Volumetric Feeder for Fumed Silica

Fumed silica is also known as pyrogenic silica because it is produced in flame pyrolysis of silicon tetrachloride or from quartz sand vaporized in a 3000 °C electric arc. Fumed Silica consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles, agglomerating into tertiary particles. The resulting powder has an extremely low bulk density of 2.5-11.8 lbs/ft3 (40–190 kg/m3), a primary particle size of 5–50 nm (smaller than the average particle from cigarette smoke), and a high surface area. Fumed silica is a universal thickening agent and an anticaking agent (free-flow agent) in powders. It is used in cosmetics for its light-diffusing properties. It is used as a light abrasive in products like toothpaste. Other uses include filler in silicone elastomer and viscosity adjustment in paints, coatings, printing inks, adhesives, and unsaturated polyester resins. Because of its very low bulk density and small particle size, fumed silica is a challenging material to feed accurately into the process. Vibra Screw has been metering fumed silica with our controlled vibration screw feeders for decades. The photo shows a Vibra Screw Live Bottom Bin and a 2” VersiFeeder volumetric screw feeder. Both works use controlled vibration to de-aerate the material to a constant bulk density and ensure the flights of the feed screw are filled with material. Typical feed accuracy of 1-2% can be obtained. If you are looking for high quality, high purity, and cost-effective Fumed Silica, or if you require the latest price of Fumed Silica, please feel free to email contact mis-asia.

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