Obtaining of Granulated Gypsum Anhydrite on the Basis of Technogenic Wastes of Chemical and Metallurgical Complex for Use in Portland Cement Production
Abstract
The composition and properties of fluorine–anhydrite and steel–refining slag which are wastes of production of hydrogen fluoride and steel were determined. It is established that fluorine–anhydrite of the current output does not meet the requirements to materials for the production of Portland cement. Therefore to improve the technical and consumer properties of fluorine-anhydrite (for increasing the amount of CaSO4 ⋅2H2O and neutralization of H2SO4) the studies of its’ conditioning processes with steel– refining slag were carried out. It was found that the mass transfer coefficient of sulfuric acid through the capillary and the degree of its neutralization by slag depend on the dispersion of fluorine–anhydrite, its porosity and initial acidity. The most effective binding of sulfuric acid occurs with the introduction of slag in stoichiometric amounts, the size of fluorine–anhydrite granules up to 20 mm and a processing time of 60 minutes. After storage in air-humid conditions for 12 hours of fluorine–anhydrite treated with slag the strength of its granules, the amount of dihydrate gypsum and toxicological properties meet the requirements.
Keywords: techno–gypsum, refining slag, neutralization, conditioning, gypsum stone, Portland cement
References
[1] Chowdhury, F. H. (2017). Effect of Phosphogypsum on the Properties of Portland Cement. Procedia Engineering, vol. 171, pp. 744–751.
[2] Holanda F. C. and Schmidt H. (2017). Influence of Phosphorus from Phosphogypsum on the Initial Hydration of Portland Cement in the Presence of Superplasticizers. Cement and Concrete Composites, vol. 83, pp. 384–393.
[3] Troshin, M. A. (2010). Phospho–Gypsum Stone is a Regulator of Setting Time of the Cement. Presented at The Conference “Phosphogypsum: storage and use as large–capacity secondary raw materials”. Moscow: NIUIF.
[4] Troshin, M. A., et al. (2009). Phospho–Gypsum Stone is a Regulator of Setting Time of the Cement. Presented at The III (XI) International Meeting on Cement Chemistry and Technology. Moscow: Alit.
[5] Suchkov, V. P., et al. (2009). Production of Granular Phosphogypsum for the Cement Industry and Construction Products. Building materials, issue 5, pp. 58–63.
[6] Mikheenkov, A. M. (2009). Features of the Production of Artificial Gypsum Stone based on FluorineAnhydrite. Cement and its application, issue 6, pp. 121–122.
[7] Taher, M. A. (2007). Influence of Thermally Treated Phosphogypsum on the Properties of Portland Slag Cement. Resources, Conservation and Recycling, vol. 52, pp. 28–38.
[8] Papageorgiou, A. and Tzouvalas G. (2005). Use of Inorganic Setting Retarders in Cement Industry.Cement and Concrete Composites, vol. 27, pp. 183–189.
[9] Boncukcuoğlu, R. and Tolga Yılmaz, M. (2002). Utilization of Borogypsum as Set Retarder in Portland Cement Production. Cement and Concrete Research, vol. 32, pp. 471–475.
[10] Laskorin, B. N., Barsky, L. A. and Persitc, V. Z. (1984). Waste–free Technology of Mineral Materials Processing: System Analysis. Moscow: Nedra.
[11] Kokotov, Y. A. and Pasechnik, V. A. (1970). Equilibrium and Kinetics of Ion Exchange. Leningrad: Chimiya.
[12] Reichenberg, D. (1953). Properties of Ion-Exchange Resins in Relation to their Structure. III. Kinetics of Exchange. J. Am. Chem. Soc., vol. 75, pp. 589–597.