Classification in mineral processing refers to the separation of particles according to their size, shape, density, or settling velocity in a fluid medium — typically water or air — to produce fractions of different size distributions for further processing. In bauxite mining, classification using vibrating screens, hydrocyclones, or spiral classifiers is used to separate coarse bauxite particles from fine clay and silica fractions before feeding the refinery digestion circuit. In gold mining, classification is a fundamental component of grinding circuits, where hydrocyclones classify mill discharge into a coarse underflow (returned to the mill for further grinding) and a fine overflow (directed to leaching or flotation). Classification ensures that ore particles are ground to the optimal liberation size for efficient gold recovery. In iron ore processing, wet screening and hydrocyclone classification are used extensively to separate liberated iron mineral particles from gangue, enabling downstream magnetic separation or flotation. In diamond mining, classification by screen size is critical to ensure that diamonds are directed to the appropriate recovery circuit based on their expected size distribution, preventing loss of fine diamonds in reject streams. Efficiency of classification is quantified by cut size (d50), sharpness of separation, and circulating load in grinding-classification loops.
