An efficient method is described for the production of reinforcing silica from porcellanite, a mineral rich in amorphous silica. The resulting silica, Dimosil~R, is produce by a low-temperature solution process without the use of caustic acids or high pressures. The highly efficient synthetic process yields silica with specific surface areas (BET) in the range of 100 -400 m~2/g. By studying a series of silicas produced in a pilot plant-reactor located at Ben Gurion University in Beer-Sheba, Israel, we show that silica with a range of morphological characteristics can be achieved including those with morphological and reinforcing characteristics similar to those of commercially available highly dispersing precipitated silica. The process is being optimized by Dimona Silica Industries with a planned annual silica production of 40,000 metric tons in 2008.The silica was evaluated using light scattering and ultra small angle x-ray scattering to determine the particle structures at different size scales. The scattering data were analyzed using a unified model and fractal scaling laws. Distinct differences were observed in the size of the primary particles, aggregates, and agglomerates, depending on the process protocol. Sonication studies were also performed to observe the break up of the agglomerated structures. The results show that the Dimona process produces silica with a ramified structure that can be tailored through processing protocol.The silica samples were incorporated into organic tire-rubber formulations and the mechanical properties were measured. The Dimosil~R-reinforced compounds were compared to compounds reinforced with conventional precipitated silica. The Dimosil~R shows excellent dispersion and reinforcement properties.
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