Use of secondary mineralizing raw materials in cement production. A case study of a wolframite-stibnite ore

It has been found that certain foreign elements, despite their low concentration in cement raw mix, improve the reactivity of the cement raw mix. The aim of this research is to investigate the possibility of introducing small amounts of minerals, containing these elements, into the cement raw mix. A stibnite-wolframite mineral was selected in order to introduce W, Sb and S in the cement raw mix. One reference mixture and four modified mixtures, containing 0.5%, 1.0%, 1.5% and 2.0% w/w of the above mineral, were examined. The reactivity of the mixture, the sintering reactions, and the structure of the products were studied. In addition, the hydration rate and some typical properties of cements, produced from the modified clinkers, were measured. It was concluded that the added mineral improves the burnability of the cement raw mixture without affecting significantly the hydration rate and the cement properties.