The Metallurgy of Iron

The calcium oxide then reacts with the impurities in the iron, which are mostly sand (SiOa) and aluminum oxide (AI2O3J  

The mixture of calcium silicate and calcium aluminate that remains molten at the furnace temperature is known as slag. 

Iron extracted in this way contains many impurities and is called pig iwn it may contain up to 5 percent carbon and some silicon, phosphorus, manganese, and sulfur. Some of the impurities stem from the silicate and phosphate minerals, while carbon and sulfur come from coke. Pig iron is granular and brittle. It has a relatively low melting point (about 1180°C), so it can be cast in various forms for this reason it is also called cast iron. 

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Most of the first-row transition metals and several in the second and third groups have important uses. For example, iron is the basis of the enormous range of ferrous alloys in which other first-row metals are often combined. The metallurgy of iron-based alloys is a vast and complex field. Among the many... 

Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between silicon carbide and a variety of compounds at relatively high temperatures. Sodium silicate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal silicide. Silicon carbide decomposes in fused alkalies such as potassium chromate or sodium chromate and in fused borax or cryolite, and reacts with carbon dioxide, hydrogen, air, and steam. Silicon carbide, resistant to chlorine below 700°C, reacts to form carbon and silicon tetrachloride at high temperature. SiC dissociates in molten iron and the silicon reacts with oxides present in the melt, a reaction of use in the metallurgy of iron and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new silicon nitride-bonded type exhibits improved resistance to cryolite. 

The preceding examples and the treatment of the metallurgy of iron are typical of the processes involved in the production of metals of relatively high density. The remaining heavy metals that are used industrially are not considered in detail here. However, Table 11.8 gives a limited selection of information on the mode of occurrence, metallurgy, and uses of these metals. 

In 1350 or thereabouts cast iron was produced in Sussex, which county was at that period one of England s most important centres of the iron industry. The introduction of cast iron made it possible to utilise our ores to far greater advantage than would otherwise have been the case, and constituted an important advance in the metallurgy of iron. It was in the little Sussex village of Buxted that... 

For a more detailed discussion of this subject and its bearing upon the metallurgy of iron and steel, see this volume, Part III. 

The Metallurgy of Iron. The ores of iron are usually first roasted, in order to remove water, to decompose carbonates, and to oxidize sulfides. They are then reduced with coke, in a structure called a blast furnace (Fig. 26-2). Ores containing limestone or magnesium carbonate are mixed with an acidic flux (containing an, excess of silica), such as sand or clay, in order to make a liquid slag. Limestone is used as flux for ores containing an excess o silica. The mixture of ore, flux, and coke is introduced at the top of the blast furnace, and pre heated air is blown in at the bottom through tuyeres. As the solid... 

Lime, CaO, is added to molten iron ore during the manufacture of pig iron. It lowers the melting point of the mixture. The metallurgy of iron is discussed in more detail in Chapter 22. 

Turner, T. The Metallurgy of Iron. London, 1915, White, Edmund. Thorium. Lecture, Institute of Chemistry. London, 1912. 

See Gmelin-Durrer, The Metallurgy of Iron, Vols. 3a,b, Verlag Chemie, 1971. 

Steel Production FI y d rometallu rg y The Metallurgy of Iron Production of Steel Heat Treatment of Steel... 

The metallurgy of iron most common method for reduction uses a blast furnace process involves iron ore, coke, and limestone... 

Lee] Lee, G.M.C., The Metallurgy of Iron-Nickel and Iron-Niekel-Cobalt Diffusion Coatings , Canad. Metall. Quart., 25(4), 327-335 (1986) (Experimental, Phase Diagram, Phase Relations, Interface Phenomena, Transport Phenomena, 15)... 

We then smdy the sequence of steps from the preparation of the ores to the production of metals. We focus mainly on the metallurgy of iron and the making of steel. We also examine several methods of metal purification. (20.2)... 

Because carbon is a ubiquitous element in both iron- and steelmaking processes due to its essential use as a reductant during the extractive process of iron from its ores, carbon has a predominant role in siderurgy (i.e., the metallurgy of iron and its alloys). Although other... 

We have already discussed the metallurgy of iron in considerable detail in Section 23.2. Here we consider some of its important aqueous solution chemistry. Iron exists in aqueous solution in either the +2 (ferrous) or +3 (ferric) oxidation states. It often appears in natural waters because these waters come in contact with deposits of FeCOs Kg = 3.2 X 10 ). Dissolved C02inthewatercanthenhelp dissolve the mineral ... 

Metallurgical Processes Preparation of the Ore Productioft of Metals The Metallurgy of Iron Steelmaking Purification of Metals... 

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