Abstract: Effects of an organic high-molecular flocculant polyacrylamide (PAAm), PAAm and FeCl₃,and PAAm and AlCl₃ on settling characteristics of a flotation phosphate concentrate are studied in this Paper.Test results show that the optimum consumption of PAAm is in the range of 1020 g/t and decreases with the growth of its molecular weight. Settling characteristics of the concentrate can be improved in using PAAm together with FeCl₃ or AlCl₃. The reagent scheme of 2.0 kg/t of AlCl₃ and 10 g/t of PAAm-6, or 2.0 kg/t of FeCl₃ and 20 g/t of PAAm-6 is worthy to be recommended in thickening of the flotation phosphate concentrate.