Determination of optimum conditions for the production of suitable green pellets from concentrates of iron ore with a low blain by organic and inorganic additives

Basically, the limitation on the grinding capacity of iron ore mines is one of the challenges of increasing the capacity of pelletizing units along with the program of increasing steel production in our country. Therefore, the purpose of this research is to investigate the operational solution for obtaining appropriate quality of green pellets of fine concentrate with low specific surface area (less than 1500 cm2/g). Pilot pelletizing process was carried out by mixing fine concentrates of Chadermallo and Bafgh with blain number from 1220 to 1392 cm2/g and various additives such as bentonite, sodium carboxymethylcellulose (CMC), sodium hydroxide and sodium carbonate. Wettability of iron ore particles was evaluated with distilled water, process water, CMC solution and sodium hydroxide. The particle size analyzer and Fisher were used for determination of particle size distribution and specific surface area of concentrate powder, respectively. The drop number, wet strength and dry strength were measured for evaluation of the quality of green pellets produced. High wettability was measured when Carboxymethyl cellulose organic binder solution was used. To maintain the qualitative properties of green pellet, proportional to reduction of blain number of concentrate powder from 1396 to 1220 cm2/g and as well as avoid the increasing bentonite consumption, the CMC organic viscose solution has been added to the mixture of 0.01 to 0.03 %wt. the dry strength of the pellets to 5.5 kg/pellet was increased, by addition of sodium carbonate without of NaOH.