| The main steps involved in the production of pellets at ESML’s facility are: the mining of iron ore; the crushing of the mined ore; the concentration of the crushed ore; and the pelletization of the concentrate. |
The initial step consists of extracting sufficient iron ore to establish a crude ore stockpile adjacent to the crusher and to develop adequate volume of both in-pit blasted and drilled iron ore inventory required for actual pellet plant startup.
The primary crusher operation will consist of a dump pocket located above the primary crusher and within the primary crusher building. Crude ore from the dump pocket will flow by gravity to the primary crusher, and product from the primary crusher will be transported by a conveyor to a scalping screen located in the scalping / grizzly building.
The scalping screen separates ore by weight into oversized and undersized ore. The primary crusher product that is oversized will be conveyed to the coarse ore storage yard, while the undersized ore will be transported to a secondary screening facility, which will be located in a secondary crushing/dry cobbing building.
The secondary crusher product will then be transferred to the dry cobbing operation located in the secondary crushing/dry cobbing building. In the dry cobbing operation, the crude ore fed to the conveyor belt of each dry cobbing unit will be separated into magnetic (product) and non-magnetic (reject) size fractions as it passes over the magnetic head pulley. The magnetic product will then be delivered to conveyor belt that goes to the fine ore storage yard.
The secondary screens will further separate the iron ore into oversized and undersized ore by weight. The undersized iron ore from the secondary screening process will be transported to the dry cobbing operation, while the oversized ore from the secondary screening process will be transported to the secondary crushers.
The concentration process mainly involves the grinding of ore and the separation of gangue. The concentration operation will consist of a mill feed system, primary grinding equipment, magnetic separation equipment, a dewatering cyclone, a ball mill, primary screening equipment, hydro separation equipment, magnetic separator equipment and flotation cells. The concentration process has been designed to produce blast furnace (BF) grade concentrate containing approximately 66 per cent iron with silica content of approximately 4.5 per cent to 4.8 per cent with the bypass of flotation cells. In addition, with the use of flotation, the concentration process will be capable of producing direct reduction (DR) grade concentrate containing approximately 70 per cent iron with silica content ranging from approximately 1.7 per cent to 2 per cent.
Pellets are heat-hardened balls produced from concentrates with different mineralogical and chemical composition to produce materials with improved properties for iron making. The various steps involved in the pelletization process are: feed preparation; green ball formation; and pellet induration.
Iron ore slurry will be received in the slurry tank for further pumping to the distributor of vacuum filters. The vacuum filters will then separate iron ore filter cake, with about 8.8 per cent moisture, from the slurry, and the filtrate will be pumped to the process water tank. For the making of blast furnace pellets, the filter cake will be conveyed to a mixer where ground additives such as limestone, dolomite, bentonite and bauxite will be introduced and mixed thoroughly.
The mixed material will be conveyed to balling disc feed bins. The mixed material will then be made into green balls in the balling disc facilities. These green balls / pellets will then be screened for size in a single deck and double deck roller screen, with oversize and undersize material being returned to mixed material bins.
The green balls of appropriate size will be fed onto the travelling grate of the indurating machine where these are heat hardened and later cooled.