Importance of Steel Slag in road sector

Jul 01, 2024

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Steel slag is a solid waste generated in the process of steel making and is mainly composed of oxides of calcium, iron, silicon, magnesium, and some other elements.

In the production of steel, oxides of metal impurities in the iron combine with the flux (which is usually a mixture of lime and dolomite) to form a molten layer of steel slag that floats on top of the steel. The molten slag is later cooled and granulated.

Generally steel slags consist of CaO, MgO, SiO2 and FeO oxides, which found within the range of about 88% to 90 %. The total concentration of these oxides in liquid slags is in the range of 88%–92%

Other uses:

Figure below shows an overview of the generation, treatment, and disposal of steel slag.

Due to the leaching of heavy metals from steel slag, direct dump or accumulation of steel slag at landfills without treatment causes serious pollutions to the farmland and rivers.

Different attempts have been made to effectively reuse steel slag by reducing its potential risk. In general, steel slags are first treated by means of crushing, magnetic separation, and screening in the steel plant. More than 90% of the scrap steel and some magnetic pole oxides can be recovered during these processes.

Alternatively, steel slag can be directly used as:

  1. sinter flux and iron smelting flux for the production of steel.
  2. The pretreated steel slag can be used as aggregate in the production of concrete or asphalt
  3. Another recycling option is to grind steel slag into fine fillers, which are then used as raw materials for cement production or concrete mixture.

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