Cooks, M & Plaatjies, B 2012, 'Flocculant testing through the application of experimental design techniques and the application of a flocculant pipe reactor', in R Jewell, AB Fourie & A Paterson (eds), Paste 2012: Proceedings of the 15th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 169-181, https://doi.org/10.36487/ACG_rep/1263_15_Cooks (https://papers.acg.uwa.edu.au/p/1263_15_Cooks/) Abstract: This work presents the experience with the application of a flocculent pipe reactor for flocculant evaluation and selection at Langer Heinrich Mine. Other processes could give different results. Parameters considered in determining the conditions that generate the optimum solids settling rate and overflow clarity are: slurry density, reaction time, turbulent shear rate (slurry flow rate), flocculent make-up concentration, flocculant dosing rate and type of flocculant. Two polyacrylamide flocculants used in the process were tested: Alclar 665 and Magna 333. The data was generated and processed in accordance with the response surface methodology. This methodology renders a mathematical model from which the optimum for each parameter in combination with the other parameters can be determined. The distinctive feature of this method of conducting settling tests is the ability to verify the interaction between parameters and higher order effects of parameters.