FORMULATION AND RECYCLING OF WATER-BASED DEGREASING AGENTS - EFFECTS ON OCCUPATIONAL-HEALTH AND ENVIRONMENTAL-PROTECTION

In metal degreasing, aqueous alkaline solutions can often be substitut ed for organic solvents. Such water-based degreasing agents should be formulated so that associated negative impacts on occupational health and the environment are minimized. With these goals in mind, a review and an evaluation of chemicals utilization in water-based degreasing a gents has been carried out. These include strongly alkaline agents, so dium metasilicate, complexing agents, corrosion inhibitors, surfactant s, organic solvents, bactericides, coloring agents, and perfumes. In a shop test a water-based degreasing agent formulated in accordance wit h these criteria has been shown to be able to degrease aluminum parts contaminated with oils from a draw process to an acceptable duality of cleanness before burnishing. By recycling the degreasing agent in a m icrofiltration unit it was possible to increase the service life of th e bath 5 times, and to reduce the use of chemicals such as the builder component to 20%, the surfactant component to 30%, and water utilizat ion for setting up baths to 20%. Further, process down time has been d ecreased for emptying and setting up baths thereby also reducing the a ttendant occupational health and safety risks. There is a need for fur ther tests of other degreasing agents formulated with the same criteri a for additional metals and metal parts with different contamination a nd cleanliness standards. New developments in microfiltration units sh ould also be exploited.