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Smelting has serious effects on the environment, producing wastewater and slag and releasing such toxic metals as copper, silver, iron, cobalt, and selenium into the atmosphere. [25] Smelters also release gaseous sulfur dioxide , contributing to acid rain , which acidifies soil and water.
16th century cupellation furnaces (per Agricola). Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to 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.
The mining water contains copper salts in the form of copper sulfate CuSO 4. The iron then reacts with the copper, displacing it from the sulfate ions, causing the copper to precipitate onto the iron sheets, forming a "wet" powder. Finally, the precipitated copper is collected and refined further through the traditional smelting process.
The purest copper is obtained by an electrolytic process, undertaken using a slab of impure copper as the anode and a thin sheet of pure copper as the cathode. The electrolyte is an acidic solution of copper (II) sulfate. By passing electricity through the cell, copper is dissolved from the anode and deposited on the cathode. However ...
The coke is used to melt and reduce the lead. Limestone reacts with impurities and floats to the top. This process also keeps the lead from oxidizing. The molten lead flows from the blast furnace into holding pots. Lead may be mixed with alloys, including antimony, tin, arsenic, copper and nickel. It is then cast into ingots. [3] [4]
Tumbaga is an alloy composed mostly of gold and copper. It has a significantly lower melting point than gold or copper alone [citation needed]. It is harder than copper, but maintains malleability after being pounded. Tumbaga can be treated with a carboxylic acid, such as oxalic acid, to dissolve copper off the surface. What remains is a shiny ...
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Converting is a type of metallurgical smelting that includes several processes; the most commercially important form is the treatment of molten metal sulfides to produce crude metal and slag, as in the case of copper and nickel converting. A now-uncommon form is batch treatment of pig iron to produce steel by the Bessemer process.