Application of Albite on glass-ceramics

2010-05-10 15:28:51 Author：admin Source： Views：0

Glass-ceramics are popular in today's new international architectural decoration materials, it is a polycrystalline solid materials based on high-tech glass-controlled crystallization.The material has excellent physical and chemical properties, it is considered as the ideal substitute of the middle-grade natural stone. In China, Many construction decorative has begun to use on glass-ceramic,and has begun mass production . At present, the production of glass-ceramics using a large number of chemical materials, especially some high price chemicals such as aluminum oxide ,soda ash, etc. So that it caused higher raw material costs, and affect the products sales. After the study of the professor of Hunan Building Materials College, sintering Hunan Hengyang albite as the main raw materials instead of alumina and soda ash, appropriate to add other materials, determine the crystallite
the basis composition of crystallite-glass and the quantity of albite. It can reduce costs (15 yuan per square meter), and widen Albite applications.

Effect on glass melting process

Obtained by trial and error, albite can reduce melting temperature of glass ablut 5 ~ 15 ℃, which
Because albite itself has the following advantages: ①Low melting point, small high-temperature viscosity, the glass melting speed can be improved .②High solvability of quartz.

2 Effects of the crystallization process
Sintering process with the special requirements of glass composition , not only easy crystallization, but also its liquidity ,in order to facilitate adhesion sintering among the particles. The crystallization of glass makes the crystallization of the glass surface , which different from the bulk crystallization evenly by nucleating .The glass
Ingredients must meet the requirements of this process.

The results show that, CaO content is high, the glass crystallization is easier, at the same time it reduce the high temperature viscosity; Low CaO content is not good for β-wollastonite precipitation . Na2O and K2O as the network transfer , can reduce the melting temperature of glass.When its content is too high, it will cause a large number of heterogeneous precipitation of crystals,and break the physical and chemical properties of products; ZnO and BaO is good for the crystallization of glass, but the ZnO content should not be high, BaO will also help to improve the optical properties; SiO2 as a network former at a higher number, can enhance the network structure,slow the high-temperature crystallization ,to ensure the formation of glass，on the other hand ,it will make glass melting difficult.

3 Effect of Heat treatment
After the chemical composition of glass-ceramics are identified, the heat treatment system determines glass microstructure, and affect the physical and chemical properties of glass-ceramics.

Heat treatment systems, including the nucleation temperature, crystallization temperature, nucleation time and crystallization time and temperature-speed,etc.
If the nucleation temperature is too low and time is too short ,the nuclear volume will be small and require a lot of time, decrease the mechanical properties.Conversely, if the temperature is too high , part of the crystal grown lead to increase of the glass viscosity ,it is not good for sintering. On the other hand, if the crystal temperature is too low, it is not fully crystallized; the high crystallization temperature and long crystallization time will cause coarse-grained structure，and affect the mechanical properties and a large number bubble of the surface, so that impact the product quality and decorative effect.

The physical and chemical properties of glass-ceramics are reached or exceeded the natural granite. It is entirely feasible by using Hengshan albite.

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