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Lithium Aluminosilicate Glass Ceramics (Environmental Issues (Reduce noise…
Lithium Aluminosilicate Glass Ceramics
Processing
To obtain Powders
Ammonia solution added dropwise into Aluminum Nitrate solution (heated under controlled temperature 80℃ with vigorous stirring)
LiNO3 is added to Alumina sol (stirring at r.t., maintaining pH for clear sol)
Rice husk ash added to Alumina-lithia
(under stirring at r.t.)
LA2S & LA4S sol
(continuously stirred at 80℃)
LA2S & LA4S gel were grinded and were subjected to calcinations from 400 °C to 1000 °C for 1 hour.
𝛽−𝑒𝑢𝑐𝑟𝑦𝑡𝑖𝑡𝑒 & 𝛽−𝑠𝑝𝑜𝑑𝑢𝑚𝑒𝑛𝑒 is obtain
To obtain LAS glass-ceramic
200g of powders melted at 1500℃ for 3 hour
The melt is poured into distilled water at r.t.
Glass frit was remelted at 1450°C for another 3 h
Melt was poured into a graphite mould kept at r.t.
For the relief of internal stresses in the cast glass blocks, the latter were heated up to 510°C for 30 minutes
The blocks were allowed to cool down naturally to r.t.
A small amount of the LAS glass-ceramic frit was prepared by pouring again a small amount of the melt into distilled water.
Raw Materials
Consists of
Aluminium oxide
27.04
Lithium oxide
8.02%
Silicon oxide
64.58%
Usually use in the cooktop - low thermal expansion coefficient and chemical durability
A solid solution of spodumene and SiO2 from residual glass matrix
Problem Solving
Ion Exchange
exchange of lithium for sodium
low temperature and short time for significant diffusion
increase in volume of crystals
increase in mechanical strenghth
Changing sintering techniques
Spark Plasma Sintering
grain rotation and sliding
high-rate densification
partial melting of plastic deformation in materials of low yield stress
expensive
presence of electric field might affect the surface phenomena
low temperature and dwelling time
Microwave sintering
volumetric and rapid heating
uniform microstructures
reduction in processing time and cycles
Strengthening by lithium disilicate
in situ reinforcement
co-crystallization of lithium disilicate and beta-spodumene
Environmental Issues
Reduce agriculture waste
Use rice husk ash as silica source
Reduce air pollution
Use rice husk furnace
Reduce noise pollution
Grinding machine
Regular servicing of machine
Sound absorption material
Mixing machine
Use speedmixer
Reduce water pollution
Proper chemical waste disposal