Abstract: The trouble with the plant is that the normal operation its slurry treatment system is adversely affected due to the presence of a large amount of oversize material in underflow of disliming screen. In the light of the current situation,an analysis is made on the feasibility of making technical remoulding of the slurry treatment system. Through comparison of 2 alternative schemes,a more practical one is finally selected,that is,to send the thickener's underflow to the middlings medium draining screen. The successful application of the renovation scheme makes it possible to make full use of the existing pipework,moreover,there can be seen a save of renovation cost,absence of oversize material in screen underflow,and drastic reduction of labour intensity and danger in operation.