JPS6164830A - Dry type refining method of ag alloy - Google Patents

Abstract

PURPOSE:To separate high-purity Ag from an Ag alloy by refining the Ag alloy incorporating a metal which is more oxidizable than Ag and whose oxide is low in wettability to Age is dispersed into component Ag, under specified condition by the dry method. CONSTITUTION:An Ag alloy incorporating a metal which is more oxidizable than Ag and whose oxide is low in wettability to Ag is dispersed into component Ag is put into an crucible 1. This alloy is heated to above the m.p. of Ag through an induction heating coil 2. Then oxygen or air is blown against the molten alloy from a nozzle 5. The above-mentioned metal dispersed in Ag is oxidized and the Ag alloy can be separated into Ag and oxides owing to the difference in specific gravity between Ag and oxides.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for dry refining Ag alloys.

(Prior art and its problems) As a method for separating and refining Ag, wet methods include an electrolytic method in which Ag is directly deposited on an electrode from a nitric acid solution, oxides, chlorides,
A method of separating Ag as sulfide and reducing it is generally known. In addition, the dry method of separating precious metals from base metals has been known for a long time.

However, in the wet method, chemicals such as acids, alkalis, or reducing agents must be used, and waste liquid treatment is required due to problems such as environmental pollution. In addition, the ash blowing method requires lead and bone ash and is not economical, and there is a risk that lead may be mixed into the Ag.

(Object of the Invention) The present invention is characterized by providing a dry refining method for Ag alloys that is simpler than the above-mentioned conventional methods and is capable of separating and refining high-purity Ag from Ag alloys. .

(Structure of the Invention) The dry refining method of Ag alloy of the present invention is to produce an Ag alloy in which a metal which is more easily oxidized than Ag and whose oxide has poor wettability with Ag is dispersed in Ag alloy at a temperature higher than the melting point of Ag. The above metals dispersed in Ag are oxidized by blowing oxygen or air onto it, and the Ag alloy is separated into Ag and oxides due to the difference in specific gravity between Ag and oxides. Characterized by refining.

(Example) An example of the dry refining method for Ag alloy according to the present invention will be described with reference to the drawings. The figure shows a device for carrying out the process. 1 is a crucible, 2 is an induction heating coil installed on the outer surface of crucible 1, and 3 is an F4 hot water dripping hole drilled in the center of the bottom of crucible 1. is closed by press-fitting the stopper rod 4. 5 is a quartz nozzle for blowing oxygen or air, and 6 is a cooling water tank disposed below the crucible 1, in which cooling water 7 is stored.

In order to separate and refine an Ag alloy, for example, an Ag-NilO wt% alloy by the dry refining method of the present invention using the apparatus configured as described above, 20 kg of Ag-NilO wt% alloy is first placed in crucible 1, and then was melted at 1100° C. by induction heating using induction heating coil 2. Then, while maintaining this temperature, 1.5~'l atm of oxygen was supplied from the quartz nozzle 5.
It was sprayed onto the molten metal 8 at a moderate pressure. At this time, as a heating power source for the molten metal 8, in order to evenly apply oxygen to the molten metal 8,
A low frequency power source was used to generate convection. After approximately 30 minutes have passed after melting, turn off the power and remove stopper rod 4.
was loosened to slightly open the molten metal dripping hole 3, and the molten metal 8 was dropped into the cooling water 7 in the cooling water tank 6. The dripping of the molten metal 8 stopped immediately before the melt dripping hole 3 was clogged with slag of Ni oxide. Then, by repeating the dropping and stopping of the molten metal 8 twice and three times, A
The test for separating Ag was conducted three times, and Ag with purity as shown in the table below was obtained.

As is clear from the table above, according to the examples of the dry refining method for Ag alloys of the present invention, extremely highly pure Ag can be separated and purified.

(Effect of the invention) As detailed above, the dry refining method of Ag alloy of the present invention is
An Ag alloy in which a metal that is more easily oxidized than Ag and whose oxide has poor wettability with Ag is dispersed in Ag is melted at a temperature higher than the melting point of Ag, and then oxygen or air is blown onto the Ag alloy. The metal dispersed in the oxide is oxidized, and the Ag alloy is separated and purified into Ag and oxide based on the difference in specific gravity between Ag and the oxide, so the separation and purification work is extremely simple compared to the conventional wet method. In addition, there is no need for waste liquid treatment, and it is more economical than the conventional ash blowing method, and there is no risk of lead intrusion, and the separated and purified Ag has excellent effects, such as high purity.

[Brief explanation of drawings]

The figure is a schematic longitudinal sectional view showing an apparatus for carrying out the dry refining method of Ag alloy of the present invention.

Claims (1)

[Claims] An Ag alloy in which a metal that is more easily oxidized than Ag and whose oxide has poor wettability with Ag is dispersed in Ag.
The above-mentioned metals dispersed in Ag are oxidized by blowing oxygen or air onto this at a temperature higher than the melting point of Ag. A dry refining method for Ag alloys, which is characterized by dispersion refining of Ag alloys.