These tuyeres are equally spaced around the circumference of the furnace. There may be fourteen tuyeres on a small blast furnace and forty tuyeres on a large blast furnace.
Oil, tar, natural gas, powdered coal and oxygen can also be injected into the furnace at tuyere level to combine with the coke to release additional energy which is necessary to increase productivity. The molten iron and slag drip past the tuyeres on the way to the furnace hearth which starts immediately below tuyere level. Around the bottom half of the blast furnace the "casthouse" 1 encloses the bustle pipe, tuyeres and the equipment for "casting" the liquid iron and slag.
The opening in the furnace hearth for casting or draining the furnace is called the "iron notch" A large drill mounted on a pivoting base called the "taphole drill" 23 swings up to the iron notch and drills a hole through the refractory clay plug into the liquid iron. Another opening on the furnace called the "cinder notch" 21 is used to draw off slag or iron in emergency situations.
Once the taphole is drilled open, liquid iron and slag flow down a deep trench called a "trough" Set across and into the trough is a block of refractory, called a "skimmer", which has a small opening underneath it.
The hot metal flows through this skimmer opening, over the "iron dam" and down the "iron runners" Since the slag is less dense than iron, it floats on top of the iron, down the trough, hits the skimmer and is diverted into the "slag runners" The liquid slag flows into "slag pots" 25 or into slag pits not shown and the liquid iron flows into refractory lined "ladles" 26 known as torpedo cars or sub cars due to their shape.
When the liquids in the furnace are drained down to taphole level, some of the blast from the tuyeres causes the taphole to spit.
This signals the end of the cast, so the "mudgun" 29 is swung into the iron notch. The mudgun cylinder, which was previously filled with a refractory clay, is actuated and the cylinder ram pushes clay into the iron notch stopping the flow of liquids. When the cast is complete, the iron ladles are taken to the steel shops for processing into steel and the slag is taken to the slag dump where it is processed into roadfill or railroad ballast.
The casthouse is then clean-up and readied for the next cast which may occur in 45 minutes to 2 hours. Modern, larger blast furnaces may have as many as four tapholes and two casthouses. Liquid levels above the tuyeres can burn the copper casting and damage the furnace lining. The first blast furnaces appeared in the 14th Century and produced one ton per day. Blast furnace equipment is in continuous evolution and modern, giant furnaces produce 13, tons per day.
Even though equipment is improved and higher production rates can be achieved, the processes inside the blast furnace remain the same. Blast furnaces will survive into the millennium because the larger, efficient furnaces can produce hot metal at costs competitive with other iron making technologies.
As both the material is mixed, the chemical reaction takes place causing the molten metal to fall down where it is tapped off and collected. The molten metal and this slag are the end products of this procedure. These flow of both the products in opposite directions along with different combustion gases are termed as countercurrent exchange. However, there are similar procedures used for various purposes including blowing houses to obtain tin, lead and can be extracted by smelting mills and similarly, iron is obtained by bloomer furnace.
These all are classified as blast furnaces. Nevertheless, this term is used for a very limited purpose as for smelting iron ore. This smelting would help for the production of pig iron, which is a majorly used material in the processing of iron and steel production. It is the total furnace area where we inject the hot metal with the slag which is generated from the raw material.
In the cast house, hot metal with slag flowing through a channel where it is divided into two forms, one is hot metal and another one is slag and then further going to the iron and slag side sequentially of the Furnace. In this section raw material are stored, it designed so carefully that raw material can easily be transferred from this section. As the name denotes it is a charging station.
Here in this section, we can see a hopper through which the raw material enters the furnace. As we use several types of fuel to generate the heat, in this scenario also there is a lot of burned gas is generated inside the blast furnace, so we need to have point or section, from which we can easily extract the burned gases. In a blast furnace, while the process of extracting the iron has occurred at that time, we also get slag or impurities.
To remove this we use two types of method. One is using of a high-pressure water jet, which blends with the slag or impurities then we send the mixture to the granulation plan, secondly if it is unable to granulate in the granulation plant then we make a separate area where we dumped the slag.
It is a cone-shaped funnel which is used for pouring the raw material which comes from the raw material storage section. To control the flow and quantity of the raw material we need to use the adjustable gate. It can be controlled manually, however, in modern blast furnaces it is opened or closed electronically. Basic Oxygen Process. Electric Furnace Process.
Ingot Casting — Forming Solid Steel. Continuous Casting — Forming Solid Steel. Hot Rolling — Shaping Solid Steel. Hot Forging — Shaping Solid Steel. Finishing — Galvanizing. This gas reduces the iron III oxide in the ore to iron. How does the blast furnace work? The Blast Furnace is a large steel structure about 30 metres high. It is lined with refractory firebricks that can withstand temperatures approaching o C.
The furnace gets its name from the method that is used to heat it. Pre-heated air at about o C is blasted into the furnace through nozzles near its base.
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