Corrosion of Al2SiO5–SiC and Al2SiO5–ZrSiO4 Refractories in the Corroding Medium of the External Heat Exchanger of Cement Kiln

Jacek Szczerba, Dominika Madej

AGH University of Science and Technology, Faculty of Materials Science and Ceramics, 30-059, rakow/Poland

Revision 31.05.2013, 24.09.2013

Volume 6, Issue 1, Pages 91 - 94

Abstract

The paper presents the results regarding changes in the chemical (XRF, chloride Cl– and sulphur SO3 content), phase (XRD, FT-IR) compositions and microstructure (SEM/EDS) of Al2SiO5–SiC and Al2SiO5–ZrSiO4 refractories under the influence of the selective interaction between the refractory phases of brick and corrosive solids, liquids and vapours present in a corrosive environment of the cement cyclone preheater. Reactions of the SiC or ZrSiO4-containing andalusite refractory bricks with the components of a corroding medium in the external heat exchanger of cement kiln at 1000 ± 100 °C were discussed. The calcium-rich hot kiln meal moving in a counter-current relative to the furnace gas reacted with a refractory component of the both ceramic materials. The Al2SiO5–SiC refractory brick was constantly affected by the corrosive agents in gaseous form such as K+/K2O, SO2, CO2 and Pb vapor. According to the XRD and SEM/EDS examinations it has been found that the initial phase of refractory brick were disappeared and the new phases were formed. Mainly, potassium aluminosilicates, calcium aluminosilicates, CaSiO3, Ca2SiO4, K2Si4O9, Ca2PbSi3O9, spurrites 2Ca2SiO4 • CaCO3 and 2Ca2SiO4 • CaSO4 and also KCl were identified in the corroded Al2SiO5–SiC refractory brick. Andalusite refractory brick containing ZrSiO4 was subjected to corrosion by Ca2+/CaO, K+/K2O, Pb vapor and Cl–. Post-mortem examination of the corroded brick enabled the identification of potassium aluminosilicates, calcium aluminosilicates, Ca3ZrSi2O9, CaZrO3, Ca12Al14O32Cl2, Ca2SiO4 and KCl as the predominant corrosion products.

Keywords

corrosion, external heat exchanger of cement kiln, andalusite refractories, SiC, ZrSiO4

References

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