JPS6352093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for easily separating and collecting palladium components in high yield from scrap of porcelain electronic parts containing palladium.

When separating precious metals from ores or scraps containing precious metals, the ore or scraps are melted together with lead and the precious metals are collected in the lead to form precious lead, which is then separated into each element by ash blowing and hydrometallurgy. There are two methods: one method is to separate each precious metal element by directly dissolving and extracting it with a strong acid.

However, the former is a source of pollution because the lead used to collect precious metals becomes lead oxide and volatilizes during ash blowing, and if it is coated with common salt to prevent the lead oxide from volatilizing, precious metals can be removed. This method is not practical because some parts become chlorides and are lost by volatilization, and precious metals such as palladium and lead may interact to form poorly soluble intermetallic compounds, making subsequent acid treatment difficult. There were various problems. The latter method is superior at first glance, as it directly dissolves the precious metal with a strong acid to create a leachate and separates and purifies each element, but this requires a long time to separate the leachate and the residue, and is susceptible to contamination by impurities. Not only is separation difficult, but it is also dangerous because a large amount of acid is used. Particularly when the quality of the raw material is low, a large amount of impurities are eluted, making it difficult to separate the leachate, resulting in a large amount of processing time. Therefore, attempts have been made to simplify the separation of the leachate and residue by some means and shorten the time required, but no satisfactory results have been obtained.

The inventors of the present invention believed that solving the defects of the former method would have more advantages than the latter method, and as a result of various studies, we found that as long as lead was used, good results could not be obtained even if the processing conditions and additives were devised. They came to the conclusion that there was no such thing, and after further research considering the ease of subsequent separation, they developed a method to use silver to alloy silver and precious metals, and remove the gangue as slag.

The method for collecting palladium of the present invention involves mixing electronic component scrap with a silver supply material consisting of silver bullion or high-silver content scrap, and a silicic acid-based combustible agent, and melting the mixture to alloy the palladium component with silver. Components other than precious metals are separated from the silver alloy as slag.

Compared to the method of collection using lead, this method does not create a poorly soluble alloy and the subsequent wet treatment is easy. It has outstanding advantages such as no need for oxidation removal by the process and therefore no generation of harmful vapors or loss of precious metals. Also, compared to extraction methods using strong acids, there is less loss and contamination of impurities during the separation process.
It is also easy to operate.

As described above, the present invention is a refining method that is non-polluting and has a high recovery rate of precious metals, and can significantly shorten the procedure and time and facilitate the subsequent refining process.

The silver supply material used in the present invention may be pure silver ingot, but scrap or the like with a relatively high silver content can be used. It is desirable to use at least twice the amount of silver as the amount of palladium to be collected.

Addition of a flocculant is a common practice in the art in order to combine with components other than the target metal during melting and separate them as slag. As a flocculant, SiO ₂ , Fe ₂ O ₃ , CaCO ₃ , Na ₂ CO ₃ ,
A reducing agent, an oxidizing agent, etc. are appropriately blended with a commonly used silicic acid solvent component such as Na ₂ B ₄ O ₇ depending on the composition of the raw material ore and scrap. The composition must be determined in advance so that the slag that is formed has a smooth, glass-like shape that is easily separated from the alloy part.
Practically speaking, the silicic acidity of the slag is calculated using the following formula:
It is adjusted to about 0.5 to 2.5, preferably about 0.8 to 1.5.

Silicic acidity=Amount of oxygen in SiO ₂ /Amount of oxygen in basic oxide It is desirable that the ore, scrap and silver feed material be pulverized in advance to the extent that they can be uniformly mixed with the flocculant.

A suitable melting temperature is 1100°C or higher. At temperatures lower than this, the fluidity of the slag is insufficient.

Palladium collected as an alloy with silver by this method is separated and purified into each component metal according to a known purification method.

Next, the present invention will be explained with reference to examples.

In each example, the scrap and silver supply materials were quantitatively analyzed in advance to determine the blending agent. Among the flocculant ingredients, Fe ₂ O ₃ is used to form slag with SiO ₂ , and Na ₂ CO ₃ and Na ₂ B ₄ O ₇ make the slag flow easily, so flour creates a reducing atmosphere. KNO ₃ was added to prevent the loss of useful metals, and to oxidize coexisting unnecessary metals.

Example 1 2.5 kg of BaTiO ₃ -based porcelain scrap containing 10% by weight of palladium and 2% by weight of platinum that has been crushed into approximately 50 meshes in advance, 5.0 kg of scrap containing 90% by weight of silver as a silver supply material, and a pelletizer having the following composition. were mixed uniformly.

[Bottling agent] Fe ₂ O ₃ 0.7Kg SiO ₂ 4.1Kg Na ₂ CO ₃ 6.5Kg Na ₂ B ₄ O ₇ 2.3Kg Flour 1.0Kg The mixture was placed in an unglazed crucible and heated in an electric furnace.
After melting by holding at 1200°C for 30 minutes, it was taken out of the furnace and poured into a cone mold. When it was taken out from the mold after cooling, the alloy part was separated into the lower layer and the slag was separated into the upper layer.

As a result of analyzing the alloy part and slag, silver,
Palladium and platinum were all present in the alloy, and the recovery rate was approximately 99%, with almost no loss of precious metals.

Example 2 Using scrap containing 90% silver as a silver supply material
The same treatment as in Example 1 was carried out except that the weight was 2.5 kg and a flocculant having the following composition was used.

[Bottling agent] Fe ₂ O ₃ 2.5Kg SiO ₂ 2.7Kg Na ₂ CO ₃ 4.3Kg Na ₂ B ₄ O ₇ 1.4Kg Flour 0.5Kg As a result, almost no precious metals were lost, and 99
% in high yield.

Example 3 Scrap containing 70% silver as silver supply material
The same treatment as in Example 1 was carried out except that the weight was 2.5 kg and a flocculant having the following composition was used.

[Bottling agent] Fe ₂ O ₃ 2.5Kg SiO ₂ 1.6Kg Na ₂ CO ₃ 2.7Kg Na ₂ B ₄ O ₇ 2.3Kg KNO ₃ 0.5Kg As a result, 99
% in high yield.

Although the above embodiments are all examples of collection from porcelain scrap, it goes without saying that ore and other precious metal-containing scraps can be similarly collected.

Claims (1)

[Claims] 1 Mix and melt palladium-containing porcelain electronic component scrap, a silver supply material consisting of silver bullion or high-silver content scrap, and a silicic acid-based combustible agent to alloy the palladium component with silver to produce silver. A method of collecting palladium by collecting it in a slag and separating components other than precious metals as slag.