Experiences with continuous on-stream XRD at the Ash Grove Leamington plant

An on-stream X-ray diffraction analyzer has been monitoring the finished cement at the Ash Grove Leamington plant since October 2001. The complete mineralogical composition of the cement is provided by continuous analysis of cement extracted from the product conveyor with results presented as trends. The analyzer has been operating well, showing consistent agreement with traditional forms of analysis such as XRF and free lime titration. Trends of the XRD analysis have been used to identify contamination of the gypsum additive, and variation of the gypsum hydration states can be clearly seen. The XRD analysis has been used to control the rate of gypsum addition to the finish mill, starting from mid-2002. Further control loops are expected as relationships between mineralogy, strength and setting times evolve, The continuous XRD has provided plant personnel with a dynamic real time trend window into the quality of their cement production process.