Evaluation of Compaction Characteristics of Iron Ore Tailings Treated Bentonite

Abstract

This paper reports the evaluation of compaction parameters (optimum moisture content and maximum dry density) of Iron Ore Tailings mixed with bentonite (IOT-bentonite mixtures) as a potential material for landfill liner purposes. Different percentages of bentonite (20, 25, 30, 35 and 40%) by dry weight of IOT were added to IOT and the mixtures evaluated in this study. Laboratory tests to evaluate the index properties and compaction characteristics of the mixtures were conducted. The index properties of the mixtures were also seen to improve with increase in bentonite content. The liquid limits of the mixtures containing 25 to 40% were seen to increase from 31 to 34.5% while their plasticity index also increased from 12.1 to 19.8%. These values satisfy the liquid limit and plasticity index requirements for landfill liners as reported in some regulatory codes. The mixtures were compacted using three compactive efforts namely British Standard Light (BSL), West African Standard (WAS) and British Standard Heavy (BSH) which simulates compaction efforts expected in the field. Findings show an increasing trend in the Optimum Moisture Content (OMC) and decreasing trend in the Maximum Dry Density (MDD) of the mixtures with increase in bentonite content. The OMC increased from 13.0 to 16.9% for BSL, 11.0 to 12.8% for WAS and 8.8 to 10.1% for BSH. While their MDDs decreased from 2.34 to 2.14 g/cm3 for BSL, 2.47 to 2.38g/cm3 for WAS and 2.5 to 2.42g/cm3 for BSH