Stability of SiC, Si/sub 3/N/sub 4/, Si/sub 2/N/sub 2/O, SIALON and chromium oxide-containing refractories in coal gasification environments. Second annual report, September 1, 1978-August 31, 1979

Technical Report · Mon Oct 15 04:00:00 EDT 1979

OSTI ID:5402742

Muan, A

The main conclusions of this work are as follows: (1) the corrosive action of coal-ash slags on SiC refractories is caused mainly by the reduction-oxidation reaction between SiC and the iron oxide component of the slag. (2) The rate of attack on SiC by coal-ash slag is critically dependent on temperature, i.e. whether or not the SiC-slag interface is above or below the solidus temperature of the silicates involved (as a first approximation selected compositions in the system CaO-FeO-Al/sub 2/O/sub 3/-SiO/sub 2/). This temperature is approx. 1100/sup 0/C. (3) Studies of equilibrium relations in selected chromium oxide-containing silicate systems have established the low solubility of Cr/sub 2/O/sub 3/-containing refractory phases in silicate melts. The solubility of these phases in silicate melts increases drastically, however, at extremely low oxygen pressures, under which cnditions a substantial fraction of the chromium is present in the silicate liquid as a Cr/sup 2 +/. The oxygen pressures at which this situation prevails, however, are somewhat lower than those prevailing in coal gasification atmospheres.

• Research Organization: Pennsylvania State Univ., University Park (USA). Coll. of Earth and Mineral Sciences
• OSTI ID: 5402742
• Report Number(s): FE-2708-8
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
36 MATERIALS SCIENCE
360205 -- Ceramics
Cermets
& Refractories-- Corrosion & Erosion
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
COAL GASIFICATION
COAL GASIFICATION PLANTS
CORROSIVE EFFECTS
DATA
DATA FORMS
DIAGRAMS
EXPERIMENTAL DATA
GASIFICATION
GRAPHS
INDUSTRIAL PLANTS
INFORMATION
NITRIDES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PNICTIDES
REDUCTION
REFRACTORIES
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
SLAGS
STABILITY
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS