What is iron smelting?
Smelting is production of metal, especially iron, from ore in a process that involves melting and chemical reduction of metal compounds into purified metal. or Any of the various liquids or semi-molten solids produced and used during the course of such production.
In this article, you’ll have understanding on what is smelting, iron ore smelting process and iron smelting in the blast furnace.
Iron Ore Smelting Process
Iron Ore Smelting requires some preparation before they can be done. It enable the furnace to work perfectly and sometimes economically. It needs a regular and uniform ‘diets’ from which as much as possible of the unwanted materials has been removed.
Either the richness or size and density of the lumps needs to be improved and this can done in a numbers of ways: (1) by the concentration (up-grading) of low quality ores with the removal of unwanted materials by washing and/or gravity separation or, in the case of magnetic ores, by magnetic separation; (2) by crushing and screening (sieving) to a suitable size.
The powdering residue from the screening, known as ‘fines’ is mixed with coal dust or coke breeze and a sintering (controlled burning) process follows, resulting in the fusion of the fines into hard lumps that can be included in the furnace charge.
Sinter is being used more and more nowadays and in some plants it forms 100% of the charge; (3) by the blending of different ores to obtain a consistency in quality, or (4) by forming powdery ores into pellets.
As mentioned earlier iron ore smelting is needed to be performed to improves the efficiency of the furnace and to work economically. It is done by removing the unwanted materials and by improving the density of lumps, size or richness.
Iron smelting in blast furnace
Iron smelting involves two main processes in the blast furnace: (1) the reduction of iron from it compounds and (2) its separation from its physical mixture with gangue materials.
In furnace, the charge is constantly moving slowing downward against the force flow of the very hot gases which bring about the evaporation of moisture from the charge at the top. A little further down, limestone decomposes into lime and liberates carbondioxide. The main reaction is the reduction of the iron oxides, forming carbondioxide and leaving the iron free. Reduction begins quite high in the stack and is progressive as the charge descends and, at the melting zone, both iron and slag trickle down into the hearth. The slag, being lighter floats on the iron.
At regular interval as the hearth fills, slag is tapped off, followed by the iron, which goes into huge storage vessels called ‘mixer’, for holding the molten state until required in the steel making plant, usually quite near the furnace. In addition to holding a reserve of hot metal, mixers serve a useful purposes in that they will compensate for variations in composition between successive additions of hot metal, giving a more uniform product.
An inactive mixer does no more than to hold a stock of metal but in an active mixer, some refining takes place with the making of slag there in.
And that is it for this article, what is smelting, iron ore smelting process, and iron smelting in blast furnace. I hopefully believe you understand, but you can freely ask questions via our comment box and please don’t forget to share. Thanks for reading!