Recycling of rolling oil emulsions: towards an economic and sustainable process

The main aim of the project has been to propose, evaluate and test methods for recovery of water and oil from cold rolling oil emulsions for possible recycling to the cold rolling process. This would reduce the environmental impact of cold rolling to a large extent and increase the possibilities of the rolling mills to meet future increased environmental legislations. Tests have been made in laboratory, pilot-plant and full scales. Analytical methods and function tests have been developed and tested and used for investigations of oil, emulsion and water during the recycling tests. These data are necessary in order to determine if the oil and water can be recycled or if additional treatment or additions are needed. These measurements will also give added knowledge about the influence of different emulsion parameters on the rolling properties. It is known that some compounds in the rolling oil may be transformed into potentially hazardous chemical compounds during the rolling and subsequent treatment of the oil. One part of the project has concentrated on this issue in order to increase the knowledge about the impact of rolling oils on the working environment. An LCI model has been developed as a tool, which may be used for evaluation of different alternatives for handling of used oil emulsions. The model could also be used for minimizing the environmental emissions from the cold rolling process. Alternative uses of the recovered oil phase have been assessed through a literature survey.