A key constituent of many blended cements is blast furnace slag which replaces a proportion of the clinker during the cement’s production. It is well known that this approach not only brings environmental and economic benefits to the production process, but can also confer additional properties on the cement itself. As with all raw materials, determining and controlling the chemical composition of the slag is critical to the quality and integrity of the cement produced. Quantifying the major and minor element oxides is especially important. Here we report on the analysis of slag using an energy dispersive X-ray fluorescence spectrometer (MiniPal QC, from PANalytical) that can make all measurements in air. This is in contrast with other systems which mostly require a sophisticated vacuum system or a helium atmosphere to boost sensitivity for the light elements.
X-ray slag monitoring
According to market research published by the Freedonia Group in June 2006, global demand for cement is forecast to ‘grow to 4.7 per cent yearly through 2010’. While demand for Portland cement, which currently accounts for three-quarters of all cement sales worldwide, will be healthy, sales of blended cements are expected to climb at a faster pace. Similarly, the Slag Cement Association reports a 14-fold increase in blended cement shipments in the period 1996 to 2005.