The Use Of High Borosilicate Glass Tube

According to the properties of introduced oxides, they can be divided into acid oxides, alkali metal oxides and alkaline earth metal oxides.

(1) Acid oxide raw materials: SiO2, B2O3, Al2O3 and other raw materials. SiO2 is the skeleton of the glass structure in silicate glass. It gives glass height, good chemical stability, heat resistance and low expansibility, but can make the melting temperature of glass increase, viscosity increase. SiO2 reference materials are silica sand or sandstone, quartzite. Add B2O3 to glass, can reduce the thermal expansion of glass, improve the refractive index, heat resistance and chemical erosion resistance, can reduce the glass viscosity at higher temperature, improve the glass viscosity at lower temperature. The reference material of B2O3 is borax or boric acid. Adding Al2O3 to glass can reduce the tendency of glass crystallization and enhance the chemical stability, improve the degree, increase the viscosity of glass. The raw material is usually accompanied by K2O or Na2O and SiO2 feldspar, industrial alumina can also be used. Cangzhou tianchang craft glass products factory has experience in producing various types of high borosilicate glass tubes

Alkali metal oxide raw materials: Na2O, K2O raw materials. Adding Na2O and K2O into glass can reduce melting temperature and viscosity, but make the chemical stability of glass worse. Its raw materials are soda (Na2CO3) and potassium alkali (K2CO3).

③ Alkali earth metal oxide raw materials: CaO, MgO, BaO, ZnO, PbO raw materials. Adding CaO and MgO to glass can weaken the tendency of crystallization of sodium-silicon glass, enhance the chemical stability, reduce the glass viscosity at high temperature, promote glass melting and clarification, but the viscosity increases quickly when the temperature decreases, forming operation is difficult. The raw materials used are limestone (CaCO3) and magnesite (MgCO3), or dolomite containing both CaO and MgO. BaO and ZnO are often added to the glass to adjust the chemical stability and refractive index of the glass, and the reference materials are usually industrial ZnO and BaCO3, BaSO4 or Ba(NO3)2. The addition of PbO to glass can significantly improve the refractive index and dispersion, so that the glass can absorb short-wavelength rays. Meanwhile, the specific gravity increases, the melting temperature decreases, and the metal wetting is good. The raw materials for PbO are red and yellow lead or industrial lead nitrate.

In addition, broken glass is also a major raw material, often called clinker, which is able to melt at lower temperatures, helping to dissolve the glass compound.