The efficiency of the two-stage process can be improved by separating the gas reaction zone from the smelting zone. High smelting intensity with high productivity because of faster reaction kinetics and increased transport rate due to convection. Processes such as HIsmelt, DIOS, AISI-DOE, etc., belong to this group. The objectives for the development of SR ironmaking process were as follows. Increased flexibility – SR ironmaking process with low capital costs and with the use of non-coking coal can have higher flexibility during operation. FIG. Ability to integrate with available technologies in other areas – This is another objective for the development of a SR ironmaking process. The single stage process is the simplest of all the iron bath process and theoretically represents the ideal designs where hot metal is produced in a single reactor in which both reduction and smelting takes place. It is carried out in blast furnace or electric furnace. Smelting involves more than just melting the metal out of its ore. The reduction smelting process involves the reduction of oxidic sources of metals with carbon in the presence of a flux mineral + reducing agent + ßux = metal + … The reaction is synthetically very useful, due to the formation of cyclic products. Gangue in ore and ash in fuel contain some compounds with high melting point (for example, the melting point of SiO2 is 1625 ℃ and that of Al2O3 is 2050 ℃). In this process concept, the aim is to minimize coke consumption. The basic assumption in these concepts is that with time nuclear power generation will provide abundant electrical energy at very low cost, and that fossil fuels will become progressively more expensive as resources become depleted. There are two ways in which galena can be transformed into lead and each process requires two chemical reactions to occur in the furnace: In the first reaction of the first process, galena is roasted in order to remove the sulfur component of the metal sulfide. In modern ore treatment, in order to concentrate the metal ore as much as possible, different preliminary steps are usually performed before smelting. The concept of two stage SR process utilizing O2 an coal without and with post combustion is shown in Fig 3. Most ores are the chemical compound of the metal and other elements, such as oxygen (as an oxide), sulfur (as a sulfide), or carbon and oxygen together (as a carbonate). FIG. Smelting reduction of iron ores to give a liquid iron product in processes other than the BF has long been recognized as a technically feasible and attractive process route and a number of process concepts have been proposed. The process needs highly efficient post-combustion for meeting the energy requirement of the smelting process. Some of these DR processes use natural gas as the feedstock for production of reducing gases. [REACTION:SMELT_COPPER_FROM_GALENA] [NAME:Smelt galena to bars] [BUILDING:SMELTER:NONE] [REAGENT:A:STONE:NO_SUBTYPE:STONE:GALENA] [PRODUCT:100:1:BAR:NO_SUBTYPE:METAL:COPPER][PRODUCT_DIMENSION:150] [PRODUCT:50:1:BAR:NO_SUBTYPE:METAL:SILVER][PRODUCT_DIMENSION:150] [FUEL] [SKILL:SMELT] … Copper oxide + carbon → copper + carbon dioxide. Corex process belongs to this category. Based on the number of stages involved, these processes can be divided mainly into two types namely (i) single-stage process,  and (ii) two-stage process. google_ad_width = 300; The heat of the post-combustion is efficiently transferred from the gas phase to the liquid bath. In the second group, those processes are there which have low degree of pre-reduction and a high degree of post-combustion. The exothermic reaction coupled with a heat recovery system saves a lot of energy for smelting. This process needs an additional step of gasification/gas reformation between smelting reactor and pre-reduction reactor. A small and fairly self-contained process unit of SR process can also be logistically and managerially more flexible than a large integrated complex (consisting of coking, sintering and BF processes) in which changes or production delays in one area have effects on all other areas. /* 300x250, created 1/18/11 */ Fig 4 Concept of three stage SR process utilizing O2 and coal. It is suitable for use as a scrap substitute during steelmaking operations and has quality advantages over scrap, principally in its low residual content and its ease of handling and feeding. The process gives improved energy economy by utilizing exhaust gases for electricity generation. It will take less then a minute, Technological and other processes/equipments associated with steel industry, Management in steel plant along with training and development, Raw materials and other materials used in steel plants, Marketing Concepts and Comparison with Selling Concepts, Bulk Material Storage and Storage Yard Machines, Role of Safety and its Importance in a Steel Organization, Role of Leadership in the Management of Organizations. The heat of the post-combustion is efficiently transferred from the gas phase to the liquid bath. Amorphous Objectives for development of SR ironmaking process. For example, iron melts at 1536°C, copper melts at 1083°C, and aluminum melts at 660°C. If the dependence of SR ironmaking process on the associated units can be avoided, then the overall investment cost can be consequently reduced making it possible to operate such a process economically at a much smaller capacity (say around 0.5 Mt per year). Fig 2 Concept of single stage SR process utilizing O2 and coal without and with post combustion. Top jetting lance smelters include the Mitsubishi smelting reactor. This is the direct reduction (DR) technology in which iron oxide feed stock is reduced to metallic iron by reducing gases at temperatures below the melting point of iron. The hot pre-reduced iron oxides are generally charged into smelting reactor along with non-coking coal and O2/preheated air. The melted iron and slag percolate through the coke to collect in the bottom of the reactor, and the hot gases leave the melting zone through the coke bed. The concept of three stage SR process utilizing O2 and coal is shown in Fig 4. The electrons are easily released from metal atoms so that layers of metal atoms exist in a 'sea' of electrons. The process must produce iron which can be used by the existing steelmaking processes. The cobalt partitions of the calcine/green nickel concentrate blend analyzed in Table I above are summarized in Table Ia below. The direct utilization of iron ore fines and coal fines is possible. In recent years, around twenty SR processes have been under development throughout the world. The SR processes for ironmaking can be broadly divided into two categories namely (i) process utilizing coal and electricity, and (ii) process utilizing O2 and non-coking coal. The presence of carbon in gasification zone helps in reducing the temperature of the smelter off gases without the loss of energy. Other examples of pericyclic reactions are electrocyclic reactions, sigmatropic reactions) in which an alkene adds to a 1,3-diene to form a 6-membered ring. Some of these processes are BSC, CIG, Hoogovens, Kobe, Krupp, Korf, BSC Oxy/Coal BF, Kawasaki, Pirogas, Plasmasmelt, Sumitomo, DSS, Combismelt, Elred, and Inred etc. To focus more on the specifics, lead smelting will be used as the main example, although all other metals go through a relatively similar process. 4 illustrates a flash smelting furnace used in the example. Small scale operation – The second objective for the development of SR ironmaking process is to have an economic size of the process. It is possible to recycle of existing stock-piles, in-plant dusts, sludge and other reverts to the extent possible. In this process, both reduction and smelting take place in the electric smelter. Initially the feeding of hot DRI from the reduction unit to the steelmaking reactor was seen as a difficult engineering issue, and processes were proposed in which DRI was cooled before discharge from the reduction unit. Examples of chemical reaction includes burning wood into ashes. The total energy is supplied by the combustion of coal with O2. This results into high capital intensity of a modern BF complex which not only needs a very long time period for its construction but also needs to be operated to near capacity levels to be economically viable. There is no requirement of expensive coking coal. This is another Nobel-prize-winning reaction (1950) that provides exibility to synthetic organic chemists. The product from DR processes, direct reduced iron (DRI), is physically similar to the feedstock in form (usually iron ore lumps and/or pellets) and contains the gangue minerals present in the original ore. DRI is also known as sponge iron. To focus more on the specifics, lead smelting will be used as the main example, although all other metals go through a relatively similar process. The campfire theory suggests that metal ores may have been used by ancient civilizations in the formation of fire pits or stone enclosures around cooking fires. For example, cobalt partitions in reverberatory smelting processes are about 5. They require little supporting infrastructure, and are much less capital intensive than the BF. Reduced cost – Since the BF is a thermally and chemically efficient process, there is very little scope for any competitor process to reduce the costs spent on the raw materials and energy. There is an abundance of lead deposits in Canada and many of these mines are located to the Northwestern area of Canada. The process offers greater flexibility compared with any other oxy-coal process. So the obvious objective for the SR ironmaking processes was the use of non-coking coal directly as a process fuel and reductant so as to avoid the requirement for a coke making unit. Reaction smelting is also called ore-hearth smelting in the case of lead metallurgy. The high cost of the electricity makes electric melting less attractive. In a pure crystalline solid, this process occurs at a fixed temperature called the melting point; an impure solid generally melts over a range of temperatures below the melting point of the principal component. They can not be melted into liquid at the smelting temperature of blast furnace, so they can not be well separated from molten iron. However, serious efforts started from 1980 onwards. The history of the development of SR processes goes back to the 1950s. Limitations of the SR process include the following. Further the SR process is not to interfere with the already operating ironmaking process within the plant. google_ad_height = 250; Development of Smelting Reduction Processes for Ironmaking. Example 1: Reaction Between Hydrogen and Fluorine. Process concepts with input of electrical energy – These concepts have been the basis for several processes. The ore of the metal, in this case, galena is removed from. In this process, all the metallurgical reactions are carried out in a single reactor where iron ore, coal, and O2 are fed and the gases evolved from the liquid bath are post combusted to a very high degree (around 75 %) and the major portion of heat is transferred back to the liquid bath. The process offers greater flexibility compared with other oxy-coal processes. All Rights Reserved © 2019, Design & Developed By: Star Web Maker. 1 is composed of the elementary reactions given by Eqs. Under these concepts, usually the fuels are introduced at the reduction stage and the exhaust gases from reduction, together with other waste heat arising are used to generate the electrical energy used in the melting operation. But there are opportunities available to reduce the high cost connected with the BF ironmaking avoiding capital intensive associated plant and equipment and production units. Flexibility is available in selection of thermochemical design. Based on above objectives and concepts, development work was carried out for several processes. From the chemical analysis of the Ferro-chrome sample it is observed that up to 60 % chromium have been recovered in the alloys. In the second reaction of the first process, the lead (II) oxide reacts again with coke to produce lead and carbon dioxide. Instead of coke, galena is added to the lead (II) oxide and the reaction produces more lead but also sulfur dioxide. A further development of the concept has been in the direction of making the reduction stage in the upper part of the melting reactor rather than a separate process unit, giving a continuous counter current oxy/coal smelting reduction process. However, this concept was taken forward, and a melter- gasifier of an innovative design was proposed which was linked to a reduction shaft of a fairly conventional type. The DR processes are capable of economic operation at much lower output levels than a BF, typically less than 0.6 Mt per year. The process is performed in a special crucible charged with a rich lead concentrate and coke. Examples of Redox Reactions. Several of these processes propose to use tonnage O2 as the oxidant to enable the process heat requirements to be satisfied by combustion of the coal fuel. The improved control over process parameters is possible. The flash smelting process is an example of an energy-saving pyrometallurgical process in which iron and sulphur of the ore concentrate are oxidized. Coal based DR processes are principally rotary kiln based processes and they are popular only in a few countries because of a variety of technical and economic reasons. However, if carbon is present in the gas reaction zone, it can help reduce the temperature of the off gas because of the endothermic reactions C+ CO2= 2 CO, and C + H2O = CO + H2. 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