JPH0747783B2 - Metal melting method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dissolving a metal, and more particularly to a method for dissolving a metal which is characterized by bringing the halogen into contact with a polar organic solvent solution.

[0002]

2. Description of the Related Art Dissolving a metal in a liquid is an essential step for extracting and recovering the metal from a mixture containing the metal and is extremely important industrially. For this purpose, conventionally, a method of dissolving a metal in an aqueous solution of an inorganic acid such as hydrochloric acid has been used. Further, recently, a method of dissolving a metal by contacting it with a halogenated hydrocarbon in the presence of a cationic surfactant has been found (JP-A-1-294830).

[0003]

In the conventional metal dissolution method using an inorganic acid, since a strongly acidic aqueous solution is used, the work is dangerous and a large amount of waste water is generated, and a large amount of cost is required for the treatment of this waste water. Takes. Further, in the method of contacting with a halogenated hydrocarbon in the presence of a cationic surfactant, the cationic surfactant used is relatively expensive, and
Since the solvent is a halogenated hydrocarbon having a strong odor and toxicity, there are problems such as difficulty in working.

[Means for Solving the Problems] In order to solve the problems of the conventional methods, the present inventors have made various investigations for a method of dissolving a metal using an organic solvent other than a halogenated hydrocarbon without using an inorganic acid. As a result, they found that many metals dissolve when they are brought into contact with a polar organic solvent solution of a simple substance of halogen, and the present invention has been accomplished. That is, the present invention provides a method for dissolving a metal, which comprises contacting with a polar organic solvent solution of a simple substance of halogen. In the method of the present invention, a simple substance of chlorine, bromine or iodine is used as a simple substance of halogen. A polar organic solvent is used as the solvent. As the polar organic solvent, for example,
Examples thereof include nitriles such as acetonitrile, alcohols such as methanol, ketones such as acetone, and esters such as ethyl acetate. Such a polar organic solvent dissolves halogen well, and at the same time dissolves metal halide well, and is therefore suitable as a solvent for dissolving metal. In the method of the present invention, a metal is converted to a halide by bringing the metal into contact with a simple substance of halogen in a polar organic solvent solution. That is, when a halogen atom is given to a target metal from a simple substance of halogen, a metal halide is generated, and this is dissolved in a polar organic solvent. The time required to dissolve the metal depends on the target metal, the type and concentration of the halogen used, and the like. Further, the treatment temperature is selected within a range not higher than the boiling point of the polar organic solvent, and the higher the treatment temperature is, the more the dissolution of the metal is promoted. The end point of melting of the metal can be confirmed by disappearing the charged metal. The metals dissolved by the process of the present invention include both typical metals and transition metals, such as beryllium, magnesium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel,
Examples include copper, zinc, selenium, palladium, indium, tin, antimony, tellurium, hafnium, gold, mercury and bismuth.

[0004]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Examples 1 to 15 0.5 g of bromine in 10 g of acetonitrile
0.2 mol of metal powder shown in Table 1 was added and dissolved.
While stirring by adding mg-atom, the mixture was heated under reflux at a liquid temperature of 80 ° C. Here, when the metal powder does not remain, the dissolution rate is set to 100%, and when there is a metal residue, this residue is separated from the solution by decanting, washed with methanol, dried, and then weighed. . The dissolution rate of the metal was obtained from the difference between the amount of the residual metal thus obtained and the amount of the charged metal. The results are shown in Table 1.

Examples 16 to 21 0.5 mmol of chlorine was added to and dissolved in 10 g of acetonitrile, 0.2 mg-atom of 0.2 mmφ linear metal shown in Table 2 was added, and the mixture was stirred at 30 ° C. It was as follows.

Examples 22 to 25 Bromine 0.5 mmo in 10 g of methanol
l was added and dissolved, and 0.2 mgφ linear metal 0.2 mg-atom shown in Table 3 was further added and stirred at 30 ° C. The dissolution rate was as follows.

Examples 26 to 27 Iodine 0.5 mmo in 10 g of acetone
l was added and dissolved, and 0.2 mg-linear metal 0.2 mg-atom shown in Table 4 was further added, and the liquid temperature 56 while stirring.
Upon heating under reflux at ℃, the dissolution rate was as follows.

Example 28 Iodine 0.5 mmo in 10 g of acetonitrile
When 1 ml was added and dissolved, and then 0.2 mg-atom of mercury was added and the mixture was stirred and refluxed at a liquid temperature of 80 ° C. for 1 hour, all the mercury was dissolved.

Example 29 0.5 mmol of iodine was added to and dissolved in 10 g of ethyl acetate, and 0.2 mg-atom of 0.2 mmφ linear iron was added.
Was added and stirred under reflux at a liquid temperature of 77 ° C. for 0.5 hour to dissolve all iron.

[0005]

As described in the examples, the method for dissolving a metal according to the present invention is simple in operation and can be applied to many metals. Both halogen simple substance and polar organic solvent used are inexpensive. It is something. Therefore, according to this method, the metal can be economically dissolved.

Claims (1)

[Claims] 1. A method for dissolving a metal, which comprises bringing the metal into contact with a polar organic solvent solution of a simple substance of halogen.