Transfer of know-how, the need for a holistic approach

Experience shows that many products and processes developed in the laboratory do not see the light of day due to lack of a holistic approach. The scientists who develop know-how are often satisfied with the publication and patents. Their efforts do not mature in the form of technology because the development of technology is a group activity where the involvement of entrepreneur is also needed. The good work done by scientists remains in the archives of the laboratory in the form of reports due to lack of a systematic approach in its commercialization. The paper discusses various factors, which inhibit the development of know-how into a marketable technology, and the factors, which hinder its transfer to the user's place. It also suggests ways for effective utilization of R& D efforts

Dephosphorization of high carbon ferromanganese using BaCO3 based fluxes

Manganese is added to steel in the form of ferromanganese to improve the rolling and forging qualities, strength, toughness, stiffness, wear resistance and hardenability. It is also used extensively as a deoxidizer. In view of its wide applications, the consumption of ferromanganese is more than that of all other ferroalloys combined. However, ferromanganese is one of the main sources of phosphorus (P) contamination in steels because it usually contains more than 0.4% phosphorus. On one hand there is a greater demand on steelmakers to produce steel with stringent limit on phosphorus content (because its presence makes the steel brittle and susceptible to stress corrosion cracking), on the other hand the quality of manganese ores with respect to its phosphorus content goes on deteriorating day by day. In these circumstances, it is virtually impossible for the ferromanganese manufacturers to produce high carbon ferromanganese with low phosphorus content (0.2%P) manganese ores. Since ferromanganese is one of the late additives in the steel making process, virtually all the phosphorus present in ferromanganese goes straightway into the product. It is, therefore necessary to restrict the phosphorus content in ferromanganese itself, so that its entry into liquid steel is minimized. Since phosphorus is intimately mixed in the ore, its removal by physical separation technique is not feasible. During last decade, several laboratory scale investigations have been carried out to remove phosphorus by various routes but no established economically viable method exists today for lowering the phosphorus content in ferromanganese to the desired level. The phosphorus removal under oxidizing conditions is usually accompanied by loss of manganese whereas under reducing conditions the product is a phosphide which is not considered environmentally friendly and also it is uneconomical because of the extra cost involved in the post treatment of slag. Gaseous dephosphorization is also not suitable because the partial pressure of manganese is higher than that of phosphorus at smelting temperatures. Therefore, the present investigation focused on the development of a suitable flux for selective removal of phosphorus under oxidizing conditions. Predominance area diagrams for various flux systems ( Ba-P-O and Ca-P-O superimposed by Mn-MnO line) were drawn at standard as well as non standard states and at various temperatures to provide guidelines to select the suitable flux system and temperature for removal of phosphorus without significant loss of manganese. BaO based fluxes rich in MnO at comparatively lower temperature were found to be effective in removing phosphorus with minimal loss of manganese. Feasibility tests were carried out in a graphite crucible fitted in an induction furnace using BaCO3-based fluxes rich in MnO. BaCO3 was selected as a substitute for BaO because of its ready availability at a low cost. Initial trials were unsuccessful because of the difficulties experienced in melting BaCO3, MnO2 mixture at moderate temperatures (<15000C) possibly because of the high melting points of pure BaO and MnO. However, after repeated trials, the flux (BaCO3 ) was found to melt at 1300-13500C in the presence of carbon when it was added from the top without external addition of MnO2. Addition of BaF2/ BaCl2 helped in improving the fluidity of slag. Once it was possible to melt the flux at 13000C, the effects of various parameters such as (i) type of flux, (ii) quantity of flux, (iii) silicon content of the alloy, (iv) temperature were studied on the degree of dephosphorization. The phosphorus level was reduced to 0.18 % from an initial level of 0.56 % when the reaction was carried out at 13000C using 16 Wt % BaCO3-BaF2 fluxes. The manganese loss was restricted in the range of 2-5%. However, it was found that the degree of dephosphorization decreased significantly with increase in the initial silicon content of the alloy. An initial silicon content less than 0.2 % is required to achieve effective dephosphorization. Amongst the various additives used, BaF2 was found most effective. The results clearly indicated that the addition of BaF2 to BaCO3 not only increased the extent of phosphorus removal but also contained the manganese loss to a tolerable level. Dephosphorization tests were also carried out using calcined BaCO3-based flux pellets (major phase BaO) in order to develop a reagent for commercial application and to improve the degree of dephosphorization over BaCO3based powder. It was also possible to study the effect of variation of MnO content in the flux / slag. A comparison of dephosphorization efficiency using calcined BaCO3-MnO2-BaF2 pellets with that using BaCO3-BaF2 powders showed an improvement over powders (80% for calcined pellets against 68% only for powders). The % content of the slag was found to increase with increase in MnO2 content in the reagent up to 30% beyond which it starts decreasing. Therefore, 30 % MnO2 content in the reagent which generates about 30% MnO in slag was considered to be optimum amount, which was attributed to possible increase in softening temperature of BaO-MnO flux beyond this value. The results of the feasibility tests as discussed above using BaCO3-BaF2 fluxes were found encouraging which indicated that more than 60 % phosphorus could be removed but the time taken was about 30 minutes. This large duration for dephosphorization was not considered suitable for plant scale trials. Therefore, a kinetic study was also taken up to reduce the reaction time by enhancing the reaction rate through powder injection. For this purpose an injection system was designed for injecting the flux at laboratory scale (7 Kg melt). The results showed that it is possible to remove 80% phosphorus in 5 minutes by injecting 10 wt% BaCO3 - based flux in liquid ferromanganese using submerged graphite lance from top. A mathematical model developed to understand the injection process showed that transitory reactions contribute approximately 62 % to overall reaction

Extractive Metallurgy

Metal is extracted from ores. The main factors which determine whether a particular mineral is an ore of the metal are a)the percentage metal content b)the cost of extraction c) the market price. Broadly, the ore consists of mainly two parts: Metal and Gangue (impurities). The metal is usually reduced from their oxides (ores). The separation of the metal from their impurities is carried out in the extraction the metal. The entire process is known as extractive metall-urgy. The metal can be extracted by different methods. They are classified into the following categories: a) Pyro metlallurgy b) Hydrometallurgy and c) Electrometallurg

Dephosphorization of Liquid Ferromanganese

Ferromanganese is used as deoxidizing and alloying agent in steelmaking. In order to produce high quality steel, it is desirable to have phosphorus contents in the ferro-manganese less than 0.25%. However, the ferromanganese alloys produced in India continue to have high (>0.4%) phosphorus levels.There are no established methods exis-ting for lowering the phoshorus levels in ferromanganese

An Overview of Treatment of Steel-Making Slag for Recovery of Lime Phosphorus Values

The steelmaking slag containing high phosphorus (1-3 % P2O5) can not be used in blast furnace, as it increases the refining load. Removal of phosphorus is essential for the recycling of slag which consists of major phases like dicalcium silicate, dicalcium ferrite and wustite. The majority of phosphorus is present in the dicalcium silicate. The objective of this study is to remove this phase selectively to the extent of 90% by different methods. The paper reviews these methods and suggests a methodology for removal of phosphorus

Village Baseline Study: Site Analysis Report for Rupandehi, Madhuri Village, Nepal

This is the report of the village baseline study of Madhuri Village in the CCAFS benchmark site of Rupandehi, Nepal conducted from June 5-9, 2011 to complement an earlier household baseline survey done in the same village. Madhuri is located in the fertile area of the Indo-Gangetic Plain in Nepal yet faces challenges due to increasing populations, encroachment on forests, decreasing soil fertility, limited agriculture and animal productivity, lack of opportunities, and variable climatic conditions. Its circumstances present manageable opportunities to prevent an increase in food insecurity and further degradation natural resources. Madhuri has yet to incur any food or environmental crises

Participatory Ranking of Fodders in the Western Hills of Nepal

Fodder is an important source of feed of the ruminants in Nepal. In the mid hills of Nepal, farmers generally practice integrated farming system that combines crop cultivation with livestock husbandry and agroforestry. Tree fodders are good sources of protein during the forage and green grass scarcity periods especially in dry season. Local communities possess indigenous knowledge for the selection of grasses and tree fodders at different seasons in mid hills of western Nepal. A study was conducted on the perception of farmers with respect to selection of fodder species in eight clusters in Kaski and Lumjung districts that range 900-2000 meter above sea level and receive average precipitation of 2000- 4500mm per annum. During the fodder preference ranking, farmers prepared the inventory of fodders found around the villages and nearby forests and selected top ten most important fodders in terms of their availability, palatability, fodder yield, milk yield and milk fat yield. In total, 23 top ranking fodders species were selected from the eight clusters. These fodder species were also ranked using pairwise ranking and weighted scoring methods and ranking was done on the basis of merit numbers obtained from weighted scores. The analysis revealed Artocarpus lakoocha as best tree fodder followed by Ficus semicordata, Thysanolena maxima and Ficus calvata. Similarly, the calendar of fodders trees for lopping season and the best feeding time was prepared on the basis of farmers\u27 local knowledge. This study suggests strategies for promotion of locally preferred tree fodder species and supplementing tree fodder with feed in different seasons depending on their availability and local preferences

Failure analysis of rolls of cold rolling mill in steel plant

Failures of rolls occur due to improper manufacturing and operational parameters. The samples of prematurely failed roll samples collected from steel plant were examined for their chemistry, inclusion content, microstructures, carbide characteristics, hardness and the retained auste¬nite content. The residual stresses were also measured on the inner as well as the outer surface of the spalled roll pieces. The results obtained have been discussed in this paper. The higher content of retained austenite was primarily responsible for the spalling of indigenous rolls for which sub zero treatment has been recommended. Several suggestions have also been made for smooth operation of the mill and consequently for the ex¬tension of life of a work roll