Abstract: The essential mineral compositions of dolomitic phosphorus tailings are calcareous dolomite，fluorapatite，and quartz，and its calcining product can be used to extract industrial magnesia，active lime，and phosphate concentrate.The phosphorus tailings from Wengfu were calcined with the high solid-gas ratio suspension calcining technology.The system was easy to control，and the furnace temperature was steady.The residence time of powder in the furnace was only at 20~30 s，the apparent decomposition rate of calcined products reached 92.9%，and MgCO₃ in dolomite was almost completely decomposed. The as-prepared product particles were all small grains，loose and porous，and exhibited a higher hydration activity.The mass fractions of CaO and MgO were 43.31% and 29.20%，respectively.Mass fraction of P₂O₅ increased to 10.00% from 6.36%， which was favorable to further extract phosphate concentrate.

Key words: phosphorus tailings, high solid-gas ratio, suspension calcination, apparent decomposition rate, hydration activity