Coal Preparation » Fine Coal
Control of flotation frothers at appropriate concentrations in flotation cells is critical for producing desirable bubble size, froth stability, and froth mobility, which in turn enhances the separation efficiency of the flotation process. Excessive residual frother in plant water can cause over-frothing in pumps, sumps, thickeners, and dense medium circuits, whereas insufficient frother dosing, applied conservatively to prevent over-frothing, often reduces yield. To manage frother levels effectively, it is essential to measure concentrations both in flotation cells and across water circuits. Previous projects, C23035 and C26012, developed an offline method based on specific interactions between frother molecules and a formulated liquid. Using this technique, the concentration of a standard frother, MIBC, could be measured within one minute, at an accuracy of 0.9 ppm or better, with negligible interference from flocculants, diesel, or salts. While these studies demonstrated the potential for mapping residual frother across coal handling and preparation plants (CHPP), measurements were taken offsite, and the system was not automated.
In this project an automated prototype unit was developed for online MIBC measurement. The liquid formulation was upgraded to a non-flammable version for safer on-site operation, and advanced signal processing was implemented to improve sensitivity and repeatability of the measurements. The prototype was deployed at the laboratory of a participating CHPP to measure residual MIBC concentrations in various slurry and water streams. The reliability of the automated measurements was validated against the colorimetric method developed by McGill University.
The automated prototype enables safe and rapid monitoring of residual MIBC, requiring only 15 minutes per measurement including cleaning. On-site implementation allows operators to optimise MIBC dosing and transforming frother management from a reactive strategy to a data-driven one, thereby improving flotation performance, reducing reagent consumption, minimising freshwater usage, and enhancing operational stability.