The paper deals with a systematic investigation into the flow of copper slag abrasive particles through a metering valve. The investigation involves abrasive mass flow rate measurements, and the results are statistically interpreted based on DoE (Design of Experiments) and ANOVA (Analysis of Variance). Three process parameters are varied, namely static air pressure, nozzle diameter and valve opening. Abrasive mass flow rate increases if air pressure, nozzle diameter or valve opening increase. All three main factors provide statistically significant effects, whereby the strongest effect occurs due to changes in valve opening. Although a non-standardized quadratic regression model delivers a satisfactory agreement with experimental results, it misjudges the statistical significance of the process parameters. A standardization of the regression function omits multicollinear effects and simplifies the regression function. A standardized quadratic regression model is found to be capable to statistically describe the relationships in the scope of the evaluation effort. (C) 2016 Elsevier B.V. All rights reserved.