Selection criteria for mine tailings as SCM: A Comprehensive Review of Types, Properties and Performance

Abstract

The use of mine tailings as supplementary cementitious materials (SCM) offers a sustainable solution for addressing the environmental issues faced while handling the mine tailings, and it can also address the high carbon footprint of Portland cement production. The enormous quantities of tailings that are generated all around the world from the mining sector are currently causing an alarming situation. The possibility of pollution is increasing as the consequences of frequent disposal of these tailings in tailing dams or impoundments. This paper provides a comprehensive review of mine tailings, including copper tailing, iron tailing, gold tailing, gold silver tailing, coal tailing, tungsten tailing, molybdenum tailing, boron tailing, phosphate tailing, red mud and silicate tailing as supplementary cementitious materials to reduce its negative effects on the environment. From the review of above-mentioned tailings, it is comprehended that copper and iron ore tailings are easily accessible and also possess high pozzolanic reactivity due to the presence of reactive oxides (>70 %), but they generally contain iron bearing minerals like hematite, fayalite, magnetite, which necessitate the requirement for activation methods. Gold tailings, coal tailings and silicate tailings also contain pozzolanic properties mainly due to the presence of reactive clay minerals like muscovite, kaolinite, tremolite, etc, and also due to the possession of active oxide content. Mechanical activation proved to be very reliable method in enhancing the pozzolanic potential of gold and silicate tailings, whereas coal tailing performed better with thermal activation. However, the heavy metal leaching in case of gold and coal tailings should be handled priorly before its utilization in cement matrices. Molybdenum tailing and tungsten tailing are also promising when considering their properties, but long-term availability of this tailings does not make it a promising candidate for usage as SCM. Similar with the case of phosphate tailings as the excess percentage of phosphates can hinder the hydration of cement. The optimum percentage of tailings in cement mix was observed to be between 5 % to 20 % but even higher replacement was used by employing different activation methods. Using mine tailings as SCM will be a viable option as it is a sustainable, reliable and eco-friendly option which can simultaneously tackle the environmental impacts of mining pollution and cement pollution.