The extraction of metals from their ores, heat treatments and the production of alloys
اسلاید 1: MetallurgyThe extraction of metals from their ores, heat treatments and the production of alloys
اسلاید 2: Production of metalsMiningConcentrationMetal extraction
اسلاید 3: MiningFive main types of mining: Open cast miningUnderground miningOpen pit miningDredgingSolution mining
اسلاید 4: Open cast mining
اسلاید 5: Underground mining
اسلاید 6: Open pit mining
اسلاید 7: Dredging
اسلاید 8: Solution mining
اسلاید 9: Ore concentrationAlso called ore dressing, the aim is to increasethe amount of metal in each tonne of ore. Theore is crushed then ground and concentrated,the following methods may be used:Gravity concentrationFlotationMagnetic separationAmalgamation
اسلاید 10: Gravity concentrationSome ores are heavier than the waste. The ore is shaken by a jolting box, or similar, while wet. Particles will separate into layers depending on weight, the metal may be removed as a layer.
اسلاید 11: Flotation The fine particles of ore are swirled around in large tanks with air blown in and flotation agents added. The particles attach to the bubbles and float to the surface where the froth is skimmed off.
اسلاید 12:
اسلاید 13: Magnetic seperationIn the seperation of ores that have magnetic properties, the ore is ground and passed over a rotating drum. The drum has a magnet inside it which holds the magnetic ore particles as the waste falls outside the screen.The ore held on the drum can be released or scraped off.
اسلاید 14: Magnetic seperationhttp://www.youtube.com/watch?v=XZjPr8WZtas
اسلاید 15:
اسلاید 16: Metal extractionThe process of extracting metals fromconcentrates:Pyrometallurgy – furnace heat is used with a reducing agent (iron uses coke) and a flux to produce metal and slag waste.Hydrometallurgy – leaching dissolves ore in a solvent and then electrolysis is used to separate the metal.
اسلاید 17: Thermo-electrometallurgy. Aluminium can be extracted from salt or mineral mixtures by electrolysis. It uses a lot of electricity making it an expensive process. Blister copper is refined by electrolysis.
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