Abstract: The magnetic separation tailings grain size of Baiquan Iron Mine in Hebei Province is relatively coarse， and the yield of -0.074 mm is 30.76%. The useful mineral apatite is mainly enriched in the fine fraction and the dissociation degree is low. In the plant， when the slurry temperature is 37 ℃， the oxidized paraffin soap + fatty acid + MES is used as the collector， and the phosphorus is selected by one roughing three cleaning one scavenging and the middle ore sequence returning to the closed circuit， and the P2O5 grade and recovery rate of 33% and 85% respectively in phosphate concentrate are obtained. In order to solve the problem that the floating phosphorus needs to be warmed and the concentrate index is not ideal， the phosphorus selection test was carried out by using the new normal temperature floating phosphorus collector DJX-6 developed by the relevant research group of Northeastern University. The results show that when the sample has a grinding fineness of 60% -0.074 mm， the flotation temperature is 20 ℃， the pH is 10 （the amount of Na₂CO₃ is 400 g/t）， and the amount of sodium silicate is 200 g/t， the dosage of DJX-6 is 400 g/t， through one roughing-three cleaning-one scavenging process， the phosphorus concentrate with P₂O₅ grade of 33.30% and P₂O₅ recovery rate of 93.36% is finally obtained. Compared with the on-site process， not only the dosage of the agent is greatly reduced， but also the flotation slurry does not need to be heated， and the P₂O₅ recovery rate of the phosphate concentrate is increased from 85% to 93.36%. Therefore， the use of DJX-6 as a collector in the field of floating phosphorus will greatly reduce energy costs， eliminate the supporting heating system， increase the output of concentrates， and create significant economic benefits for enterprises.

Key words: Apatite, Room temperature collector DJX-6, Process optimization