JPS62270735A - Recovering method for tin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 3. Detailed description of the invention Mitsaratategobunken The present invention relates to a method for recovering tin.

This method is especially suitable for producing high-purity electric tin.

Conventional tin recovery methods include leaching tin-containing substances with water, etc., and then performing sulfurization treatment to remove impurities such as PB and SB, or replacing them with Sn metal. was performed and processed.

However, purification by sulfidation treatment and tin metal replacement could not sufficiently remove sb from the purification liquid, and the purity of electrolytic tin obtained by electrowinning could not be increased to 99.9% or more.

This is because sb in the purified solution is a harmful metal, and almost all of the sb in the solution is precipitated by electrode reaction and contaminates the electrical Sn.

The present inventors made the following invention as a result of intensive studies to solve the drawbacks of the prior art.

11 sides and places The present invention provides a method for recovering tin from a tin-containing basic solution containing impure metals. This invention relates to a method for recovering tin, which comprises substituting and reducing impurities in the liquid, including a base metal and a reoxidation inhibitor, removing precipitated impurities by filtration, etc., and recovering tin by a predetermined method.

Further, as an embodiment thereof, there is provided the above-mentioned tin recovery method characterized in that one reaction is carried out in a rotary furnace.

The target treatment liquid of the present invention is a tin-containing basic solution containing impure metals.

For example, it is water-leached Sn-containing scum generated from lead smelting.

These solutions are basic with a pH of 12 or higher.

If it is strongly basic, tin is present in the form of sodium stannate or the like.

A reducing metal is added to the above-mentioned target liquid to perform reduction, and at this time, it is important to add a reoxidation inhibitor.

As the reducing metal, tin is preferable since tin is recovered. Tin is preferably metallic because it is sufficient to dissolve only the required amount. Further, it is preferable that the purity is high, that is, 99.99% or more.

As a reoxidation inhibitor, sodium thiosulfate (NazS
zO3) hydrazine (N2 H4), etc. are used.

Thereby, it is possible to prevent the reduced and precipitated sb and pb from being redissolved.

These treatments allow impurities to precipitate and tin to be in a dissolved state.

This reaction is carried out using a rotating type reaction vessel.

It is preferable to conduct the reaction while flowing the reduced metal into the solution. For example, a one-rotary furnace type furnace is used. This is to efficiently exfoliate the impurities deposited on the surface of the reducing metal and to ensure that the reducing metal always comes into contact with the impurity ions in the liquid, thereby rapidly promoting the reduction reaction.

This is also because the reducing metal is not excessively dissolved and can perform a preferable reduction reaction.

Particularly during the reaction, it is preferable to rotate the inlet section while holding it horizontally.

This is because the reaction space is wide and the leachate can be held at a shallow level, allowing the reaction to occur quickly.

Further, the reaction temperature is preferably 60°C or higher, preferably 80°C or higher. This is because substitution with tin is preferably performed.

The precipitated impurities are removed by filtration or the like to obtain a highly pure tin solution.

Filtration etc. includes all means for removing impure products such as sedimentation method and filtration method.

Metallic tin with a high purity of 99.99% or more can be recovered by subjecting the tin-containing liquid obtained in the present invention to electrowinning or H□ reduction.

Further, by neutralizing this purified liquid with a neutralizing agent such as sulfuric acid, highly pure tin hydroxide and tin oxide can be recovered.

Note that if As is mixed into the metal, it is preferable to carry out soda treatment.

By implementing the present invention as described above, the following effects can be obtained.

A1RυExample (1) Recovery of high purity metal tin of 99.99% or more is
It can be done easily.

(2) It is particularly suitable for recovering high-purity tin and tin salt from scum containing many impurities produced in lead smelting and the like.

(3) Furthermore, the liquid purification time can be shortened.

Example 1 Scum produced in lead smelting was dissolved in water. Sn metal is charged into a ball mill-type substitution reaction layer, and the liquid is circulated to cause a substitution reaction.

During the reaction, the antioxidant Na2S, O, 5H, O
2gIQ of was added.

The reaction temperature was 80°C.

As a result, as shown in Table 1, a liquid containing low amounts of Pb, Sb, and Cu was obtained.

Metallic tin was obtained by electrowinning the above treatment solution.

Since As is 70 ppm, it is treated with soda treatment,
It was possible to obtain 99.99% electric tin.

Comparative Example When reduction treatment was performed without adding Na, S, O, .5H, O, almost no sb crystallized and could not be removed.

Claims (2)

[Claims] (1) In a method for recovering tin from a tin-containing basic solution containing impure metals, impurities in the solution are reduced by substitution, including reducing metals and reoxidation inhibitors, and precipitated impurities are removed by filtration etc. A tin recovery method characterized by recovering tin using a predetermined method. (2) The method for recovering tin according to claim 1, characterized in that the reaction is carried out in a rotary furnace.