What are the three raw materials for making glass?

The main raw materials for glass production are glass forming agents, glass modifiers and glass intermediates, and the rest are auxiliary raw materials. The main raw materials are oxides, intermediate oxides and out-of-network oxides introduced into glass to form a network; Auxiliary raw materials include clarifier, flux, opacifier, colorant, decolorant, oxidant and reducing agent.

The main components of glass are silicon dioxide and other oxides. The chemical composition of ordinary glass is Na2SiO3, CaSiO3, SiO2 or Na2O CaO 6SiO2, etc. The main component is silicate double salt, which is an amorphous solid with irregular structure.

Extended data:

Characteristics of glass

1, isotropic

The molecular arrangement of glass is irregular, and its molecules have statistical uniformity in space. In an ideal state, the physical and chemical properties of homogeneous glass (such as refractive index, hardness, elastic modulus, thermal expansion coefficient, thermal conductivity, electrical conductivity, etc. ) It's the same in all directions.

2. There is no fixed melting point.

Because glass is a mixture, it is amorphous and has no fixed melting point. The transition of glass from solid to liquid is carried out in a certain temperature range (that is, the softening temperature range), which is different from crystalline substances and has no fixed melting point. The softening temperature range is Tg~T 1, Tg is the transition temperature, and T 1 is the liquidus temperature, and the corresponding viscosities are10/3.4 dpa s and104 ~ 6 dpa s respectively.

3. Metastability

Generally speaking, glassy substances are obtained by rapid cooling of the melt. When the melt is transformed into glassy, the viscosity increases sharply during the cooling process, so that the particles can not be arranged regularly to form crystals, and the latent heat of crystallization can not be released. Therefore, glassy substances contain higher internal energy than crystalline substances, and their energy is between molten and crystalline substances, which belongs to metastable state.