Processing & metallurgy
Extractive Metallurgy
5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.
Topics
- PyrometallurgyPyrometallurgy uses high temperature — Ellingham diagrams show oxide stability; ΔG = ΔH − TΔS determines roast/smelting feasibility. Slag basicity B controls sulphur and metal losses in Indian copper and iron smelters.
- HydrometallurgyHydrometallurgy dissolves metals in aqueous leach — extraction % tracks solution concentration drop. Heap leach suits low-grade Indian copper oxides; CIP/CIL recovers gold; SX separates Cu/Ni/Co from pregnant leach solution.
- ElectrometallurgyElectrometallurgy deposits metal by electrolysis — Faraday law sizes mass from current and time; cell voltage exceeds E° due to overpotential and IR drop. Hall-Héroult process produces aluminium; copper electrowinning follows SX in Indian plants.
- Smelting and RefiningSmelting produces matte (Cu-Fe sulphide) converted to blister copper; refining removes impurities to LME grade. Converter air blow oxidises FeS to slag; electrorefining achieves 99.99% Cu cathode in Indian custom smelters.
- Metal Recovery OptimizationPlant metal recovery multiplies stage recoveries R_total = R₁ × R₂ × … — metallurgical accounting closes mass balance input = output + accumulation. Payable metal adjusts for smelter terms below contained metal.