Steel

Ferro Silicon (FeSi)

  • Ferro silicon is a ferroalloy composed primarily of iron and silicon, typically containing between 15% and 90% silicon. 
     
    • Production: It is produced by reducing silica (sand/quartz) with coke in the presence of iron (scrap or ore) in electric arc furnaces.
    • Key Properties:
       
      • Deoxidiser: Acts as a powerful agent in steelmaking to remove oxygen.
      • Inoculant: Used in cast iron production to promote graphitisation and improve mechanical properties.
      • Magnetic Utility: Used in manufacturing silicon steel for electrical transformer cores and motor rotors.
    • Special Use: Employed in the Pidgeon process to produce magnesium metal from dolomite. 

Quick Lime (CaO)

Quick lime, or calcium oxide, is a highly reactive chemical compound obtained by heating limestone (calcination) at temperatures above 900°C.
 
 
  • Key Properties:
     
    • Highly Exothermic: Reacts vigorously with water to form slaked lime ($Ca(OH)_2$), releasing significant heat.
    • Strongly Alkaline: Has a pH of approximately 12.4, making it effective for neutralising acids.
  • Major Uses:
     
    • Steelmaking: Acts as a flux to remove impurities like silica, phosphorus, and sulfur from molten iron.
    • Environmental: Used in wastewater treatment and flue gas desulfurization to capture pollutants.
    • Construction: A fundamental ingredient in cement, mortar, and for soil stabilisation in road building. 

Dolomite 

Dolomite is a calcium magnesium carbonate mineral; “Low Iron” grades are specifically selected or processed to contain minimal iron oxide ($Fe_2O_3$) impurities. 
 
  • Key Properties:
     
    • High Purity: Essential for applications where iron-induced discolouration is unacceptable.
    • Refractory Nature: Withstands extreme temperatures, making it a critical lining material for furnaces.
  • Major Uses:
     
    • Glass Manufacturing: Primarily used in flat glass and container glass production where low iron content ensures maximum transparency and prevents green tints.
    • Steel Industry: Used as a slag modifier to protect furnace linings and maintain MgO levels in the slag.
    • Ceramics: Enhances the whiteness and mechanical strength of high-end ceramic tiles and sanitaryware. 

Ferro Manganese

(FeMn) is a crucial ferroalloy of iron and manganese (70–82% Mn) used in heavy industry.
 
  • Deoxidizer & Desulfurizer: Removes oxygen and sulfur during steelmaking to prevent cracks and brittleness.
  • Alloying Agent: Boosts steel hardness, toughness, and tensile strength.
 
  • High Carbon (HC): Standard, cost-effective grade for general steel.
  • Medium/Low Carbon (MC/LC): Used for specialized stainless and alloy steels where carbon must be kept low.
 
  • Steelmaking: Essential for railway tracks, structural beams, and armor plates.
  • Welding: Used in electrode coatings for better arc stability.