Effect of high pressure roller grinding on green pellets properties of ultra fine iron concentrate containing pyrite cinder

The preparation of pellet mixture by high pressure roller grinding was studied to solve the problem of poor pelletization and green pellet performance for adding 20 mass% pyrite cinder into ultrafine iron concentrate powder. The influences of roller speed, roller pressure, and roller grinding ratio on the mixture′s pelletization and green pellets performance were investigated. Meanwhile, the effect of adding organic binder on the burst temperature of green pellets was evaluated under the condition of suitable roller milling parameters. The results show that under the conditions of roller speed of 280r/min, roller pressure of 1.0MPa, and roller grinding ratio of 100%, the mixture′s static ballability index and green pellets performance are significantly improved. Specifically, the ballability index increases from 0.28 to 0.81, and the drop number and compressive strength of green pellets increase from 2.9times/(0.5m) and 13.62N/pellet to 4.2times/(0.5m) and 18.52N/pellet, respectively. At the same time, when the proportion of organic binder is 0.2 mass%, the burst temperature increases from 385℃ to 445℃, and the drop number and compressive strength of the green pellets are further augmented to 6.4times/(0.5m) and 20.22N/pellet. Finally, the performance of green pellets meet the production requirements.