Technical Bulletin: ALKALI RESISTANT
MONOLITHICS-An Evaluation
11/10/2009
There has been controversy over the types of Silicon Carbide containing monolithics and the
percentage of SiC to use with high alkali environments. There are many schools of thought and
papers written on this subject. We have conducted a laboratory test to determine,
determine if in fact,
there are any significant and profound performance differences.
Silicon carbide without question provides alkali resistance to a refractory mass. Its uniqueness
lies in the fact that upon oxidizing, a siliceous skin is developed on the refractory and it is this
skin that fills the pores and inhibits penetration of alkalies and their compounds. It is the nonnon
wetting characteristic of SiC that also assists in buil
build-up
up removal with minimal damage to the
underlying refractory.
Our testing was conducted at our West Mifflin Technology Center. The test used was the
internationally recognized standard for testing “Alkali Resi
Resistance”.
stance”. This test consisted of
o precise
sample
ple preparation, inserting anhydrous potassium carbonate in the test hole and heating the
sample for five (5) hours at 2012ºF(1100ºC). Upon completion, the sample is cut and the
amount of penetration is measured. If the sample has 0.12” (3 mm’s) or less penetration, and
no cracking or splitting can be observed, it is rated as satisfactory.
The following table summarizes the tests results.
Product
THOR 30 ADTECH
THOR 60 ADTECH
THOR AZSP ADTECH
THOR AZS-PT ADTECH
% SiC
30
60
5
0
Penetration (mm’s)
5
3
0
0
Splitting/Cracking
No
No
No
No
NOTE: This
his is a highly aggressive test and does not preclude the use of those products that have
not rated satisfactory.
THOR 30 ADTECH
30%
% Silicon Carbide
5 mm’s Penetration
enetration
C&L TB 100
Page 1 of 2
Technical Bulletin: ALKALI RESISTANT
MONOLITHICS-An Evaluation
11/10/2009
THOR 60 ADTECH
60% Silicon Carbide
3 mm’s Penetration
THOR AZSP ADTECH
Fused Zirconia Mullite
M
5% Silicon Carbide
No penetration, no splitting
sp
or cracking
THOR AZS-PT ADTECH
Fused Zirconia M
Mullite
No Silicon Carbide
No
o penetration, no sp
splitting
or cracking
THOR AZS-PT
C&L TB 100
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