Abstract: Deep-cone thickener as a high-effective thickening equipment was developed in 1970s,which owns a great production capacity and can get a higher underflow density.It provides guarantee for the preparation of paste filling materials.In this paper,the structure and operating principle of a deep-cone thickener are described.The thickening processes are divided into: clarification area,sedimentation area,critical concentration area,and compression area by on-field observation.The laws of concentration changing and the major influencing factors by experiments are studied respectively.The results indicate that the sedimentation of tailings has three steps and the 76%~82% change range of underflow density in normal operating was obtained,providing a theoretical basis for prediction and control of system fault.

Key words: Paste-filling, Tailings thickening, Underflow density, Deep-cone thickener