A Process-Based Method for Substitution of Hazardous Chemicals and its Application to Metal Degreasing

ABSTRACT

To reduce risk due to dangerous chemicals a process-based method has been developed. The method includes: listing chemical products; obtaining information on composition; developing data sheets; describing the processes; assessing the risk; and providing possibilities for substitution. In a substitution, the chemicals in the final situation should be potentially less dangerous than in the initial situation. A substitution may consist of the introduction of new chemicals, new process design or even a new processs. It is especially important to avoid chemicals with long-term effects.

The method has been applied to metal degreasing, manually and by vapor degreasing, dipping, lye-boiling, high pressure hosing and electrodegreasing. The main strategy is to substitute from the use of organic solvents to aqueous alkaline solutions. Another substitution is from cyanide to phosphate solutions in electrodegreasing. Degreasing solutions can be recirculated, e.g. through an ultrafiltration unit, reducing environmental problems.