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Direct reduction processes can be divided roughly into two categories: gas-based and coal-based. In both cases, the objective of the process is to remove the oxygen contained in various forms of iron ore (sized ore, concentrates, pellets, mill scale, furnace dust, etc.) in order to convert the ore to metallic iron, without melting it (below 1,200 °C (2,190 °F)).
New Zealand Steel steel complex, fed by direct reduction rotary furnaces (SL/RN process) [1] (capacity 650,000 t/year). [2] In the iron and steel industry, direct reduction is a set of processes for obtaining iron from iron ore, by reducing iron oxides without melting the metal. The resulting product is pre-reduced iron ore.
Iron treated this way is said to be wrought (worked), and the resulting iron, with reduced amounts of slag, is called wrought iron or bar iron. Because of the creation process, individual blooms can often have differing carbon contents between the original top and bottom surfaces, differences that will also be somewhat blended together through ...
Direct reduction is the fraction of iron oxide reduction that occurs in a blast furnace due to the presence of coke carbon, while the remainder - indirect reduction - consists mainly of carbon monoxide from coke combustion. It should also be noted that many non-ferrous oxides are reduced by this type of reaction in a blast furnace.
The iron ore is introduced into the furnace upstream and mixed with a small amount of fuel, typically hard coal. [21] After 6 to 8 hours, [22] it exits the furnace as pre-reduced iron ore at 1,000 °C. The amount of iron recovered ranges from 94% to 97.5% of the initial iron in the ore. [21]
The HIsarna ironmaking process is a direct reduced iron process for iron making in which iron ore is processed almost directly into liquid iron ().The process combines two process units, the Cyclone Converter Furnace (CCF) for ore melting and pre-reduction and a Smelting Reduction Vessel (SRV) where the final reduction stage to liquid iron takes place.
Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200 °C and 700 °C, the iron oxide is partially reduced to iron(II,III) oxide, Fe 3 O 4. 3 Fe 2 O 3(s) + CO (g) → 2 Fe 3 O 4(s) + CO 2(g) [9]
Electric phosphate smelting furnace in a TVA chemical plant (1942) Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. [1] It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zinc.