Abstract: In order to determine the beneficiation process of a low-grade collophanite ore in Yunnan,according to the technological mineralogical characteristics of the phosphate ore and the principle of preferential flotation of easily-selected minerals and less flotation and more suppression,the beneficiation test was carried out by adopting reverse combined direct flotation process.The results show that when the raw ore with P₂O₅ grade of 25.93%,with grinding fineness of -0.074 mm 80.0%,treated by the process of one roughing one scavenging reverse flotation-concentrate of reverse flotation dehydration-one roughing one cleaning one scavenging direct flotation and medium returned back process.The concentrate with P₂O₅ grade of 31.30% and recovery of 84.75% is obtained,The MER value of the concentrate is 10.06%,which is 9.04 percentage points lower than the original ore,and the SiO₂ content is 15.23%,which is 7.34 percentage points lower than the original ore.The reverse combined direct flotation process is an efficient and simple process to separate low-grade collophanite.

Key words: Medium and low grade collophanite, Reverse flotation, , Direct flotation, Remove magnesium and degrading silicon 