JP2019131877A - LEACHING METHOD OF Sn AND MANUFACTURING METHOD OF Sn - Google Patents

Abstract

To provide a leaching method of Sn and a manufacturing method of Sn, capable of suppressing reduction of leaching rate of Sn.SOLUTION: A leaching method of Sn includes a Sn leaching process for leaching Sn to Sn scum containing Pb by using a leaching liquid, and a solid-liquid separation process for conducting solid-liquid separation on the leaching liquid within 1.5 hr. after completion of leaching of Sn in the Sn leaching process.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for leaching Sn and a method for producing Sn.

  For example, in lead smelting that produces a product Pb from a lead raw material such as lead (Pb) soot generated in copper smelting or the like, tin (Sn) scum containing Pb is generated. When Sn scum is subjected to the leaching step, Sn elutes in the leaching solution. Product Sn can be manufactured by performing electrowinning on the obtained liquid after leaching (see, for example, Patent Document 1).

JP 2013-234356 A

  However, in the Sn leaching step, Sn once eluted may form a composite oxide together with Pb and precipitate. In this case, the Sn leaching rate may be reduced.

  In view of the above problems, an object of the present invention is to provide a Sn leaching method and a Sn manufacturing method capable of suppressing a decrease in Sn leaching rate.

  The Sn leaching method according to the present invention includes an Sn leaching step of leaching Sn with respect to Sn scum containing Pb, and within 1.5 hours after completion of Sn leaching in the Sn leaching step. And a solid-liquid separation step of performing solid-liquid separation on the leachate.

  The Sn leaching method according to the present invention includes a Sn leaching process for leaching Sn with respect to Sn scum containing Pb, and the leaching liquid within 1 hour to 3 hours after the start of the Sn leaching process. And a solid-liquid separation step of performing solid-liquid separation.

  In the Sn leaching step, the leachate may be stirred. The leaching residue generated in the Sn leaching step may be supplied to a lead electric furnace or a carbonation step. The Sn scum may be obtained by performing a soda treatment on the crude lead obtained in the lead electric furnace.

  The method for producing Sn according to the present invention is characterized in that Sn is deposited by electrolytically collecting the leached solution obtained by the above-described Sn leaching method.

  ADVANTAGE OF THE INVENTION According to this invention, the Sn leaching method and Sn manufacturing method which can suppress the leaching rate fall of Sn can be provided.

It is a figure explaining an example of the process of manufacturing Sn and Pb. It is a figure which shows the measurement result of an Example. It is a figure which shows the measurement result of an Example. It is a figure which shows the measurement result of a comparative example. It is a figure which shows the measurement result of a comparative example.

  Hereinafter, an embodiment for carrying out the present invention will be described.

  FIG. 1 is a diagram illustrating an example of a manufacturing process for manufacturing the product Sn and the product Pb. As illustrated in FIG. 1, copper removal and carbonation are performed on lead raw materials such as lead soot, chelate neutralization soot, and exhaust batteries generated in a copper smelting process, a copper electrolysis process, and the like. Lead carbonate obtained by copper removal and carbonation is put into a Pb electric furnace as a Pb raw material. Lead carbonate is separated into crude Pb metal and slag by melting at 800 ° C. to 900 ° C. in a Pb electric furnace.

The crude Pb metal contains Sn as an impurity. Therefore, the cooled crude Pb metal is put into a Harris furnace. In the Harris furnace, the crude Pb metal is soda-treated. In the soda treatment, for example, caustic soda is added to the crude Pb metal heated to about 500 ° C. and melted, and additional caustic soda and sodium nitrate are added in some cases to convert Sn into a soda salt (Na ₂ SnCO ₃ ). This is a treatment for solidifying the molten metal surface. Solidified soda salt of Sn is generally called Sn scum. As an example, Sn scum contains 10 mass% to 30 mass% of Sn, 5.0 mass% to 20 mass% of Pb, 2 mass% to 15 mass% of Sb, and 0.5 mass% to 5. 0 mass% is contained, As is contained 1.0 mass% to 10 mass%, and Bi is contained 0.5 mass% to 7.0 mass%.

  Sn scum is used as an Sn raw material for producing Sn. Specifically, the Sn scum is subjected to a Sn leaching process for leaching Sn. The obtained post-leaching solution is subjected to an electrowinning process to produce a product Sn. The leaching residue of the Sn leaching process is repeated in the lead electric furnace or the carbonation process. On the other hand, Pb metal is obtained by soda processing the crude Pb metal in a Harris furnace. This Pb metal is subjected to an electrolytic purification process to produce a product Pb.

  In the Sn leaching step, Sn scum is put into a leaching solution such as pure water, and the leaching solution is heated and stirred. Since Sn scum is generated when a soda treatment is performed in a Harris furnace, a solution leached with pure water exhibits alkalinity. Sn elutes as Sn ions in the leachate showing alkalinity. The NaOH concentration of the leachate is preferably 70 g / L to 80 g /. If the NaOH concentration of the leachate is less than 70 g / L, an alkali such as NaOH may be added. Moreover, when it is anticipated that the NaOH concentration of the leachate will be lowered, an NaOH solution or the like may be used as the leachate instead of pure water.

  Moreover, since Sn scum contains Pb, Pb ions are eluted in the leachate. If heating and stirring are continued in this state, Sn ions and Pb ions coexist in the leachate. In the leachate in which Sn ions and Pb ions coexist, if a solid content is present, a composite oxide of Sn and Pb is formed and precipitated with the solid content as a nucleus. That is, once eluted Sn is precipitated, the leaching rate is reduced. Since the residue of the Sn leaching process is repeated in the lead electric furnace or the carbonation process, the amount of Sn repeated with respect to the lead electric furnace increases, which may increase the processing cost and Sn slag loss.

  Therefore, in the present embodiment, solid-liquid separation is performed after a certain amount of leaching has progressed after the start of the leaching process. Thereby, since the solid content which becomes the nucleus for complex oxide formation of Sn and Pb is removed from the leachate, the formation of complex oxide of Sn and Pb is suppressed. In addition, when solid-liquid separation is performed after a short time after the start of the leaching process, Sn leaching may not be sufficient.

  Therefore, an upper limit is set for the time after the end of Sn leaching. The time when Sn leaching ends is the time when the Sn concentration in the leaching solution becomes maximum. Specifically, a Sn leaching beaker test of Sn scum to be leached is performed in advance, and the concentration at the time when Sn is completely dissolved is confirmed. In the Sn leaching process in actual operation, the Sn concentration may be confirmed, and if the Sn concentration becomes 95% or more of the confirmed concentration, that point may be determined as the maximum concentration point. In the present embodiment, solid-liquid separation is performed within 1.5 hours after the completion of Sn leaching. In this case, the formation of a composite oxide of Sn and Pb is suppressed. It is preferable to perform solid-liquid separation within 1.0 hour after completion of Sn leaching, and it is more preferable to perform solid-liquid separation immediately after completion of Sn leaching.

  Or you may provide a minimum in the time after the leaching process start, and may perform solid-liquid separation. On the other hand, when solid-liquid separation is performed for a long time after the start of the leaching process, formation of a composite oxide of Sn and Pb may proceed. Therefore, an upper limit is set for the time after the start of the leaching process. In this embodiment, solid-liquid separation is performed within 1 hour and 3 hours after the start of the leaching process. Thereby, formation of complex oxides of Sn and Pb can be suppressed after sufficiently leaching Sn. The start time of the leaching process is the time when Sn scum is introduced into the leaching solution. In this method, it is not necessary to check the Sn concentration each time, and only time management is required, so that labor is not required.

In addition, the solid content which becomes a nucleus is a solid content which does not elute from Sn scum in the leaching step, and is, for example, a composite oxide of Sn and Pb (for example, PbSnO ₃ , Pb ₂ Sn ₂ O ₆ ) or the like. Due to the presence of this solid content, Sn and Pb grow as crystals, and the composite oxide of Sn and Pb becomes larger and precipitates. Although the magnitude | size of solid content used as a nucleus is not specifically limited, In this embodiment, it is a grade from sand to powder.

  As an example, the Sn ion concentration in the leachate is 45 g / L to 75 g / L, the Pb ion concentration is 3 g / L to 15 g / L, the NaOH concentration is 50 g / L to 90 g / L, and the liquid temperature is 40 ° C. to 70 ° C. By performing solid-liquid separation in the case of ° C., it is possible to suppress the formation of complex oxides of Sn and Pb while allowing a large amount of Sn ions to be present in the leachate.

(Example)
According to the embodiment, the Sn leaching process was performed on the Sn scum. The composition of the Sn scum used is shown in Table 1. In addition, each component density | concentration is a density | concentration at the time of drying Sn scum.

  200 ml of pure water was added to 60 g of this Sn scum, stirred at 65 ° C., and solid-liquid separation was performed after 1.5 hours. Stirring was continued at 65 ° C. for the filtrate after solid-liquid separation. Thereafter, the metal ion concentration was analyzed by ICP. The results are shown in FIGS. 2A and 2B.

(Comparative example)
In the comparative example, the conditions were the same as in the example except that solid-liquid separation was not performed. The results of ICP analysis are shown in FIGS. 3A and 3B.

(analysis)
As shown in FIGS. 3A and 3B, in the comparative example, the Sn ion concentration decreased from about 3 hours after the start of the leaching process, and the Sn leaching rate at 24 hours after the start of the leaching process became 79%. . In contrast, as shown in FIGS. 2A and 2B, in the examples, the Sn ion concentration was not reduced even when stirring was continued. The Sn leaching rate 24 hours after the start of the leaching process was 92%, which was significantly larger than that of the comparative example. This is considered to be because the formation of composite oxides of Sn ions and Pb ions having solid contents as nuclei was suppressed by performing solid-liquid separation within 1 to 3 hours after the start of the leaching process. .

  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 (6)

A Sn leaching step of leaching Sn using a leaching solution for Sn scum containing Pb;
And a solid-liquid separation step of performing solid-liquid separation on the leachate within 1.5 hours after completion of Sn leaching in the Sn leaching step. A Sn leaching step of leaching Sn using a leaching solution for Sn scum containing Pb;
And a solid-liquid separation step of performing solid-liquid separation on the leachate within 1 hour to 3 hours after the start of the Sn leaching step.   3. The Sn leaching method according to claim 1, wherein the leaching solution is stirred in the Sn leaching step.   The leaching residue produced in the Sn leaching step is supplied to a lead electric furnace or a carbonation step, and the Sn leaching method according to any one of claims 1 to 3.   5. The Sn leaching method according to claim 4, wherein the Sn scum is obtained by subjecting crude lead obtained in the lead electric furnace to soda treatment.   The manufacturing method of Sn characterized by precipitating Sn by carrying out the electrolytic extraction with respect to the liquid after the leaching obtained by the Sn leaching method as described in any one of Claims 1-5.

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