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標題:
metallurgy and chemistry
發問:
How were changes made to the metals? Explain these changes by referring to the metal atoms.How did different physical processes make changes to metals to change the metal properties?How were different metals extracted from their minerals?What are the chemical equations for these reactions?What conditions were... 顯示更多 How were changes made to the metals? Explain these changes by referring to the metal atoms.How did different physical processes make changes to metals to change the metal properties?How were different metals extracted from their minerals?What are the chemical equations for these reactions?What conditions were necessary for these reactions?How were different alloys made?Why did the alloys have different physical properties?What properties of existing tools or weapons were enhanced by the different metallurgy technologies? 更新: is on iron, bronze and copper age
最佳解答:
鋅的提取方法&鋅的礦產 There are zinc mines throughout the world, with the largest producers being Australia, Canada, China, Peru and the U.S.A. Mines and refiners in Europe include Umicore in Belgium, Tara, Galmoy and Lisheen in Ireland, and Zinkgruvan in Sweden. Zinc metal is produced using extractive metallurgy. Zinc sulfide (sphalerite) minerals are concentrated using the froth flotation method and then usually roasted using pyrometallurgy to oxidise the zinc sulfide to zinc oxide. The zinc oxide is leached in several stages of increasingly stronger sulfuric acid (H2SO4). Iron is usually rejected as Jarosite or goethite, removing other impurities at the same time. The final purification uses zinc dust to remove copper, cadmium and cobalt. The metal is then extracted from the solution by electrowinning as cathodic deposits. Zinc cathodes can be directly cast or alloyed with aluminium. Electrolyte solutions must be very pure for electrowinning to be at all efficient. Impurities can change the decomposition voltage enough to where the electrolysis cell produces largely hydrogen gas rather than zinc metal.[6] There are two common processes for electrowinning the metal, the low current density process, and the Tainton high current density process. The former uses a 10% sulfuric acid solution as the electolyte, with current density of 270–325 amperes per square meter. The latter uses 22-28% sulfuric acid solution as the electrolyte with current density of about 1000 amperes per square meter. The latter gives better purity and has higher production capacity per volume of electrolyte, but has the disadvantage of running hotter and being more corrosive to the vessel in which it is done. In either of the electrolytic processes, each metric ton of zinc production expends about 3900 kW·h (14 MJ) of electric power.[6]
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