Steel Scrap and Scrap Sorting and Preparation Processes Jan23

Steel Scrap and Scrap Sorting and Preparation Processes...

Steel Scrap and Scrap Sorting and Preparation Processes Recycling of steel scrap is receiving increased impetus these days due to the focus of an emerging environmental initiative since the increased consumption of scrap reduces the needs for additional resource extraction and hence reduces the environmental impact. Recycling of steel scrap is also a part of wise management of iron resources. Recovery of 1 metric ton of steel from scrap conserves iron ore, coal, and limestone.  As per the world steel association, the integrated steelmaking route, based on the blast furnace (BF) and basic oxygen furnace (BOF), uses 1,400 kg of iron ore, 800 kg of coal, 300 kg of limestone, and 120 kg of recycled steel to produce 1,000 kg of crude steel and the electric arc furnace (EAF) route on average uses 880 kg of recycled steel combined with varying amounts of other sources (DRI, hot metal, and granulated iron), 16 kg of coal and 64 kg of limestone, to produce 1,000 kg of crude steel.  On an average, recovery of 1 ton of steel from scrap conserves an estimated 1,030 kg of iron ore, 580 kg of coal, and 50 kg of limestone. Steel scrap recycling also saves the energy consumption.  In the production of steel, 99.9 % of scrap melted is consumed in the production of new steel while producing negligible environmentally undesirable waste. Steel scrap is classified in three main categories namely (i) home scrap, (ii) new scrap, and (iii) old scrap depending on when it becomes scrap in its life cycle. Home scrap is the internally generated scrap during the manufacturing of the new steel products in the steel plants. It is also known as runaround scrap and is the material in the form of trimmings or rejects generated...

Ferrous Scrap and its Collection and Recycling...

Ferrous Scrap and its Collection and Recycling Ferrous scrap also referred to as, iron and steel scrap, or simply scrap comes from end of life products (old or obsolete scrap) as well as scrap generated from the manufacturing process (new, prime or prompt scrap). It is metal that contains iron. Iron and steel scrap can be processed and re-melted repeatedly to form new products. Due to the value of metal in the ferrous scrap, it is recycled or reused wherever it is possible.  In fact, ferrous scrap is being recycled long before current awareness of environmental concerns started. Ferrous scrap is generated during the production of iron and steel, fabrication or manufacture of iron and steel products, or when the product made of iron and steel reaches its end of life. Due to the high value of the metal, the ferrous scrap is largely being recovered. Given the chemical and physical properties of the material, iron and steel produced from ferrous scrap can, in almost all applications, compete with primary iron and steel produced from ore. However the amount of scrap collected and finally recovered depends on many factors, such as the collection system, the possibility and techniques used for the collection, etc. as well as a variety of legislation. The main sources for ferrous scrap are those products, for which iron and steel is the main constituent. These are namely, vehicles (including ships and rail coaches and wagons), products of construction, machinery, electrical and electronic equipment, and packaging etc. There is a difference between carbon steel scrap and stainless steel scrap since the carbon steel differs from stainless steel by composition and treatment. Carbon steel scrap is mainly used for the production of steel in induction furnace (IF), electric arc furnace (EAF) and partly...

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...

Induction Furnace and Important Operational Aspects Feb14

Induction Furnace and Important Operational Aspects...

Induction Furnace and Important Operational Aspects   The development of the induction furnace for steel making has been a boon to the small steel producers. These furnaces are easy to install, operate and maintain. These furnaces are smaller in heat size with a low cost investment and preferred by lower capacity steel plants. In these furnaces, steel is produced by melting the charge material using the heat produced by electromagnetic field. The induction furnace consists basically of a crucible, inductor coil, and shell, cooling system and tilting mechanism. The crucible is formed from refractory material, which the furnace coils is lined with. This crucible holds the charge material and subsequently the melt. The choice of refractory material depends on the type of the charge and basically consist of either acidic, basic or neutral refractories. The inductor coil is a tubular copper coil with specific number of turns. An alternating current (AC) passes through it and magnetic flux is generated within the conductor. The magnetic flux generated induces eddy currents that enable the heating and subsequently the melting process in the crucible. The shell is the outer part of the furnace. This houses the crucible and the inductor coils, and has higher thermal capacity. It is made of rectangular parallelepiped with low carbon steel plate and joined at the corners by edge carriers from angular pieces and strips of non-magnetic metal. The cooling system is normally a through one way flow system with the tubular copper coils connected to water source through flexible rubber hoses. The cooling process is important because the circuit of the furnace appears resistive, and the real power is not only consumed in the charged material but also in the resistance of the coil. This coil loss as well as the loss...

Solid Waste Management in a Steel Plant Sep29

Solid Waste Management in a Steel Plant...

Solid Waste Management in a Steel Plant  Steel industry in general, produces large amounts of solid wastes while processing materials through its various processes. These solid wastes have many valuable products, which can be reused if recovered economically. Steel industry throughout the world has already taken up a number of innovative measures and continues to take further for 100 % utilization of these wastes with the ultimate objective of improving the operational efficiency and economics of steel industry. These measures not only reduce the cost of waste disposal and environmental pollution but also provide substantial amount of iron ore and flux materials as well as fuel rate benefits to the existing process, thereby conserving matching amounts of raw materials. Steel industry is both capital and energy intensive and its production volumes are very high. Process chains within the industry are long. Many different technologies are applied and the industry has a significant impact on the environment. One of the major concerns of world steel industry is the disposal of wastes generated at various stages of processing. Because of natural drive to be cost-effective, there is a growing trend of adopting such waste recovery technologies which convert wastes into wealth, thereby treating wastes as by-products. This has led to aiming at development of zero-waste technologies. The technologies developed to economically convert wastes of steel plants into wealth also provide new business opportunities for prospective entrepreneurs. As per World Steel Association (WSA), the world steel industry applies the principles of reduction, reuse and recycling (3 ‘R’s) in many ways, in order to improve the sustainability of the industry. Due to this the industry has dramatically reduced need for raw materials. In the 1970s and 1980s, modern steel plants needed an average of 1.44 tons of raw...