The Effect of Mixing Impeller Geometry and Pumping Direction on Solids Suspension Homogeneity

Authors:

Richard A. Howk

Jeffrey R. Kelly

Paul M. Kubera 

This study examines how mixing impeller geometry and pumping direction affect solids suspension homogeneity in slurry tanks, particularly in mineral processing applications. Laboratory and computational fluid mixing (CFM) studies revealed that combining a lower down-pumping impeller with an upper up-pumping impeller improves solids uniformity while reducing power consumption compared to conventional configurations. The findings demonstrate that optimized impeller design can enhance process efficiency, lower operating costs, and be validated through computational modeling before full-scale implementation.

Key Learnings

• Mixing impeller geometry and pumping direction significantly influence solids suspension and overall homogeneity in slurry mixing.
• A dual-impeller setup—combining a lower down-pumping impeller with an upper up-pumping impeller—achieves better solids uniformity than traditional configurations.
• Optimized impeller design can improve process efficiency while reducing power consumption and operating costs.
• Computational fluid mixing (CFM) and CFD modeling are effective tools for predicting and validating mixing performance before industrial application.
• Uniform solids suspension leads to more consistent process outcomes, making it critical for applications such as mineral processing, CIP/CIL systems, and other slurry-based operations.