In general, the silica gel according to their nature and components can be divided into organic and inorganic silica gel two broad categories. Inorganic silica is a highly active adsorption material, usually with sodium silicate and sulfuric acid reaction, and by the aging, a series of acid bubble and post-processing system must process. An amorphous silica material, the chemical formula for mSiO2. nH2O. Do not dissolve in water and any solvent, non-toxic tasteless, chemically stable, with the exception of alkali, hydrofluoric acid addition does not react with any material. Various types of silica because of their different manufacturing methods and the formation of different pore structure. Silica gel chemical composition and physical structure, and decided it has many other materials can hardly be substituted by similar characteristics: high adsorption properties, thermal stability, and chemical properties of stability, high mechanical strength. Silica gel according to the size of its aperture is divided into: Macroporous silica gel, silica rough hole, B-type silica gel, silica gel pore. Pore structure as a result of the different adsorption properties of their own characteristics. Coarse pore silica with high relative humidity in the case of a higher adsorption capacity, pore silica with lower relative humidity in the case of adsorption pore volume of silica gel is higher than crude, and the B-type silica gel pore structure as a result of referral in the rough, among the pore, between the adsorption amount of thick, between the pore. Macroporous silica gel used as catalyst support in general, extinction agent, abrasive, such as toothpaste. And should therefore be based on different uses of different species. Safety Performance Main ingredient is silica gel, chemically stable, non-burning. Silica is an amorphous silica, the dust content of the workshop should be controlled not more than 10 mg / cu m, the need to enhance the ventilation, wear a mask operation. Silica gel has a strong adsorption capacity of people to have a dry skin effect, therefore, the operation should be good to wear overalls. If the silica gel into the eyes of a great deal of water washing, seek medical treatment as soon as possible. Blue silica gel containing a small amount of cobalt chloride, toxic, should be avoided and food contact and inhalation of the mouth, such as the occurrence of poisoning should immediately seek medical treatment. Silica gel in the course of the medium due to absorption of water vapor or other organic matter, adsorption ability can be used repeatedly after regeneration. First, silica gel after steam regeneration of Adsorbed Water Silica gel after absorption of water through thermal desorption way to remove water, heating in different ways, such as electric stoves, flue waste heat such as heating and hot air drying. Desorption heating in the temperature control 120 - 180 ℃ appropriate, for the Blue plastic indicator, color gel, DL-type control in the blue silica gel 100 - 120 ℃ appropriate. A variety of renewable sources of industrial silica gel at the time of maximum temperature should not exceed the following limits: Coarse pore silica shall not exceed 600 ℃; Pore silica shall not exceed 200 ℃; Blue plastic indicator agent (silica gel or discoloration) not higher than 120 ℃; Si-Al-plastic shall not exceed 350 ℃. Regeneration after the silica gel, the water in the 2% of the general control of the following can be used to re-enter. Second, after the silica gel adsorption of organic impurities in the renewable ⒈ Roasting Pore silica gel for the crude can be gradually warming up on the roaster to 500 - 600 ℃, after about 6-8 hours to particles can be white or brown. Of pore silica gel, calcination temperature should not exceed 200 ℃. ⒉ rinse method To silica in the saturated water vapor to reach saturation in the adsorption heat in the water after the rinsing water and detergent to remove a combination of waste oil or other organic impurities, and then dried after washing by clean water dehydration. ⒊ solvent washing method Adsorption of organic matter in accordance with the type of silica gel, suitable solvents will be absorbed on the organic silica dissolution, and then heated to gel the solvent removal. Third, silicone should be noted that the issue of renewable Caution should be taken when drying 1.renewable master a gradual increase in temperature, so as to avoid severe drying cracks caused by particles and reduce the recovery rate. ⒉ regeneration of silica calcination temperature is too high will cause changes in pore structure of silica gel and significantly reduce the adsorption effects, the impact of use value. The blue silica gel indicator or change, renewable desorption temperature should not exceed 120 ℃, otherwise they will be gradually reagent oxidation and the role of loss of color. ⒊ by silica gel regeneration should normally be after the screening to remove fine particles, so that uniform particles. Storage and packaging Silica gel with a strong moisture absorption ability, and should therefore be stored in a dry place, packaging and have a shelf between the ground. Packaging, there are steel drums, drum, carton, plastic bottle, polyethylene plastic compound bag, flexible container bags, etc.. Category specific packaging requirements, see product descriptions. During transport to avoid the rain, damp and exposure. Organic silicone products is the basic structural unit of silicon - oxygen chain composition, side-chain through the silicon atoms and other types of organic groups linked to. As a result, the structure of organic silicon products that contain both "organic group" and contain "inorganic structure", this particular composition and molecular structure of organic matter so that it sets the characteristics and functions of the inorganic. Compared with other polymer materials, silicone products, the performance of the most prominent are: 1. Temperature characteristics Silicone products are silicon - oxygen (Si-O) bond structure of the main chain, C-C bond to 82.6 kcal / mol, Si-O bond in silicone for 121 kcal / mole, so silicone products, high thermal stability, high temperature (or radiation) of the chemical bonds in molecules are not broken, do not break down. Silicone will not only heat, but also resistant to low temperature, can be a very wide temperature range. Whether it is physical or chemical properties of mechanical properties, as a function of temperature are small. 2. Weatherability Silicone Products for the main chain-Si-O-, unique key and therefore can not easily be decomposed by ultraviolet light and ozone. Than other silicone polymer materials, as well as better thermal stability and weathering resistant ability irradiation. Silicone in the natural environment of up to several decades of life. 3. Electrical insulation properties Silicone products have good electrical insulation properties, the dielectric loss resistance, voltage, arc resistance, corona resistance, volume resistivity and surface resistivity of insulating materials, etc. in the top, and their electrical properties by the temperature and frequency little impact. Therefore, they are a stable electrical insulation materials, are widely used in electronics and electrical industries. In addition to silicone has excellent heat resistance, but also has excellent water-based resist, which is electrica |
