Blast Furnace Processing, part 1 of 2: Systems and Components used in Blast Furnaces
How work blast furnaces? How is blast furnace coke used?
Modern blast furnaces are equipped with an array of various supporting facilities which increase total efficiency of processing. One of them is for example an ore storage yard, used for unloading barges. The raw materials are transferred by ore bridges (or transfer cars or rail hoppers) to the stockhouse complex. Computer controlled weight hoppers or rail-mounted scales cars weigh out the various raw materials to yield the desired hot metal and unwanted slag chemistry. The raw materials are brought via a skip car (powered by winches or conveyor belts) to the top of the blast furnace.
Blast Furnace Processing, part 2 of 2: Processing in the Blast Furnace
All modern iron making blast furnaces are built in the form of a tall chimney-like structures lined with refractory brick. Metallurgical coke, iron ore (iron oxide) and limestone flux are put into the top part of the furnace in a precise filling order, thanks to which all the chemical reactions and flowing gas are under control. Four “uptakes” allow the dirty, hot gas to exit the furnace dome. “Bleeder valves” are to protect the top part of the furnace from sudden gas pressure surges. A bleader cleaner is for cleaning the bleeder valves. The coarse particles in the gas settle in The “dust catcher” catches the coarse particles dumps them into a truck or railroad car for disposal. Then the gas itself flows through a venturi scrubber and a gas cooler reduces the temperature of the cleaned gas.
The “casthouse” at the bottom half of the furnace contains tuyeres, the bustle pipe and whole equipment needed to cast the liquid iron and slag. When a “taphole” is being drilled through the refractory clay plug, slag and liquid iron are flowing down a trough through a “skimmer” opening, which is used to separate flowing iron and slag. Modern large blast furnaces use to have two casthosues and four tapholes. When slag and the pig irona are already tapped, the taphole is plugged again with the refractory clay.
Met coke production, part 1 of 2
Met coke is being produced in the process of carbonization of coal blends or coal at temperatures up to one thousand four hundred degrees. Such temperature transforms a regular coal into a macroporous carbon material, which is relatively large lump size and high strength. Metallurgical coke must have a high strength, because it supports heavy loads in the blast furnace without disintegration. Met coke can be also used as a filler coke for the polygranular carbon products. What else can we say about met coke and the process of its production?
Met coke production, part 2 of 2
The final product is a non-melting carbon, which is called metallurgical coke or met coke. After partial melting and loosing volatile gases, metallurgical coke has a porous, open morphology and in some specimens it may appear glassy. Thanks to the heating process Met coke has hardly no volatile contents, however the “ash” constituents, which were the part of the original bituminous coal feedstock, remain encapsulated in the resultant coke. Metallurgical coke feedstocks are available in a really wide range of sizes – from fine powder to basketball-sized lumps. Typical purities range from eighty eight to ninety two percent fixed carbon.