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MINING AND PROCESSING OF METALS

Before we examine the structures and properties of metallic classes in further detail, it is useful to consider the natural sources of the metals, generally as oxide and/or silicate-based mineral formations. If the mineral deposit contains an economically recoverable amount of a metal, it is referred to as an ore. The waste material of the rock formation is known as gangue, which must be separated from the desired portion of the ore through a variety of processing steps. [Pg.87]

Most metals are obtained through physical and chemical modiflcation of ores that contain a sufficiently high concentration of the desired metal. Table 3.1 lists some metals, regions of their primary occurrence, and some applications for the metallic materials. Quite often, the processing steps used to isolate and purify metals from ores have a significant impact on the overall microstructure, which will affect the physical properties of the materials fabricated from them. [Pg.88]

Of course, once the ore is obtained from its deposit, the actual work of extracting the desired metal has yet to be accomplished. In addition to metals, a variety of other substances comprise natural minerals. Since aluminum and silicon are the most prevalent elements in the Earth s crust, most of the metals exist naturally as aluminates, silicates, or aluminosilicates. The most common minerals are feldspars and clays. These materials have been used since ancient times for the production of materials such as pottery, brick, and china. An example of a feldspar is K2Al2Si60i6, which corresponds to a mixture of potassium superoxide, alumina, and silica (K20-Al203 6Si02). Upon contact with water and carbon dioxide, a weathering reaction results in kaolinite, an aluminosilicate clay (Eq. 1). However, in addition to these oxidized sources of metals, there are substances such as alkaline carbonates, sulfates, phosphates, as well as organic matter that need to be removed to yield the desired metal. As you would expect, the yield for this process is quite low ores typically possess less than 1 % of the desired metal  [Pg.88]

Li Batteries, glasses, aerospace components US, Chile, China, Argent [Pg.89]

Na Dyes, pigments, lamps, photoelectric cells Chile, Peru, US [Pg.89]

K Nuclear reactors, respiratory equipment Ger., Can., France, Spain [Pg.158]


Occupational Protection and Radiation Consideration. The main adverse factor during the mining and processing of uranium and uranium-containing minerals is airborne dust. Personal protection should be used. Finely divided uranium metal, some alloys, and uranium hydride are pyrophoric, therefore such materials should be handled in an inert atmosphere glovebox. [Pg.1650]

Aluminum occurs naturally in soil, water, and air. It is redistributed or moved by natural and human activities. High levels in the environment can be caused by the mining and processing of its ores and by the production of aluminum metal, alloys, and compounds. Small amounts of aluminum are released into the environment from coal-fired power plants and incinerators. Virtually all food, water, and air contain some aluminum, which nature is well adapted to handle. [Pg.21]

The oil shale in southwestern Montana occurs in structurally complex folded and faulted mountains. Mining and processing of large quantities of these shales would require difficult subsurface methods. Economical exploitation will depend upon the development of extraction technology that may require the recovery of the multiple resources of hydrocarbons, phosphorous, and the other metals. [Pg.226]

Jinzu Valley, Japan. One of the most infamous cases of contaminated land and health occurred in Japan and the effects were most prominent immediately after the Second World War. Around the end of the 19th century, soils in the Jinzu River basin, part of the Toyama prefecture, became contaminated with cadmium as a result of activities upstream at the Kamioka mines. The main activity at this mine was the mining and processing of zinc (cadmium is often associated with zinc ores) with the result that wastewater rich in heavy metals was discharged into the Jinzu River. Contaminants from this industry moved down-stream and caused contamination of soils in paddy fields as a result of abstraction of river water into fields in order to cultivate the local rice crop. Under favourable conditions, cadmium can be a fairly mobile heavy metal, particularly in soils with low pH, and increases in soil cadmium can often result in an increase in the uptake of cadmium by plants. This in turn results in an increase in dietary exposure and the consumption of contaminated agricultural crops can be a major pathway of human exposure. [Pg.81]

The primary sources of Al exposure for the human and their relative contributions to daily intake are shown in Table 3.1. Concurrent consumption of citrate enhances Al absorption and tissue distribution, and in people with renal function increases its elimination. Antacids and allergy immunotherapy can provide daily Al exposures of up to 5000 and 0.007-0.040 mg in adults, respectively (Yokel and McNamara 2001). Industrial Al exposure during Al ore mining and processing, scrap metal recovery, production and use of Al compounds... [Pg.646]

A major consequence of the activities associated with the exploitation of mineral deposits (i.e., exploration, the development of mines and processing facilities, the extraction and concentration, which is also called beneficiation, of ores containing the desired minerals, and the decommissioning or abandonment of mine facilities) is the production of extremely large volumes of unwanted materials. Waste volumes vary from ca. 30% of the mass of the ore in the case of gypsum and other non-metals, to about 50% for base metals to more than 80% for strip-mined... [Pg.405]

Cadmium is an extremely toxic metal that finds its way into the aqueous environment as a result of some human activities. A major cause of cadmium pollution is zinc mining and processing, because natural deposits of ZnS ores usually also contain CdS. During the processing of these ores, highly insoluble cadmium sulfide ( sp = 7.9 X 10 ) maybe converted into considerably less insoluble cadmium hydroxide (.E p — 7.2 X 10" ). What mass of Cd (OH)2 will dissolve in l.OOx lO L of an aqueous solution ... [Pg.1313]

Another important consideration pertains to the metal content of the deposit. A deposit with a content of iron of about 20% can have little value as an iron ore since there are several deposits with 30-50% iron. Earlier, a copper ore with a minimum of 5% copper was regarded or accepted as a copper ore. However, today, thanks to advancements in technology, rocks with as little as 0.5% copper are mined and processed economically despite the fact that the price of copper, in comparison with those of some other metals, might be showing a downward trend. It is possible that in the future, other resources, which are not considered to be worth exploiting today (such as the manganese nodules or the clays), would become acceptable ores for manganese, copper, nickel, cobalt, and aluminum. [Pg.38]


See other pages where MINING AND PROCESSING OF METALS is mentioned: [Pg.87]    [Pg.88]    [Pg.90]    [Pg.92]    [Pg.94]    [Pg.96]    [Pg.98]    [Pg.547]    [Pg.157]    [Pg.159]    [Pg.161]    [Pg.163]    [Pg.165]    [Pg.167]    [Pg.169]    [Pg.171]    [Pg.173]    [Pg.175]    [Pg.288]    [Pg.87]    [Pg.88]    [Pg.90]    [Pg.92]    [Pg.94]    [Pg.96]    [Pg.98]    [Pg.547]    [Pg.157]    [Pg.159]    [Pg.161]    [Pg.163]    [Pg.165]    [Pg.167]    [Pg.169]    [Pg.171]    [Pg.173]    [Pg.175]    [Pg.288]    [Pg.106]    [Pg.336]    [Pg.199]    [Pg.72]    [Pg.306]    [Pg.672]    [Pg.366]    [Pg.202]    [Pg.336]    [Pg.4562]    [Pg.672]    [Pg.199]    [Pg.1416]    [Pg.122]    [Pg.20]    [Pg.216]    [Pg.171]    [Pg.162]    [Pg.286]    [Pg.3]    [Pg.38]   


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