JPS61133334A - Recovering method of silver - Google Patents

Abstract

PURPOSE:To recover silver easily and efficiently, requiring only inexpensive equipment, by heating the scrap of silver-plated material at high temp. for required time and by agitating the above scrap with or after heating. CONSTITUTION:The scrap 1 of silver-plated material such as a silver-plated wire, a silver-plated lead frame and the like is put into a barrel 2, and the barrel 2 is heated in an electric furnace 3 for about 10min at high temps. of about 300-600 deg.C, below the melting temp. of silver. After that, the barrel 2 is taken out of the electric furnace 3, and the scrap 1 is moved into a mixer of a fixed type or the like and is agitated. In this way, the silver can be easily peeled from the matrix to be recovered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for recovering silver from scraps such as integrated circuits (referred to as IC), silver-plated wires of high-performance switches, silver-plated lead frames, etc. be.

[Conventional technology]

Conventionally, the method of recovering silver from the scrap of silver-plated glands and silver-plated lead frames was to
Methods of melting silver by iJD heating and methods of dissolving silver in a cyanide aqueous solution by spraying scrap with a cyanide aqueous solution (for example, JP-A-58-39215) have been used.

[Problems to be solved by the invention]

However, in these conventional techniques, the molten silver must be further separated from the base metal, and the equipment costs for this are expensive and the work is complicated. However, there were problems with wastewater treatment, equipment costs were high, and the work was complicated.

[Failure to solve the problem]

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a method for recovering silver that is relatively inexpensive in equipment cost, easy to operate, and highly efficient. This was done based on the idea that the silver solder would easily peel off from the substrate when heated.
The gist of this method is to recover silver from scraps of silver-plated materials such as silver-plated wire and silver-plated lead frames, in which the scraps are heated at a high temperature for a required period of time, and while heating or heated hindlimb scraps are recovered. The silver recovery method is characterized by stirring the silver.

[Effect]

When scraps of silver-plated materials are heated at high temperatures, they tend to peel off from the substrate at the silver solder area, as described above. The melting temperature of the silver solder varies depending on the components, but generally starts around 670°C to 720°C and finishes around 690°C to 740°C. By heating at a high temperature of 300 to 600° C. that does not reach the melting temperature, silver and silver solder remain solid and are easily peeled off from the substrate.

At this time, by stirring the scrap and applying vibration and impact, force is applied to the silver solder, causing the silver to peel off from the base.

〔Example〕

FIG. 1 is an explanatory diagram showing an example of the silver recovery method of the present invention. Put silver plated lead frame scrap 1 into barrel 2
After heating the barrel 2 at 600°C for 10 minutes in an electric furnace 6, it is taken out and stirred, or
As shown in the figure, the scrap 1 was transferred to a container-fixed mixer 5, and the stirring blade 6 was rotated to stir the scrap 1, thereby exfoliating and separating the silver from the substrate.

〔Effect of the invention〕

As shown in the above example, silver is separated from the substrate while remaining solid, so less energy is required for heating, the equipment is extremely simple, and since the recovered silver is also solid, the volume is small.
The refining process requires only small equipment volume, and equipment costs are low.
It was easy to work with and has great industrial significance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the silver recovery method of the present invention. FIG. 2 is an explanatory diagram showing another embodiment of the present invention. 1; Scrap of silver-plated lead frame; 2; Barrel; 3; Electric furnace; 4; Scrap inlet; 5; Container-fixed mixer; 6; Stirring blade; 7; Recovered silver outlet.
4 Figure 1 %2!21 Furnace 6: Evaluation Feather IT: Recovered carcass outlet

Claims (1)

[Claims] (1) A method for recovering silver from scraps of silver-plated materials, which comprises heating the scraps at high temperatures for a necessary period of time, and stirring the scraps while or after heating. Collection method.