steps and processes from extraction of ores to manufacturing of steel - BINQ Mining BINQ Mining steps and processes from extraction of ores to manufacturing of steel Posted at:April 27, 2013[ 4.9 - 1540 Ratings] MANUFACTURING PROCESS Some of the technological options … Some of the technological options for converting iron ore to steel products is schematically shown below. … The energy required for extracting iron from ore is about 25 % of what is ….. A major feature is there is no pre-reduction process step . » More detailed Steel Production – Metals – Modern Production Process: Steel production can be broken down into six steps: 1. Ironmaking: In the first step, the raw inputs iron ore, coke and lime are melted … » More detailed EXTRACTION OF IRON- EXTRACTION OF IRON FROM HAEMATITE Iron is extracted from its oxide, ore called HAEMATITE (Fe2O3). PRINCIPLE … The process of the extraction of iron is carried out by the following steps: … of ore. The process of reduction is carried out in a blast furnace. … It has an outer shell of steel. … in road making, cement manufacturing a light weight building materials.

» More detailed Steel – Wikipedia, the free encyclopedia Iron is extracted from iron ore by removing the oxygen and combining the ore with a … The excess carbon and other impurities are removed in a subsequent step. …. The production of steel by the cementation process was described in a … » More detailed The Steel Making Industry – P2 InfoHouse Integrated steel plants produce steel by refining iron ore in several steps and … The resulting water can be reused in other manufacturing processes or released. » More detailed How iron is made – material, manufacture, making, history, used … Iron ore is converted into various types of iron through several processes. … The metal they used was apparently extracted from meteorites. … Benjamin Huntsman took out a patent for the melting of material for the production of steel springs to … » More detailed Steel Manufacturing Process | The first stage of the steel manufacturing process is converting iron ore into molten iron that can be used for steel. There are three methods of making iron. » More detailed Extraction of Metals – Doc Brown's Chemistry Clinic There are detailed notes on the extraction of iron and its conversion to steel. The extraction and manufacture of aluminium and sodium are described. The extraction … Mining of Minerals and Methods of Extracting of Metals from Ores. 1.

» More detailed gcse 2. Blast furnace extraction of iron recycling, steel making … How do we extract iron from its mineral ores? … The manufacture of steel alloys is further described. … Mining of Minerals and Methods of Extracting of Metals. 2. » More detailed Metallurgy – ChemWiki It concludes with a brief description of steel production using the concepts of equilibrium … The process converts the ores to their oxides which can then be reduced. … Hydrometallurgy is the process of extraction & refining that involves the use of water … It is carreid out at moderate temps & is generally carried out in 3 steps: … » More detailed Production of iron from iron ore (hematite & magnetite) – Cli Houston The production of iron or steel is a process unless the desired final product is cast iron. The first … 90% of all mining of metallic ores is for the extraction of iron. » More detailed Steel Production Process – Yahoo! Voices – 9 Nov 2008 … When iron ore is found in rocks it is usually rich in oxygen and contains other impurities.

The first step in the steel production process is to … » More detailed The Manufacture of Steel share of the domestic steel market is about 90%. THE MANUFACTURING PROCESS. Iron ore is converted to steel via two main steps. The first involves the … » More detailed Metallurgy – The Canadian Encyclopedia The steps in extracting metals from their ores are mineral processing, which processes …. and converting processes similar to those used in copper production. … CaO) is mixed with ferrosilicon and then placed in a tubular stainless steel retort … » More detailed From ore to steel – ArcelorMittal ArcelorMittal's operations extend from iron ore and coal mining to providing a full … of iron ore and coal to the production of the full range of steel products and services. … The steelmaking process starts with the processing of iron ore. The rock containing iron ore is ground and the ore is extracted using magnetic rollers. » More detailed Sustainability Report 2008 – Better ecobalance in steel production We've succeeded in developing new processes for producing iron and steel that are … allows pig iron to be produced from fine ore in just a single process step.

… the extraction and conditioning of raw materials to the manufacturing process, … » More detailed Steelmaking – Wikipedia, the free encyclopedia Steelmaking is the second step in producing steel from iron ore. In this … Pennsylvania was one of the world's largest manufacturers of steel before its 2003 closure. … Modern steelmaking processes are broken into two categories: primary and … » More detailed Metal production – Vestlandsforsking Table 1 CO2-emissions pr tonne of steel by process and components . …. The production of primary steel starts by reducing iron ore which is iron in oxidized form. ….. extraction of alumina (aluminium oxide) from ore, mainly from bauxite ( the …. The numbers for fissile fuel and nuclear power for the electrolysis step show their … » More detailed Extraction of Metals – Principles of metal extraction A level chemistry AQA specification: Extraction of Metals – Principles of … look at some of the most important metals and their manufacturing processes … metal being extracted, but can be broken down into roughly the same steps: … The electrolytic cell used is a steel tank with a carbon base which is made the cathode.

» More detailed Towards Lowest-Energy Steel Production – Climate VISION need to refocus attention on energy intensity in steel production. … coal, iron ore pellets, scrap and lime; and in the production of process gases such as oxygen. …. processes, consideration of these process steps should provide the most significant ….. and practical means to extract energy from these outputs for use in other … BBC - GCSE Bitesize: Making iron In the blast furnace Blast furnace in a modern steel works Iron is extracted from iron ore in a huge container called a blast furnace. Iron ores such as haematite contain iron oxide. The oxygen must be removed from the iron oxide to leave the iron behind. Reactions in which oxygen is removed are called reduction reactions. Carbon is more reactive than iron, so it can push out or displace the iron from iron oxide. Here are the equations for the reaction: iron oxide + carbon → iron + carbon dioxide 2Fe2O3 + 3C → 4Fe + 3CO2 In this reaction, the iron oxide is reduced to iron, and the carbon is oxidised to carbon dioxide.

In the blast furnace, it is so hot that carbon monoxide can be used to reduce the iron oxide in place of carbon: iron oxide + carbon monoxide → iron + carbon dioxide Fe2O3 + 3CO → 2Fe + 3CO2 Raw materials for the reaction The raw materials for extracting iron and their function in the process Raw material How iron is made - material, manufacture, making, history, used, processing, parts, structure, procedure Iron Background Iron is one of the most common elements on earth. Nearly every construction of man contains at least a little iron. It is also one of the oldest metals and was first fashioned into useful and ornamental objects at least 3,500 years ago. Pure iron is a soft, grayish-white metal. Although iron is a common element, pure iron is almost never found in nature. The only pure iron known to exist naturally comes from fallen meteorites. Most iron is found in minerals formed by the combination of iron with other elements. Iron oxides are the most common. Those minerals near the surface of the earth that have the highest iron content are known as iron ores and are mined commercially. Iron ore is converted into various types of iron through several processes.

The most common process is the use of a blast furnace to produce pig iron which is about 92-94% iron and 3-5% carbon with smaller amounts of other elements. Pig iron has only limited uses, and most of this iron goes on to a steel mill where it is converted into various steel alloys by further reducing the carbon content and adding other elements such as manganese and nickel to give the steel specific properties. History Historians believe that the Egyptians were the first people to work with small amounts of iron, some five or six thousand years ago. The metal they used was apparently extracted from meteorites. Evidence of what is believed to be the first example of iron mining and smelting points to the ancient Hittite culture in what is now Turkey. Because iron was a far superior material for the manufacture of weapons and tools than any other known metal, its production was a closely guarded secret. However, the basic technique was simple, and the use of iron gradually spread. As useful as it was compared to other materials, iron had disadvantages. The quality of the tools made from it was highly variable, depending on the region from which the iron ore was taken and the method used to extract the iron.

The chemical nature of the changes taking place during the extraction were not understood; in particular, the importance of carbon to the metal's hardness. Practices varied widely in different parts of the world. There is evidence, for example, that the Chinese were able to melt and cast iron implements very early, and that the Japanese produced amazing results with steel in small amounts, as evidenced by heirloom swords dating back centuries. Similar breakthroughs were made in the Middle East and India, but the processes never emerged into the rest of the world. For centuries the Europeans lacked methods for heating iron to the melting point at all. To produce iron, they slowly burned iron ore with wood in a clay-lined oven. The iron separated from the surrounding rock but never quite melted. Instead, it formed a crusty slag which was removed by hammering. This repeated heating and hammering process mixed oxygen with the iron oxide to produce iron, and removed the carbon from the metal. The result was nearly pure iron, easily shaped with hammers and tongs but too soft to take and keep a good edge. Because the metal was shaped, or wrought, by hammering, it came to be called wrought iron.

Tools and weapons brought back to Europe from the East were made of an iron that had been melted and cast into shape. Retaining more carbon, cast iron is harder than wrought iron and will hold a cutting edge. However, it is also more brittle than wrought iron. The European iron workers knew the Easterners had better iron, but not the processes involved in fashioning stronger iron products. Entire nations launched efforts to discover the process. The first known European breakthrough in the production of cast iron, which led quickly to the first practical steel, did not come until 1740. In that year, Benjamin Huntsman took out a patent for the melting of material for the production of steel springs to be used in clockmaking. Over the next 20 years or so, the procedure became more widely adopted. Huntsman used a blast furnace to melt wrought iron in a clay crucible. He then added carefully measured amounts of pure charcoal to the melted metal. The resulting alloy was both strong and flexible when cast into springs.

Since Huntsman was originally interested only in making better clocks, his crucible steel led directly to the development of nautical chronometers, which, in turn, made global navigation possible by allowing mariners to precisely determine their east/west position. The fact that he had also invented modern metallurgy was a side-effect which he apparently failed to notice. Raw Materials The raw materials used to produce pig iron in a blast furnace are iron ore, coke, sinter, and limestone. Iron ores are mainly iron oxides and include magnetite, hematite, limonite, and many other rocks. The iron content of these ores ranges from 70% down to 20% or less. Coke is a substance made by heating coal until it becomes almost pure carbon. Sinter is made of lesser grade, finely divided iron ore which, is roasted with coke and lime to remove a large amount of the impurities in the ore. Limestone occurs naturally and is a source of calcium carbonate. Other metals are sometimes mixed with iron in the production of various forms of steel, such as chromium, nickel, manganese, molybdenum, and tungsten.

The Ore Extraction and Refining Process Before iron ore can be used in a blast furnace, it must be extracted from the ground and partially refined to remove most of the impurities. Leaning on his long tongs, this young iron puddler's helper posed for this photograph in the early 1860s, when the Sons of Vulcan was a young union. (From the collections of Henry Ford Museum & Greenfield Village.) Historically, iron was produced by the hot-blast method, or later, the anthracite furnace. Either way, the fundamental activity in iron making involved a worker stirring small batches of pig iron and cinder until the iron separated from the slag. Called "puddling," this was highly skilled work, but was also hot, strenuous, and dangerous. It required a lot of experience as well as a hearty constitution. Puddlers were proud, independent, and highly paid. Puddlers founded the first trade union in the iron and steel industry, the Sons of Vulcan, in Pittsburgh in 1858. In 1876, this union merged with three other labor organizations to form the Amalgamated Association of Iron and Steel Workers.

This was the union that Andrew Carnegie defeated in the Homestead Strike of 1892, leaving the union in shambles and the industry essentially unorganized until the 1930s. William S. Pretzer Extraction 1 Much of the world's iron ore is extracted through open pit mining in which the Pure iron is a soft, grayish-white metal. Although iron is a common element, pure iron is almost never found in nature. Minerals near the surface of the earth that have the highest iron content are known as iron ores and are mined commercially. surface of the ground is removed by heavy machines, often over a very large area, to expose the ore beneath. In cases where it is not economical to remove the surface, shafts are dug into the earth, with side tunnels to follow the layer of ore. Refining 2 The mined ore is crushed and sorted. The best grades of ore contain over 60% iron. Lesser grades are treated, or refined, to remove various contaminants before the ore is shipped to the blast furnace. Collectively, these refining methods are called beneficiation and include further crushing, washing with water to float sand and clay away, magnetic separation, pelletizing, and sintering.

As more of the world's known supply of high iron content ore is depleted, these refining techniques have become increasingly important. 3 The refined ore is then loaded on trains or ships and transported to the blast furnace site. The Manufacturing Process Charging the blast furnace 1 After processing, the ore is blended with other ore and goes to the blast furnace. A blast furnace is a tower-shaped structure, made of steel, and lined with refractory, or heat-resistant bricks. The mixture of raw material, or charge, enters at the top of the blast furnace. At the bottom of the furnace, very hot air is blown, or blasted, in through nozzles called tuye'res. The coke burns in the presence of the hot air. The oxygen in the air reacts with the carbon in the coke to form carbon monoxide. The carbon monoxide then reacts with the iron ore to form carbon dioxide and pure iron. Separating the iron from the slag 2 The melted iron sinks to the bottom of the furnace. The limestone combines with the rock and other impurities in the ore to form a slag which is lighter than the iron and floats on top. As the volume of the charge is reduced, more is continually added at the top of the furnace.

The iron and slag are drawn off separately from the bottom of the furnace. The melted iron might go to a further alloying process, or might be cast into ingots called pigs. The slag is carried away for disposal. Treating the gases 3 The hot gases produced in the chemical reactions are drawn off at the top and routed to a gas cleaning plant where they are cleaned, or scrubbed, and sent back into the furnace; the remaining carbon monoxide, in particular, is useful to the chemical reactions going on within the furnace. A blast furnace normally runs day and night for several years. Eventually the brick lining begins to crumble, and the furnace is then shut down for maintenance. Quality Control The blast furnace operation is highly instrumented and is monitored continuously. Times and temperatures are checked and recorded. The chemical content of the iron ores received from the various mines are checked, and the ore is blended with other iron ore to achieve the desired charge. Samples are taken from each pour and checked for chemical content and mechanical properties such as strength and hardness. Byproducts/Waste There are a great many possible environmental effects from the iron industry. The first and most obvious is the process of open pit mining. Huge tracts of land are stripped to bare rock.

Today, depleted mining sites are commonly used as landfills, then covered over and landscaped. Some of these landfills themselves become environmental problems, since in the recent past, some were used for the disposal of highly toxic substances which leached into soil and water. The process of extracting iron from ore produces great quantities of poisonous and corrosive gases. In practice, these gases are scrubbed and recycled. Inevitably, however, some small amounts of toxic gases escape to the atmosphere. A byproduct of iron purification is slag, which is produced in huge amounts. This material is largely inert, but must still be disposed of in landfills. Ironmaking uses up huge amounts of coal. The coal is not used directly, but is first reduced to coke which consists of almost pure carbon. The many chemical byproducts of coking are almost all toxic, but they are also commercially useful. These products include ammonia, which is used in a vast number of products; phenol, which is used to make plastics, cutting oils, and antiseptics; cresols, which go into herbicides, pesticides, pharmaceuticals, and photographic chemicals; and toluene, which is an ingredient in many complex chemical products such as solvents and explosives.

Scrap iron and steel—in the form of old cars, appliances and even entire steel-girdered buildings—are also an environmental concern. Most of this material is recycled, however, since steel scrap is an essential resource in steelmaking. Scrap which isn't recycled eventually turns into iron oxide, or rust, and returns to the ground. The Future On the surface, the future of iron production—especially in the United States—appears troubled. Reserves of high-quality ore have become considerably depleted in areas where it can be economically extracted. Many long-time steel mills have closed. However, these appearances are deceiving. New ore-enrichment techniques have made the use of lower-grade ore much more attractive, and there is a vast supply of that ore. Many steel plants have closed in recent decades, but this is largely because fewer are needed. The efficiency of blast furnaces alone has improved remarkably. At the beginning of this century, the largest blast furnace in the United States produced 644 tons of pig iron a day. It is believed that soon the possible production of a single furnace will reach 4,000 tons per day.

Since many of these more modern plants have been built overseas, it has actually become more economical in some cases to ship steel across the ocean than to produce it in older U.S. plants. Where To Learn More gcse 2. Blast furnace extraction of iron recycling, steel making reduction of haematite ore magnetite description of processs igcse O Level KS4 science chemistry revision notes revising Why do we need to convert most iron into steel alloys? Most metals in everyday use are alloys. Iron is a good conductor of heat and can be bent or hammered into shape (malleable), quite strong physically ï¿½ made stronger when alloyed with other materials. This makes iron useful as structural material and for making things that must allow heat to pass through easily and useful construction materials. Steel is an alloy because it is a mixture of a metal (iron) with other elements (carbon and perhaps other metals too). Iron from the blast furnace contains about ~96% iron with ~4% of impurities including carbon, silica and phosphorus. In this state the cast iron is too hard and too brittle for most purposes.

Cast iron is hard and can be used directly for some purposes eg manhole covers, ornamental railings because of its strength in compression and is very hard wearing. However, if all the impurities are removed, the resulting very pure iron is too soft for any useful purpose. Therefore, strong useful steel is made by controlling the amount of carbon and selected metals to produce an alloy mixture with the right physical properties fit for a particular application e.g. steel for car bodies, chrome stainless steel, extremely hard and tough tungstenï¿½iron steel alloys etc. The real importance of alloys is that they can be designed to have properties for specific uses in terms of eg compression/tensile strength or corrosion reduction ie less susceptible to rusting. Lowï¿½carbon steels (0.1% carbon) are easily shaped for car bodies Highï¿½carbon steels (1.5% carbon, often with other metals too) are hard wearing and inflexible and can be used for cutting tools, bridge construction. Stainless steels have chromium (and maybe nickel) added and are much resistant to corrosion (from oxygen/water) than iron or plain steel which readily rust.

Objects made of iron or plain steel, particularly those exposed to the weather, regularly have to be painted or coated with some other protective layer from the effects of water and oxygen. The properties of iron can be altered by adding small quantities of other metals or carbon to make steel , one of the useful metal alloys in widespread use today. Steels are alloys since they are mixtures of iron with other metals or with nonï¿½metals like carbon or silicon. Making Steel: (1) Molten iron from the blast furnace is mixed with recycled scrap iron (2) Then pure oxygen is passed into the mixture and the nonï¿½metal impurities such as silicon or phosphorus are then converted into acidic oxides (the BOS oxidation process) .. e.g. Si + O2 ==> SiO2, or 4P + 5O2 ==> P4O10 (3) Calcium carbonate (a base) is then added to remove the acidic oxide impurities (in an acidï¿½base reaction). The salts produced by this reaction form a slag which can be tapped off separately. e.g.

CaCO3 + SiO2 ==> CaSiO3 + CO2 (calcium silicate slag) Reactions (1)ï¿½(3) produce pure iron. Calculated quantities of carbon and/or other metallic elements such as titanium, manganese or chromium are then added to make a wide range of steels with particular properties. Because of the high temperatures the mixture is stirred by bubbling in unreactive argon gas! Economics of recycling scrap steel or ion: Most steel consists of >25% recycled iron/steel and you do have the 'scrap' collection costs and problems with varying steel composition* BUT you save enormously because there is no mining cost or overseas transport costs AND less junk lying around! (NOTE: * some companies send their own scrap to be mixed with the next batch of 'specialised' steel they order, this saves both companies money!). More on this below. ï¿½ NOTE on RECYCLING Iron and Steel About 42% of iron/steel in goods/components manufactured in iron/steel is recycled iron/steel, whether it be steel pans, car bodies, bridge girders, stainless steel cutlery etc.

This makes good economics because recycling saves on several costs AND allows a mineral resource like iron's haematite or magnetite ore resources to last a lot longer ï¿½ slower depletion of the Earth's mineral ore resources will make it last longer. Transport costs may be less (ie within UK now), but much more importantly mining costs are omitted ï¿½ energy/machinery involved in digging out the ore, crushing it, transporting the ore, and the cost of actually extracting the metal from its finite ore resource ï¿½ chemicals needed (coke, limestone), constructing and running a blast furnace So, scrap metal merchants are doing a roaring trade at the moment. The savings are partly reduced by the cost off collecting waste/scrap metal. There are particular problems due to the varying composition of alloys, but if the composition is known, or obtained from chemical analysis, the different compositions can be blended together to a desired alloy composition. extraction of titanium TITANIUM As far as I can see there is only one UK-based Exam Board that wants the extraction of titanium, and that is AQA. They only want the conditions and equations for the reactions involved, and that is all you will find on this page together with a few comments related to method used.

If you want more details, you can find them on a useful page from The Essential Chemistry Industry from the University of York. Titanium extraction The overall process Titanium is extracted from its ore, rutile - TiO2. It is first converted into titanium(IV) chloride, which is then reduced to titanium using either magnesium or sodium. Conversion of TiO2 into TiCl4 The ore rutile (impure titanium(IV) oxide) is heated with chlorine and coke at a temperature of about 1000°C. Note: There are other reactions occurring as well in which the other product is either carbon dioxide or carbonyl chloride, COCl2. AQA give the one producing carbon monoxide as their first choice, but will also accept one producing carbon dioxide. Other metal chlorides are formed as well because of other metal compounds in the ore. Very pure liquid titanium(IV) chloride can be separated from the other chlorides by fractional distillation under an argon or nitrogen atmosphere, and is stored in totally dry tanks. Note: Titanium(IV) chloride is a typical covalent chloride.

It is a colourless liquid which fumes in moist air due to reaction with water to give titanium(IV) oxide and fumes of hydrogen chloride. Everything has to be kept very dry to prevent this happening. Reduction of the titanium(IV) chloride TiCl4 can be reduced using either magnesium or sodium. AQA will accept either, and so I am just giving the magnesium one. Titanium(IV) chloride vapour is passed into a reaction vessel containing molten magnesium in an argon atmosphere, and the temperature is increased to about 1000°C. The reduction process is very slow, taking about 2 days, followed by several more days of cooling. When it is cool, the reaction mixture is crushed, and dilute hydrochloric acid is added to react with any excess magnesium to form more magnesium chloride. All the magnesium chloride dissolves in the water present, and the remaining titanium is processed further to purify it. Other thoughts Why is this extraction process used? Titanium can't be extracted by reducing the ore using carbon as a cheap reducing agent. The problem is that titanium forms a carbide, TiC, if it is heated with carbon, so you don't get the pure metal that you need.

The presence of the carbide makes the metal very brittle. That means that you have to use an alternative reducing agent. In the case of titanium, the reducing agent is either sodium or magnesium. Both of these would, of course, first have to be extracted from their ores by expensive processes. Other problems Traces of oxygen or nitrogen in the titanium tend to make the metal brittle. The reduction has to be carried out in an inert argon atmosphere rather than in air. Titanium is made by a batch process. In the production of iron, for example, there is a continuous flow through the Blast Furnace. Iron ore and coke and limestone are added to the top, and iron and slag removed from the bottom. This is a very efficient way of making something. With titanium, however, you make it one batch at a time. Titanium(IV) chloride is heated with sodium or magnesium to produce titanium. The titanium is then separated from the waste products, and an entirely new reaction is set up in the same reactor. This is a slow and inefficient way of doing things.

Note: If you follow the link at the top of the page, you will find that there is now a continuous flow method involving sodium, and even a method of producing titanium electrolytically. Questions to test your understanding If this is the first set of questions you have done, please read the introductory page before you start. You will need to use the BACK BUTTON on your browser to come back here afterwards. iron and steel IRON AND STEEL This page looks at the use of the Blast Furnace in the extraction of iron from iron ore, and the conversion of the raw iron from the furnace into various kinds of steel. Extracting iron from iron ore using a Blast Furnace Introduction The common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Coke is produced by heating coal in the absence of air. Coke is cheap and provides both the reducing agent for the reaction and also the heat source - as you will see below. Iron ores The most commonly used iron ores are haematite (US: hematite), Fe2O3, and magnetite, Fe3O4.

Note: The two equations for the reduction of the ore on this page are for haematite. In the fairly unlikely event that you need the equations for magnetite, they aren't difficult to work out for yourself. The Blast Furnace The heat source The air blown into the bottom of the furnace is heated using the hot waste gases from the top. Heat energy is valuable, and it is important not to waste any. The coke (essentially impure carbon) burns in the blast of hot air to form carbon dioxide - a strongly exothermic reaction. This reaction is the main source of heat in the furnace. The reduction of the ore At the high temperature at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide. It is the carbon monoxide which is the main reducing agent in the furnace. In the hotter parts of the furnace, the carbon itself also acts as a reducing agent. Notice that at these temperatures, the other product of the reaction is carbon monoxide, not carbon dioxide. The temperature of the furnace is hot enough to melt the iron which trickles down to the bottom where it can be tapped off. The function of the limestone Iron ore isn't pure iron oxide - it also contains an assortment of rocky material.

This wouldn't melt at the temperature of the furnace, and would eventually clog it up. The limestone is added to convert this into slag which melts and runs to the bottom. The heat of the furnace decomposes the limestone to give calcium oxide. This is an endothermic reaction, absorbing heat from the furnace. It is therefore important not to add too much limestone because it would otherwise cool the furnace. Calcium oxide is a basic oxide and reacts with acidic oxides such as silicon dioxide present in the rock. Calcium oxide reacts with silicon dioxide to give calcium silicate. The calcium silicate melts and runs down through the furnace to form a layer on top of the molten iron. It can be tapped off from time to time as slag. Slag is used in road making and as "slag cement" - a final ground slag which can be used in cement, often mixed with Portland cement. Cast iron The molten iron from the bottom of the furnace can be used as cast iron. Cast iron is very runny when it is molten and doesn't shrink much when it solidifies. It is therefore ideal for making castings - hence its name. However, it is very impure, containing about 4% of carbon.

This carbon makes it very hard, but also very brittle. If you hit it hard, it tends to shatter rather than bend or dent. Cast iron is used for things like manhole covers, cast iron pipes, valves and pump bodies in the water industry, guttering and drainpipes, cylinder blocks in car engines, Aga-type cookers, and very expensive and very heavy cookware. At the time of writing (2015), world production of iron castings was about 75 million tonnes per year. Steel Most of the molten iron from a Blast Furnace is used to make one of a number of types of steel. There isn't just one substance called steel - they are a family of alloys of iron with carbon or various metals. More about this later . . . Steel-making: the basic oxygen process Impurities in the iron from the Blast Furnace include carbon, sulphur, phosphorus and silicon. These have to be removed. Removal of sulphur Sulphur has to be removed first in a separate process. Magnesium powder is blown through the molten iron and the sulphur reacts with it to form magnesium sulphide. This forms a slag on top of the iron and can be removed.

Removal of carbon etc The still impure molten iron is mixed with scrap iron (from recycling) and oxygen is blown on to the mixture. The oxygen reacts with the remaining impurities to form various oxides. The carbon forms carbon monoxide. Since this is a gas it removes itself from the iron! This carbon monoxide can be cleaned and used as a fuel gas. Elements like phosphorus and silicon react with the oxygen to form acidic oxides. These are removed using quicklime (calcium oxide) which is added to the furnace during the oxygen blow. They react to form compounds such as calcium silicate or calcium phosphate which form a slag on top of the iron. Types of iron and steel Cast iron has already been mentioned above. This section deals with the types of iron and steel which are produced as a result of the steel-making process. Wrought iron If all the carbon is removed from the iron to give high purity iron, it is known as wrought iron. Wrought iron is quite soft and easily worked and has little structural strength. It was once used to make decorative gates and railings, but these days mild steel is normally used instead. Mild steel Mild steel is iron containing up to about 0.25% of carbon.

The presence of the carbon makes the steel stronger and harder than pure iron. The higher the percentage of carbon, the harder the steel becomes. Mild steel is used for lots of things - nails, wire, car bodies, ship building, girders and bridges amongst others. High carbon steel High carbon steel contains up to about 1.5% of carbon. The presence of the extra carbon makes it very hard, but it also makes it more brittle. High carbon steel is used for cutting tools and masonry nails (nails designed to be driven into concrete blocks or brickwork without bending). You have to be careful with high carbon steel because it tends to fracture rather than bend if you mistreat it. Special steels Loss of landscape due to mining, processing and transporting the iron ore, coke and limestone. Noise and air pollution (greenhouse effect, acid rain) involved in these operations. Extracting iron from the ore Think about: Loss of landscape due to the size of the chemical plant needed. Noise. Atmospheric pollution from the various stages of extraction. For example: carbon dioxide (greenhouse effect); carbon monoxide (poisonous); sulphur dioxide from the sulphur content of the ores (poisonous, acid rain).

Disposal of slag, some of which is just dumped. Transport of the finished iron. Recycling Think about: Saving of raw materials and energy by not having to first extract the iron from the ore. Avoiding the pollution problems in the extraction of iron from the ore. Not having to find space to dump the unwanted iron if it wasn't recycled. (Offsetting these to a minor extent) Energy and pollution costs in collecting and transporting the recycled iron to the steel works. Questions to test your understanding If this is the first set of questions you have done, please read the introductory page before you start. You will need to use the BACK BUTTON on your browser to come back here afterwards. Nickel Chemistry Nickel Chemistry An excellent site for finding the properties of the elements, including nickel is at For the chapter on Nickel chemistry from the Elsevier text "Chemistry of the Elements" by Greenwood and Earnshaw see On-Line Metals Based Surveys Further information on Nickel can be found at the Nickel Institute and the page on Nickel at Wikipedia. History Nickel had been in use centuries before its actual discovery and isolation. As far back as 3500 BC Syrian bronzes contained a small amount of the element.

In 235 BC, coins in China were minted from nickel. However there was no real documentation of the element until thousands of years later. In the 17thcentury, German miners discovered a red coloured ore they believed to contain copper. They discovered upon analysis that there was no copper but that a useless, smelly material was actually present. Thinking the ore was evil they dubbed it "Kupfernickel" or Old Nick's Copper, which meant false or bad copper. Swedish scientist Baron Axel Frederich Cronstedt in 1751 finally isolated nickel from an ore closely resembling kupfernickel. Hence, he named this new element after the traditional mineral. At the time of its discovery nickel was thought to be useless but over time as its valuable properties came to light the demand for the metal dramatically increased. The usefulness of nickel as a material in alloys was eventually appreciated since it added to the strength, corrosion resistance and hardness of the other metals. In the 1800s, the technique of silver plating was developed with a nickel-copper-zinc alloy being utilised in the process.

Today, stainless steel, another nickel containing alloy, is recognised as one of the most valuable materials of the 20th and 21st centuries. Occurrence Nickel is the earth's 22nd most abundant element and the 7th most abundant transition metal. It is a silver white crystalline metal that occurs in meteors or combined with other elements in ores. Two important groups of ores are: Laterites: oxide or silicate ores such as garnierite, (Ni,Mg)6 Si4O10(OH)8 which are predominantly found in tropical areas such as New Caledonia, Cuba and Queensland. Sulphides: these are ores such as pentlandite, (Ni,Fe)9S8 which contain about 1.5%, nickel associated with copper, cobalt and other metals. They are predominant in more temperate regions such as Canada, Russia and South Africa. Canada is the world's leading nickel producer and the Sudbury Basin of Ontario contains one of the largest nickel deposits in the world. Extraction of Nickel In 1899 Ludwig Mond developed a process for extracting and purifying nickel.

The so-called "Mond Process" involves the conversion of nickel oxides to pure nickel metal. The oxide is obtained from nickel ores by a series of treatments including concentration, roasting and smelting of the minerals. In the first step of the process, nickel oxide is reacted with water gas, a mixture of H2 and CO, at atmospheric pressure and a temperature of 50 °C. The oxide is thus reduced to impure nickel. Reaction of this impure material with residual carbon monoxide gives the toxic and volatile compound, nickel tetracarbonyl, Ni(CO)4. This compound decomposes on heating to about 230 °C to give pure nickel metal and CO, which can then be recycled. The actual temperatures and pressures used in this process may very slightly from one processing plant to the next. However the basic process as outlined is common to all. The process can be summarised as follows: 50°C 230°C Ni + 4CO → Ni(CO)4 → Ni + 4CO. (impure) (pure) Properties Nickel is a hard silver white metal, which occurs as cubic crystals.

It is malleable, ductile and has superior strength and corrosion resistance. The metal is a fair conductor of heat and electricity and exhibits magnetic properties below 345°C. Five isotopes of nickel are known. In its metallic form nickel is chemically unreactive. It is insoluble in cold and hot water and ammonia and is unaffected by concentrated nitric acid and alkalis. It is however soluble in dilute nitric acid and sparingly soluble in dilute hydrochloric and sulphuric acids. Nickel Compounds Nickel is known primarily for its divalent compounds since the most important oxidation state of the element is +2. There do exist however certain compounds in which the oxidation state of the metal is between -1 to +4. Blue and green are the characteristic colours of nickel compounds and they are often hydrated. Nickel hydroxide usually occurs as green crystals that can be precipitated when aqueous alkali is added to a solution of a nickel (II) salt. It is insoluble in water but dissolves readily in acids and ammonium hydroxide. Nickel oxide is a powdery green solid that becomes yellow on heating.

It is difficult to prepare this compound by simply heating nickel in oxygen and it is more conveniently obtained by heating nickel hydroxide, carbonate or nitrate. Nickel oxide is readily soluble in acids but insoluble in hot and cold water. Nickel oxides Thermal decomposition of Ni(OH)2, NiCO3, or NiNO3 gives NiO. Nickel sulfides consist of NiS2, which has a pyrite structure, and Ni3S4, which has a spinel structure. All the nickel dihalides are known to exist. These compounds are usually yellow to dark brown in colour. Preparation directly from the elements is possible for all except NiF2, which is best prepared from reaction of F2 on NiCl2 at 350°C. Most are soluble in water and crystallisation of the hexahydrate containing the [Ni(H2O)6]2+ ion can be achieved. NiF2 however is only slightly soluble in water from which the trihydrate crystallizes. The only nickel trihalide known to exist is an impure specimen of NiF3.

Nickel(II) halides Ni + F2 55°C /slow → NiF2 Ni + Cl2 EtOH/ 20°C → NiCl2 Ni + Br2 red heat → NiBr2 NiCl2 + 2NaI → NiI2 + 2NaCl Nickel carbonate usually occurs as a light green crystalline solid or a brown powder. It dissolves in ammonia and dilute acids but is insoluble in hot water. It exhibits vigorous reaction with iodine, hydrogen sulphide or a mixture of barium oxide and air. It decomposes on heating before melting occurs. Nickel carbonyl is a colourless, volatile, liquid. It is soluble in alcohol, benzene, and nitric acid but only slightly soluble in water, and insoluble in dilute acids and alkalis. Upon heating or in contact with acid or acid fumes, nickel carbonyl emits toxic carbon monoxide gas, a property exploited in preparation of nickel metal. When exposed to heat or flame the compound explodes and it can react violently with air, oxygen and bromine. Identification of nickel compounds can be achieved by employing the use of an organic reagent dimethylglyoxine.

This compound forms a red flocculent precipitate on addition to a solution of a nickel compound. Nickel complexes The Nickel (II) ion forms many stable complexes as predicted by the Irving Williams series . Whilst there are no other important oxidation states to consider, the Ni(II) ion can exist in a wide variety of CN's which complicates its coordination chemistry. For example, for CN=4 both tetrahedral and square planar complexes can be found. For CN=5 both square pyramid and trigonal bipyramid complexes are formed. The phrase "anomalous nickel" has been used to describe this behaviour and the fact that equilibria often exist between these forms. Some examples include: (a) addition of ligands to square planar complexes to give 5 or 6 coordinate species (b) monomer/polymer equilibria (c) square-planar/ tetrahedron equilibria (d) trigonal-bipyramid/ square pyramid equilibria. (a) substituted acacs react with Ni2+ to give green dihydrates (6 coordinate). On heating, the two coordinated water groups are generally removed to give tetrahedral species.

The unsubstituted acac complex, Ni(acac)2 normally exists as a trimer, see below. Lifschitz salts containing substituted 1,2-diaminoethanes can be isolated as either 4 or 6 coordinate species depending on the presence of coordinated solvent. (b) Ni(acac)2 is only found to be monomeric at temperatures around 200°C in non-coordinating solvents such as n-decane. 6-coordinate monomeric species are formed at room temperature in solvents such as pyridine, but in the solid state Ni(acac)2 is a trimer, where each Ni atom is 6-coordinate. Note that Co(acac)2 actually exists as a tetramer. [Ni(acac)2]3 [Co(acac)2]4 (c) Complexes of the type NiL2X2, where L are phosphines, can give rise to either tetrahedral or square planar complexes. It has been found that: L=P(aryl)3 are tetrahedral L=P(alkyl)3 are square planar for L= mixed aryl and alkyl phosphines, both stereochemistries can occur in the same crystalline substance.

The energy of activation for conversion of one form to the other has been found to be around 50kJ mol-1. Similar changes have been observed with variation of the X group: Ni(PΦ3)2Cl2 μ =0 BM where Φ is shorthand for C6H5 Ni2+ reacts with CN- to give Ni(CN)2.nH2O (blue-green) which on heating at 180-200°C is dehydrated to yield Ni(CN)2. Reaction with excess KCN gives K2Ni(CN)4.H2O (orange crystals) which can be dehydrated at 100°C. Addition of strong concentrations of KCN produces red solutions of Ni(CN)53-. The crystal structure of the double salt prepared by addition of Cr(en)33+ to Ni(CN)53- showed that two types of Ni stereochemistry were present in the crystals in approximately equal proportions. 50% as square pyramid and 50% as trigonal bipyramid.

Uses of Nickel and its Compounds The primary use of nickel is in the preparation of alloys such as stainless steel, which accounts for approximately 67% of all nickel used in manufacture. The greatest application of stainless steel is in the manufacturing of kitchen sinks but it has numerous other uses as well. Other nickel alloys also have important applications. An alloy of nickel and copper for example is a component of the tubing used in the desalination of sea water. Nickel steel is used in the manufacture of armour plates and burglar proof vaults. Nickel alloys are especially valued for their strength, resistance to corrosion and in the case of stainless steel for example, aesthetic value. Electroplating is another major use of the metal. Nickel plating is used in protective coating of other metals. In wire form, nickel is used in pins, staples, jewellry and surgical wire. Finely divided nickel catalyses the hydrogenation of vegetable oils. Nickel is also used in the colouring of glass to which it gives a green hue. Other applications of nickel include: -Coinage Nickel utilisation in microorganisms - 1987 review The first crystallisation of an enzyme was reported in the 1920's.

The enzyme was urease which converts urea to ammonia and bicarbonate. One source of the enzyme is the bacterium Helicobacter Pylori. The release of ammonia is beneficial to the bacterium since it partially neutralizes the very acidic environment of the stomach (whose function in part helps kill bacteria). In the initial study it was claimed that there were no metals in the enzyme. Fifty years later this was corrected when it was discovered that nickel ions were present and an integral part of the system. The Nobel Prize in Physiology or Medicine for 2005 was awarded to Barry J. Marshall and J. Robin Warren "for their discovery of the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease". The display below shows the crystal structure found for a Helicobacter Pylori urease [published 2001] . The nickel ions can be identified by clicking the approriate button. gcse 1. Introduction to the Extraction of Metals method related to the activity of reactivity series of metals igcse O Level KS4 science chemistry revision notes revising The social, economic and environmental impacts of exploiting metal ores are discussed on a separate page.

The rock must contain enough of the metal compound, hence enough of the metal, to be worth exploiting the ore reserve and extract the metal by physical and chemical processes. Low grade ores are usually uneconomic to mine and process, but high grade ores have a high enough metal content to be worth mining and extracting the metal. The metal ore, a mineral or mixture of minerals from which economically viable amounts of metal can be extracted, i.e. its got to have enough of the metal, or one of its compounds, in it to be worth digging out! Ores are often oxides, carbonates or sulphides because these non-metals readily combine with many metals. e.g. iron + oxygen ===> iron oxide ores Fe + O2(air) ===> Fe2O3 or Fe3O4 (not balanced equations, just the idea!) This the typical chemistry involved in metal ore formation. In extracting metals from ores you have to reverse the process e.g. by heating the ore with carbon (coke or charcoal) in a very hot smelting furnace e.g. in a blast furnace to make iron ...

iron oxide ore + carbon ===> free iron + carbon dioxide waste gas Fe3O4 + 2C ===> 3Fe + 2CO2 The iron oxide is reduced (oxygen loss) and the carbon reducing agent is oxidised (oxygen gain). This is typical extraction chemistry for less reactive metals. These ores are all finite resources so we should use them wisely! Any ore must contain enough of the metal to make it worthwhile to mine and then extract the metal. High grade ores will therefore be the most economical to exploit BUT over time the better qualityï¿½richer sources will decrease, especially with the power of the global economy and powerful and growing economies of Brazil, China, India and other Asian economies. The economics of metal extraction are not only dependent on the quality of the ore and the cost of extraction (ie richer ores lead to cheaper production), but also depend on the market price and demand. If demand is high the metal price rises and may offï¿½set the price of mining lower grade ores, but if demand is low, the metal price falls and inefficient mines and smelters will go out of business ie its not worth extracting the metal.

Of course it is possible to improve the technology of metal extraction and enable companies to produce more metal from the ore than was previously possible and even utilise low grade ores previously discarded and not considered worthwhile mining. Since the majority of metals are found combined with nonï¿½metals like oxygen (oxide ion) or sulfur (sulfide ion) or the carbonate ion, chemical reactions are needed to free the metal from its mineral source. In order to extract a metal, the ore or compound of the metal must undergo a process called REDUCTION to free the metal i.e. The oxide/sulfide loses oxygen/sulfur, to form the free metallic atoms, or the positive metal ion gains negative electrons to form the neutral metal atom. The chemical that removes the oxygen from an oxide is called the reducing agent i.e. carbon, carbon monoxide or sometimes hydrogen.

Order of decreasing reactivity related to the earliest know date of extraction and use: francium (1939, very radioactive), caesium (1860, ?), rubidium (1861, ?) potassium (1807, 1855 from electrolysis), sodium (1807, from electrolysis) lithium (1817, electrolysis?), calcium (1808, from electrolysis) magnesium (1755, 1808 from electrolysis), aluminium (1825, by electrolysis) zinc (before 1500, ), iron (extracted with charcoal before 3000 BP) tin (~4500 BP, used to make bronze) lead (over 9000 BP, archaeologist have found lead beads 9000 years old, used by the Romans for plumbing well over 2000 years ago) copper (~11000 BP extracted via charcoal from ores >4000 years ago, found 'native' and was beaten out of rocks and into a useful shape!) silver (~7000 BP, used by ancient civilisations) gold (~800

0 BP, used by ancient civilisations, e.g.

Egyptian civilisations, found 'native' in streams and extracted by 'panning') platinum (~1735, rare metal but known to ancient South American civilisations before Europeans arrived in the 15th century, brought to Europe ~1750) Detailed notes on the 'Reactivity Series of Metals' I've tried to indicate the earliest date of extraction and use, however impure the metal might be, like bronze age copper and iron age iron!). The date is quoted as the 'normal' year (BCE/AD) or BP meaning years before present year (I've not used BC). 'native' seems a politically incorrect term, but it is a term that means finding the element in its free chemically uncombined state e.g. gold in alluvial deposits washed into mountain streams or 'native' copper was beaten out of rocks over 6000 years ago. The understanding of electricity and the development of d.c. electrical supplies e.g. using simple voltaic batteries meant that reactive metals could then be extracted by electrolysis. Once more reactive metals could be produced in larger quantities by electrolysis, these metals themselves were (and still are) used to extract other metals e.g.

chromium, which were often difficult to extract by conventional smelting furnaces using carbon. Generally speaking the more reactive the metal the later it is extracted and used as the technology of metal extraction improves. Detailed notes on the 'Reactivity Series of Metals' As described above, historically as technology and science have developed the methods of extraction have improved to the point were all metals can be produced. The reactivity is a measure of the ease of compound formation and stability. The more reactive the metal, the more readily the metal forms a stable compound eg with oxygen or sulfur, and therefore because of this greater compound stability, the more difficult it is to reduce the compound to the metal. The least reactive (unreactive) metals such as gold, silver and copper have been used for the past 10000 years because the pure metal was found naturally. Their lack of chemical reactivity allows them to exist as the uncombined element. Conversely, the more reactive a metal, the stronger it bonds to other elements like oxygen and sulfur.

Therefore it is far less likely such a metal is found as the uncombined element AND the more reactive a metal the more difficult it is to extract from its ores AND more costly to extract it from the compounds the metal had formed over geological time. Moderately reactive metals like copper, iron, lead, tin have been extracted using carbon based smelting for the past 2000ï¿½4000 years. This is possible because carbon is sufficiently reactive to displace these less reactive metals. Any metal below carbon can theoretically be extracted from its oxide by heating with carbon (coke or charcoal). Compounds of these less reactive are reduced by heating with carbon e.g. copper and silver. Reduction is the loss of oxygen from a compound. BUT it is only in the last 200 years that very reactive metals like sodium or aluminium have been extracted by electrolysis. Electrolysis is required because carbon is NOT sufficiently reactive to displace these more reactive metals. Electrolysis doesn't even require a high voltage to split a metal from its molten ore. In other words, our exploitation of metal mineral resources as developed and expanded as the technology of metal extraction has also developed and improved.

Therefore the economics of extraction may change over time with eg reduced costs by technological advances or increased by depletion of high grade ore reserves. The depletion of high grade ore reserves has resulted in technology research increasingly looking at ways of extracting metals from low grade ores which were previously uneconomic to use. The crucial point is that generally speaking, the method of extraction depends on the metals position in the reactivity series. The reactivity series of metals can be presented to include two nonï¿½metals, carbon and hydrogen, to help predict which method could be used to extract the metal. lower Pt Au Ag Cu (H) Pb Sn Fe Zn (C) Al Mg Ca Na K higher in series RULE: Any element higher in the series can displace any other lower element Notes on Reactivity Series of Metals & Metal Reactivity Experimentsï¿½Observations Generally speaking, the more reactive a metal, the more difficult it is to extract. This is because the more reactive a metal, the more strongly it combines with another nonï¿½metallic element like as oxygen or sulfur and therefore the oxide or sulfide is more difficult to reduce to the metal.

Although most metals occur as compounds, some metals are so unreactive that they do not readily combine with oxygen in the air or any other element present in the Earth's crust, and so can be found as the metal itself (sometimes referred to as 'native' metal). For example, a metal, most frequently found as the uncombined metal is gold (and sometimes copper and silver) and no chemical separation is needed. In fact all the metals below hydrogen can be found as the 'free' or 'native' element, though they occur mainly as compounds combined with nonï¿½metals like oxygen (oxide ion) or sulfur (sulfide ion) or the carbonate ion in their ores. Therefore, for most metals, their naturally occurring compounds require processing via chemical reactions to obtain the free metals. At this point we need to say more about oxidation and reduction and redox reactions. One definition of oxidation is oxygen gain. Somewhere in the past aluminium combined with oxygen to form aluminium oxide, the main compound in bauxite ore from which aluminium is extracted. aluminium + oxygen ==> aluminium oxide. We would therefore say the aluminium was oxidised by oxygen gain. Therefore to extract aluminium we must reduce it and remove the oxygen.

One definition of reduction is oxygen loss. Copper ores are processed to give copper oxide from which copper may be obtained by a reduction process to remove the oxygen (reduction). This can be done by heating with carbon. copper oxide + carbon ==> copper + carbon dioxide. Here the copper oxide is reduced by oxygen loss, and the carbon is the 'oxygen remover' and is referred to as the reducing agent. Similarly in a blast furnace, the iron oxide is reduced with carbon to free the iron from oxygen. iron oxide + carbon ==> iron + carbon dioxide. The method employed to extract a metal by a reduction process largely depends on its reactivity See a separate page for a detailed discussion of oxidation - reduction ('redox') reactions Metals below carbon in the reactivity series (see table on right) can be extracted by heating the oxide with carbon or carbon monoxide. The nonï¿½metallic elements carbon will displace the metals less reactive than carbon in a smelter or blast furnace e.g. iron or zinc and metals lower in the series. Therefore metals like iron, copper, tin, lead, zinc can readily be extracted by reactionï¿½reduction of their e.g. oxides using cheap carbon (i.e.

coke made from coal). As described above, the carbon removes the oxygen from the metal oxide. Iron ore is used to make iron and steel and iron is produced in a blast furnace by reducing iron oxides with carbon and it is the carbon that removes the oxygen from the iron oxides ï¿½ the carbon is known as the reducing agent. The metal copper can be easily extracted BUT copperï¿½rich ores are becoming scarce so new methods of extracting copper are being developed to exploit low grade ores. A low grade ore is one with low concentrations of copper and research is going on to try and exploit waste material left over from processing high grade ores. Metals below hydrogen will not displace hydrogen from acids. Their oxides are easily reduced to the metal by heating in a stream of hydrogen, though this is an extraction method rarely used in industry. In fact most metal oxides below carbon can be reduced when heated in hydrogen, even if the metal reacts with acid. Metals above carbon in the reactivity series cannot usually be extracted with carbon or carbon monoxide. So, metals more reactive than carbon are usually extracted by electrolysis of the purified molten ore or other suitable compound.

Electrolysis is the process of breaking down a compound using electrical energy and is needed to extract the most reactive metals. The process of electrolysis uses of large amounts of energy in the extraction of these reactive metals and makes them expensive to produce. The metal ions in the ore compound are forced by electrical energy into accepting electrons and producing free metal atoms. Another definition of reduction is electron gain. e.g. during the electrolysis of molten aluminium oxide the following reaction happens .. aluminium ion (3+) + 3 electrons (ï¿½) ==> neutral and free aluminium atoms Al3+ + 3eï¿½ ==> Al so, once again the metal ore compound is reduced to the metal, that is the positive metal ion in the ore is reduced to the metal by electron gain. Aluminium is a very useful metal but expensive to produce. e.g. aluminium from molten aluminium oxide or sodium from molten sodium chloride. The ore or compound must be molten or dissolved in a solution in an electrolysis cell to allow free movement of ions (electrical current). The conducting melt or solution is called the electrolyte. Theory given in the appropriate sections.

Because these reactive metals cannot be obtained by relatively cheap carbon reduction methods, their extraction tends to be more costly due to more specialised stages in the extraction process, more energy is needed (maybe costly electricity) and more costly specialist chemicals like a more reactive metal or chlorine (remember carbonï¿½coke is relatively cheap e.g. as used in the blast furnace extraction of iron). Other methods are used in special cases using the displacement rule. A more reactive metal can be used to displace and extract a less reactive metal but these are costly processes since the more reactive metal also has to be produced in the first place! Titanium is another very useful metal but expensive to produce. See Titanium or see at the end of the section on copper extraction . Sometimes electrolysis is used to purify less reactive metals which have previously been extracted using carbon or hydrogen (e.g. copper and zinc ). Electrolysis is also used to plate one metal with another. The demand for raw materials does have social, economic and environmental implications e.g. conservation of mineral resources by recycling metals, minimising pollution etc. Metals can be mixed together to make alloys to improve the metal's properties to better suit a particular purpose.

Question: As a first step to manufacturing steel, iron is extracted from ore by removing oxygen and combining it with what element?
Answer: Carbon