Besides other possible applications, the thermitic compositions based on iron oxides are meant to the achieving of the permanent joints of the railroad tracks. In addition to the iron oxides, the thermitic kit include also the reducing agent – aluminum powder, a carbon source to adjust the percent of this element in the obtained steel and a flux with a view to allow the steel composition and temperature control. The metallothermic process efficiency is given by strictness in the selection of ratio of the thermitic components and mainly in that of the iron oxides types. Their correct dosage makes possible the estimation and rigorous control of the thermal effect of reactions. In this work, using thermodynamic calculations, is analyzed and quantified the development of the thermal effect of the metallothermic reduction reactions of iron oxides depending on the iron oxides proportions in the thermitic composition.
Thermite welding (TW) is now widely used all over the world to weld, maintenance and modernization railway and tram rails [1]. The main materials from the thermite composition (TC), results from manufacturing scraps, which can be retrieved all over the country. Exothermic welding (EW) which is based on the exothermal reaction between iron oxides (FeO, Fe2O3 and Fe3O4) and aluminium powder, takes place at temperatures up to 3500 °C and during casting rail ends are melted in order to be welded.In was studied the thermal effects of the aluminothermic reduction reactions of the iron oxides, which were dosed in different percentages. The aluminothermic reaction efficiency is given by strictness in the ratio of the TC selection and mainly in the iron oxides types. Their correct dosage makes possible the control the exothermic reaction (ER) effect. Also it is revealed the effect of particle size from thermite powder (TP) on the thermite dynamics reactions. Is also presented a model of optimization and control the thermite kits (TK) for aluminothermic welding (AW). Finally, the TK composition can be calculated from "QUARK1" Diagram, as function of the heat amount necessary for the welding.
"The paper presents the results and conclusions of the statistical processing of data on aluminothermic reduction reactions of iron oxides. Starting from the thermodynamic and chemical information regarding the aluminothermic reduction reactions of the iron oxide mixtures, their thermal and chemical effects were estimated and the information thus obtained was statistically processed. The results obtained by statistical processing of information obtained by theoretical reasons, presented in the form of regression equations or their graphical expressions, can be used to effectively determine the optimal phase composition of thermit kits based on iron oxides and forecast the value of reaction heat, resulting from the actual reactions development. The practical application of these results was ensured by the company QUARK IMPEX SRL, one of the main producers and users of thermit welding kits for rail joints by aluminothermal welding, in Romania. "
Our experimental research has confirmed many practical results regarding the possibilities of ferrous waste recovery and has generated new perspectives for their use. It turned out that through an adequate preparation of ferrous waste involving washing - calcination - fragmentation - magnetic and granulometric sorting - rigorous dosing of the reducer - with or without the addition of new components (alloying elements, fluxes, etc.), depending on the purpose pursued, by carrying out closed, opened or virtual metallothermic reactions, pure technical iron, ferroalloys, alloy steels, additives used for non-removable joints by welding (welding aluminothermy) or powdery active components (virtual thermitic mixtures) used in thermochemical treatments can be obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.