地质相关专业英语作业.doc

英译汉 原文： Aluminum Alternative processes for the treatment of ores other than bauxite have?been under consideration for many years. Of some importance is the recent?Alcoa smelting process which is claimed to require only about?10?kwh of?electrical energy per kg Al.?The alumina is converted to AlCl3?which is?electrolysed. The chlorine is recycled. Apart from the saving in energy?this new process avoids the problem associated with emission of fluorine? which give a lot of trouble in the Hall-Heroult process. Copper? Matte may contain between 20 and 60% Cu or exceptionally, higher. It?is transferred in the molten state to a Pierce-Smith converter?where it?is blown in successive batches to “white metal”(Cu2S)and then to??“blister copper” which is cast into slabs. Converter slag is recycled?through the smelter. Blister copper is about 98-99.5% pure. If there are?precious metals to be recovered it is further fire-refined and cast into?anodes for electrolytic refining. The precious metals collected in the?anode sludge along with S and Se and some insoluble?compounds of As、Sb?and Bi; soluble salts of Fe、Ni、Co、As、etc。Will accumulate in the?electrolyte and will contaminate the cathode copper if they are not held?to very low concentrations by continuously bleeding off a portion of the?electrolyte for chemical purification .Cathodes are re-melted to get rid?of hydrogen and adjust the oxygen to the level appropriate to the required?grade, and cast. In the absence of precious metals blister copper is?fire-refined to give a saleable product. Iron? Ore dressing: Large ore is crushed to about 30 mm and the -10 mm fraction?removed for sintering. Magnetic and heavy medium separation are?occasionally practiced on ores?in which iron is distributed as nodules?or otherwise as discrete particles. Magnetic separation may follow?magnetic roasting. Blending of ore mixes in bedding plants is now commonly?practiced either before charging direct or prior to sintering or?pelletizing. This has the