WATER PROTON RELAXATION IN DILUTE AND UNSATURATED SUSPENSIONS OF NONPOROUS PARTICLES

NMR water proton transverse and longitudinal relaxation time measurements are reported for aqueous suspensions of silica powder of varying silica/water ratios. For compositions ranging from the dilute suspension to the saturated randomly packed powder the relaxation is sensitive to the particle distribution function. A simple cluster model is developed to interpret the results in this regime. For compositions ranging from the saturated randomly packed suspension to the almost dry powder the relaxation is sensitive to the distribution of water throughout the packed solid matrix. A simple capillary model is developed for this regime. The models are tested on two sizes of silica particle, and the potential of NMR for studying other types of solid suspension is discussed.