The process gives improved energy economy by utilizing exhaust gases for electricity generation. 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. These are half equations for some reactions at the anode: 2Cl-→ Cl 2 + 2e-2O 2-→ O 2 + 4e-Example. It was quickly realized that these gases were very suitable for use as reducing gases in direct reduction, which was a well understood technology. These processes combine the gasification of non-coking coal with the melt reduction of iron ore. Energy intensity of SR processes is lower than that of blast furnace (BF), since the production of coke is not needed and the need for preparation of iron ore is also reduced. 2CuO (s) + C (s) → 2Cu (l) + CO2(g) Copper oxide is reduced as carbon is oxidised, so this is an example of a redox reaction. Fig 1 Concepts of single stage and two stage processes utilizing coal and electricity. Depending on the degree of pre-reduction and post-combustion, these processes can be further divided into two groups. Reaction smelting is also called ore-hearth smelting in the case of lead metallurgy. The concepts of single stage and two stage processes utilizing coal and electricity is shown in Fig 1. The cobalt partitions of the calcine/green nickel concentrate blend analyzed in Table I above are summarized in Table Ia below. 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 small capacity SR processes can also provide the opportunity for a less complex plant which needs considerably shorter construction time for its commissioning and which is much simpler to operate. 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. The exhaust gases from the smelter are used for internal generation of electricity. The hot pre-reduced iron oxides are generally charged into smelting reactor along with non-coking coal and O2/preheated air. These processes differ in the number of reactors and the ore feed used (pellets, lump ore, or fines). In case of two stage process, the DRI produced in a reduction unit is smelted in the electric smelter. Calcine melts and its compounds react with the fluxes. The process offers greater flexibility compared with other oxy-coal processes. 1 is composed of the elementary reactions given by Eqs. There is a plethora of riddles and conceptions pertaining to not only the way in which smelting was first done, but how smelting was invented or discovered in the first place. The availability of natural gas is not wide spread around the globe. In the two stage process, two separate reactors for pre-reduction and smelting reduction are used. 6 is a graph showing the distribution of grain sizes of the powder coke used in the examples. It is to be noted that cobalt partitions increase uniformly with the increasing iron of the matte. The history of the development of SR processes goes back to the 1950s. The charge is blown with compressed air, and the temperature in the crucible increases to 700°-900°C from the combustion of coke and the heat liberated in the oxidation of metallic sulfides. [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] … Coke reduces the metal oxides into free metal. The improved control over process parameters is possible. 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 ℃). Baking bread Examples of exothermic reactions: 1. any combustion reaction 2. a neutralization reaction 3. rusting of iron (rust steel wool with vinegar) 4. the thermite reaction 5. reaction between water and calcium chloride 6. reaction between sodium sulfite and bleach (dilute sodium The process consumes large amount of O2, the generation of which needs high amount of power (around 0.6 kWh per N cum of O2). To extract the metal, workers must make these compounds undergo a chemical reaction. The high sulphur recovery of the process is also beneficial for environmental protection. The process offers greater flexibility compared with any other oxy-coal process. SR process has many advantages with respect to raw materials, energy cost, capital cost, economy of scale, and environmental compatibility. 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. The heat of the post-combustion is efficiently transferred from the gas phase to the liquid bath. Both unit processes can be carried out simultaneously in one reactor or in two independent interconnected reactors. These SR processes utilize oxy-coal combustion as the source of energy as well as for the reduction purpose. The requirements of O2 and coal are high because of the limited possibilities available for the utilization of the reducing gas. 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. In this process, both reduction and smelting take place in the electric smelter. 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. Process concepts employing electric melting furnaces with fossil fuel as primary energy – There are several processes which use electric furnaces for the melting and final reduction, and the use of fossil fuels, usually non-coking coals, as the primary energy source. For example reduction of Fe 6O, ZnOand PbO. Ability to integrate with available technologies in other areas – This is another objective for the development of a SR ironmaking process. Melting, change of a solid into a liquid when heat is applied. These SR processes utilize electricity as the source of energy and non-coking coal as reductant. The bottom line is that no one can be 100% sure when or how smelting started. The chemical change is one in which the substance loses or gains an electron (oxidation or reduction). Top jetting lance smelters include the Mitsubishi smelting reactor. 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 alloy and slag sample collected after smelting is shown in figure 3.3. In the end, we cannot fathom how ancient civilizations began the art of smelting, however, we do know that smelting has drastically evolved and advanced to what it is today; a major contribution to the economy and a major concern for the environment. Also, ironmaking in the BF needs considerable associated infrastructure and production units which include coke making and facilities for iron ore fines sintering. Besides, in the smelting process, they mix material with oxygen. The reaction is synthetically very useful, due to the formation of cyclic products. The ability to use iron ore fines also was another objective which offer an opportunity to cut out the cost of agglomeration units such as sintering/pelletizing plant. Heat loss occurs because the melter exhaust gases are to be cooled from 1600 deg C to 800 deg C before they can be used for reduction. Reaction Mechanism on the Smelting Reduction of Iron Ore by Solid Carbon JAE-CHEOL LEE, DONG-JOON MIN, and SUNG-SOO KIM The kinetics of the smelting reduction of iron ore by a graphite crucible and carbon-saturated molten iron was investigated between 1400 7C and 1550 7C, and its reaction phenomena were continuously observed in situ by X-ray ﬂuoroscopy. The basic principle of a SR process is to melt the pre-reduced iron ore/sinter/pellets with non-coking coal and O2 or hot blast in a reactor. Some examples of bath smelters include the Noranda furnace, the Isasmelt furnace, the Teniente reactor, the Vunyukov smelter and the SKS technology to name a few. narrow channels called veins and spherical deposits in the Earth called lodes. google_ad_client = "ca-pub-7057920448327527"; Abstract. The ore of the metal, in this case, galena is removed from. Examples of Redox Reactions. The process maintains quality of hot metal which is same as being obtained in a BF. In general, this line of the development did not encompass any radical process changes in the furnace itself. The efficiency of the two-stage process can be improved by separating the gas reaction zone from the smelting zone. The concept of three stage SR process utilizing O2 and coal is shown in Fig 4. Based on the number of stages involved (according to their thermochemical design), these processes can be divided into three types namely (i) single stage process, (ii) two stage process, and (iii) three stage process. 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