نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه معدن، دانشگاه آزاد اسلامی بافق
2 گروه معدن دانشگاه آزاد اسلامی واحد بافق
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Pelletization is a technique in which fine particles of iron ore concentrate are gradually mixed with lime and a binder material (bentonite or Ciment Fondu), and by rolling the mixture and spraying a certain volume of water in a balling disc, the mixture turns into balls (diameters ranging from 8 to 16 mm), which are called raw pellets. Under a temperature of 1100 °C, the pellets are baked and thus hardened, forming the raw material used in the production of sponge iron. In this research, the parameters affecting the pelletizing process, including the speed and rotation angle of the balling disc, the moisture content, the type and combination of the adhesive used, and the optimal conditions for the production of pellets with the desired dimensional characteristics and mechanical properties were determined. Bentonite and a combination of bentonite and Ciment Fondu were used as an adhesive. The falling number and fracture strength tests were carried out on raw and dried pellets. Based on the results of the conducted experiments, the best pelletizing efficiency was recorded for a rotation angle of 40 degrees relative to the horizon, a rotation speed of 30 rpm, and a pelletizing duration of 60 minutes in the balling disc. The optimal moisture level in the moisture testing was determined to be around 9%. The increased bentonite content in the pellet showed an increasing/decreasing trend for the strength and falling number, and the highest strength was recorded for 3-4% bentonite content. The maximum compressive strength of dry pellets increased about six times compared to wet pellets with 9% moisture content. Using a mixture of Ciment Fondu and bentonite in the pellets increases the strength, but after baking at high temperatures, lower strength was obtained compared to that of the pellet containing bentonite. Also, according to the results, the positive effect of increased fracture strength at high temperatures for the pellets made with a combination of 2% bentonite and 2% Ciment Fondu is far less than pellets made with 3% bentonite and 1% Ciment Fondu, while the same pellet showed an opposite result at ambient temperature.
کلیدواژهها [English]
)