Steel production is not a technologically simple process. It consists of a number of stages, among which the production of iron ore concentrates is of great importance. Concentrates in metallurgy are the enriched powdered raw materials that need to be brought to the sintered state. Agglomerated (sintered into large lumps) metal ores are already suitable for processing in blast furnaces.
The iron ore concentra
te itself is a highly enriched ore, which contains a lot of iron. Mining and processing plants can achieve iron concentrations of 85 or even 90% in the finished product. If you make the decision retire my car, you will get a lot of money and contribute to the replenishment of iron ore.
However, most often the ore is sold with iron content of 60% or 65%. It is micro-granulated (powder particles are no more than five hundredths of a millimeter). In terms of specific weight of the desired substance, it is already a good raw material, however, in practice, additional sintering is made, so that it is easier to transport, store and use the concentrate, or rather the agglomerate.
At the earliest stage the iron ore is crushed, and then by means of magnetic separation, the most valuable particles are extracted. The iron content in the same volume can be doubled.
Since other production operations except crushing and magnetic sorting are not used in the production of iron ore concentrate, it can have different composition. In the middle belt of Russia there are the most concentrating plants. Their concentrate may contain both pure iron (up to 65%) and its oxides – up to 63%. There are also necessarily impurities: oxides of magnesium, manganese, calcium, silicon, potassium and sodium.
Iron itself and the elements that improve its quality are estimated as positive impurities; at the same time, t
he presence of copper, zinc, sodium, silicon, calcium, aluminum and magnesium significantly reduces the quality of the iron ore conce
ntrate. If copper is present in it, the melted iron will be red-brittle. Zinc makes the smelting itself more labo
r-intensive. And silicon, calcium, magnesium – contribute to increased formation of metallurgical waste (slag).
Since the iron ore concentrate is designed to smelt steel, its mineralogical composition must m
eet certain requirements. They are determined according to the process to which the given batch of metal needs to be subjected. In addition to agglomerate, there are also arizonite, ilmenite, collective (equal concentration of several metals), gravitational (there are particles of quartz and sulfide inclusions), nepheline and some other varieties.
For obtaining iron the agglomerated concentrate is mainly used, which is best sintered, giving a high-grade sinter. But other types of these raw materials are also used in modern metallurgy, although they are a more niche product. There is also primary concentrate, which needs additional processing before it is suitable for any purpose.