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US 2003/0216243 A1Published application
Halogen-resistant media
AssigneeSaint-Gobain Ceramics & Plastics, Inc.
InventorsJohn S. Reid, Thomas Szymanski, Karen C. Beal
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Abstract
Ceramic mass and thermal transfer media suitable for use in thermal regenerative oxidizers made using a mixture of a ball clay, talc and optionally a dolomitic limestone have enhanced resistance to environments containing halogens and hydrogen halides. The media preferably comprises less than 0.25% by weight of alkali metal, expressed as the oxide, and has a cordierite: silica phase ratio of less than 1.2:1, as determined by X-ray diffraction.
Claims28
Ceramic media comprising:
- 40-65% by weight SiO2;
- 10-45% by weight Al2O3;
- less than 0.25% by weight of alkali metal, expressed as the oxide;
- less than 31% by weight alkaline earth metals, expressed as the oxide;
- and
- wherein the media has a ratio of cordierite:
- crystalline silica phase of less than 1.2, as determined by X-ray diffraction analysis.
4 more elements
Ceramic media comprising:
- 40-65% by weight SiO2;
- 10-45% by weight Al2O3;
- less than 0.25% by weight of alkali metal, expressed as the oxide;
- less than 31% by weight alkaline earth metals, expressed as the oxide;
- and
- wherein less than about 40% by weight of the media is in the form of cordierite, as measured by X-ray diffraction.
3 more elements
A process for the production of ceramic media which comprises:
- forming a mixture comprising 10 to 98%, by weight of a clay having an alumina content of at least 36% by weight;
- from 2 to 90% by weight of a talc containing at least 95% by weight of magnesium silicate as determined by X-ray diffraction analysis;
- and from 0 to 10% by weight of a dolomitic limestone containing 60 to 90% by weight of calcium carbonate and 10% to 40% by weight of magnesium carbonate and less than 10% of non-carbonate impurities, the mixture containing less than 0.25% by weight of alkali metals, measured as the corresponding alkali metal oxides in the product remaining after firing;
- adding water in an amount sufficient to make a shapeable product;
- shaping the product to a desired shape;
- and
- d) calcining the shaped product at a temperature of from 1100° C. to 1400° C. for sufficient time to form ceramic media having a ratio of cordierite:crystalline silica phase of less than 1.2.
4 more elements
Dependencies are inferred from the claim text.