The 4 × 10⁶ t /a vertical dry grinding system，pioneered by Nanjing Steel Group’s straight grate pellet production line，is put into operation in November 2023. After dry grinding，the ball formation and pellet roasting performance of the sintered coarse powder are significantly improved. In addition，on the basis of dry grinding，by optimizing the ore blending and pellet roasting system and improving the thermal stability of the green pellet，the high-quality pellets are produced，which have a w( TFe) of 63. 5% ，a w( SiO₂ ) of 4. 7% ，a basicity of 0. 15，a compressive strength of over 2 500 N/P，and excellent metallurgical properties[reduction degree 80% ，low-temperature reduction pulverization index ( ＞ 3. 15 mm) 96% ，and reduction expansion index 18% ]，and realize the development and application of key technologies for the binder-free production of acidic pellets. The successful application of this technology can reduce the binder cost by 64 million yuan per year，and at the same time make the iron grade cost of pellets 1. 83 yuan /t lower than that of pellet，creating significant economic benefits.