FEASIBILITY OF USING X-RAY-DIFFRACTION FOR ONLINE ANALYSIS OF GYPSUM DURING WALL BOARD MANUFACTURING

A preliminary study was conducted to determine the feasibility of deve loping an on-line x-ray diffraction (XRD) monitor to determine gypsum during wall board manufacturing. Samples of bassanite (CaSO4 . 1/2H(2) O) containing 0, 1, 3, and 5% gypsum (CaSO4 . 2H(2)O) were analyzed in the laboratory using an experimental on-line XRD monitor and a conven tional x-ray diffractometer. Results of this study indicate that the d evelopment of a gypsum monitor is technically feasible. When sample pa cking was used, gypsum was detected in all of the samples containing a dded gypsum and the sensitivity was adequate to differentiate between each of the gypsum concentrations. Without sample packing, 1% gypsum c ould not be detected under the analytical conditions employed. The pre cision was reasonably good for these exploratory tests, with relative standard deviations ranging from 10-30%. Precision can probably be imp roved through instrument modifications. Once developed an on-line gyps um monitor is anticipated to cost on the order of $75,000.