zinc refining is the process of purifying zinc to special high grade shg zinc, which is at least 99.995% pure. this process is not usually required when smelting of zinc is done through electrolysis processes, but is needed when zinc is produced by pyrometallurgical processes, because it is only 98.5% pure.
english: zinc smelting flowchart, adapted from us epa document. the top path is the pyrometallurgical process of smelting zinc and the bottom path is the electrolytic process. source classification codes are given in parentheses.
in metallurgy, refining consists of purifying an impure metal. it is to be distinguished from other processes such as smelting and calcining in that those two involve a chemical change to the seven trust material, whereas in refining, the final material is usually identical chemically to the original one, only it is purer. the processes used are of many types, including pyrometallurgical and .
the choice of process depends on the composition of the ore and other factors. typical steps include mining, crushing and grinding of ore, sometimes followed by froth flotation and separation of the metal using pyrometallurgical processes smelting or roasting or in a few cases e.g. when the ore is rich in precious metals by hydrometallurgical processes.
another pyrometallurgical process is flash smelting. then zinc oxide is obtained, usually producing zinc of lesser quality than the hydrometallurgical process. zinc oxide treatment has much fewer applications, but high grade deposits have been successful in producing zinc from zinc oxides and zinc carbonates using
this process is usually expensive to operate due to the fuel requirement of the dryers. other processes. many mechanical plants also incorporate hydrometallurgical or pyrometallurgical processes as part of an extractive metallurgical operation.
hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. hydrometallurgy involve the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual materials. processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. hydrometallurgy is typically divided into three general areas: leaching solution concentration and purification meta
electrometallurgy is usually the last stage in metal production and is therefore preceded by pyrometallurgical or hydrometallurgical operations. the electrolysis can be done on a molten metal oxide smelt electrolysis which is used for example to produce aluminium from aluminium oxide via the hall-hérault process. electrolysis can be used as .
pyrometallurgical processes are generally grouped into one or more of the following categories: citation needed calcining, roasting, smelting, refining. most pyrometallurgical processes require energy input to sustain the temperature at which the process takes place. the energy is usually provided in the form of combustion or from electrical heat.
alternatively to the pyrometallurgical processes, very pure lead can be obtained by processing smelted lead electrolytically using the betts process. anodes of impure lead and cathodes of pure lead are placed in an electrolyte of lead fluorosilicate pbsif 6 . once electrical potential is applied, impure lead at the anode dissolves and plates .
pyrometallurgical processes that involve gases and solids are typified by calcining and roasting operations. processes that produce molten products are collectively referred to as smelting operations.
the parkes process is used to separate silver or gold from lead. finally, the molten lead is refined. pyrometallurgical methods are usually used to remove the remaining non-lead components of the mixture, for example the betterton-kroll process and the betts electrolytic process. the non-lead metals are usually sold to other metal processing plants.
nickel-cobalt lateritic ores can be treated by either hydrometallurgical processes or pyrometallurgical processes, such as matte or ferronickel smelting, which require the entire ore to be melted and the metal values to be separated from the residual components of the ore. the hydrometallurgical process for laterite ore can use sulfuric acid or .
wikimedia commons has media related to metalworking. the following processes are applied to metals and alloys, in order to change their shape, to alter their structure or composition, or some combination of these. the main article for this category is metallurgical processes. this category has the following 7 subcategories, out of 7 total.