Silica and its role in the production of iron and steel...

Silica and its role in the production of iron and steel Silicon, the element, is the second most abundant element in the earth’s crust. Silica is the scientific name for a group of minerals made of silicon and oxygen. It is one of the most abundant oxide materials in the earth’s crust and is found in most mineral deposits found on the earth. It is the starting material for the production of ceramics and silicate glasses. Silica (from the Latin word ‘silex’), is an oxide of silicon. It is a compound made up of silicon and oxygen atoms and has the chemical formula SiO2. It occurs commonly in nature as sandstone, silica sand or quartzite. It is the most frequently found in nature as quartz (SiO4). It is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound in several minerals. Silica occurs in a variety of crystalline modifications and also as an under-cooled melt called quartz glass. The crystal structure of the individual SiO2 modifications can differ widely, so that distinct density changes occur during transformation. This is of great importance during heating and cooling because of the change in the volume. Silica can be a naturally occurring substance, like quartz, or it can result from human activities. It occurs in many forms. It can exist in an amorphous form (vitreous silica) or in a variety of crystalline forms. Amorphous silica is found in nature (e.g., diatomaceous earth and plants), as well as in synthetic materials. In amorphous silica, the silicon and oxygen atoms are not arranged in any particular pattern. Amorphous forms of silica have a random pattern while in crystalline silica, atoms of silicon and oxygen are arranged in a repeating, three dimensional pattern which is known as crystal lattice. Crystalline silica...

Management of Workplace Activities...

Management of Workplace Activities Workers are the employees of the organization who physically carry out the work at the workplace. To perform efficiently and in a professional manner workers need knowledge, capability, and many qualities and traits.  For doing the work at the workplace, workers work with various tools, equipments, instruments, implements and processes.  The performance of the organization depends on how efficient the workers are at their workplace. Further, healthy, well trained, knowledgeable, disciplined, motivated, safe, alert, honest, and hardworking workers manage their workplaces in a manner which make them more productive. The traits, which the workers need for efficiently managing the activities at the workplace, include teamwork, integrity, commitment, and work ethic. Workplace is the place where a worker performs his activities. There need to be dynamic alignment of workplace activities with the work environment for efficiency, peak performance, and reduction in the costs. In a way, what is workplace for a worker is very much similar to what is an organization for a management. The performance of the worker depends on how he manages his workplace activities. He is required to manage the workplace activities (Fig 1) ably, strongly, and proficiently to be productive. Workers who manage the workplace activities well make a difference in the workplace and have a voice, a say in how the work is done. Fig 1 Management of workplace activities A worker to be professional is to conduct himself with responsibility, accountability, and excellence. It means proper planning of the workplace activities along with communicating effectively and appropriately and always finding a way to be productive. It also means managing of available resources at the workplace efficiently. The worker is required to be ethical, team oriented, and to possess strong interpersonal and problem solving skills. Main...

Steelmaking in Induction Furnace May24

Steelmaking in Induction Furnace...

Steelmaking in Induction Furnace Coreless induction furnaces have been used in the ferrous industry for over 50 years and are now one of the most popular means of melting and holding ferrous materials. Induction melting had dramatic growth during the 1960s based on line frequency technology, and later with the large-scale introduction of medium frequency power supply during the 1980s. Making of mild steel in the induction furnace was first experimented during early 1980s and it gained popularity when the production of sponge iron utilizing coal based process of rotary kilns became popular. Induction furnace is a type of electric melting furnace which uses electric current to melt metal. The principle of induction melting is that a high voltage electrical source from a primary coil induces a low voltage, high current in the metal (secondary coil). Induction heating is simply a method of transfer of the heat energy. Two laws which govern induction heating are (i) electromagnetic induction, and (ii) the joule effect. Coreless induction furnace comprises a relatively thin refractory crucible encircled by a water cooled copper coil excited from a single AC supply. When the coil is energized, the fluctuating axial magnetic field causes a current to flow in electrically conducting pieces of charge material within the crucible. The power induced in the charge depends on the physical properties of the material, the flux linking it and its geometric shape. Dependent on the resistivity of the material being melted, the coreless induction furnace converts electrical energy to heat the charge at an efficiency of between 50 % and 85 %, although furnace efficiency is further reduced by thermal losses from radiation from the melt surface and conduction through the furnace lining. Medium frequency induction furnaces which are commonly used for steelmaking use...