ELIMINATION OF SOLVENTS AND WASTE BY USING SUPERCRITICAL CARBON DIOXIDE IN PRECISION CLEANING

Physiochemical properties of supercritical carbon dioxide make it ideally suited for removing com-monly encountered contaminants found in the precision cleaning of optical components, computer parts, and electronic assemblies. Data will be presented on a survey demonstrating the successful removal of cutting and machine oils, silicone oils, body oils and hydraulic fluids from a variety of surfaces with supercritical carbon dioxide to, at, or below precision cleaning standards (less than 10 micrograms of contaminant per square centimeter of surface). Replicate studies were performed in both a small bench-scale unit (10 milliliter cleaning vessel) and in a large-scale unit (60 liter, 14 inch diameter cleaning vessel) showing the ability to scale small experiments to commercial sizes. Appli-cability of this supercritical fluid cleaning technique to commercial operations was evaluated in the areas of contaminant removal efficiencies, surface interactions, operational costs, and environmental waste reduction/elimination. Los Alamos National Laboratory ID Number LA-UR-94-331