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Patent No: IN265435 [India] Application No: 1211/DEL/2004
Title: A process for the production of dense magnesia-rich magnesium aluminate spinel useful as refractory aggregates
Issue Date: 24-02-2015 File Date: 30-06-2004
Inventor(s): Arup Ghosh; Barundeb Mukherjee; Manas Kamal Haldar; Samir Kumar Das
IPC Classification: C09K211/02
Abstract: In the present invention there is to provided a process for the production of dense magnesia-rich magnesium aluminate spinal useful as refractory aggregates, wherein Al2O3-rich spinal (56to 66 percent Al2O3) is densified to a high degree by a single firing process at a relatively low temperature (<1600 deg C). This is done by proper milling, introduction of mixed additives such as incorporation of two additives, ZnO and ZrSiO4, using only single pressing and controlled firing schedule. One of the additives creates lattice strain, while the other additive develops viscous liquid and facilitates liquid phase sintering. The firing schedule is particularly controlled around the spinal formation temperature to lower the rate of expansion due to spinellisation reaction and enhance densification. Sintered magnesia-rich spinel thus produced has a density of 96 to 98 percent of theoretical density, average grain size 10 to 15 micro-m, hot modulus of rupture at 1300 deg C is 1300 to 1450 Kg/cm2 and thermal expansion coefficient at 1000 deg C is in the range of 9.2 to 9.6 x 10-6 deg C-1. Spinel is a properties. Magnesia-rich spinel is extensively used now-a-days as a shaped refractory of a constituent for castables which are used in various secondary refining vessels of steel making.
Licensing Option: Basic patent license only available.
CSIR-Central Glass and Ceramic Research Institute
CSIR-Central Glass and Ceramic Research Institute[CSIR-CGCRI]
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Industrial Applications Chemistry, Chemical Processes Polymers [Chemistry, Chemical Processes]

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CSIR-Themes Chemicals (including leather) and Petrochemicals