Upscaling and optimization of reagents systems in froth flotation: A DoE and numerical-optimization-based methodology

• Optimizing and upscaling flotation reagents using DoE and numerical optimization. • Approach includes micro and batch flotation, pilot tests, and industrial trials. • Method bridges batch and continuous operations, reducing risks and costs. • New Grade Recovery Performance index applied successfully at industrial scale. • Considering the whole system is key for effective ore variability management. We introduce a unique approach for faster and more systematic optimization and upscaling of reagent systems in froth flotation processes. By integrating the statistical design of experiments with numerical optimization techniques, our method ensures a seamless transition from laboratory experimentation to pilot and industrial-scale implementation. This approach uses comprehensive lab-scale experimental data to assign the effects of reagent system operating parameters and pre-identify optimal conditions. These predictions streamline the optimization algorithm for continuous process improvement, minimizing its convergence issues and, consequently, the test work time and resource consumption. We validated this methodology with a case study on a low-grade scheelite ore, demonstrating a reduction of 60 % in required test work at pilot scale. A four-day industrial campaign resulted in a 16 % increase in concentrate grade without hindering recovery. Additionally, we discuss the influence of variations in ore feed properties on froth flotation performance while optimizing the reagent system. Within this context, we introduce the Grade-Recovery-Performance (GRP) index, a two-dimensional metric to quantify the performance of separation processes according to grade and recovery simultaneously.