JP2017137557A - Method of treating Sb-containing residue - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of treating Sb-containing residues that allow Sb to be recovered from Sb-containing residues with improved efficiency.SOLUTION: A method of treating Sb-containing residues is characterized in that Sb-containing residues, resulting from decopperizing and leaching of copper electrolytic sediments in a copper smelting step, are chlorinated and leached with hydrochloric acid and hydrogen peroxide, and the hydrochloric acid concentration in the chlorinating and leaching reaction is controlled to exceed 4 mol/L.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for treating Sb-containing residues.

  In recent years, in the nonferrous metal smelting business, the ratio of recycled raw materials has increased, and the need to efficiently separate and recover accompanying rare valuables has increased. Antimony (Sb) is added as a flame retardant aid for preventing ignition of electronic substrate scraps and the like, and is one of the metals whose amount of input to the copper smelting process is increasing.

  Antimony is distributed to the mat and slag in the smelting process, after which the mat is refined and cast into the anode. The anode is electrolyzed in an electrolysis process. During electrolysis, a part of the antimony contained in the anode is eluted into the electrolytic solution, and the rest is distributed as an insoluble antimony compound to the copper electrolytic starch. Since the noble metal is concentrated in the copper electrolytic starch, the residue containing antimony generated during the processing of the copper electrolytic starch is re-introduced into the smelting process for the purpose of preventing the loss of the noble metal.

  In the process of treating a copper electrolytic starch by a wet method, first, the copper electrolytic starch is oxidized and leached in a sulfuric acid bath to separate copper. Next, the copper electrolyzed starch after copper removal is leached with hydrochloric acid and hydrogen peroxide to dissolve gold, platinum, palladium, selenium, tellurium, antimony and lead, and silver is separated as silver chloride and reduced with iron. (Patent Documents 1 and 2).

  In order to avoid the precipitation of impurities in the tank and piping in the post-process and to improve the quality of the product, the hydrochloric acid concentration and the liquid temperature should be lowered in advance for the liquid after leaching from the silver chloride separated. Reduces the solubility of antimony, lead and tellurium and separates the precipitate formed. The deposits of antimony, lead and tellurium are dissolved in tellurium in the alkaline leaching step and neutralized with sulfuric acid to recover crude tellurium dioxide. Antimony and lead are not dissolved but collected as a residue and re-introduced into the flash furnace (Patent Document 3).

  Gold, platinum, palladium, selenium, tellurium, and the like are separated and recovered from the filtrate obtained by separating antimony, lead, and tellurium from the solution after leaching with chloride. On the other hand, the effluent containing the components that could not be separated is neutralized and then re-entered into the flash smelting furnace (Patent Documents 1 and 2).

JP 2001-316735 A JP 2001-316736 A JP 2011-68528 A

  In the chloride leaching step, a part of antimony is distributed to silver chloride, and the recovery rate of antimony is lowered in the next precipitation step.

  Moreover, in the alkali leaching process, the alkali leaching residue containing antimony after leaching of tellurium is recharged into the flash smelting furnace, and the amount of recharging of antimony into the smelting process increases.

  An object of this invention is to provide the processing method of Sb containing residue which improves the Sb collection | recovery efficiency from Sb containing residue in view of said subject.

  The method for treating a Sb-containing residue according to the present invention includes a Sb-containing residue obtained by leaching copper electrolytic starch in a copper smelting process by leaching with hydrochloric acid and hydrogen peroxide, and the hydrochloric acid concentration during the leaching reaction is 4 mol / mol. It adjusts so that it may exceed L, It is characterized by the above-mentioned.

  In this case, the hydrochloric acid concentration during the leaching reaction may be adjusted to 5 mol / L or more. Silver chloride is separated from the solution after leaching with chloride, and the solution after leaching with chloride containing antimony after separation of silver chloride may be adjusted so that the hydrochloric acid concentration is 4 mol / L or less. In this case, the chlorinated leaching solution containing antimony after separation of the silver chloride may be adjusted so that the hydrochloric acid concentration is 3 mol / L or less.

  The solution after leaching with chloride containing antimony after separating the silver chloride may be cooled. In this case, the solution after leaching containing antimony after separation of the silver chloride may be cooled so that the liquid temperature is less than 50 ° C. Or you may cool the liquid after leaching containing antimony after separating the silver chloride so that the liquid temperature becomes 25 ° C. or less.

  According to the method for treating an Sb-containing residue according to the present invention, Sb recovery efficiency from the Sb-containing residue can be improved.

It is process drawing showing the process of a copper electrolytic starch.

  FIG. 1 is a process diagram showing a process for treating a copper electrolytic starch. As illustrated in FIG. 1, the starting material is a copper electrolytic starch.

(Copper removal process)
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. Antimony (Sb) in the copper electrolytic starch becomes an oxide and remains in the decoppered starch.

(Chloride leaching process)
The decoppered starch is leached with hydrochloric acid and hydrogen peroxide. As shown in the chemical reaction formula below, antimony reacts with hydrogen peroxide and dissolves.
H ₃ SbO ₃ + H ₂ O ₂ → H ₃ SbO ₄ + H ₂ O
Metals that cause chloride precipitation include silver, lead, and antimony.

  When the hydrochloric acid concentration exceeds 4 mol / L, the solubility of antimony and lead becomes very large. Therefore, the hydrochloric acid concentration during the leaching reaction is adjusted to exceed 4 mol / L. Thereby, the separability between antimony and lead and silver chloride can be improved. By adjusting the concentration of hydrochloric acid during the leaching reaction to exceed 4 mol / L, the concentration of hydrochloric acid in the leached solution after leaching also exceeds 4 mol / L. Thereby, antimony can be dissolved in the solution after leaching with chloride. The hydrochloric acid concentration during the leaching reaction is preferably 5 mol / L or more, more preferably 6 mol / L or more.

  Separation of silver chloride and antimony improves as the temperature of the solution after leaching from the chloride increases, so that the effect is high when it is kept at 50 ° C. or higher.

(Precipitation process)
Next, silver chloride is separated from the solution after leaching with chloride, and the hydrochloric acid concentration in the solution after leaching after separation after silver chloride is adjusted to 4 mol / L or less by dilution or the like. Thereby, the solubility of lead and antimony is reduced, and lead and antimony are precipitated. The hydrochloric acid concentration in the solution after leaching after separation of silver chloride is preferably 3 mol / L or less, more preferably 2 mol / L or less. Further, the solution after leaching with chloride may be cooled. In this case, the temperature of the solution after leaching of chloride by cooling is preferably less than 50 ° C, more preferably 25 ° C or less, and further preferably 5 ° C or less. Thereby, the solubility of lead and antimony can be further reduced. There is no particular lower limit to the temperature of the solution after leaching of chloride by cooling, as long as the solution after leaching of chloride is not frozen. As a result of X-ray diffraction analysis of the precipitate deposited from the solution after leaching with chloride, it is presumed that the form of lead is lead chloride and the form of antimony is an oxide or a tellurium compound.

(Alkaline leaching)
The deposited precipitate containing lead and antimony contains tellurium and selenium. For this reason, alkali leaching is performed to dissolve and separate tellurium and selenium. The leaching conditions are preferably leached with an alkaline solution at 80 ° C. composed of 30 to 60 g / L NaOH. The slurry concentration is 100 to 200 g / L, and the leaching time is 2 to 4 hours. By this method, selenium and tellurium can be leached, and antimony can be concentrated in the leaching residue (Patent Document 3). This leaching residue is an alkali leaching residue.

(Reduction process)
Since the alkali leaching residue contains moisture, the moisture content is reduced by drying. For example, the alkali leaching residue is put in a corrugated can and dried with a drying facility using steam heat. Next, the dried alkali leaching residue is put into a melting furnace, and 0 to 10% of coke by weight with respect to the alkali leaching residue is put into the melting furnace. At this time, when the amount of sodium required for slag formation cannot be secured by sodium in the alkali leaching residue, soda ash (anhydrous sodium carbonate) may be added together with the alkali leaching residue. 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 alkali leaching residue decomposes 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 alkali leaching residue can be promoted.

  Moreover, the alkali leaching residue can be reduced by adding the coke. By the reduction, chlorine is removed from the chlorinated component in the alkali 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 and the like as well as Na and O contained in the alkali leaching residue and soda ash. Since dust generated from the melting furnace contains Sb, Pb, etc., the dust is again put into the melting furnace together with the alkaline leaching residue.

  Note that coke exists in a solid state in the temperature range of the melting furnace. If the alkali 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 alkali 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 inventor, it has been found that the amount of coke introduced relative to the amount of alkali leaching residue introduced into 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 charged so that the total amount (weight ratio) of coke with respect to the alkaline leaching residue charged into the melting furnace is 5% to 30%. The total amount (weight ratio) of coke with respect to the alkaline leaching residue charged into the melting furnace is more preferably 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 Sb-containing residue obtained by leaching copper electrolytic starch is leached with hydrochloric acid and hydrogen peroxide, and the hydrochloric acid concentration during the leaching reaction is adjusted to always exceed 4 mol / L. Thus, the solubility of antimony in the solution after leaching with chloride can be increased. Thereby, the separability between antimony and silver chloride can be improved. That is, since antimony distributed to silver chloride can be reduced, antimony recovery efficiency can be improved. The hydrochloric acid concentration during the leaching reaction is preferably 5 mol / L or more, more preferably 6 mol / L or more.

  In addition, according to the present embodiment, silver chloride is separated from the solution after chloride leaching, and the concentration of hydrochloric acid in the solution after chloride leaching containing antimony after separation of silver chloride is adjusted to 4 mol / L or less, so that after chloride leaching. The solubility of antimony in the liquid can be lowered, and the precipitate containing antimony can be recovered. The hydrochloric acid concentration in the solution after leaching after separation of silver chloride is preferably 3 mol / L or less, more preferably 2 mol / L or less.

  Moreover, according to this embodiment, by cooling the solution after leaching after separation of silver chloride, the solubility of antimony in the solution after leaching of chloride can be further reduced, and the precipitate containing antimony can be recovered. In addition, the liquid temperature of the solution after leaching of chloride by cooling is preferably less than 50 ° C, more preferably 25 ° C or less, and further preferably 5 ° C or less.

After pre-adjusting the hydrochloric acid concentration of the solution after leaching with chloride, the solution is heated to 80 ° C., then antimony chloride and lead chloride are added excessively until they become saturated, and then stirred at 50 ° C., 25 ° C., 5 ° C. Sampling was performed in the process of lowering the temperature to 0 ° C., and the concentrations of dissolved antimony and lead were measured. Moreover, the same process was performed with respect to silver chloride, and the density | concentration of the melt | dissolved silver was measured. The solubility of antimony with respect to hydrochloric acid concentration and liquid temperature is as shown in Table 1. Further, the solubility of lead with respect to hydrochloric acid concentration and liquid temperature is as shown in Table 2. Further, the solubility of silver with respect to the hydrochloric acid concentration is as shown in Table 3.

  As shown in Tables 1 and 2, when the concentration of hydrochloric acid in the solution after leaching of chloride exceeds 4 mol / L, the solubility of antimony and lead becomes very large, and antimony contained in the copper electrolytic starch is used as a standard amount. Antimony distributed to silver chloride was reduced from 33% to 19%.

  On the other hand, as shown in Table 3, the solubility of silver in the solution after leaching with chloride increased as the hydrochloric acid concentration increased, but the silver concentration was 200 to 400 mg / L even if the hydrochloric acid concentration was 4 to 5 mol / L. Since it is about L, the distribution ratio of silver to the solution after leaching with respect to the amount of silver in the silver chloride is about 0.3%, which does not greatly affect the silver recovery rate.

  Thereafter, the hydrochloric acid concentration in the solution after leaching of chloride after separation of silver chloride was adjusted to 2 mol / L, and the solution temperature was cooled to 5 ° C. As a result, the solubility of antimony could be reduced, and the collected precipitates were alkaline leached to obtain a residue enriched with antimony. Using antimony contained in the copper electrolytic starch as a reference amount, antimony distributed to the residue was improved from 63% to 70%.

  The form of antimony in the alkali leaching residue was sodium antimonate, and the antimony quality was around 40 mass%. The lead in the residue was considered to be lead hydroxide, and the lead quality was around 10 mass%.

  From the above results, it was revealed that the recovery efficiency of antimony can be improved by adjusting the hydrochloric acid concentration during the leaching reaction to exceed 4 mol / L. It was also found that the solubility of antimony can be lowered and antimony can be precipitated by adjusting the concentration of hydrochloric acid in the solution after leaching after separation of silver chloride to 4 mol / L or less. Furthermore, it became clear that the solubility of antimony can be further lowered and the antimony can be precipitated by cooling the solution after leaching with chloride. Furthermore, it has become clear that tellurium can be separated by alkali leaching of a precipitate containing antimony and lead, and the quality of antimony in the leaching residue can be improved.

  Further, the Sb-containing residue obtained by the alkali leaching step was put into a melting furnace and oxidized, and then coke was added to perform reduction. In the reduction, the melting furnace was maintained at 1000 ° C., and the reduction time was 8 hours. The distribution ratio of Sb to metal was confirmed by setting the addition ratio of coke to the residue to 5%, 10%, 15%, and 25% by weight. As a result, when the addition ratio of coke to the residue was 10% and 15%, the distribution ratio could exceed 80%, but when it was 5% and 25%, it was less than 70%.

Moreover, the volatilization process was implemented with respect to the molten metal after a soda processing process. With respect to 7.1 t of molten metal, the molten metal temperature was set to 680 ° C. to 700 ° C., the amount of air blown to the molten metal was set to 100 m ³ / h, and the spray position was set to a height of 20 mm to 40 mm from the molten metal surface. Sb can be recovered by oxidizing Sb to produce volatile Sb ₂ O ₃ , but when Sb concentration is reduced to 50% or less by adding Pb electrolytic starch reduced metal having low Sb quality, Sb ₂ O ₃ could be volatilized at a better rate. At that time, 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.

  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 (7)

  The Sb-containing residue obtained by copper leaching of the copper electrolytic starch in the copper smelting process is leached with hydrochloric acid and hydrogen peroxide, and the hydrochloric acid concentration during the leaching reaction is adjusted to exceed 4 mol / L. Processing method of Sb containing residue.   It adjusts so that the hydrochloric acid density | concentration at the time of the said leaching reaction may be 5 mol / L or more, The processing method of the Sb containing residue of Claim 1 characterized by the above-mentioned.   The silver chloride is separated from the solution after leaching with chloride, and the solution after leaching with chloride containing antimony after the silver chloride is separated is adjusted so that the hydrochloric acid concentration is 4 mol / L or less. The processing method of Sb containing residue of description.   4. The method for treating an Sb-containing residue according to claim 3, wherein the solution after anti-chlorine leaching containing antimony after separating the silver chloride is adjusted so that the hydrochloric acid concentration is 3 mol / L or less.   The method for treating an Sb-containing residue according to claim 3 or 4, wherein the solution after anti-chlorine leaching containing antimony after separating the silver chloride is cooled.   6. The method for treating an Sb-containing residue according to claim 5, wherein the solution after anti-chlorine leaching containing antimony after separating the silver chloride is cooled so that the liquid temperature is less than 50 ° C.   6. The method for treating an Sb-containing residue according to claim 5, wherein the solution after anti-chlorine leaching containing antimony after separating the silver chloride is cooled so that the liquid temperature becomes 25 ° C. or less.

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