Materials needed for Steel Production in Basic Oxygen Furnace Oct16

Materials needed for Steel Production in Basic Oxygen Furnace...

Materials needed for Steel Production in Basic Oxygen Furnace The following types of materials are needed for the production of liquid steel in the basic oxygen furnace (BOF) steelmaking process (Fig 1). Basic raw materials such as hot metal, scrap, and lime etc. Secondary raw materials such as deoxidizers and carburizers. Utility gases such as oxygen, nitrogen, and argon etc. Refractories and Refractory materials such as lining material, gunning material and patching materials etc. Consumable probes such as temperature probes and sampling probes etc. Cooling water for cooling of oxygen blowing lance and exhaust gases. Fig 1 Materials needed for the production of steel in basic oxygen furnace Basic raw Materials The basic raw materials needed for making steel in the BOF converter include (i) hot metal from the blast furnace, (ii) steel scrap and/or any other metallic iron source, (iii) iron ore, and (iv) fluxes.  Scrap, charged from a scrap box, is the first material to be charged into the BOF. The hot metal is then poured into the converter from a hot metal charging ladle, after which the blowing with oxygen gas is started. The fluxes, usually in lump form, are charged into the BOF through a bin system after the start of the oxygen blow. The fluxes can also be injected into the furnace in powder form through bottom tuyeres. The composition and amounts of basic raw materials used in the BOF converter vary from one steel melting shop to another, depending on their availability and the economics of the process. The hot metal or liquid iron is the primary source of iron units and energy. Hot metal is received from the blast furnaces in either open top or torpedo cars. In case of open top ladles, hot metal is poured...

Chains and their Types...

Chains and their Types A chain is a series of connected links which are typically made of metal. A chain may consist of two or more links. Chains can be classified in many different ways. From a theoretical viewpoint, a chain is a continuous flexible rack engaging the teeth on a pair of gears. A sprocket, being a toothed wheel whose teeth are shaped to mesh with a chain, is a form of gear. From a viewpoint based on its history and development, chain is a mechanical belt running over sprockets that can be used to transmit power or convey materials. Chains have the following four basic functions. Transmit power. Convey objects or materials. Convert rotary motion to linear motion, or linear motion to rotary motion. Synchronize or to time motion Chains have the following general advantages over other equipment intended to do the same functions. Have controlled flexibility in only one plane. Have a positive action over sprockets, no slippage takes place. Carry very heavy loads with little stretch. Efficiency of a chain joint passing around a sprocket approaches 100 % because of the large internal mechanical advantages of links in flexure. Provide extended wear life because flexure takes place between bearing surfaces with high hardness designed specifically to resist wear. Can be operated satisfactorily in adverse environments, such as under high temperatures or where they are subject to moisture or foreign materials. Can be manufactured from special steels to resist specific environments. Have an unlimited shelf life. They do not deteriorate with age or with sun, oil, or grease. Types of chains From industry stand point, the major types of chains are (i) roller chains, (ii) leaf chains, (iii) silent chains, (iv) engineering steel chains, and (v) flat-top chains. (Fig 1) Fig 1 Types...

Managing Fire related Processes in a Steel...

Managing Fire related Processes in a Steel Plant Steel plant is a fire hazard industry. In a steel plant heat meets flammable materials almost everywhere. People, plant and equipments, and production all are exposed to high risk of fire almost in every area of the plant. Fires result into service disruptions and production downtimes. It causes damage to the plant and equipments and burn injuries, many times fatal injuries to the people. Even a small fire can paralyze the entire plant with disastrous economic damage. The fire risk in the steel plant is immense. There are processes with very high temperatures and at many places with open flames. There are control rooms, motor control rooms, hydraulic rooms, transformer rooms, oil cellars, cable tunnels, and rubber conveyor belts etc. which are fire prone. Handling of liquid metals and slags, products with high temperatures, hot waste materials, and sediments containing hot materials are involved. There are also handling, storages and transport of flammable materials such as fuel oils, fuel gases, coal and coke, cryogenic liquids, etc., as well as requirement of cutting and welding everywhere for meeting the maintenance needs. There is presence of electrical ignition sources. There are areas where there is significant unit related fire loads are there. Due to these reasons, fire related processes such as fire protection, fire prevention, fire safety, and firefighting all have important significance in a steel plant. Classification of fires Fires are classified in the following four classes (Fig 1) as per the internationally accepted classification. Class A – These are fires involving solid materials normally of an organic nature (compounds of carbon), in which combustion generally occurs with the formation of glowing embers. Class A fires are the most common. Effective extinguishing agent is generally water in...

Oxygen Blowing Lance and its Role in Basic Oxygen Furnace Oct10

Oxygen Blowing Lance and its Role in Basic Oxygen Furnace...

Oxygen Blowing Lance and its Role in Basic Oxygen Furnace In the basic oxygen furnace (BOF) steel making a water-cooled lance is used for injecting a high velocity (super-sonic) stream of oxygen onto the liquid bath for its refining. The velocity or momentum of the oxygen jet results in the penetration of the liquid slag and metal to promote oxidation reactions over a relatively small area. The velocity of the oxygen jet and the penetration characteristics are functions of the nozzle (lance tip) design. The top-blowing lance oxygen jet of the BOF converter works as the source of feeding oxygen and energy for stirring of the liquid metal in the bath. Major in-furnace phenomena of a BOF converter that involve the top-blowing lance oxygen jet are formation of a cavity as a result of physical interaction between the oxygen jet and liquid metal, stirring of liquid metal, generation of spitting and dust, and post combustion of CO gas generated by decarburization and reaction with oxygen. For the optimization of BOF converter operation and control the above phenomena, different devices and improvements have been made and applied to the design and operation of top-blowing lance. Examples of these include the employment of Laval nozzles capable of converting pressure energy to jet kinetic energy with high efficiency in order to promote stirring of liquid metal, and the use of a multi-hole lance that enables high-speed oxygen feeding while suppressing generation of spitting and dust by dispersing of the oxygen jet. With the introduction of combined blowing in the BOF converters, the role of top-blowing lance jets as the source of energy for stirring liquid metal iron declined and flexibility in design and operation has been enhanced significantly. The main reason for blowing oxygen into the liquid...

Belt Conveyors for Movement of Bulk Materials...

Belt Conveyors for Movement of Bulk Materials The development of belt conveyors, capable of transporting virtually any bulk material at thousands of tons per hour in a continuous and uniform stream, has been one of the most important innovations for the modern industry especially for the steel and mining industry. Today the use of belt conveyors is an important and broadly accepted means of long distance transport of bulk materials. Belt conveyors have been in use for decades to transport bulk and unit loads. They have proved their worth everywhere because belt conveyor installations can be adapted to meet nearly all local conditions. They have attained a dominant position in transporting bulk materials because of inherent advantages such as their economy and safety of operation, reliability, versatility, and practically unlimited ranges of capacities. In addition, they are suitable for performing numerous processing functions in addition to their normal purpose of providing a continuous flow of material between two operations. Recently, their conformity to environmental requirements has provided a further incentive for selection of belt conveyors over other means of transportation. Low labour and low energy requirements are fundamental with belt conveyors as compared with other means of transportation. The dramatic increase in the operating costs of other means of transport since the oil crisis of the seventies has placed conveyors in an extremely favourable position for applications that were not considered previously. Belt conveying as a means of handling bulk materials has been greatly advanced and today it has assumed dominance in the steel and the mining industries. The increased dependence of these industries on belt conveyors is primarily because of the fact that they have had ‘everything going for them’. Demands of the steel and mining industries have been calling for ever higher...