Limestone and Lime

Limestone and Lime Limestone is an odorless white, grayish-white or tan material that ranges from sized stone to a granular powder. It is often described as the most versatile mineral. Limestone is the name given to any rock formed which consists mostly of calcium carbonate (CaCO3), but to geologists, limestone is only one of several types of carbonate rocks. These rocks are composed of more than 50 % carbonate minerals, generally containing the mineral calcite (pure CaCO3). Limestone is a sedimentary rock composed mainly of CaCO3. It is formed by the deposition either of the skeletons of small creatures and/or plants (organic limestones), or by chemical precipitation, or by deposition of fragments of limestone rock, on the beds of seas and lakes. Limestones are contaminated to a greater or lesser extent by the deposition of sand or clay which is the source of the impurities usually found in the limestone. Generally there is a difference in quality in a deposit from one layer to the next. The purest carbonates and the most suitable from the production point of view tend to be the thick bedded type. Carbonate deposits may be found in horizontal layers as deposited, or at an angle from the horizontal due to earth movements. They will vary in density, hardness and chemical purity. Limestone rocks are extremely common and make up a significant portion of the crust of the Earth. They serve as one of the largest carbon repositories on our planet. The properties of limestone make it one of the most widely used minerals. Some limestones may contain small percentage of magnesium carbonate (MgCO3). These limestones are known as dolomitic limestones. Impurities (such as clay, sand, organic remains, iron oxide, and other materials) cause limestones to show different colours, especially with weathered surfaces. Limestone may be crystalline, clastic, granular,...

Standardization and the Process of Standardization...

Standardization and the Process of Standardization There is practically no economic activity nowadays which is not outlined, whether partly or totally, by the process of standardization. The worldwide acceptance of standardization is closely related to the economic globalization and the transformation of regulatory processes at the national, regional, and international levels. Standardization helps in reducing, simplifying, and organizing matters which are apt to become diversified, complicated, and chaotic if left uncontrolled. It is the process of formulating, issuing, and implementing standards. Standardization creates value at many levels. The output of the process of standardization is the creation of standards. The development of standardization as an engineering activity was pioneered in 1793 by Eli Whitney. Standardization of screw threads by Sir Joseph Whitworth dates back to 1841. Other instances of early standardization can be found during the emergence of the railway industry. Mass production became possible only through standardization. By the turn of the 19th century, standardization was already recognized in industrialized countries as a powerful tool to increase productivity through interchangeability and reduction of variety. The early part of the 20th century saw the establishment of several standardization organizations, which turned standardization into an organized and ongoing effort for industrial applications. By 1928, national standards organizations had been established in 16 industrialized countries. After the First World War, standardization, through reduction in variety, was established as a useful management tool for reducing costs. Some three decades later, seller market conditions, which prevailed for some time after the Second World War, put consumer interest under threat. To safeguard this interest and to meet the rising demand for standards for finished products, standardization activities increased in various countries, with the additional support and involvement of government and industry Definitions of standardization The standardization process is often...

Limestone – Its Processing and Application in Iron and Steel Industry Jul07

Limestone – Its Processing and Application in Iron and Steel Industry...

Limestone – Its Processing and Application in Iron and Steel Industry Limestone is a naturally occurring and abundant sedimentary rock consisting of high levels of calcium carbonate (CaCO3) in the form of the mineral calcite. Some limestones may contain small percentage of magnesium carbonate (MgCO3). These limestones are known as dolomitic limestones. Limestone is also a very important industrial mineral. Its chemical properties make it a valuable mineral for a wide range of industrial/manufacturing uses. Limestone is also one of the vital raw materials used in production of iron and steel. Limestone, by definition, is a rock that contains at least 50 % of CaCO3 in the form of calcite by weight. There can be small particles of quartz (silica), feldspar (alumino-silicates), clay minerals, pyrite (iron sulphide), siderite (iron carbonate), and other minerals associated with the limestone. All limestones contain at least a few percent other materials. The Impurities in limestone can consists of silica (SiO2), alumina (Al2O3), iron oxide (Fe2O3), sulphur (as sulphides or sulphates), phosphorus (P2O5), potash (K2O), and soda (Na2O). Silica and alumina are the main impurities of limestone. The limestone which is used in ironmaking is required to contain at least 85 % of calcium carbonate and a low percentage of alumina. Similarly limestone which is used for steelmaking is required to contain at least 92 % of calcium carbonate and a very low percent of impurities especially the silica percentage. The main uses of limestone in iron and steel industry are (i) as a fluxing material, and (ii) other usage which consists of desulphurizing agent, coating of moulds of pig casting machine, neutralizing of acidic water, water treatment, waste water(effluent) treatment, flue gas treatment, and sludge and sewage treatment. It is also a component of synthetic slag. Limestone is...