Abstract：In view of sulfur powder's characters of being flammable and explosive, sulfurs were grinded by using LNI-330 A nitrogen protection classify-impact mill and industrial tests were carried out. The results show that during the operation, the system pressure distribution is from -1.1 kPa to 12.8 kPa, under which the oxygen content can be stabilized at about 2%. Adjusting the rotation speed of classifier from 150 to 1 200 r/min, the finished product yield of sulfur powder is 750~1 500 kg/h, the particle size of d₅₀ is in 15~25 μm, and the unit power consumption is less than 83.601 kW h/t. When the rotation speed is above 450 r/min, the technical specification of insoluble sulfur for rubber is reached, the mass fraction of 150 μm sieve residue is less than or equal to1%. Considering the industry requirements, the optimum classifier speed of LNI-330 A nitrogen protection classify-impact mill for preparation of sulfur powder is 450 r/min, the finished product yield is 1 375 kg/h, the mass fraction of 150 μm sieve residue is 0.74%, the particle size of d₅₀ is 24.50 μm, and the unit power consumption is 65.77 kW h/t.

Keywords: nitrogen protection; classify-impact mill; sulfur powder; oxygen content; power consumption