Development of High Alumina Refractories from
Technical Alumina and Kyanite |
K. K. SINGH, A. V. SUBRAMANYAM* AND M. R. K. RAo
Pages : 25-27
DOI : 10.1080/0371750X.1984.10822670 |
Abstract |
The study aims at developing dense high alumina refractories
containing 84-85% alumina with improved thermal shock resistance.
The raw materials taken were raw Bayers alumina,
i.e. technical grade alumina and Lapsaburu kyanite Jumps. In this
work, an attempt has been made to replace the use of costly fused
alumina grains by dense sintered alumina grog. Dense sintered
alumina grog was prepared by adding 1 % Ti02 as a sintering aid to
raw Bayers alumina followed by wet pot-milling, drying, briquetting
(600 kg/em•) and sintering in a high temperature gas fired furnace at
1650°C for 5 hours. Raw kyanite Jumps were calcined at 1550°C for
a soaking period of 4 hrs and then crushed, ground and graded to
required sieve fractions. Cylindrical buttons of 2 dia x 2 ht (approx)
and quarter size bricks (4! x 2 x 2) were fabricated in a
hydraulic press at a pressure of 1000 kg/cm2 from the thoroughly
prepared homogeneous mix of graded dense sintered alumina grog,
calcined kyanite grains and 0.5-3.0% additions of MgF2 as mineralisers.
These samples were fired at 1680° ± 20°C for a soaking period
of 4 hrs and their sintering behaviour studied. Certain physicochemical
and microstructural properties of fired samplt>s were determined
and compared with those of similar imported products available
in the market. It has been found that the properties of high alumina
samples developed in this work, compared well with those of imported
products. |
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