Compressive behaviour of polypropylene filled with iron ore tailings

Abstract

Purpose – This paper aims to produce iron ore tailings reinforced polypropylene composites (ITR-PPCs) from conventional compo-casting (CC) and a proposed compo-indirect squeeze casting (C-ISC) processes. It intends to quantify the compressive behaviour of ITR-PPC with respect to production process, iron ore tailings volume and particle size inclusion in polypropylene (PP) through controlled material and compressive testing. The study aims to provide useful information on possibility of the use of ITR-PP for compressive applications which will culminate to judicious use of iron ore tailings that is been piled up as waste material at the iron ore beneficiation sites. Design/methodology/approach – ITR-PPC compression specimens were produced using C-ISC and CC processes. Prior to production, the iron ore tailings was dried at room temperature according to ASTM 618, ASTM 171 and ASTM E 41. The different particle sizes were generated using standard laboratory sieves. Uniaxial compressive test procedure according to ASTM D 695 was carried out on ITR-PPC compression specimens with length/diameter ratio equal to 2.0 under standard laboratory atmosphere on an Instrom 3,369 machine. Findings – It was discovered that pure PP produced using the C-ISC process exhibited better compressive strength and Young’s modulus of about 12 and 4.5 per cent, respectively, while a reduction of 9.2 per cent in yield strength was recorded. ITR-PPCs with 150-μm fillers produced from C-ISC process have lower yield stress, compressive strength and Young’s modulus at volume contents above 10 per cent. It also exhibited lower strain at fracture at volume content above 15 per cent, while composites filled with 212- and 300-μm particle size iron ore tailings using the C-ISC process had better strain at fracture. Research limitations/implications – The present work cannot ascertain the compressive behaviour of ITR-PPC produced from other production processes, hence the need for further work in this area. Practical implications – The paper provides an avenue to address the pollutant effect of iron ore tailings by putting it to judicious use through addition as fillers in plastics. It also removes the need for expensive and repeated experimentation to determine the compressive behaviour of ITR-PPCs. Originality/value – This paper has brought to fore the need to study iron ore tailings as filler in plastics and other material matrices.