Abstract
Fine particles misclassification in the underflow (UF) of grinding-classification hydrocyclones might result in ore over-grinding, leading to both reduced ball mill throughput and metal recovery. In the current research, a W-shaped hydrocyclone is proposed, to efficiently decrease the misclassification of fine particles in UF. The effects of the following parameters (including cross-effects) on W-shaped hydrocyclone classification performance were studied experimentally—inlet pressure, apex diameter, and vortex finder insertion depth and diameter. A mathematical model on the basis of the response surface method was established for the prediction of W-shaped hydrocyclone separation performance. The significance of the effects of the factors on the fine particle content in UF decreased in the following order—vortex finder diameter > inlet pressure > vortex finder insertion depth > apex diameter. The significance of influences of different factors on quality effectively decreased in the following order—inlet pressure > vortex finder insertion depth > vortex finder diameter > apex diameter. The significance of factor effects on the quantity efficiency decreased in the following order—inlet pressure > vortex finder insertion depth > apex diameter > vortex finder diameter. All influence factors were considered to obtain the optimal parameter configuration—an apex diameter of 0.14 D, a vortex finder diameter of 0.31 D, an insertion depth of 1.87 D, and an inlet pressure of 0.18 MPa. The corresponding optimal result was a −25 μm particle content (C−25) in UF of 11.92%, a quality efficiency of 42.48%, and a quantity efficiency of 98.99%.
Highlights
Hydrocyclones are extensively applied as separation and classification machines for grinding-classification
The cut size of a traditional cylindrical–conical hydrocyclone is directly proportional to the cone angle [11,12]
The results showed that an appropriate insertion depth reduced coarse particle misclassification in the OF from the flow of short-circuit
Summary
Hydrocyclones are extensively applied as separation and classification machines for grinding-classification. The hydrocyclone classification principle [1,2,3,4] can result in a “misclassification” phenomenon (misclassification of fine particles in underflow (UF) and coarse particles in overflow (OF)). When classifying high-concentration, coarse-grained materials, the settling velocity of multi-component particles in swirling flow fields, results in fine particle misclassification in UF, which in turn often causes ore over-grinding that reduces metal recovery and ball mill throughput. The cut size of a traditional cylindrical–conical hydrocyclone is directly proportional to the cone angle [11,12]. Using a traditional cylindrical–conical hydrocyclone for the classification of high-concentration coarse-grained materials results in a small cut size. In the grinding-classification, this small cut size often causes problems, such as an excessive circulating load, increased fine particle misclassification in UF, and easy clogging, Minerals 2021, 11, 118.
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