Abstract
Mining activities are inevitable for the growing industrialization and urbanization in the world. Disposal of mine tailings creates a severe impact to the environment and ultimately to the society. Identifying the applications of mine tailings as potential secondary raw materials would help the mining industries in achieving circular economy. Alkali activation of tailings for their utilization as building materials or backfill in mining sites is one such popular technique. In this paper, mechanically treated silicate tailings rich in magnesium/aluminum content were chosen, to be used as aluminosilicate precursors. The effect of different alkaline sources was accessed by using sodium silicate (Na2SiO3), sodium sulphate (Na2SO4) and sodium carbonate (Na2CO3) as activators. Alkali activated tailings pastes were studied by examining the compressive strength and microstructural properties. High magnesium tailings show good strength results with sodium silicate activator whereas sulphate-based activator performed well in high alumina tailings. Sodium carbonate seems to be efficient in early phases but does not display improvement in later ages. This behavior of alkali activated tailings with different alkali sources were tried to be correlated with the mineralogy of the tailings and its reactivity using FTIR, XRD and TGA.
Highlights
Mining industry produces billions of tons of different solid waste streams during the mining operations
Positive influence of magnesium is the formation of hydrotalcite which is known for its effect on strength development [18,19]
In the presence of magnesium oxide and calcium sil icates in the system, akermanite can be formed as a hydration product as well [24], as is the case in the present system with high magnesium (HM) tailings
Summary
Mining industry produces billions of tons of different solid waste streams during the mining operations. Most of the tailings are landfilled into the open environment near mining sites, mainly under water coverage to prevent their contact with the environment. Such management technologies require expensive and massive constructions and controlling during mining and longer after its closure [2]. A possible method to utilize mine tailings is solidification/stabi lization by alkali-activation technology [2,3,4]. Alkali activated materials can be produced by mixing silicon and aluminum rich raw materials with highly alkaline solution. Besides the Si and Al, elements such as Fe, Mg and Ca, can react in the matrix formation producing other solid phases, which can affect the final properties of the structure [5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
