What is Cupellation method?
cupellation, separation of gold or silver from impurities by melting the impure metal in a cupel (a flat, porous dish made of a refractory, or high-temperature-resistant, material) and then directing a blast of hot air on it in a special furnace.
Why is Cupellation important?
Cupellation is at once the neatest and the most important of the dry methods of assaying. Its purpose is to remove easily oxidisable metals, such as lead and copper, from silver and gold, which are oxidisable with difficulty. Metals of the first class are often spoken of as base, and gold and silver as noble metals.
What is Cupellation process and for what it is used?
Cupellation is a refining process in metallurgy where ores or alloyed metals are treated under very high temperatures and have controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore.
Why is silver removed from lead?
From lead concentrates Zinc reacts rapidly and completely with gold and silver, forming very insoluble compounds that float to the top of the bullion. These are skimmed off and their zinc content recovered by vacuum retorting.
What is Liquation in metallurgy?
liquation, technique for separating constituents of an ore, a metal, or an alloy by partial melting. When the material is heated to a temperature where one of the constituents melts and the other remains solid, the liquid constituent can be drained off.
What is slag in smelting?
Slag is the silicon dioxide and metal oxide mixture left over as a by-product of extracting metal from its ore during the smelting process. Once the metal is smelted out of its ore, the ore appears to be glassy. This glassy appearance is caused by the formation of slag on the ore’s surface during the smelting process.
What is the process of liquation?
What is the principle of liquation?
Liquation is a metallurgical process to purify mineral metals. It is employed to separate valuable metals from ores that are a mixture of two or more valuable metals. The process involves heating the ore until the metal with a lower melting point is separated from the one with higher melting point.