Semiaqueous Overview Semiaqueous solutions are semistable mixtures of water and solvents, also called emulsions. Semiaqueous cleaning also includes processes where parts are first cleaned in a solvent, then rinsed in water. The solvents are usually volatile organic compounds (VOCs) such as terpenes, glycol ethers, esters, or hydrocarbons. These solvents are also flammable when used by themselves, or pure. Most semiaqueous solutions leave a residue that can be removed with a water rinse. Sometimes the film is left on the part as a protective coating. Semiaqueous solutions can be very effective for cleaning parts with heavy soil loadings. Examples of soils they clean well are oils, greases, rosin flux, and drawing compounds. The semiaqueous processes usually require at least a partially closed-loop process where the used semiaqueous solution is collected then separated in a decanter. This produces two waste streams, water and solvent. The water can be recycled, and the solvent can often be filtered and reused in the wash tank. Semiaqueous systems also may be set up as completely closed-loop processes, reusing both the water and solvent in wash or rinse processes. State Information | Glossary | Conversion Checklist | Comments Home | Process Advisor | Alternatives | Links | Search All SAGE material, Copyright© 1992, Research Triangle Institute Last Update: 18 March 1995 sage@rti.org http://clean.rti.org/alt.cfm?id=se&cat=ov