Major minerals

In only rare cases does one find minerals or metals in pure form (such as gold). The earth s surface consists of a variety of minerals (major components iron, silica oxides, calcium, magnesium, aluminum, chromium, cobalt, and titanium). 

Ni comprises between 5 and 50% of the weight of meteorites, and an abundance of nickel helps to distinguish meteorites from other minerals. Major deposits of nickel ores are located in Australia, Canada, Cuba, Indonesia, New Caledonia, and Russia. Ores of commercial importance are either oxidic (e.g., laterite ores, which con-... 

Compound feeds are designed to meet the nutritional needs of specific animals and encourage a predetermined level of production. Regarding the optimal nutrient content for required animal responses, the grain-dominated and therefore one-sided diets must contain adequate energy and protein, as well as sufficient vitamins and minerals (major elements, trace elements) in feed stable preparations. 

In mineralogy, the technique of separating particles of minerals from water media are of great interest. In only rare cases does one find minerals or metals in pure form (such as gold). The earth surface consists of a variety of minerals (major components are iron-silica-oxides-calcium-magnesium-aluminum-chromium-cobalt-titanium). Minerals as found in nature are always mixed with different kinds (e.g., zinc sulfide and felspar minerals). In order to separate zinc sulfide, one suspends the mixture in water and air bubbles are made to achieve separation. This process is caWeAflotation (ore [heavier than water] is floated by bubbles). 

Many refractories are derived directly from natural minerals, but synthetic materials are also widely use. Clays, espeeially those having inherent temperature resistance, are the oldest and most eommon of the naturally occurring refractory minerals. Major natural refi actoiy materials are kaolin, chromite, bauxite, zirconia, and magnesite. These are often marketed under specific trade names. Refractory materials may be acid, such as silica, or basic, such as magnesite or bauxite, for use in aeid- or basic-process steel furnaces. Graphite and chromite are generally considered neutral refractories. 

Physical properties. Majority are liquids except p toluidine and 1- and 2-naphthylamine. All are colourless when pure, but rapidly darken on exposure to air and light. All are very sparingly soluble in water, but dissolve readily in dilute mineral acids (except the naphthyl-amines, which are only moderately soluble in adds). They form colourless crystalline salts e.g., CjHjNH2,HCl) which are soluble in water these aqueous solutions usually have an add reaction owing to hydrolysis, and give the reactions of both the amine and the acid from which they are derived. Addition of alkali to the acid solution liberates the amine. 

Secondary and Micronutrients in Fertilizers The great majority of farm fertilizers are produced, marketed, and appHed with regard only to the primary plant nutrient content. The natural supply of secondary and micronutrients in the majority of soils is usually sufficient for optimum growth of most principal crops. There are, however, many identified geographical areas and crop—soil combinations for which soil appHcation of secondary and/or micronutrient sources is beneficial or even essential. The fertilizer industry accepts the responsibiHty for providing these secondary and micronutrients, most often as an additive or adjunct to primary nutrient fertilizers. However, the source chemicals used to provide the secondary and micronutrient elements are usually procured from outside the fertilizer industry, for example from mineral processors. The responsibiHties of the fertilizer producer include procurement of an acceptable source material and incorporation in a manner that does not decrease the chemical or physical acceptabiHty of the fertilizer product and provides uniform appHcation of the added elements on the field. 

Although the size separation/classification methods are adequate in some cases to produce a final saleable mineral product, in a vast majority of cases these produce Httle separation of valuable minerals from gangue. Minerals can be separated from one another based on both physical and chemical properties (Fig. 8). Physical properties utilized in concentration include specific gravity, magnetic susceptibility, electrical conductivity, color, surface reflectance, and radioactivity level. Among the chemical properties, those of particle surfaces have been exploited in physico-chemical concentration methods such as flotation and flocculation. The main objective of concentration is to separate the valuable minerals into a small, concentrated mass which can be treated further to produce final mineral products. In some cases, these methods also produce a saleable product, especially in the case of industrial minerals. 

With few exceptions, extender pigments can be classified as commodity chemicals. They are manufactured in large quantities with less sophisticated production methods than most pigments. Whereas the majority of pigments is prepared synthetically, extender pigments are mainly manufactured by the beneficiation of natural minerals. Based on chemical composition, extender pigments are carbonate, sulfate, siUca-based, and siUcate-based compounds. 

Reasonably Assured Resources (RAR) refers to uranium in known mineral deposits of size, grade, and configuration such that recovery is within the given production cost ranges with currentiy proven mining and processing technology. The majority of these resources are found in AustraUa, Brazil,... 

The efficiency of the weathering of rocks in using carbonic acid produced in the carbon cycle is affected by various hydrologic, environmental, and cultural controls. The fact that the principal anion in fresh surface water worldwide almost always is bicarbonate attests to the overriding importance of this process. Exceptions are systems in which evaporite minerals are available for dissolution by groundwater or where human activities are major sources of sulfate or chloride inflow. 

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