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Interceram - International Ceramic Review

, Volume 64, Issue 4–5, pp 188–192 | Cite as

Alkali Salt Corrosion of Calcium Silicate Thermal Insulation Materials

  • E. Schlegel
  • T. Hölscher
  • H.-J. Schneider
  • C. G. Aneziris
Review Papers
  • 2 Downloads

Abstract

There have been considerations calcium silicate thermal insulation materials not to use in high temperature furnaces, where there is a huge content of alkaline in the combustion atmosphere. This is linked to the increasing usage of secondary fuels starting about 20 years ago. Methodical researches of alkali corrosion of calcium silicates are unknown. Therefore conferring to V DIN 51069 calcium silicate crucibles have been scanned with salts of KCl, K2SO4 and K2CO3 separately and in combination. Infiltration and crystal phases by X-ray have been checked. Only K2CO3 leads to a catastrophic dissolution and destruction whereas the other salts infiltrate only. KCl and K2SO4 — separately and in combination as well — do not react with the calcium silicate phases. To verify this theory typically alkaline dust out of the bypass of cement kilns was used in crucible tests. The analysis of the dust showed highly corrosive substances close to 69%. However, crucible tests with this dust prove that calcium silicates are suitable to withstand the industrial practice. Finally the alkali corrosion was researched on post-mortem specimens and analysed after use of 1 to 8 years in cement kilns. K2CO3 was never detected in post-mortem-analyses of calcium silicate products. In conclusion, it has no or hardly any relevance for the industrial practice and cannot cause corrosion of calcium silicate materials therefore.

Keywords

calcium silicate thermal insulation materials alkali salt high temperature corrosion alternative fuels alkali bypass dust post mortem investigations 

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Copyright information

© Springer Fachmedien Wiesbaden 2015

Authors and Affiliations

  • E. Schlegel
    • 1
  • T. Hölscher
    • 2
  • H.-J. Schneider
    • 2
  • C. G. Aneziris
    • 1
  1. 1.Institut für Keramik, Glas- und BaustofftechnikTU Bergakademie FreibergFreibergGermany
  2. 2.Calsitherm Silikatbaustoffe GmbHPaderbornGermany

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