Evaluation of Surface Chemistry Throughout Processing Plant, and Determination of Effects on Plant Performance

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Objective(s): Investigate the surface chemistry changes that occur throughout an operating plant as the ore is processed, with particular emphasis on how these changes affect filtration performance.

Justification: Recent work by the investigators has shown that the surface chemistry of the ore in operating plants is significantly different from what is expected based on the values for pure minerals that are reported in the literature. Since surface chemistry affects a number of processes in the plants, particularly filtration, thickening, and froth flotation, it is important to understand how the surface chemistry varies throughout the plants and how these variations affect plant performance. It has already been shown in one of the Minnesota operations that the surface chemistry was outside of the ideal range for filtration, and that alterations of the surface chemistry could have a marked benefit on filtration rates.

Description of Proposed Work: Personnel from MTU will conduct in-plant sampling at an operating plant, with samples collected at all stages of processing from comminution through filtration. These samples will be analyzed to determine changes in surface chemistry, using streaming potential measurements to measure zeta potential as a function of pH. The plant water in each stage will also be analyzed by atomic absorption spectroscopy to determine the levels of calcium and other dissolved ions that can have a strong effect on surface chemistry. This study will determine not only what the surface chemistry is at each point in the process, but also which processes and chemical additions produce changes in behavior that could impact the final dewatering stages.

GRADUATE STUDENT: Joshua Carlson