Development and performance analysis of wear resistant polypropylene composites filled with micro sized Linz–Donawitz sludge particulates

Abstract

Integrated steel plants, in general, produce large amounts of solid wastes during the production of iron and steel. Linz–Donawitz sludge (LDS) is an industrial solid waste generated in huge quantities during steelmaking. These fine solid particles were recovered after wet cleaning of the gas emerging from LD converters. This work aims at processing, characterization, and wear response of a class of polypropylene composites utilizing LDS as a filler material. Mechanical properties of these thermoplastic composites were evaluated under standard test conditions. The actual and the theoretical density values of the polypropylene-LDS composites were measured using Archimedes’ principle and rule of mixture respectively. The micro-structural features of the worn surfaces of various particulate filled composite specimens were examined using scanning electron microscopy in order to ascertain the wear mechanisms. X-Ray Diffraction analysis was carried out to determine the phases and planes of the components present within a material. Sliding wear tests were conducted using Taguchi’s L25 orthogonal arrays over a range of sliding velocities (0.63–3.15 m/s), normal loads (5–25  N), sliding distances (500–2500 m), and LDS contents (0–20 wt.%). The sliding wear tests were performed on the prepared polypropylene-LDS composite specimens as per ASTM G99 using Taguchi’s Orthogonal Arrays followed by the parametric appraisal of the wear process by response surface methodology (RSM). Both Taguchi analysis and RSM suggest that the filler content and the sliding velocity are the most significant factors affecting the specific wear rate of the composite specimens. This work opens up a new avenue for the utilization of LD sludge as a potential filler material.