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Platinum mining and production entails extreme difficulties. Extraction, concentration and refining of the metal require quite complex processes that may take up to six months. It is estimated that in order to produce a single ounce of platinum a volume of 7 to 12 tonnes of ore must be processed.
Usually platinum mining is underground although there is some open-pit mining. The extraction stage of platinum is labour-intensive. Miners bore holes with hand-held pneumatic drills and blast them with explosives. Afterward ore is removed and transported to the surface. Normally, mill-head grades of BIC (the measure for the PGM content for the ore) are between 4 and 7 grams per tone.
Once in the surface, ore is crushed and milled in order to obtain smaller rock particles and to expose the minerals which contain the PGM. In a "froth flotation" process these particles are mixed with water and special reagents, before air is pumped through the liquid. As a result bubbles to which the PGM-containing particles adhere are created and they float to the surface. This flotation concentrate is removed as a soapy froth. The pgm content, at this stage, varies between 100 and 1000 grams per tonne. In order to obtain the maximum amount of pgm, the material, which fails to float, goes through a second milling and flotation process.
Concentration
The flotation concentrate, once dried, is smelted in an electric furnace at temperatures that may be over 1500o C. Then, a matte which contains the valuable metals is separated from the unwanted minerals that are discarded. After being periodically tapped, air is blown through this matte in the converters with the purpose of removing iron and sulfur. Now the "converter matte" PGM content is higher than 1400 grams per ton.
Refining
At a base metals refinery, nickel, copper and cobalt are separated from the PGM using standard electrolytic techniques. Residues in which PGM are concentrated are obtained. The last stage of the platinum production requires the separation and purification of the platinum group metals, apart from gold and small amounts of silver. This is the most difficult and intricate part of the process, combining solvent extraction, distillation and ion-exchange techniques. Finally, the soluble metals, which dissolve in hydrochloric acid and chlorine gas, are obtained: first gold and then palladium and platinum. The insoluble PGM are the last to be extracted. Platinum
Recycling
Platinum is recovered from a diversity of post-consumer scrap. There is not a universally applicable technique for this recycling and it usually depends on the proportion of platinum in the scrap. The largest part of platinum recycling comes from the autocatalyst sector. Normally, in order to fuse the catalyst substrate and dissolve the PGM, it is melted at a very high temperature with iron or copper. The obtained alloy is leached to dissolve the copper or iron, extracting a PGM concentrate which is refined in a process similar to that described above.
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Platinum Mining - CommodityMine |
Topical Platinum Mining Links. Top platinum producing companies: Anglo American Platinum, ... Platinum Mining Companies. Platinum companies from InfoMine db ...
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Northam Platinum - Mining Charter |
This Charter will apply to mining companies in respect of their involvement in beneficiation ... Northam Platinum Limited Registration number 1977/003282/06 ...
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