This semi-annual progress reports includes further findings on CO2-in-Water (C/W) emulsions stabilized by fine particles. In previous reports we described C/W emulsions using pulverized limestone (CaCO3), flyash, and a pulverized magnesium silicate mineral, lizardite, Mg3Si2O5(OH)4, which has a similar composition as the more abundant mineral, serpentine. All these materials formed stable emulsions consisting of droplets of liquid or supercritical CO2 coated with a sheath of particles dispersed in water. During this semi-annual period we experimented with pulverized beach sand (10 20 mm particle diameter). Pulverized sand produced an emulsion similar to the previously used materials. The globules are heavier than water, thus they accumulate at the bottom of the water column. Energy Dispersive X-ray (EDX) analysis revealed that the sand particles consisted mainly of SiO2. Sand is one of the most abundant materials on earth, so the economic and energy penalties of using it for ocean sequestration consist mainly of the cost of transporting the sand to the user, the capital and operating costs of the pulverizer, and the energy expenditure for mining, shipping and grinding the sand. Most likely, sand powder would be innocuous to marine organisms if released together with CO2 in the deep ocean.
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