Recovery of Cr from chrome-containing leather wastes to develop aluminum-based composite material along with Al2O3 ceramic particles: An ingenious approach

Abstract

Leather industries cause soil pollution in terms of leather wastes. Chrome-containing leather wastes (CCLW) also cause various types of pollutions such as air and soil pollution. The utilization of CCLW in the development of aluminum-based composite is the emerging area in the synthesis of materials. In this study, chromium(Cr) in the form of collagen powder was extracted from CCLW. Extracted collagen powder was ball milled with alumina particles for 12.5, 25, 50, 75, and 100 h. The average density of the mixture of ball-milled collagen and alumina particles was reduced by about 1.20% after ball milling for about 100 h. The stir casting technique was employed to develop the aluminum-based composite material. The ball-milled reinforced aluminum-based composite material showed a fair distribution of reinforcement particles as compared without ball-milled reinforced composite material. Tensile strength and hardness of composite material improved by about 35.53 and 46.61%, respectively, after using the mixture of ball-milled 5% collagen powder and 5% alumina particles in the aluminum alloy. However, ductility and toughness were reduced. Corrosion weight loss and thermal expansion of the Al/5% collagen/5% alumina particles with ball-milled composite were found to be 0.022 mg and 5.44 mm3, respectively. X-Ray diffraction of the Al/5% collagen/5% alumina particles with ball-milled composite showed the presence of Al, Al2O3, Cr2O3, and Cr phases. The presence of hard phases such as Al2O3, Cr2O3, and Cr was responsible for enhancing the hardness and tensile strength of the composite. The developed composite material can be utilized in the fabrication of engine blocks, connecting rods, and piston rings.