Abstract: A mid-low grade silicon phosphate rock from Hubei contains large amounts of iron，magnesium，aluminum impurities.In order to make use of phosphorus resources and reduce the handling difficulty of subsequent processing，the process mineralogy and flotation process on the ore was studied.The results showed that sesquioxides R₂O₃ (Fe₂O₃ and Al₂O₃) mainly existed in mica-clay minerals and iron-carbon minerals，calcium magnesium paragenetic minerals exist in the form of dolomite;The phosphate concentrate containing P₂O₅ of 32.98% with the recovery rate of 92.30%，the content of R2O₃ 2.94% with the removal rate of 69.17%，the content of MgO 1.02% with the removal rate of 67.54% was obtained by the process of two direct flotation and one reverse flotation.The quality of concentrate reaches the high-class standard of phosphate ore for the acidic processing.

Key words: Collophanite, Flotation, Sesquioxide