Chapter+1&2

The three raw materials used to make iron are Iron ore, Coke and Limestone. Iron ore comes from under the ground in places such as India. Coke is ground down coal. Limestone is a rock found all over the world. These are all transported on ships and trains. Coke is the first material “produced” as it is not a natural material, it is ground down coal. Iron ore is placed in a blast furnace and mainly forms iron but a little iron ore is not converted to iron. The iron ore is mixed with small pieces of coke and heated to form an iron rich clinker called ‘sinter’. Sintering is very important as it reduces waste and provides an efficient raw material for ironmaking in the Blast Furnace. The coke is produced at the works from carefully selected grades of coal. Different grades of coal are blended, for consistency, before they transfer it to ‘batteries’ of coke ovens. It’s heated in sealed ovens to erase the unwanted materials for about 15 hours, then it’s graded and cooled before they put it in the Blast Furnace. Coke ore and sinter are ‘charged’ into the top of the Blast Furnace, together with limestone. The coke reacts with the iron ore and removes the oxygen. A lot of heat is generated which melts the iron ore. The limestone reacts with the iron ore too and removes any impurities. These processes form a waste material called slag which floats on the top. It is easy to remove from the iron. Mining in the countries which supply iron ore could damage the environment. The machines would destroy the landscape and release CO2. Also with the transportation alot of fuel is consumed and will pollute the atmosphere. The bad side effects can be reduced by producing less steel. This is already being done through recycling. The iron ore should also be mined closer to the factory. Scrap is used to reduce the costs of producing steel and to reduce waste. More than 45% of the steel is made from waste and worldwide the recovery rate is 80%. Also recycling saves on raw materials and emissions of greenhouse gases. Advantages: Using scrap reduces waste and costs. Because the possibilities for making new products from steel are endless, the world’s steel is kept in continuous circulation. Produced ---> Used ---> Recycled Fe 94.9 % = 94.9 kg of Iron C 4.55 % = 4.55 kg of Carbon Si 0.25 % = 0.25 kg of Silicon Mn 0.33 % = 0.3 kg of Manganes ** How many kg of each element are oxidised (take Fe-effieciency into account) of the 100 kg of hot metal? **   Fe= 2% / 100 = 0.02 0.02 * 94.9kg = Fe 1.898kg C4.55kg - 0.05kg = C 4.5kg Si 0.25kg - 0kg = Si 0.25kg Mn 0.3kg - 0.1kg = Mn 0.2kg ** How many kg of steel are produced? **   Fe = 1.898kg C = 4.5kg Si = 0.25kg Mn = 0.2kg + 6.848kg 100kg - 6.848kg = 93.152kg of steel is produced. Fe = 1.898kg * 4.3MJ = 8.1614MJ C =4.5kg * 11.7MJ= 52.65MJ Si = 0.25kg * 33.9MJ = 8.475MJ Mn = 0.2kg * 7.4MJ = 1.48MJ+ 70.7664MJ 2000m³ x 32MJ = 64000MJ/m³ 64000MJ/m³ / (70.7664MJ / 100) = 90438.40014kg of steel. ** if 45% of the heat generated bij the C combustions will leave the process through the waste gasses, what will be the temperature of the liquid steel? **   The amount of C which is oxidised is 4.5kg (4.55%of 100kg)-0.05kg= 4.5kg).    11.7 amount of jheat generated (MJ) by oxidation per Kg    11.7MJx 4.5kg= 52.65MJ    52.65 is 100%, but you need 55%    52.65:100x55= 28.9575MJ=amount energy generated and warms up the liquid steel    28.96Mjx1000000=289560000J    70.7664MJ-52.65MJ=18.1164MJ= is the amount of energy generated exept the Carbon (because we alreay calculated that)    18.1164*1000000= 18116400 J + 289560000 J = 47072400 J = 47.07 MJ    47.07 * 1000000 : 690 = 68217.391 : 93.152 = 732.32342 °C + 1350 = 2082.3 °C    Heat capacity of steel = 690J (kg °C)    Latent heat of steel 271 kJ/kg    1650°C-20°C = 1630°C    1630°C * 690J + 271000J/kg = 1395700J    ( 47.0739 - 19.282464 ) :1.3957 = 19.91218 kg of scrap    The total amount of steel produced is 93.251 + 19.91218 = 113.0642 kg of steel.    For 320 ton we need:    320 : 113.0642 * 93.251 = 263.64 ton of hot metal 320 : 113.0642 * 19.91218 = 56.36 ton of scrap 320 ton steel with density 7000 kg / m³ = 7 ton/m³ Gives 320 : 7 = 45.71 m³   Surface of ladle bottom = pi r² = 3.1415 * (4:2)² = 12.57 m²    Ladle height 0.5 m + 45.71 : 12.57 = 4.14 meter
 * Chapter 1. **
 * What are the main three raw materials used to make iron? **
 * Where do the raw materials come from and how are they transported to the plant? **
 * How and why are the raw materials processed before they are used in the blast furnace? **
 * What role does each of these three raw materials play in the iron-making process? **
 * What can you say about the ecological effects of using these raw materials (for the country where they come from and for the means of transportation)? **
 * How can the bad side effects be reduced? **
 * Why is scrap used? **
 * What are the advantages and disadvantages of using scrap in the steel making process? (think for example of temperature control, composition control and production volume.) **
 * Chapter 2. **
 * Calculate the mass of each element **
 * Calculate the amount of energy that is generated during the process per 100kg hot metal. **
 * How much energy is used in natural gas a year per household? **
 * the energy from how many kg of hot metal is equivelant to the energy used in natural gas of one household? **
 * If we want to melt one kilogram of scrap and heat it to 1650°C how much energy is required? **
 * How many of scrap can be melted with the 100 kg of hot metal making steel of 1650 °C? **
 * How many kg of steel are produced? **
 * If we want to make 320 tons of this steel, how many tons of hot metal and scrap are required? **
 * How many cubic metres of steel are that? **
 * Suppose a steel ladle has an internal diameter of 4 meters. What is the required height of the ladle if the steel surface must be 50 cm below the top of the ladle? **