RECOVERY AND REUSE OF WASTE CALCIUM/SODIUM SOAPS USED IN WIRE DRAWING PROCESSES

Çetinkaya G., Birol B., Gençten M.

Eskişehir Technical University Journal of Science and and Technology A- Applied Sciences and Engineering, vol.27, no.2, pp.254-263, 2026 (TRDizin)

Abstract

In this study, the recovery of dry soap-based (calcium/sodium) lubricants used and discarded in wire drawing processes was investigated. The chemical structure of the waste soaps was analyzed using FT-IR, XRF, TG/DTA, and SEM techniques. While no significant chemical degradation was observed in the soaps after use, a considerable increase in metallic contaminants, particularly iron, was detected. Therefore, chemical cleaning with HCl at various concentrations was applied to remove iron from the waste soaps. The optimal recovery conditions were achieved with 0.5 M HCl treatment for 8 hours at 60 °C. Under these conditions, the chemical structure of the soap was preserved, the iron content was significantly reduced, and the morphology closely resembled that of the original soap. The findings demonstrate the reusability of the waste soaps and offer a sustainable recovery approach for industrial applications.