Cupellation: methods, precautions, and requirements for cupellation
Release time:
2020-06-16
Fire assay is a classic statistical analysis method that applies metallurgical principles and techniques to analytical chemistry. It has a long history in the field of analytical chemistry.
This method has the advantages of wide acceptability and ease of use. It is a key method for the chemical composition analysis of gold, silver and precious metals. It is also a common litigation method for measuring gold and silver in minerals and metal composites.
Determination of gold and silver in lead concentrates. Includes principle, testing process, efficiency of each process and common problems in practical operation.
Fire assay is a method to quantitatively analyze and measure the content of precious metals in iron ore and metallurgical industrial products by adding solutions. The specific application is mainly based on the lead fire assay method, and the whole process is divided into three parts:
It relies on the mixing of solid experimental reagents with the test sample, heating and melting in a crucible, and using lead to capture gold, silver and precious metals under melting conditions to produce a lead alloy (commonly known as a lead button). The lead alloy moves down to the bottom of the crucible due to its high specific gravity.
In addition, the metal oxides and gangue of base metal materials in the test items react with solutions such as silica, borax, and sodium carbonate. To convert them into slag, such as aluminosilicate or borate, which floats on top in a small proportion, thus taking this opportunity to extract gold and silver from the test items. Therefore, in the whole process of fire assay testing, two additional effects of dissolving test items and containing precious metals are achieved.
The obtained lead alloy is placed in a cupel, and the lead is removed in a cupellation furnace at medium temperature. During cupellation, the lead air is oxidized into lead oxide and penetrates into the porous structure of the cupel, thus removing the lead and a small amount of base metal materials in the lead button. Gold, silver and precious metals are protected from air oxidation and remain in the cupel to form gold and silver particles.
Sodium cyanide is used to dissolve gold and silver particles to dissolve silver, while gold remains solid. After heat treatment, the obtained gold particles are weighed to calculate the extracted content. The silver content can be calculated based on the difference between the mass of gold and silver particles and the mass of gold.
Related Blog
Scan
Luoyang Turner High Temperature Instrument Co., Ltd.
+86-400-880-7095
Sales (same as WeChat):18695992058
Contact:+86-379-69755886
Address: South Section of Shuangxiang Road, Luoxin Industrial Cluster, Luoyang City, Henan Province
Email:tnkinstrument@163.com
Copyright © Luoyang Tainake High-Temperature Instrument Equipment Co., Ltd. IPV6