Developing environmentally friendly rolling lubricants

Swerea MEFOS pilot mill has been used as a rolling lubricant development tool. The objectives were to improve the lubrication during rolling and thereby improve the operation of the rolling mills. This was done taking into account both the technological aspect, rolling mill output, and the ecological aspect, investigating ways to use rolling lubricants that are more ecologic sustainable, i.e. alternatives to oil-based lubricants as well as the recycling/recovering of oil-based lubricants. Oil-in-water emulsions and an aqueous solution, by the producer termed a conditional emulsion, were tested where the lubricant formulation was altered to optimize the performance for hot rolling of aluminium. Cold-rolling tests were also run on steel coils, where the presence of rust protective oil was studied as well as the influence of aged emulsion behaviour compared with fresh emulsion. Finally, Sapa developed a vacuum evaporator system for recovering oil from dumped emulsion generated during aluminium hot rolling, followed by separation, centrifugation, and flocculation. The cleaned concentrates were reconditioned for reuse. The recycled and recovered emulsion was tested and compared with the original fresh emulsion in Swerea MEFOS pilot mill with results as good as the fresh emulsion.