Landmark in History; the Iron Age
The Iron Age occurred after
the Bronze Age; in Europe it was from 800 BCE until 43 AD. Before iron, only bronze was used for cutting tools and
weapons. When iron weapons were heated and hammered into shape, it was discovered
that they were stronger, less brittle and more reliable than bronze weapons. The
initial use of iron originated in Southeast Asia/Middle East in 4000 BCE . The Hattians (from Hatti – a part of what is now Turkey
Smelting is the process by
which metal is produced from a rock ore. It uses heat and a chemical reducing
agent; this has to be a source of carbon. For example, charcoal. This removes
the oxygen and leaves behind elemental metal. However, the temperature of a
normal fire is not sufficient to reduce iron oxide to make the elemental iron
liquid. In the Iron Age, a way of increasing the heat of a fire would be to continually fan it.
To re-create iron the waste
needs to be melted off the rock to get what is left behind. Using a bloomery
furnace (a heating device capable of smelting iron) feed it with charcoal and
iron ore. Following this, check to see if a ‘bloom’ has begun to form. This is
a lump of iron with slag on the bottom (slag is a by-product of smelting a rock
ore). Once the bloom has formed, take it out of the furnace and remove the
excess charcoal and slag from it. From this, the blacksmiths during the Iron
Age would hammer the bloom to consolidate it.
*If we were able to have our own bloomery furnace in the forest we would easily be able to make wrought iron; without using the bloomery process we would not be able to raise the temperature of the fire hot enough. However, below is a youtube link for a ‘Pre-historic Iron Smelting Demonstration’ so we can see just how the process works with a bloomery furnace!
*If we were able to have our own bloomery furnace in the forest we would easily be able to make wrought iron; without using the bloomery process we would not be able to raise the temperature of the fire hot enough. However, below is a youtube link for a ‘Pre-historic Iron Smelting Demonstration’ so we can see just how the process works with a bloomery furnace!
Bibliography: (All Accessed 3rd February 2012 )
Emma Barkley, 5th February 2012
Could you describe what a bloomery furnace would look like if we were to make one for our wood???
ReplyDeleteA bloomery has a chimney with heat resistance walls (the one in the video below is made of clay). It has pipes at the bottom to let air in, either naturally or forced by a bellow. There is an opening at the bottom which is where the bloom is removed.
Deletehttp://www.youtube.com/watch?v=KP4DjM3jBsw
Emma Barkley, 14th April
Is it possible for you to give us a chemistry teacher's explanation of the proccess??? This might help some to understand it. Thanks.
ReplyDeleteIron occurs in rocks combined with oxygen (Fe203) and removing the oxygen is a chemical process known as smelting. Smelting isolates wrought iron from its ore by using heat and a reduction agent. Using a bloomery furnace, iron ore and charcoal is loaded, lit, and fanned with bellows. The reaction happening is the following balanced equation: 2Fe203 + 3C = 4Fe + 3CO2
DeleteCharcoal acts as the reduction agent; it takes the oxygen out of the ore, reducing it. Some of the charcoal also acts as a fuel, reacting with oxygen in the air to produce the heat needed for the smelting process.
The bloomery furnace is not hot enough to melt the iron; instead, it is hot enough to form a lump known as a ‘bloom’. The blacksmith then hammers out the impurities, consolidating the metal into wrought iron.
Emma, 16th April
http://www.henrycort.net/ffsmelt.htm