| Pre-calcination of Asbestos Tailings and Its Recycling in
Refractory Ceramics |
Wenmiao Zheng,1, 3 Hongjuan Sun,1, 3, * Tongjiang Peng,1, 2, 3 Li Zeng1, 3 and Guo Zhou1, 3
Pages : 106-111
DOI : 10.1080/0371750X.2020.1756412 |
| Abstract |
| Based on the attribute of asbestos tailings rich in silicon and magnesium, the powder
of asbestos tailings was pre-calcined followed by MgO addition in the green body and
finally sintered to develop refractory ceramics containing phases of forsterite,
magnesioferrite and merwinite. The effects of pre-calcining treatment, MgO content
and sintering temperature on crystallization, phase transition, microstructure and
physical property of refractory ceramics were investigated by means of X-ray diffraction,
thermogravimetry-differential scanning calorimetry, scanning electron microscopy and
physical properties tests. The results indicated that the hydroxyl water and volatile
components in asbestos tailings were basically eliminated after pre-calcining. The
addition of MgO in raw materials promoted the conversion of low melting phases into
refractory phases through solid state reaction. Both the flexural strength and bulk density
of the samples increased initially, then decreased with the increase in sintering
temperature, while the MgO addition would increase the optimal temperature. The optimal
temperature promoted grains of different phases to grow large and interweave to form
a dense accumulation body, which improved the compactness and flexural strength of
the sample. This study provided certain practical guidance for the preparation of
refractory ceramics from asbestos tailings.
[Keywords: Asbestos tailings, Pre-calcination, Refractory ceramics, MgO addition,
Structure and properties] |
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