Discharge options for Direct Reduced Iron and its Hot Transport Dec14

Discharge options for Direct Reduced Iron and its Hot Transport...

Discharge options for Direct Reduced Iron and its Hot Transport The two main methods of producing direct reduced iron (DRI) are (i) gas based process in a vertical shaft furnace and (ii) coal based process in a rotary furnace.  In both the processes the reduction reactions take place in solid state and the maximum furnace temperatures are in the range of 850 deg C to 1050 deg C. In the coal based process, the produced DRI is mixed with char that is needed to be separated from DRI. Hence DRI-char mixture is cooled in a rotary cooler and then char is separated from DRI by the magnetic separation process. In the case of vertical shaft furnace processes, since char is not present along with DRI, there are three discharge options available. These are cold DRI (CDRI), hot briquetted iron (HBI), and hot DRI (HDRI). Most of the vertical shaft DRI furnaces have been built for the production of CDRI. In these furnaces the DRI produced after reduction is cooled in the lower part of the furnace to about 50 deg C. CDRI is temporarily stored in Silos for passivation before it is transported to a nearby steel melting shop for its use later. CDRI has got the property of auto ignition and need special precautions during transport and storages as required by the International Maritime Organization (IMO). CDRI is most suited material for the continuous charging in the EAF. HBI is now being produced since more than 30 years. It is the desirable method of preparing DRI for storage and transporting it by sea going vessels. For the production of HBI, hot DRI is discharged from the vertical shaft furnace at a temperature of around 700 deg C. The hot DRI is sent to...

Conveyor belts

Conveyor belts Conveyor belt is the most important element of a belt conveyor installation. The conveyor belt fulfils the task of absorbing the stresses developed at the drive start up, transport the load, absorbs the impact energy at the loading point, withstand temperature and chemical effects (heat, oil and acidity etc.) and meet safety requirements (flame resistance and antistatic etc.). The selection of the conveyor belt specification depends on its application. The schematic cross section of a plied conveyor belt is shown in Fig.1. Conveyor belt has the following components. Carcase – It consists of textile plies, steel weave or steel cord. Covers –  The cover is made up of either rubber or PVC of different qualities Additional components – These components of the conveyor belts are as needed and usually are edge protection, impact protection and longitudinal slitting prevention etc. Special construction elements – These are the profiles on steep incline belts, cleats, or corrugated edges etc. Fig 1 Schematic cross section of a plied conveyor belt Carcase The carcase of a conveyor belt can be made from various materials and in different construction. The most commonly used are textile ply carcases and steel cord.  Textile ply carcases are with one or more textile plies. The maximum numbers of plies can be up to 6 numbers. In monoply belts, a PVC impregnated textile carcase is used. Depending on tensile strength and duty, the carcase fibres are in polyester, polyamide or aramid. In the carcase of steel weave type, the transmission of force is by means of the longitudinal steel cords laid to one another in the same plane. Above this carcase is a transverse layer also of steel which is held in place by a polyamide binder cord. In carcase with steel cord,...