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Zinc Smelting
Zinc smelting is the process of converting zinc concentrates (ores that contain zinc) into pure zinc. Zinc smelting has historically been more difficult than the smelting of other metals, e.g. iron, because in contrast, zinc has a low boiling point. At temperatures typically used for smelting metals, zinc is a gas that will escape from a furnace with the flue gas and be lost, unless specific measures are taken to prevent it. The most common zinc concentrate processed is zinc sulfide,. which is obtained by concentrating sphalerite using the froth flotation method. Secondary (recycled) zinc material, such as zinc oxide, is also processed with the zinc sulfide.. Approximately 30% of all zinc produced is from recycled sources. Methods There are two methods of smelting zinc: the pyrometallurgical process and the electrolysis process. Both methods are still used. Both of these processes share the same first step: roasting. Roasting Roasting is a process of oxidizing zinc sulfide co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity ( electrowinning). Zinc is an essential trace element for humans, animals, plants and for microorganisms and is necessary for prenatal and postnatal development. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled ''d'' or ''f'' electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate. Cadmium occurs as a minor component in most zinc ores and is a byproduct of zinc production. Cadmium was used for a long time as a corrosion-resistant plating on steel, and cadmium compounds are used as red, orang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avonmouth Docks
The Avonmouth Docks are part of the Port of Bristol, in England. They are situated on the northern side of the mouth of the River Avon, opposite the Royal Portbury Dock on the southern side, where the river joins the Severn estuary, within Avonmouth. Accessible via a long and wide lock, today the docks are one of the UK's major ports for chilled foods, especially fruit and vegetables. Land-side freight access and distribution is via either the M5 motorway or the Henbury Loop Line, whilst rail-passenger access is via Avonmouth railway station on the Severn Beach Line. Background Bristol Harbour had always been a major centre of trade within the wider UK economy, due to its strategic location to the west of the country, allowing access to both the Atlantic Ocean and the Mediterranean. Coastal trade was also important, with the area called "Welsh Back" concentrating on trows with cargoes from the Slate industry in Wales, stone, timber and coal. However, by the 18th century the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
