more and 700 ° C. or less, thereby suppressing generation of Sb ₂ O ₄ , Sb ₆ O _13, or the like having low volatility. Highly volatile Sb ₂ O ₃ can be produced. Thereby, Sb can be recovered at a relatively low temperature from Sb containing impurities. At the time of volatilization, Sb can be efficiently recovered by volatilizing the concentration of Sb containing impurities in the molten metal at 50 mass% or less.

Example 1
According to the above embodiment, the volatilization process was performed on the molten metal after the soda treatment process. For molten metal containing 50 mass% Sb, 33 mass% Bi, and 9 mass% Pb, the molten metal temperature is 660 ° C to 681 ° C, the amount of air blown to the molten metal is 51 m ³ / h per 1 m ² of the molten metal surface, The spraying position was set to a height of 20 mm to 40 mm from the molten metal surface. Sb ₂ O ₃ recovered by volatilization did not contain Pb and Bi.

(Example 2)
A molten metal containing 72 mass% Sb, 13 mass% Bi, and 13 mass% Pb was volatilized under the same conditions as in Example 1. Pb and Bi were not contained in Sb ₂ O ₃ obtained by volatilization.

(Comparative Example 1)
The molten metal used in Example 1 was set to 600 ° C. to 620 ° C. less than 660 ° C., and the amount of air blown to the molten metal and the height of the molten metal were the same as in Example 1. However, a sufficient volatilization rate could not be obtained due to the low temperature.

(Comparative Example 2)
The molten metal used in Example 1 was volatilized at 1000 ° C. The amount of air blown onto the molten metal and the height of the molten metal were the same as in Example 1. However, the obtained Sb ₂ O ₃ contained Pb and Bi.

In Example 2, the molten metal was covered with a black film, and the volatilization rate was 63 kg / day in terms of the amount of Sb ₂ O ₃ . As a result of XRD analysis of the film on the surface of the molten metal, it was confirmed that nonvolatile Sb ₂ O ₄ , Sb ₆ O _{13 and the} like were generated. In contrast, in Example 1, the volatilization rate was 414 kg / day in terms of the amount of Sb ₂ O ₃ , which was larger than that in Example 2. Therefore, as a result of XRD analysis of the components on the surface of the molten metal, it was confirmed that nonvolatile Sb ₂ O ₄ , Sb ₆ O _{13 and the} like were not generated on the molten metal surface. Therefore, it is considered that the generation of non-volatile Sb ₂ O ₄ , Sb ₆ O _{13 and the} like is suppressed and the large volatilization rate is obtained by setting the concentration of Sb containing impurities in the molten metal to 50 mass% 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 changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

Claims (5)

A step of obtaining Sb containing impurities by dissolving and reducing the Sb-containing residue with coke;
By introducing a raw material having an Sb concentration of 40 mass% or less into a molten Sb containing the impurities having a temperature of 660 ° C. or more and 700 ° C. or less, the Sb concentration in the molten metal is 50 mass% or less, and the Sb containing the impurities the by volatilize as Sb ₂ O _3, and recovering the Sb
A method for recovering Sb, comprising: The impurity is at least Pb, Ag Sb method of recovery according to claim 1, wherein the, and is one of Bi. The method for recovering Sb according to claim 1 or 2 , wherein the main component in the raw material is Bi. Sb containing the impurities, the Sb-containing residue after the dissolution reduction, recovery of Sb according to any one of claims 1 to 3, characterized in that one obtained by soda process Method. The method for recovering Sb according to claim 4 , wherein the volatile soot obtained by the volatilization is put into a furnace for reducing the Sb-containing residue.

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