Abstract: The unclassified tailings （UT） cementing filling is the developing direction of filling mining method in metal mine at present.Concentrated sedimentation of the UT is the key technology to achieve continuous and high-efficient filling in the mine.With the UT from Linglong Gold Mine in Shandong Province and five kinds of flocculants as raw materials，the static flocculation experiment of UT is carried out.The control method of single variable is used to study the influence of various parameters of flocculant on flocculation and sedimentation by using sedimentation velocity and sedimentation underflow concentration as reference indexes.The results show that anionic flocculants （molecular weight 12 million） has the best effect on the sedimentation of UT，with the fastest sedimentation velocity.The optimum parameters for the flocculation and sedimentation process are determined:when the flocculant solution concentration is 0.2% and the unit consumption is 75 g/t， the sedimentation effect is best.Gradually increasing the concentration and unit consumption of the flocculant solution， can result in increasing the viscosity of flocculant and UT solution，and decreasing the sedimentation rate and the underflow concentration.Based on the above discussion results，the mechanical model of flocculation sedimentation is established，and the whole process of sedimentation is divided into three stages，and the theoretical curve of the whole process of sedimentation is obtained by the mechanical analysis，so as to provide some reference for the related studies.

Key words: Unclassified tailings, Flocculating sedimentation, Sedimentation velocity, Bottom flow concentration, Mechanical model, Sedimentation curve