Abstract: The silt from Dongting Lake poses many challenges such as large production and high disposal costs with underdeveloped green disposal technology.A multi-objective model combined with ideal point method was constructed to quickly obtain the optimized sintering condition of silts in different regions.The physical and chemical properties and the sinterability of Dongting Lake silt were first analyzed from macro-and-micro perspectives,and the relationship between sintering conditions and performance of high-quality lightweight aggregates were then obtained by orthogonal experiments.The silt from Dongting Lake is a typical swellable soil when sintered,and is feasible to be prepared into high-quality lightweight aggregate as its three-phase diagram lies in the prone-to-swell zone specified by the Riley three-phase diagram.The optimum sintering conditions for preparing lightweight aggregate from Dongting Lake silt are as follows:20 min preheating time,410 ℃ preheating temperature,5 min sintering time and 1 112 ℃ sintering temperature.The sintered lightweight aggregate had a porosity of 23.31%,shrinkage of 5.75%,bulk density of 1.28 g/cm³,compressive strength of 20.35 MPa and water absorption rate of 14.33% per hour.The research findings help solve the problem of disposal of Dongting Lake silt and also provide new idea for the resource utilization of silt from other lakes.

Key words: Dongting lake slit, lightweight aggregate preparation, sintering conditions, orthogonal test, multi-objective ideal point, recycle