What is the other term used for thermal reductions?

Pyrometallurgy

The correct answer is Option (4) → Pyrometallurgy

Thermal reduction means reduction of metal compounds using heat.

Such processes come under pyrometallurgy.

Pyrometallurgy is the branch of extractive metallurgy that uses thermal treatment (high temperatures) to bring about physical and chemical transformations in minerals and ores. The term specifically refers to the reduction of metal oxides to free metals using heat and suitable reducing agents like carbon or hydrogen. Common processes within pyrometallurgy include roasting, smelting, and refining.

Option 1: Hydrometallurgy - Extraction of metals using aqueous solutions. Example: Cyanide process for gold. No heat involved. Hence, not thermal reduction.

Option 2: Leaching - Process of dissolving ore in suitable solvent. Used for concentration or extraction. Not a reduction step

Option 3: Froth floatation- Used for ore concentration. Separates ore from gangue based on surface properties. No reduction involved.

Option 4: Pyrometallurgy - Extraction of metals using high temperature. Includes processes like: • Roasting • Calcination • Smelting Reduction occurs using heat.

Hence, thermal reduction = pyrometallurgy.