Sodium polytungstate as gravity separating fluid for polymeric blasting media evaluation

Abstract

Quality assessment of Plastic Blast Media (PBM) in order to determine heavy and light particulate contamination has been carried out traditionally using gravity separation in a medium prepared using 1,1,2-trifluorotrichloroethane (TFTCE) as high density compound. Environmental concerns require the assessment of viable alternatives to ozone depleting substances like TFTCE. Sodium polytungstate (SPT) can be used to increase the density of aqueous solutions, and has been used successfully in gravity separation of minerals and rocks. Some research was carried out into the literature regarding separating microplastics – a granular contaminant in water courses that is similar to PBM-revealing that it had been carried out using concentrated solutions of metal salts. Comparison of the results obtained from the TFTCE method with results obtained from a method using SPT revealed that there is no loss of analytical accuracy by changing to the SPT method.