Investigation of a Two-Stage Aqueous Reactor Design for Carbon Dioxide Sequestration Using Steelmaking Slag
- PDF / 410,608 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 88 Downloads / 172 Views
ON
STEELMAKING slag contains a high fraction of alkaline-earth oxides that exothermically form carbonates, making this material an excellent vehicle for sequestering carbon dioxide. It has the potential to sequester 35 to 45 pct of the carbon dioxide generated from electric arc furnace production and 6 to 11 pct of the carbon dioxide generated from basic oxygen furnace production.[1] Extraction of carbon dioxide from steel manufacturing off gas using steelmaking slag was studied by quantifying the extent and rate of carbonate formation under nearatmospheric aqueous conditions.[2] Because the natural carbonate formation kinetics are very slow, fine grinding to increase slag surface area, increasing pCO2, increasing temperature, and aqueous catalysis are being investigated as a means of increasing the reaction rate to a level suitable for industrial use.[3] The goal of this research is to design a reactor for aqueous-based carbonation of steelmaking slag. Several research groups have investigated the design of an aqueous reactor system for sequestration of carbon dioxide using steelmaking slag. Huijgen et al.,[4] Eloneva et al.,[5] and Stolaroff et al.[6] have worked with leaching and carbonation of steelmaking slag under various S.N. LEKAKH, Research Associate Professor, D.G.C. ROBERTSON, Professor of Metallurgical Engineering, C.H. RAWLINS, Graduate Researcher, V.L. RICHARDS, Robert W. Wolf Professor of Metallurgical Engineering, and K.D. PEASLEE, F. Kenneth Iverson Steelmaking Chair of Metallurgical Engineering, are with the Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409-0330. Contact e-mail: [email protected] Manuscript submitted October 29, 2007. Article published online June 10, 2008. 484—VOLUME 39B, JUNE 2008
conditions. Each of their studies found that the rate and extent of aqueous leaching and carbonation were inversely related to particle size as the primary factor, while pH, temperature, and pCO2 had milder effects on Ca conversion. In comparison to naturally occurring wollastonite (CaSiO3), 11 times more carbon dioxide could be sequestered from steel slag at ambient temperatures. Other groups have actively researched methods of large-scale mineral-based carbon dioxide sequestration. O’Connor et al. conducted research in an effort to optimize the process conditions for direct aqueous carbonation of silicate minerals.[7–9] Pretreatment of serpentine or olivine through acid leaching, fine grinding, or heat treatment was necessary to achieve high carbonation levels. Additions of NaHCO3 and NaCl to the mineral suspension were found to catalyze the reaction. Park et al. investigated carbonation of olivine and serpentine in a manner similar to the work of O’Connor et al.[10] Aqueous carbonation studies revealed that increasing the reactor temperature, pCO2, and NaHCO3/NaCl concentration increased the carbonation rate. Fernandez et al. found that the reactivity of magnesite slurries for carbonation increases with pCO2, temperature, and solidliquid ratio and
Data Loading...
