Reagents for Desulphurization of Hot Metal...

Reagents for Desulphurization of Hot Metal Sulphur (S), present in solid steel as iron sulphide (FeS) inclusions, has several detrimental effects on steel processing and on steel’s physical properties. During deformation, the iron sulphide inclusions act as crack initiation sites and zones of weakness. Such inclusions from sulphur adversely affect steel’s toughness, ductility, formability, weldability, and corrosion resistance. An increase in manganese (Mn) however, helps prevent formation of iron sulphide, which is highly detrimental to steel’s hot workability and also leads to severe cracking. Sulphur is such an undesirable element in steel that its removal is desired. The ever increasing requirements to steel properties and the growing demand for steel qualities and quantities with lowest sulphur contents of down to 0.001 %, has made it necessary for the steel makers to carry out the desulphurization of hot metal. Presently hot metal is regularly being desulphurized to below 100 ppm, and in some steel plants, to 10 ppm. Besides the increased requirements of steel quality, other reasons which necessitate desulphurization of hot metal are reduced scrap quality and increasing cost of high quality iron ores. In the desulphurization process, powdered desulphurization reagents are injected into the hot metal through an immersed lance using an inert carrier gas such as argon or nitrogen, as shown in Fig 1. Since desulphurization is a diffusion-controlled reaction, and related to the reactive surface area available for reaction, the desulphurization reagents are to be as fine grained as possible. However, flowability is reduced with very fine grains and hence it is necessary to find an optimum between efficiency and conveying ability. In order to obtain good flow characteristics, normally a fluxing agent is added during the grinding operation, so that pneumatic transport during injection does not pose any problems. Fig...

Elements of Decision making...

Elements of Decision making One of the important tasks of an executive is the decision making. It generally takes a small fraction of his time. Nevertheless the decision making is a very important aspect of his work since the decisions he makes by virtue of his position, knowledge or experience have significant impact on the entire organization, its performance, and the results. Hence, executives to be effective are to make wise decisions. They are to make the decisions as a systematic process with clearly defined elements and in a distinct sequence of steps. For an effective decision making, the executive is to normally concentrate on those important and strategic decisions which have big impact for the organization. These strategic decisions need to have the highest level of conceptual understanding. The executive is required to find the constants in a situation and is to apply his skill to manipulate a great many variables arising out of the chaotic thinking in order to make an effective decision. He is to know what the decision is all about and what the underlying realities are which the decision is required to satisfy. The executive is to look out for impact rather than the technique. He is to ensure that the decision he makes needs to be sound rather than clever. An executive while making a decision is required to know whether the decision is to be based on principle or it is to be made on the merits of the case and logically. He is to be aware that the trickiest decision is the one which is between the right and the wrong compromise he has to make and he is to be able to judge one from the other. Further, the executive is to be aware that...

Coldry technology for low rank coal drying Aug19

Coldry technology for low rank coal drying...

Coldry technology for low rank coal drying Coldry technology is being developed by Environmental Clean Technologies (ECT) Limited, Australia. The technology consists of expelling of water from a wide range of low rank coals (lignite coals and sub-bituminous coals) containing up to 70 % moisture into high calorific value (CV) black coal equivalent (BCE) pellets with a moisture content of around 10 %. The BCE means that the net energy value of the Coldry pellets is similar in range to that of many black coals. Coldry technology is a patented process which changes the naturally porous form of low rank coals to produce a dry and dense pellets by a process which is called as ‘brown coal densification’(BCD). The technology is based on research initially conducted by CRA and University of Melbourne in the early 1980s. The technology has been demonstrated at pilot plant scale at Bacchus Marsh Coldry plant. This plant was commissioned in 2004, enhanced with a water recovery system in 2007, and upgraded in 2011 so that it can produce up to 20,000 tons per annum of Coldry BCE pellets. The process has been tested and proven successful on a wide range of low rank coals. Principle of the process The Coldry process combines two unique aspects namely (i) brown coal densification, and (ii) waste heat utilization. The process stimulates a natural chemical reaction within the coal. This reaction polymerizes active sites in the coal compounds and expels chemically bound water. The polymerization of the active sites collapses the coal pore structure and expels the physically trapped water. The ejected water migrates to the surface of the coal pellets. The surface water is evaporated by the utilization of waste heat from an adjacent power plant (PP). BCD is a natural phenomenon whereby the physical structure...

Crude Steel

Crude Steel  Crude steel is the term used for the first solid steel product which is produced during the solidification of liquid steel in a steel melting shop. Crude steel is part of saleable steel when it is supplied to customers for its use or for further processing. Crude steel is normally processed into finished steel either by rolling or by forging processes. World steel association also includes liquid steel which goes into production of steel castings under crude steel for statistical purpose. Various common types of crude steel products (Fig 1) include (i) ingot, (ii) slab, (iii) bloom, (iv) billet, (v) round, and (vi) dog bone section. Crude steel products are also semi-finished products since they need further processing for the production of finished steel. Fig 1 Common types of crude steel products Ingot Ingot is the product obtained by pouring liquid steel into cast iron mould of a shape appropriate for the subsequent processing generally by hot rolling or forging into semi-finished or finished products. The shape generally resembles a truncated pyramid or truncated cone. The side surfaces can be corrugated and the corners are more or less rounded. Depending on its subsequent conversion requirements, ingot can be dressed and/or hot scarfed or cropped. The usual cross section of ingot is square, rectangular, round, oval, or polygon. Ingots with square cross section are used for rolling into billets, rails and other structural sections, whereas, ingots with rectangular cross section, are generally used for rolling into flat products. These ingots usually have a width which is two times or higher than the thickness. Round ingots are used for the production of seamless pipes. Polygonal ingots are used to produce tyres, and wheels etc. Low capacity steel melting shops with induction furnaces produce very...

Financial planning and its elements...

Financial planning and its elements Financial planning is an implement which allows evaluation of the current financial situation of the organization and predicting of its future financial performance. One of the objectives of the financial planning is to determine funds requirements and capital structure in order to understand the financial soundness of the organization. In addition to it, financial planning process helps the organizational management in framing of the financial policies for the control of the cash flow as well as in ensuring that the organization is employing its financial resources in the most efficient manner. Further, the financial planning demonstrates the direction of the organizational activities and analyses how each action has its influence on the financial stability of the organization. Also, financial planning helps the organizational management to make a decision about investments since it shows different ratios (such as equity ratio, debt ratio etc.). These ratios play an important role in the decision making process. Financial plan consists of four elements. These elements are (i) profit and loss projection, (ii) projected balance sheet, (iii) projected cash flow, and (iv) break-even analysis. These four elements are shown in Fig 1. Fig 1 Four elements of financial plan Profit and loss projection Profit and loss projection presents the plan of revenues and expenses of the organization over the specific accounting period. Profit and loss projection follows the same pattern as the profit and loss statement. Nonetheless, it reflects the data about the future. The presentation of the profit and loss statement differs from organization to organization.  However, the basic structure includes the basic five measures namely (i) gross profit, (ii) operating profit or earnings before interest and tax (EBIT), (iii) operating profit or earnings before interest, tax, depreciation and amortization (EBITDA), (iv) profit...