Iron Nuggets

Iron Nuggets  The process of production of iron nuggets is capable of directly producing solid, high density, highly metalized iron nuggets from dry green balls. These green balls are made out of iron ore fines, pulverized coal, fluxes and binders. The pulverized coal is reductant which is added to the system to supply the carbon required for the reduction and carburization. Binder (bentonite) in conjunction with the finely ground iron ore particles serves to improve the properties of green balls in wet and dried conditions. The flux is limestone, which fluidizes the slag and also prevents excessive iron losses in the slag. The iron nuggets are produced using a direct reduction process. The reduction process is carried out in a rotary hearth furnace, using coal as the reductant and energy source. The direct reduction of iron by this process is more energy efficient and more environmentally friendly than traditional iron making processes. The process for producing iron nuggets by ITmk3 is described in the article having link http://ispatguru.com/itmk-3-process-of-making-iron-nuggets/ Iron nuggets are an ideal feed material for steelmaking and iron casting. This material consists of essentially all iron and carbon, with practically no gangue (slag) and low levels of metal residuals. Fig 1 shows sample of iron nuggets. Fig 1 Iron nuggets  Iron nuggets are a premium grade iron product with superior shipping and handling characteristics. They can be shipped in bulk either inland in railway wagons or trucks or in the ocean going vessels. Iron nuggets can be stored outside with no special precautions. They can be handled as a bulk commodity using conventional magnets, conveyors, bucket loaders, clams, and shovels. The physical properties of iron nuggets are as follows. Colour – Gray Shape and appearance – Pebble shaped elliptical structure Size – 5...

Direct Reduced Iron

Direct Reduced Iron Direct reduced iron (DRI) is also known as sponge iron. It is produced by the reduction of iron ore (in the form of lumps or pellets) by either non-coking coal or a reducing gas produced by reforming of natural gas. The reducing gas can also be produced by the gasification of coal. The reducing gas is normally a mixture. The majority gases in this mixture are hydrogen (H2) and carbon mono oxide (CO). These gases act as reducing agents. The reduction process is conducted at high temperature but substantially below the melting point of iron. Since the reduction reaction takes place in solid state, the lump or pellet retain their original shape, but are considerably lighter due to the removal of the oxygen from the ore. Hence the produced direct reduced iron has a highly porous structure. This porous structure gives DRI an appearance of a sponge and because of it, DRI is also known as sponge iron. Iron content in the DRI is in two forms. One is in metallic form which is known as metallic iron, Fe (M), and the second form is iron present in residual iron oxides, Fe (O). The total iron Fe (T) in DRI is the sum of these two iron components. Metallic iron is the aggregate quantity of iron, either free or combined with carbon (as cementite) present in DRI. Metallization of DRI is a measure of the conversion of iron oxides into metallic iron (either free or in combination with carbon as cementite) by removal of oxygen due to the action of the reductant used. Degree of metallization of DRI is the extent of conversion of iron oxide into metallic iron during reduction. It is defined in percentage of the mass of metallic iron divided by the mass of...

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...

Direct Reduced Iron and its Production Processes Mar16

Direct Reduced Iron and its Production Processes...

Direct Reduced Iron and its Production Processes Direct reduced iron (DRI) is technically defined as iron ore which has been reduced to metal without melting it. Hot briquetted iron (HBI) is a densified form of DRI to facilitate its handling and transport. History The first patent was in 1792 in United Kingdom presumably utilizing a rotary kiln but the development of the modern direct reduction (DR) process began in the middle of 19th century. Since 1920 more than 100 DR have been invented and operated. Most of them have not survived. The modern era of DR production began on December 5, 1957 when the HYL process plant first started production at Hylsa. The  first plant using Midrex process came into operation in May 17, 1969 at Oregon Steel mills in Portland, Oregon. DRI Production process A DRI production process is one in which the solid metallic iron is obtained directly from solid iron ore without subjecting the ore or the metal to fusion. The process principle is shown in Fig. 1. Fig 1 DRI process principle Major DRI production processes are either gas based or coal based. Feed material in a DRI process is either iron ore sized to 10 to 30mm or iron ore pellets produced in an iron ore pellet plant. In the gas based plant the reactor, the reduction reaction takes place is a shaft furnace. The shaft furnace works on counter current principle where the iron ore feed material moves downward in the furnace by gravity and gets reduced by the up flowing reducing gases. The pressure and temperature in shaft furnace in HYL process is 5-6 bars and 800-850 deg C. The same in Midrex process is 1-1.5 bar and 800-850 deg. C. In a coal based plant the...