Metals extraction from ores

Elemental mercury is used industrially in electric lamps and switches, gauges and controls (e.g. thermometers, barometers, thermostats), battery production, nuclear weapons production, and the specialty chemical industry, including the production of caustic soda. Because elemental mercury has a high affinity for gold and silver, it has been, and continues to be, used in precious metal extraction from ore. Elemental mercury has been used for over one hundred years in mercury-silver amalgam preparations to repair dental caries. Mercury continues to be used in folk remedies and in certain cultural practices, with unknown public health implications. 

GaUium(III) chloride is used to prepare other gaUium salts and in solvent extraction. The chloride is highly soluble in solvent ether. This high solubility of metal chloride in ether allows metal extraction from ore. 

The world lead production at the beginning of the year 2000 amounted to 6 million tons/year, with 60% of it coming from secondary lead, especially from spent accumulators. The production of secondary lead started a few decades ago, affecting the traditional lead market based on metal extracted from ore. Such dramatic change can be explained as follows. 

For metal clean-up applications (and in metal extraction from ores) positively charged metal ions are reduced at the cathode to their zero oxidation state. The metal then precipitates, usually onto the electrode, and can be collected. This process is known as electrowinning and is the sim-... 

AH metals come originally from natural deposits present in the earth s cmst. These ore deposits result from a geological concentration process, and consist mainly of metallic oxides and sulfides from which metals can be extracted. Seawater and brines are another natural source of metals, eg, magnesium (see Chemicals frombrine Magnesium and magnesium alloys Ocean raw materials). Metal extracted from a natural source is called primary metal. 

Rare earth (RE) is a generic name for 14 metallic elements of the lanthanide series. These elements have similar chemical propenies and are usually supplied as a mixture of oxides extracted from ores such as bastnaesite or monazite. 

Platinum family metals preparation. The platinum metals (with gold and silver) are commonly found together, and a number of schemes are in current use for their separation. Platinum metals not only are extracted from ores but, due to their high value, are also recovered from a wide range of industrial residues such as Pt, Rh gauze catalysts, defective components from glass industries, etc. 

Local stress is a potent cause of corrosion and may occasionally lead to distressing events, e.g., the falling off of a car door. Metals extracted from their ores may have been at one stage in a liquid state. They cool and solidify, thus introducing local stress points. Further, even in a solid that has not been subjected to stresses in its treatment, stress develops at its dislocations. 

Refers to the overall processes by which metals are extracted from ores. Metathesis Reactions... 

Copper is widely distributed in Nature as metal, in sulfides, arsenides, chlorides, carbonates, and so on. It is extracted from ores, usually by wet processes, for example, by leaching with dilute sulfuric acid, or by solvent extraction using salicylal-doximes and similar ligands. Copper is refined by electrolysis. 

Metal extracted from copper ore which is once fused and separated from its refuse. 

The metals in a mineral caimot always be extracted from the mineral in an economically feasible way. Sometimes, the concentration of the mineral in the surrounding rock is too low for the mineral to be mined at a reasonable cost. The cost of energy needed to mine, extract, or purify the metal also may be too high. If the metal can be extracted and purified from a mineral at a reasonable profit, the mineral is called an ore. Several ores and the metals extracted from them are shown in Figure 26-17. 

Hydrometallurgy refers to the application of aqueous solutions for metal recovery from ores, and has been practiced for copper recovery for many years. The original impetus for solution methods for copper extraction before the development of froth flotation technology was the existence of large ore bodies of low copper content which were uneconomic to work using... 

Metals are important resources and have a wide range of applications. Metals are often extracted from ores. Once the ore is mined, the metals must be extracted, usually by chemical or electrolytic reduction. Pyrometallurgy uses high temperatures to convert ore into raw metals, while hydrometalluigy employs aqueous chemistry for the same purpose. The methods used depend on the metal and their contaminants. Most metals are obtained by hydrometallurgical processes such as aqueous acids or alkalis are predominantly used to dissolve the metal oxides, sulfides, or silicates. Electrowinning and solvent extraction are frequently used to recover and concentrate the metals. A limited number of high-temperature molten salts have also been used for the recovery of refractory metals, such as titanium and aluminum, from their ores... 

The most important mineral is beryl, Be3Al2(Si03)6, which often occurs as large hexagonal prisms. The extraction from ores is complicated.5 The metal is obtained by electrolysis of BeCl2 but, since the melt has very low electrical conductivity (about 10-3 that of NaCl), sodium chloride is also added. 

Reports on the extraction of metallic gold from ores or from laboratory residues have been published. 

Take gold for example. Typically, metallic gold extracted from ore is only two percent of the available gold. The other ninety percent is in an ORME state. This provides plenty of potential for technical recovery, or ORMIC recovery. It also has major ramifications for the supply and demand equation in the gold market. 

How are metals extracted from their minerals and ores ... 

Many metals can be extracted from ores that are mainly carbonates. As mentioned earlier in the chapter, even in the Middle Ages mining engineers were able to test rocks for the presence of carbonates using hydrochloric acid. In school chemistry, many salts can be made simply from carbonates that are insoluble in water. To a dilute solution of the acid, the carbonate is added in small portions until there is no more gas given off and an obvious excess is seen. 

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