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

Investigation of interface properties of sputter deposited TiN/CrN superlattices by low-angle X-ray reflectivity

Approximately 1.8 m thick nanolayered multilayer coatings of TiN/CrN (also known as superlattices) were deposited on silicon (100) substrates at different modulation wavelengths (4.6–12.8 nm), substrate temperatures (50-400 °C) and substrate bias voltages (-50 to -200 V) using a reactive direct current magnetron sputtering system. X-ray reflectivity (XRR) technique was employed to determine various properties of the multilayers such as interface roughness, surface roughness, electron density, critical angle and individual layer thicknesses. The modulation wavelengths of the TiN/CrN superlattice coatings were calculated using modified Bragg’s law. Furthermore, the experimental X-ray reflectivity patterns were simulated using theoretically generated patterns and a good fit was obtained for a three layer model, i.e., (1) top surface roughness layer, (2) TiN/CrN multilayer coating (approximately 1.8 m) and (3) Ti interlayer (~ 0.5 m) at the film-substrate interface. For the superlattice coatings prepared at a modulation wavelength of 9.7 nm, a substrate bias of -200 V and a substrate temperature of 400 C the XRR patterns showed Bragg reflections up to 5th order, indicating well-defined periodicity of the constituent layers and relatively sharp interfaces. The simulation showed that the superlattice coatings prepared under the above conditions exhibited low surface and interface roughnesses. We also present the effect of substrate temperature and substrate bias, which are critical parameters for controlling the superlattice properties, onto the various interface properties of TiN/CrN superlattices

Evaluation of the local employment impacts of enterprise zones: A critique

Enterprise zone policy is a potential tool for the regeneration of distressed areas, based primarily on tax incentives to businesses locating in the target areas. The tool has been tested in several countries over more than 35 years but there is no consensus on whether or not it is effective and efficient in creating jobs and reducing unemployment in targeted localities. This paper reviews seminal enterprise zone evaluations in the UK, USA and France. More than one-half of the studies reported local employment benefits but the others reported none and information is limited on what affects policy success. The paper argues that typically narrow-focus research designs and a-theoretical evaluation have contributed to the lack of consensus and policy insight, potentially exacerbated by non-exact data. It proposes richer evaluations with explicit theoretical frameworks, such as the one presented in the paper, more comparative work and the use of more accurate data

Lignocellulose for ethanol production: A review of issues relating to bagasse as a source material

Fossil fuels reservoirs have been declared to serve mankind’s needs more for a very limited time period. This notion has already initiated scientific search for alternatives. Amongst renewable resources for emerging biotechnological strategies to produce high energy-less volume fuels, cellulose is the most abundantly synthesized but stable carbohydrate of the biosphere. Cellulose has earlier been taken into account for chemical/biological saccahrification and subsequent biological conversion of the monomeric sugars to ethanol. The stable nature of the substrate and some of the monomeric products’ fermentation difficulties have been the major hardles. But because of its ubiquitous nature and being the most abundantly available renewable resource, research on the utilization of cellulose for obtaining the biofuel has continued and has been representing by diverse fields. Following the recognition of different bacteria and yeasts and various kinetics of the process involved in its saccahrification, the substrate is increasingly being worked out by different laboratories. Biotechnological endeavors are in fact reshaping the economics of different countries. Production of high grade sweeteners with low caloric values by the contemporary biotechnological processes is likely to influence the conventional sucrose production negatively. The raw material for sugar industry would be available for other products such as ethanol. At present, cellulosic waste of such industries for example, sugarcane bagasse, may be targeted for sacharification and ethanologenesis. Various aspects regarding the nature of the cellulosic substrate and its potential for obtaining the biofuel are covered in this review.Key words: Biofuel, cellulose and ethanol, xylose fermentation, environmental rehabilitation

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

Using the Discrete Dipole Approximation and Holographic Microscopy to Measure Rotational Dynamics of Non-spherical Colloidal Particles

We present a new, high-speed technique to track the three-dimensional translation and rotation of non-spherical colloidal particles. We capture digital holograms of micrometer-scale silica rods and sub-micrometer-scale Janus particles freely diffusing in water, and then fit numerical scattering models based on the discrete dipole approximation to the measured holograms. This inverse-scattering approach allows us to extract the the position and orientation of the particles as a function of time, along with static parameters including the size, shape, and refractive index. The best-fit sizes and refractive indices of both particles agree well with expected values. The technique is able to track the center of mass of the rod to a precision of 35 nm and its orientation to a precision of 1.5$^\circ$, comparable to or better than the precision of other 3D diffusion measurements on non-spherical particles. Furthermore, the measured translational and rotational diffusion coefficients for the silica rods agree with hydrodynamic predictions for a spherocylinder to within 0.3%. We also show that although the Janus particles have only weak optical asymmetry, the technique can track their 2D translation and azimuthal rotation over a depth of field of several micrometers, yielding independent measurements of the effective hydrodynamic radius that agree to within 0.2%. The internal and external consistency of these measurements validate the technique. Because the discrete dipole approximation can model scattering from arbitrarily shaped particles, our technique could be used in a range of applications, including particle tracking, microrheology, and fundamental studies of colloidal self-assembly or microbial motion.Comment: 11 pages, 9 figures, 2 table