| abstract |
ABSTRACT OF DISCLOSURE A method of obtaining precipitated amorphous silicas with substantially a tertiary aggregate structure (whether as an aqueous slurry, as cake, gel or otherwise) useful for coating and/or incorporation in paper and other substrates (e.g. rubber, plastics and the like) from a geothermal fluid (naturally or artificially generated - natural, including water infusion into geothermal systems) having sufficient silicic acid concentration, said method comprising: A. ageing the fluid to effect polymerization, thus establishing a silica sol, ageing meaning a process in which the source fluid after being made supersaturated with respect to amorphous silica is held for a period of time, B. optionally (prior to, with and/or after step A -preferably prior to in order to reduce arsenic adsorption) reducing the temperature of the geothermal fluid and/or sol as the case may be, C. inducing precipitation of amorphous silica from the sol under conditions that will provide the tertiary aggregate structure, and D. thereafter harvesting the amorphous silica thus precipitated. |