Abstract: Highly pure aqueous solution of ammonia, typically electronics grade for use in semiconductor manufacturing is prepared by passing a solution of ammonia through at least one cation exchange resin bed to remove substantially all of the cation contaminants; subsequently passing the cation exchange resin effluent through at least one anion exchange resin; and recovering an aqueous solution of ammonia product substantially free of ionic contaminants.
Abstract: An apparatus and method for blending a solute and a solvent to form a solution product which substantially eliminates starting material and product operational loss while improving environmental safety both in the workplace and the ambient atmosphere. The apparatus and method employ a closed system and controls which remove substances from the overhead vapors generated in the various units by employing separate and distinct filtering systems. A high efficiency particulate air filter (HEPA) is employed in a closed solute supply means. A demister device is in fluid communication with the vent of the mixing vessel unit to remove solvent and solution products, to form droplets from the exhaust stream and return them to the mixing tank and discharging the exhaust stream without stress to the environment.