JPH0753892B2 - Metal melting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for dissolving a metal, which is characterized in that it is contacted with a halogen and a polar solvent in the presence of a soluble halide salt. The present invention relates to a method for melting a metal.

[Conventional technology]

Dissolving a metal in a liquid is an essential step for extracting and recovering the metal from a mixture containing the metal,
It is extremely important in industry. 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.

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).

[Problems to be Solved by the Invention]

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 acidic waste water is generated, and the waste water is expensive to treat. In addition, the method of contacting with a halogenated hydrocarbon in the presence of a cationic surfactant has a problem in that the solvent is limited to the halogenated hydrocarbon, and that its odor and toxicity are strong, which makes work difficult. there were.

[Means for Solving the Problems]

In order to solve the problems of the conventional methods, the present inventor has variously studied for a dissolution method of a metal that does not use an inorganic acid and can also use an organic solvent other than a halogenated hydrocarbon, and as a result, many metals are found to be present. The present invention has been accomplished by finding a phenomenon that it is easily dissolved by contact with a soluble halogenated salt, a simple substance of halogen, and a polar solvent.

That is, the present invention provides a method for dissolving a metal, which comprises contacting with a soluble halide salt, a simple substance of halogen, and a polar solvent.

In the method of the present invention, a metal is converted into a compound in which the metal is easily dissolved by bringing the metal into contact with a soluble halogenated salt, a simple substance of halogen and a polar solvent.

That is, when a halogen atom is given from a halogen to a target metal, a metal halide is generated, which is converted into a highly soluble polyhalogeno metal anion complex by the action of a soluble halide salt and is dissolved in a polar solvent. That is why.

The time required to dissolve the metal differs depending on the target metal, the type and concentration of the soluble halide salt and halogen simple substance used, the type of polar solvent, and the like. The treatment temperature is selected within a range not higher than the boiling point of the polar solvent, and the higher the treatment temperature, the more accelerated the dissolution of the metal. The end point of melting of the metal can be easily confirmed when the charged metal disappears.

As the soluble halogenated salt used in the method of the present invention, the constituent cations are alkali metal ions, alkaline earth metal ions or general formulas. (Wherein R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms or hydrocarbon groups having 6 or less carbon atoms) and the anion is a chloride ion, a bromide ion or an iodide ion Are suitable, for example sodium iodide, potassium bromide,
Calcium bromide, ammonium bromide, methylamine hydrochloride, tetramethylammonium iodide and the like are used. Soluble halide salt is equimolar or more to the metal to be dissolved, simple halogen is 0 to the metal to be dissolved.
Must use more than 5 times the molar amount.

In the method of the present invention, chlorine, bromine and iodine are used as the simple substance of halogen.

In the method of the present invention, water or a liquid polar organic solvent and a mixture thereof are used as the polar solvent. As the liquid polar organic solvent, alcohols, ketones and nitriles are suitable, and for example, methanol, ethanol, acetone and acetonitrile are used.

The metals dissolved by the method of the present invention include both typical metals and transition metals, such as beryllium, magnesium, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, selenium,
Zirconium, niobium, molybdenum, palladium, silver,
Examples include indium, tin, antimony, tellurium, hafnium, tantalum, gold, mercury, lead and bismuth.

〔Example〕

 Next, the present invention will be described in detail with reference to examples.

Examples 1 to 23 To 10 g of methanol, 1 mmol of potassium bromide and 0.5 mmol of bromine
Was dissolved, 0.2 mg-atom of metal powder shown in Table 1 was added, and the mixture was stirred at a liquid temperature of 20 ° C. Here, if all the metal powder is dissolved and does not remain, the dissolution rate is set to 100%, and if there is a metal residue, it is separated from the solution by decanting, washed with methanol, dried, and then weighed. did. 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 24-26 To 10 g of acetone, 1 mmol of sodium iodide and 0.5 m of iodine
0.2 mg- of metal powder shown in Table 2
When atom was added and the mixture was heated under reflux at a liquid temperature of 56 ° C. with stirring, all the metal powder was dissolved.

Example 27 To 10 g of acetonitrile, 1 mmol of sodium iodide and 0.5 mmol of iodine were added and dissolved, and 0.2 mmφ linear gold was added.
When 2 mg-atom was added and the mixture was heated under reflux at a liquid temperature of 82 ° C. for 8 hours with stirring, all the linear gold was dissolved.

Example 28 To 10 g of methanol, 1 mmol of calcium bromide and 0.5 mmo of bromine
l was added and dissolved, and 0.2 mmφ linear gold 0.2 mg-ato
When m was added and the mixture was stirred at a liquid temperature of 20 ° C. for 8 hours, all the linear gold was dissolved.

Example 29 To 10 g of water, 1 mmol of ammonium bromide and 0.5 mmol of bromine were added and dissolved, 0.2 mg-atom of 0.2 mmφ linear gold was further added, and the mixture was stirred at a liquid temperature of 20 ° C. for 2 hours. All the gold melted.

Example 30 10 g of methanol, 1 mmol of methylamine hydrochloride and 0.
Add 5 mmol and dissolve, and 0.2 mg φ linear gold 0.2 mg
When -atom was added and the mixture was stirred at a liquid temperature of 20 ° C for 3 hours, all the linear gold was dissolved.

Example 31 Methanol 10 g, tetramethyl ammonium iodide 1 mm
ol and 0.5 mmol of iodine were added and dissolved, and 0.2 mg-atom of 0.2 mmφ linear gold was further added, and the mixture was heated under reflux for 2 hours with stirring at a liquid temperature of 65 ° C., and all the linear gold was dissolved.

Example 32 Commercially available iodine tincture 10 ml (iodine 1.14 mmol, potassium iodide 1.14 mmol, methanol denatured ethanol 7 ml and water 2.5
0.2 mgφ linear gold 0.2 mg-atom was added to (containing 2 ml), and the mixture was heated under reflux for 1 hour with stirring at a liquid temperature of 81 ° C., and all the linear gold was dissolved.

〔The invention's effect〕

The method for melting a metal according to the present invention, as shown in Examples,
In addition to being easy to operate, it is applicable to many metals, and the soluble halide salt, simple substance of halogen, and polar solvent used are all inexpensive. Therefore, according to this method, the metal can be economically dissolved.

Claims (1)

[Claims] 1. A method for dissolving a metal, which comprises contacting the metal with (A) a halogen simple substance, (B) a soluble halogenated salt, and (C) a solvent comprising at least one of water and a polar organic solvent.