impurities

Control of Pests and crop Disease Agriculture is the single largest sector of India that provides the principal means of livelihood for over 58.4% of country’s population. It contributes approximately one-fifth of the total gross domestic product (GDP). Agriculture accounts for about 10% of the total export earnings and provides raw material to a large number of industries, however, low and volatile growth rates and the recent escalation of agrarian crisis in several parts of the Indian countryside are a threat not only to national food security but also to economic wellbeing of the nation as a whole. To satisfy ... Read more

Ore An ore is a special type of rock that contains a large enough amount of a particular mineral (usually a metal) to make it economically practical to extract that mineral from the surrounding rock. Not all minerals are found in a large enough amount in one location to make it worth it to remove the ore from the rock through a process known as mining. Ores can be mined in a number of ways, including strip mining as shown here at this uranium mine. If there is a large enough amount present, the rock will be extracted and processed in a ... Read more

Metallurgy of iron Iron is an important constituent of hemoglobin, which is in blood. Iron is the metal used most widely in industries and hence may be called the king of metals. It is the second most abundant metal after aluminum. Iron does not occur in native state, since it is oxidized easily. Ores of Iron Chemical Name Chemical formula Brown haematite or limonite Hydrated ferric oxide 2Fe2O3.3H2O Red haematite Anhydrous hematite Fe2O3 Iron pyrites Iron disulphide FeS2 Magnetite Triferric tetraoxide Fe3O4 Siderite Ferrous carbonate FeCO3 It is usually extracted from haematite and limonite.   Extraction of Iron Extraction of iron from its ore ... Read more

Metallurgy concentration, roasting, smelting Roasting It is a process wherein the ore is heated either alone or with some other material in excess of air below the fusion point of the ore. Usually, this method is used for sulphide ores. In roasting, definite chemical changes take place to form oxide or chloride of the metal. Ores of metals like zinc, lead, copper and nickel, when roasted in air, are converted to their oxides. Ores of some metals like lead may get partially oxidized and converted to sulphate. In such case, it is called sulphating roasting or partial roasting. Ores of ... Read more