Abstract:
Metalworking fluids (MWFs) can be regenerated and stabilized by the controlled addition of a chelating agent. The resulting sequestration of the dissolved metals in the MWF has been found to reduce incidence of dermatitis, to control the growth of microbes including bacteria and fungi, and to reduce the generation of odors, all without the further addition of fresh (virgin) MWF or a conventional biocide. Apparatus useful for this control includes monitoring means for determining the presence of free metal ions in the MWF, testing means for determining the concentration of free metal ions if present, and addition means for adding, in a controlled manner, a chelating agent for sequestering the free metal ions.