Improvements in Metals Extraction by Optimization of Agitation Systems through Experimentation and C

Katlyn Conaway, Antonio Iñiguez, Richard Kehn

The challenged precious and commodity metals market has caused prices to drop in recent years, reducing available resources for investment. It is under these circumstances that even minor process improvements will prove a significant advantage for a profitable operation. Agitation systems are used throughout different areas of the mine site, some of which are critical to the throughput of the plant. It is in these areas that many improvements could be achieved with reduced capital investment and lower operational cost. In this paper we will present two real life case studies where modifications in the agitation system design minimized resource utilization and optimized process yield. Experimental studies have been performed in the laboratory at scaled down geometries with simulant fluids that are comparable to the full scale constituents. Experimental studies are typically conducted in clear acrylic tanks that allow for direct observation of the flow patterns as well as solids suspension, blending or gas dispersion. With a properly selected simulant fluid and an appropriately scaled down impeller system and power, the viscosity effects can be evaluated. Laboratory results have been complemented with computational fluid dynamics (CFD) modeling. CFD is an effective research tool to visualize flow fields and analyze the interaction between agitators and tank internals, as well as inlet and outlet flows. It can be used to determine tank internal design loads, such as tank baffle forces. It can also be used to predict if inlet and outlet flow locations will allow for mixing to occur with minimal short circuiting. For the two case studies presented in this paper, both experimental and CFD analyses were utilized to reach an optimized solution for the mining slurry agitation system.