Mine Tailing as Alternative to Clay for Producing Belite Cement Clinker

Abstract

In this study, with iron ore tailing as an alternative to clay, three belite cement clinker samples were prepared in a muffle furnace at 1400°C for 10, 20 and 30 minutes respectively. And calcium sulphate and calcium fluoride were used as composite mineralizer with attempt to decrease clinkering temperature and improve hydraulic activity of dicalcium silicate. QXRD analysis shows that the major mineral components of the clinker are dicalcium silicate,account for over 80% of clinker, and trace amount of tricalcium silicate and ferrite. Scanning Electron Microscope (SEM) analysis indicates that mineral grains were growing with the prolonged soaking duration. EDS analysis identified that C2S has a Ca/Si ratio varying from 2.07 to 2.32. And XPS analysis shows substantial amount of S and F atoms indented on clinker surface. Using 4×4×16cm mortar specimen, the mechanical strength of belite cement with 5% gypsum addition was investigated based on Chinese National Standard. The testing results show that three belite clinkers give very promising strength development at early ages, and very high strength gain was achieved at 28 days. In addition, this belite cement has a Lime Saturation Factor (LSF) of 0.76, which make it have potential for significant CO2 emission reduction. Also, more than 35% iron ore tailing was exhausted for producing unit ton of belite cement clinker. High utilization rate leads to not only mineral waste exhaustion, also environmental improvement.