JPS6037866B2 - How to recover thallium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering thallium from thallium-containing materials.

Lead electrolytes, cleanliness generated from cadmium smelting processes, and certain residues and wastes from other non-ferrous smelting processes include:
Depending on the source, thallium is contained in amounts ranging from a few percent to 20 percent.

Recently, attempts have been made to recover thallium or thallium concentrate from such thallium-containing materials. Conventionally, there is no known method for efficiently recovering thallium from thallium-containing substances. As a result of studying the recovery of thallium from a thallium-containing substance by a leaching method, the inventors discovered that thallium (1) chloride (mCI) was produced by adding hydrochloric acid to a thallium-containing substance, and then this thallium (1) chloride was It has been found that by adding water to form a pulp and blowing chlorine into the pulp, hardly soluble thallium chloride (1) can be effectively converted into highly soluble thallium chloride (m) (TIC13).

A highly concentrated solution of thallium in the form of thallium chloride (m) is thus obtained, which is suitable for subsequent recovery of metallic thallium by electromechanical or displacement reaction methods. Therefore, the present invention separates thallium chloride (1) produced by adding hydrochloric acid to a thallium-containing liquid, adds water to the thallium chloride (1) to make it into a pulp, and then converts the thallium chloride (1) into a pulp. To provide a method for recovering thallium, which comprises converting thallium chloride (1) to thallium chloride (m) by blowing chlorine into the pulp of the pulp, and recovering a solution in which thallium chloride (m) is dissolved at a high concentration. .

More than 95% of the thallium in the initial thallium-containing liquid is transferred to the thallium chloride (m) concentrated solution obtained as described above, and metallic thallium can be easily recovered from this solution.

Metal thallium can be recovered by an electrolytic method, but one preferred method is to generate thallium sponge using a substitution reaction with a metal that is electrochemically more base than thallium. Therefore, the present invention also provides thallium chloride (
The present invention provides a method for recovering thallium, which comprises adding a metal electrochemically more base than thallium to a solution to produce spongy thallium. As mentioned above, there are various kinds of thallium-containing liquids, and a typical example thereof is a lead electrolyte.

In this case, since it contains bells, it is preferable to perform a demetallizing stage treatment before adding hydrochloric acid. Deleading treatment can be carried out by adding sulfuric acid to precipitate the lead as lead sulfate. According to the present invention, thallium chloride ( 1) is separated, water is added to the thallium chloride (1) to make it into a pulp, and chlorine is blown into the pulp of the thallium chloride (1) to turn the thallium chloride (1) into thallium chloride (spots). A method for recovering thallium is provided, which comprises converting and recovering a solution in which thallium (m) chloride is dissolved at a high concentration.

Hereinafter, the thallium recovery method of the present invention will be specifically explained.

The thallium-containing liquids to which the present invention is directed are intermediates and residual liquids produced in non-ferrous smelting processes, typified by lead electrolytes, clean turmeric-containing liquids generated from cadmium smelting processes, and the like.

Taking lead electrolyte as an example, it contains 3 to 20% thallium. If such thallium is left unrecovered, it will accumulate during circulation within the smelting system, and if the permissible limit is exceeded, it will have a negative impact on various process steps. It is also necessary to remove and recover thallium from thallium-containing materials. According to the invention, hydrochloric acid is first added to the thallium-containing liquid.

The amount of hydrochloric acid added is determined to be sufficient to convert thallium into thallium (1) chloride depending on the amount of thallium contained in the liquid. After the thallium chloride (1) is produced, the thallium chloride (1) and the liquid are taken up in the furnace. The liquid after passing through the furnace is repeatedly subjected to the smelting process depending on the substances it contains. For example, in the case of lead electrolyte, it is returned to the lead electrolysis process. The amount of thallium in the liquid after passing through the furnace is less than 2. The separated solid content mainly consisting of thallium chloride (1) is made into pulp by adding water. Thallium chloride (1) has low solubility in water4
．． Since it is about 5 ta', it hardly dissolves in water as it is. However, when chlorine gas was blown into this pulp to convert thallium chloride (1) to thallium chloride (m), it was found that thallium chloride (m) has a high solubility and dissolves extremely well in water. For example, thallium chloride (1) is sufficiently converted to thallium chloride (m) by blowing chlorine gas at a rate of 100 cc/min for about 4 hours based on the amount of pulp, and dissolves in water. The pulp density is
100-3009', preferably around 200'. After producing a leachate containing dissolved thallium chloride (m),
The leachate and the leachate residue are fed into a furnace 8U, and the leachate is recovered. The leaching residue is, for example, repeated in the lead smelting process. The leachate concentrates 95% or more of the amount of thallium in the pulp, and is suitable for later recovering metallic thallium therefrom. The leaching process is conventionally carried out by blowing chlorine gas through the pulp as it is transported across the ocean. Room temperature is sufficient for the leaching temperature, but higher temperatures tend to lower the thallium leaching rate because the solubility of chlorine gas decreases. If impurities such as gold 6 and zinc are included in the initial thallium-containing solution, relatively large amounts of lead and zinc will also migrate into the leachate, but these can be removed in a post-process so there is no problem. In order to show the difference in leaching effect obtained by converting thallium chloride (1) to thallium chloride (m) by blowing chlorine gas, the results of a comparative test are shown.

Two pieces of pulp of thallium chloride (1) were placed in a container equipped with a Z-based azusa blade, and chlorine gas was blown into the liquid. Pulp density is 20
0/evening and test no. In Test No. 1, chlorine gas was blown at a rate of 100 cc/min for 4 hours.
In No. 2, the air was blown at a rate of 10 cc/min for 4 hours. The fraction of thallium acid in the obtained solution after leaching was No. In 1, we. It showed a high value of 6%, whereas No. 2
It was only 0.9%. It can be seen that a highly concentrated thallium solution can be recovered according to the present invention. In order to recover metallic thallium from the post-leaching solution obtained as described above, an electrolytic method or an evaporation method may be used, but recovery of metallic thallium by a substitution method will be described here as a preferred method.

In the post-leaching solution, thallium chloride is dissolved at a high concentration.
For example, plate pieces or powder of a metal that is electrochemically more base than thallium, such as zinc, are introduced.

The input amount is considered to be slightly higher than the stoichiometric equivalent. The substitution reaction produces thallium in the form of a sponge. After the sponge thallium is separated from the furnace, the substituted liquid is sent to wastewater treatment, and the recovered crude sponge thallium is purified to remove impurities. The purification of crude spongethallium is carried out by first dissolving it under the addition of sulfuric acid and then dissolving it under the addition of sodium hydroxide; The process can also be omitted. The dissolution treatment by adding sodium hydroxide is carried out at about 400° C., and the generated metallic thallium and soda coin are separated. The metal thallium obtained is 99
．． It has a high purity of 99% or more and can be used as an insecticide and other purposes. If the starting thallium-containing solution contains lead, such as a lead electrolyte, it is convenient to remove the lead in advance before adding hydrochloric acid.

Lead can be easily removed by adding sulfuric acid to precipitate the lead as lead sulfate. The steps described above are shown as a flow sheet in the accompanying drawings as a consistent process of using lead electrolyte as a starting material and recovering metal thallium. In this flow sheet, lead in the lead electrolyte is first removed, thallium chloride (1) is produced by the dethallium treatment, and thallium chloride (1) is produced by the leaching treatment in the form of thallium chloride (m) in the solution after leaching. be dissolved. Thereafter, sponge thallium produced by the substitution process by adding zinc is recovered as high-purity metal thallium by a purification process. The details are as explained above. EXAMPLE The lead electrolyte 72 was treated according to the flow sheet shown in the attached drawings.

The electrolyte contained 10 m/s of thallium and 70 m/s of lead. By adding 2.39k9 of sulfuric acid to this, 8.5k9 of lead sulfate mud and 72ml of deleaded liquid were obtained. The thallium concentration in the solution after deleading was 9.9 m/s, and 7 of the 720 m/s of thallium contained in the electrolyte were lost as lead sulfate mud. All lead was removed as lead sulfate. Next, 101 g of hydrochloric acid was added to 72 g of the deleaded solution. As a result, 716 units of thallium chloride (1) were recovered. The thallium concentration in the solution after thallium removal was 1.9 m/s. Thereafter, a pulp of thallium chloride (1) was produced, and a leaching treatment was performed by blowing 250 m of chlorine gas into the pulp.

As a result, 200 m/27 of the leached liquid containing thallium
5 ml and 29 ml of leaching residue were generated. The amount of thallium in the liquid after leaching was 550 μm, while the amount of thallium in the leaching residue was 23 μm. After leaching, the solution was replaced with 400 days of zinc powder to recover 576 days of sponge thallium. The thallium quality in the sponge thallium was 95%. Finally, this sponge thallium was dissolved at a temperature of 400 quarts by adding 200 ml of sodium hydroxide.

In the end, 500 yen of metallic thallium was produced, which is 9
It had a high purity of 9.9%. The present invention has established a method for extremely efficiently recovering high-purity thallium from various thallium-containing liquids, including lead electrolytes, and can be widely applied to thallium recovery and washing solutions. Industrially significant.

[Brief explanation of the drawing]

The drawing is a flow sheet of the process of recovering metal urium from a lead electrolyte by applying the present invention.

Claims (1)

[Claims] 1. Thallium chloride (I) produced by adding hydrochloric acid to a thallium-containing liquid produced from a non-ferrous smelting process such as a lead electrolyte is separated, and water is added to the thallium chloride (I). The thallium (I) chloride is converted into thallium (III) chloride by blowing chlorine into the thallium (I) chloride pulp. Then, a metal electrochemically more base than thallium is added to the thallium (III) chloride solution to produce sponge thallium, and the sponge thallium is subjected to a dissolution treatment by adding sodium hydroxide to form metallic thallium and soda. and separating the metallic thallium. 2 Adding hydrochloric acid to the thallium-containing liquid after separating the lead in the liquid as lead sulfate by adding sulfuric acid to the liquid containing lead and thallium produced from the non-ferrous smelting process such as lead electrolyte. The thallium (I) chloride produced is separated, water is added to the thallium (I) chloride to form a pulp, and chlorine is blown into the pulp of the thallium chloride (I). ) is converted to thallium (III) chloride, and a solution containing a high concentration of thallium (III) chloride is separated.
Next, a metal electrochemically more base than thallium is added to the thallium (III) chloride solution to produce sponge thallium, and the sponge thallium is subjected to a dissolution treatment by adding sodium hydroxide to produce metallic thallium and soda. and separating the metallic thallium.