NEW THICKENER WITH THICK PASTE REMOVAL SYSTEM

The objective of most thickeners is to produce mud at the highest possible solids fraction in order to improve the separation efficiency. Extracting this dense mud from a thickener can be challenging and operation at high underflow rate is often causing channelling where liquor is short circuiting to the underflow. A new paste removal system that allows extraction of very thick mud at high flow rates was designed and tested in our laboratory. It consists of a device that mechanically extracts the mud out of the thickener and brings it to the underflow pump. Consistent operation with red mud at up to 54% solids was obtained in our laboratory. These results led to the development of a 3-m diameter flat-bottom pilot thickener fitted with the new paste removal system. The system is described and typical results are presented.