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Thus, smelting, or refining, is necessary to reduce the compound containing the Ag + cation into metallic Ag and to remove other byproducts to get at pure silver. [1] The process, which uses mercury amalgamation to recover silver from ore, was first used at scale by Bartolomé de Medina in Pachuca , Mexico , in 1554. [ 2 ]
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. [1] It is a form of extractive metallurgy that is used to obtain many metals such as iron , copper , silver , tin , lead and zinc .
To produce a forgeable product, a further process was needed (usually described as fining, rather than refining). From the 16th century, this was undertaken in a finery forge . At the end of the 18th century, this began to be replaced by puddling (in a puddling furnace ), which was in turn gradually superseded by the production of mild steel by ...
A typical smelt mill had an orehearth and a slaghearth, the latter being used to reprocess slags from the orehearth in order to recover further lead from the slag Further reading [ edit ]
[citation needed] Smelting with coal (or its derivative coke) was a long sought objective. The production of pig iron with coke was probably achieved by Dud Dudley around 1619, [90] and with a mixed fuel made from coal and wood again in the 1670s. However this was probably only a technological rather than a commercial success.
In operation, after the bloomery is heated typically with a wood fire, shifting to burning sized charcoal, iron ore and additional charcoal are introduced through the top. Again, traditional methods vary, but normally smaller charges of ore are added at the start of the main smelting sequence, increasing to larger amounts as the smelt progresses.
A concentration of 60 ppm would multiply out to 1.66 quadrillion tonnes over the 2.77 × 10 22 kg mass of the crust, [76] or over 90 million years' worth at the 2013 production rate of 18.3 MT per year. However, not all of it can be extracted profitably at the current level of technology and the current market value.
The ISASMELT process is an energy-efficient smelting process that was jointly developed from the 1970s to the 1990s by Mount Isa Mines (a subsidiary of MIM Holdings and now part of Glencore) and the Government of Australia's CSIRO. It has relatively low capital and operating costs for a smelting process.