Types, uses and processes of quartz glass

        Quartz glass is made by melting all kinds of pure natural quartz (such as crystal, quartz sand, etc.). The coefficient of linear expansion is very small, which is 1 / 10 ~ 1 / 20 of that of ordinary glass. It has good thermal shock resistance. Its heat resistance is very high. Its regular use temperature is 1100 ℃ ~ 1200 ℃, and its short-term use temperature can reach 1400 ℃. Equipment for refining high purity glass and special quartz products. Because it has high spectral transmission and will not be damaged by radiation (other glasses will darken after being irradiated by radiation), it is also an ideal glass for spacecraft, wind tunnel window and spectrophotometer optical system. 

       Quartz glass is a kind of special industrial technology glass with single component of silica. The glass has high hardness up to Mohs 7, high temperature resistance, low expansion coefficient, good heat shock resistance, chemical stability and electrical insulation, and can pass through ultraviolet and infrared rays. Except hydrofluoric acid and hot phosphoric acid, it has good acid resistance to general acids. According to transparency, it can be divided into two categories: transparent and opaque. According to the purity, it can be divided into three categories: high purity, ordinary and doped. It is made of crystal, silica and silicide by high temperature melting or chemical vapor deposition. Melting methods include electric melting method, gas refining method, etc.

There are two kinds of quartz glass: transparent and opaque. Transparent and unsightly quartz glass are the most economically valuable materials used in industry and scientific research. The raw materials used in its manufacturing (smelting method) are crystal or high-purity and ultra-high-purity quartz sand (transparent quartz glass) and white quartz sand (opaque quartz glass). These two kinds of raw materials exist in nature and are composed of the purest SiO2.

        Quartz glass and crystal have the same chemical composition, but they are very different in structure. One is glassy and the other is crystalline. Crystal can not withstand high-temperature thermal shock. It will break and transform into other crystals when it meets high temperature, while quartz glass can withstand the impact of extremely high temperature. The manufacture of transparent quartz glass and opaque quartz glass requires high temperature, because crystalline SiO2 can only melt above 1713 ℃.

Properties of quartz glass

        Quartz glass is called the "king of glass" because it has a series of special physical and chemical properties.

The chemical composition of quartz glass is a single component of SiO2, which is usually called purity.

        Lighting quartz glass

        Quartz glass for semiconductor industry

        Thermal properties of quartz glass

        Temperature resistance

        Thermal stability

        Volatilization of quartz glass at high temperature

        Specific heat and thermal conductivity

        Crystallinity of quartz glass (also known as crystallization or devitrification)

        Discoloration of quartz glass at high temperature

        The properties of quartz glass mentioned above are transparent quartz glass. Other varieties of quartz glass (milky quartz glass, quartz ceramics, opaque quartz glass, quartz cotton, quartz fiber, etc.) also have their own special properties.

        Main varieties and uses of quartz glass

        The variety and use of quartz glass are closely related. Users require to manufacture the quartz glass they need according to the characteristics of quartz glass, which leads to the variety of quartz glass. The new variety improves the performance and quality of quartz glass and promotes the development of quartz glass industry. Almost all walks of life use quartz glass, but because the process of quartz glass products is complex and the price of raw materials is expensive, the price of quartz glass is also expensive, which limits the extensive use of quartz glass. The main varieties and uses of quartz glass are briefly introduced here.

        Quartz glass for discharge tubes

        Transparent quartz glass is widely used in mercury lamp, ultra-high pressure mercury lamp, xenon lamp, ultraviolet lamp, iodine tungsten lamp, halogen lamp, gas laser lamp, metal halide lamp and other electric light sources because of its excellent light transmission and heat resistance from ultraviolet region to infrared region. It is the leading large user of quartz glass in China and the second largest user in foreign countries (the leading large user is semiconductor technology). The primary task is to improve the quality, Strive for more exports.

        Quartz glass for semiconductor industry (electronic industry)

        Quartz glass for infrared heater

        Opaque quartz glass (opal quartz glass) is used to manufacture infrared heaters, heaters and crystal heaters, with an annual consumption of nearly 1000 tons of opal quartz glass tubes. It is mainly used for electroplating solution heating, acid heating, household heating, heating of tempered glass, baking channels for paint baking in industry (bicycle, automobile, etc.), baking channels in food, papermaking and textile industries, etc.

        Quartz glass for various acid resistant containers

        Due to its excellent acid resistance and heat resistance, it is widely used in the field of chemical industry. Such as hydrochloric acid synthesis device; Combustion, cooling and guiding device of high temperature acid gas; Evaporation, cooling, absorption and storage device of acid solution, manufacturing device of distilled water, hydrochloric acid, sulfuric acid and nitric acid; Chlorination reaction vessel;                          Distillation tower filling, steam heating and stirring device; Acid resistant valve; Filter plate, etc.

        Quartz glass for electrical insulation

        Because of its excellent electrical insulation and heat resistance, quartz glass is used in kertier electrostatic integrator, high-frequency and various electrical meter insulation materials, power plant boiler liquid level pipe, high-voltage insulation pipe, etc.

        Various quartz glass containers for firing

        Because quartz glass is a pure sintered material without pollution, it can be used as a sintering container of phosphor materials and various cups and plates.

        Protective tube quartz glass

        Quartz glass is widely used in the protection tube of general thermometer; In addition, it can also be used as an indispensable material for the temperature measurement of immersion pyrometer protection tube and steel.

        Quartz glass for metallurgical industry

        Because of its excellent heat resistance, quartz glass can be used as tubes for oxygen and carbon analysis of open hearth and blast furnace; Quartz glass for steel-making continuous injection and rolling steel outlet; Quartz glass for smelting precious metals, gold and platinum; Quartz glass for nonferrous metal smelting (aluminum and alloy, fusible metal evaporation tank), etc.

        Quartz glass for furnace core tube

        Due to its excellent electrical performance, heat resistance and air tightness, quartz glass can be used as the core tube and outer tube of electric furnace, gas furnace and high-frequency furnace, as well as air, various gases and vacuum furnace.

        Quartz glass for various physical and chemical instruments

        Because quartz glass has many excellent characteristics, it can be used for parts of dilatometer, thermal balance, electrical meter, spring balance, seismometer, analytical appliances such as flask, beaker, evaporating dish, crucible, boat, sulfur quantitative device, condenser, absorption capacity running sleeve for spectrophotometer and other physical and chemical experimental supplies.

        Optical quartz glass

        Because quartz glass has high ultraviolet transmittance, heat resistance and low expansion, it can be used for window glass for schlieren photography, lens and window glass for heat resistance, mirror and prism for reflection telescope, window glass for gas laser, optical standard, etc. In addition, because quartz glass does not contain components other than SiO2, it can be used as crucible and tube for optical glass melting.

        Quartz glass for optical communication and high-tech

80% of the world's information business is transmitted by optical fiber. The development of optical fiber industry is of more strategic significance. The development of optical fiber is inseparable from quartz glass, because optical fiber is quartz glass fiber. The production of quartz glass fiber requires quartz glass preform and quartz glass sheath tube. Due to the high purity requirements of this kind of quartz glass, German Holly's company produces special product heralux-wg quartz glass tube, which is up to 3500 yuan per kilogram. Foreign imported tubes are widely used in the production of optical fibers in China. In addition, quartz glass is needed in high-tech fields such as bioengineering, optical communication technology, atomic energy technology, laser technology, aviation technology and aerospace technology. Quartz glass is widely used and is a very important new material.