The entrainment of fine particles in underflow of a grinding-classification hydrocydone can cause ore over-grinding, reducing both the metal recovery and the ball mill throughput. This problem is addressed in this study by proposing a W-shaped hydrocyclone that effectively reduces the fine particle in the underflow. The separation performance of the W-shaped hydrocyclone was investigated in depth by experimentally studying the influences of a structural parameter, a physical property parameter, and an operating parameter on the split ratio, the yield, the product concentration, the product particle size, and the classification efficiency of the W-shaped hydrocydone. And then the W-shaped hydrocyclone was scaled-up and successfully used in an industrial site. The results show that replacing a conventional hydrocydone with the W-shaped one can reduce the -75 mu m particle content in the underflow by 1.46 percentage points, increased the classification efficiency by 832 percentage points, and reduced the circulating load by 33.38%. (C) 2020 Elsevier B.V. All rights reserved.