TECHNOLOGY
TECHNOLOGICAL CONSIDERATION
Direct reduction processes, which are being utilized in the plant, can be broadly classified in the two groups based on the type of the reductant used namely solid or gaseous. All the gas based plants in operation use natural gas as reductant.
Most of the solid reductant based processes use non coking coal as reductant. As the non-coking coal are available abundantly in our country the processes utilizing the non-coking coal as reductant. are of much significance to us. Of the different coal based processes available the most widely accepted is the rotary kiln.
The above technology has been in used in operation of smaller plants using the wide range of raw materials from different sources like iron ore from Barbil, Bellary-Hospet region, Bailadilla, etc. The different size ranges of the iron ore like 3-12 mm, 5-15mm, 5-18mm etc. have been tried. The size combination of various types of coal with different iron ores has also been used. The size combination of various types of coals with different iron ores can be used.
MANUFACTURING PROCESS
Sponge iron production using coal involves reducing iron ore with coal. The reduction is carried out in a rotary kiln at a pre-determined temperature and controlled atmosphere . The input raw material that is iron ore, coal and limestone in the required calibrated size is feed in to the rotary kiln which is inclined and rotates at a required range of speed. Due to the inclination and the rotary motion of the kiln the raw materials move from the feed end to the discharge end. In the process it gets pre heated and reduced to sponge iron. The material discharged from the kiln is taken into a rotary cooler where the material is cooled. The cooled product at a about a temperature of 80℃ is discharged from the cooler and taken to the product separation and handling system. The product which consists of sponge iron and non-magnetic such as char etc. is screened to different size fraction and then magnetically separated by means of magnetic separations. Sponge iron is taken to a storage bin for dispatch. The char which is not magnetic and contains a certain amount of carbons is taken in to a separate bin and can be recycled if found suitable or alternatively sold as fuel for applications such as in brick making and so on.
PROCESS DIAGRAM
DETAILS OF EQUIPMENT
The main equipment of the Sponge Iron Plant is as follows :
Rotary Kiln
Rotary Cooler
Product Separation and Handling System
Waste Gases Cleaning System
Industrial Water System
Electrical System