Why is hot air blown into the bottom of the blast furnace?
Why is hot air blown into the bottom of the blast furnace?
The blast furnace is used to extract iron from its ore. The iron ore, coke and limestone are fed into the top and the hot air is blown into the bottom. This carbon dioxide will then react with more coke to form carbon monoxide. The carbon monoxide then reacts with the iron ore to extract the iron as molten iron.
Why is temperature of slag lower than 1530?
Why is the temperature of the slag coming out of the blast furnace much lower than 1530°C? Because a blast furnace does not produce steel but pig iron that melts at 1150 – 1200°C max. The exhaust gas is also rather cold because the air is blown in the bottom part of a blast furnace where it meets the coke.
Which reaction is used to keep the furnace hot?
The hot air blast to the furnace burns the coke and maintains the very high temperatures that are needed to reduce the ore to iron. The reaction between air and the fuel generates carbon monoxide. This gas reduces the iron (III) oxide in the ore to iron.
How is slag removed?
During smelting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. Slag is the collection of compounds that are removed.
What removes impurities in a blast furnace?
Extraction of Metals to the blast furnace to remove the impurities in the iron ore. to give calcium oxide (quicklime) and carbon dioxide. (see examples of other carbonates).
Why does CaO react to slag with sio2?
When it is heated with ore, it combines with the earthly impurities present in ore to form easily fusible mass known as slag. For acidic impurities link SiO2, basic flux like CaO is used and for basic impurities like MgO, acidic flux like SiO2 is used.
Why is gold not extracted from ores?
Because gold it is so unreactive, it is found as the native metal and not as a compound. It does not need to be chemically separated. However, chemical reactions may be needed to remove other elements that might contaminate the metal.
Is gold found in its native state?
Only two metals, gold and platinum, are found principally in their native state, and in both cases the native metals are the primary ore minerals. Silver, copper, iron, osmium, and several other metals also occur in the native state, and a few occurrences are large enough—and sufficiently rich—to be ore deposits.
Why is gold found in native state?
Only gold, silver, copper and the platinum metals occur in nature in larger amounts. Over geological time scales, very few metals can resist natural weathering processes like oxidation. This is why only the less reactive metals such as gold and platinum are found as native metals.
Why is gold mostly found in pure stare?
Gold is the least reactive metal. It does not react with O, C ,CO3- etc. to form any compound and hence always found in free state. It react with the atmospheric oxygen to form oxide and thus it is mostly found in oxide form.