High Borosilicate Glass Tube

main ingreadient
According to the properties of the introduced oxides, they are divided into acidic oxide raw materials, alkali metal oxide raw materials and alkaline earth metal oxide raw materials.
① Acidic oxide raw materials: SiO2, B2O3, Al2O3 and other raw materials. SiO2 is the skeleton of the glass structure in silicate glass. It endows glass with high strength, good chemical stability, heat resistance and low expansion, but it will increase the melting temperature and viscosity of glass. The cited raw materials for SiO2 are silica sand or sandstone, quartzite. Adding B2O3 to the glass can reduce the thermal expansion of the glass, improve the refractive index, thermal shock resistance and chemical corrosion resistance, reduce the viscosity of the glass when the temperature is high, and increase the viscosity of the glass when the temperature is low. The reference raw material for B2O3 is borax or boric acid. Adding Al2O3 to the glass can reduce the crystallization tendency of the glass and enhance the chemical stability, increase the strength and increase the viscosity of the glass. The reference material is usually feldspar with K2O or Na2O and SiO2, and industrial alumina can also be used. Cangzhou Tianchang Craft Glass Products Factory specializes in the production of various types of high borosilicate glass tubes
② Alkali metal oxide raw materials: There are Na2O and K2O raw materials. Adding Na2O and K2O components to the glass can lower the melting temperature and reduce the viscosity, but it will make the chemical stability of the glass worse. The reference raw materials are soda ash (Na2CO3) and potash (K2CO3).
③ Alkaline earth metal oxide raw materials: CaO, MgO, BaO, ZnO, PbO raw materials. Adding CaO and MgO to glass can weaken the crystallization tendency of sodium silicate glass, enhance chemical stability, reduce glass viscosity at high temperature, and promote glass melting and clarification. However, when the temperature decreases, the viscosity increases rapidly and the forming operation is difficult. The raw materials cited 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 often industrial ZnO and BaCO3, BaSO4 or Ba(NO3)2. Adding PbO to glass can significantly increase the refractive index and dispersion, and make the glass absorb short-wavelength rays. At the same time, the specific gravity increases, the melting temperature decreases, and the wettability with metal is good. The reference raw materials of PbO are red lead and yellow lead or industrial lead nitrate.
In addition, cullet is also a main raw material, often called clinker, which can be melted at a lower temperature and helps to melt the glass batch.
Auxiliary raw materials
Generally include clarifiers, colorants, decolorizers, opacifiers, fluxes, etc.
① Clarifying agent: decomposes and emits gas during glass melting, and accelerates the discharge of bubbles from the glass melt. There are white arsenic, antimony oxide, nitrate, sodium antimonate, Glauber's salt and so on.
②Coloring agent: make the glass have various colors, usually compounds of transition metals Co, Ni, Mn, Cr, Cu, Fe, CdS, CdSe, Se, Au, Ag, etc.
③ Decolorizing agent: decolorizing is divided into chemical decolorizing and physical decolorizing. Chemical decolorization is the addition of oxidizing agents to oxidize colored compounds into colorless or light-colored compounds. Physical decolorization is based on the principle of complementary colors, adding colorants to offset the color of impurities such as FeO, Fe2O3, Cr2O3, TiO2 and so on. For example, iron oxide makes the glass green, usually adding nitrate and cerium oxide to oxidize iron to a high price, and the coloring power is weakened. Compounds of Se, Co, Ni, and Mn can also be added to produce reddish purple, which complements the turquoise of Fe compounds to become colorless, but reduces the light transmittance.
④ Opacifier: When the glass is cooled, dense crystals are precipitated, which scatter light and become opaque. Fluorides such as crystal stone, sodium fluorosilicate and phosphates such as calcium phosphate are commonly used.