Evaluation and comparison of mineralogical, micromeritics and rheological properties of waste machining chips, coal fly ash particulates with metal and ceramic powders

Abstract

In this article, a detailed mineralogical, micromeritics and rheological study of the materials such as Fe powder, SiC powder, Al 2 O 3 powder, WC powder, coal fly ash (CFA), mild steel turning chips (MSTCs), mild steel grinding chips (MSGCs) and aluminium saw chips (ASCs) is presented. The elemental characterization of these materials was carried out using Energy-dispersive X-ray spectroscopy (EDS). The morphology of these materials was investigated using Field emission electron microscopy (FESEM). The particle size and their distribution were evaluated by processing FESEM micrographs through ImageJ software. The apparent and tap densities were estimated as per ASTM standards. The flowability of the materials was estimated through Hausner ratio, Carr’s index and further validated by angle of repose. During the analysis of the characterization results, it was perceived that the density and the morphology of the powder particles, particulates and steel chips have a significant influence on their derived properties. However, the apparent density was found to have significant influence on the angle of repose and flowability of the material under consideration. The spherical morphology of the particulates rendered them with acceptable flowability. The sharp-edged and agglomerated particulates resulted in a higher angle of repose and lower flowability. However, among the chips, MSGCs possess suitable micromeritic and rheological characteristics, which make them suitable to be processed through powder metallurgy techniques. Further, MSTCs and ASCs exhibited suitable rheological properties comparable with the powder produced through traditional methods. The results demonstrate that the waste metallic chips can be directly recycled through powder metallurgy, circumventing the time consumed in ball milling operation. • Mineralogical, micromeritics and rheological investigations of powders and waste chips. • Flowability observations through apparent density, sphericity and various charges. • Investigations based on Hausner ratio, Carr’s index and angle of repose. • Waste chips processed through powder metallurgy is established as treasures.