Compared to other technologies, you can process high volumes of slurry at a quite low cost by sedimentation using thickeners in mineral processing. The two outputs, underflow and overflow, are not often prioritized at the same time. In tailings applications where water recovery is a requirement, underflow is a target. But in concentrate applications, the overflow measurement is essential. Otherwise, the important material will return to the concentrator and will lose recovery.
With a thickener, the solid-liquid separation is mainly done by sedimentation. A thickener has several layers, the upper layer being clarified water. Below the clarified water is the interface, this is solids and water. Under this layer is mud and the lowest layer is heavy mud. Companies use sedimentation to produce two phases by thickening the incoming feed stream. In the ideal situation, the overflow contains minimal solids, and the underflow contains minimal liquid. That is why it is very important to measure the density.