(85f) Breakage of Frac and Tailing Sands in Centrifugal Pumps

A natural proppant for hydraulic fracturing, known as frac sand, is currently widely used as a substitute for manufactured proppants, which are considerably more expensive to produce. However, frac sand is significantly more costly than, for example, speciality or construction sand, as its preparation involves washing, classification, and dewatering to meet the required specifications. The mineral industry is well-versed in unit operations such as solids washing, size classification, and solids separation, all of which may produce unwanted solids tailings. Some of these tailings could be easily converted to frac sand. In this work, we compare particle size distributions (PSD) and the degree of particle breakage of frac and tailings sand - the latter is currently backfilled at a high cost in tailings ponds. Optical image analysis was used to measure PSDs of the two types of sand before and after slurry circulation by a centrifugal pump. The difference between the cumulative particle size distributions, before and after the centrifugal pump circulation, was used as a measure of particle strength. Accurate PSD measurements were further analysed to extract very detailed information about particle breakage behaviour. Critical effects of the slurry solids concentration and slurry residence time on breakage behaviour of sand were assessed.