C

Contact Process

2SO₂+O₂⇌2SO₃ (V₂O₅, 450°C); SO₃+H₂SO₄→H₂S₂O₇+H₂O→2H₂SO₄
Quick Reference
Formula / Notation2SO₂+O₂⇌2SO₃ (V₂O₅, 450°C); SO₃+H₂SO₄→H₂S₂O₇+H₂O→2H₂SO₄
Also Known AsSulfuric acid manufacturing process, V₂O₅ catalytic oxidation process

What is Contact Process?

The Contact Process is the industrial method for manufacturing sulfuric acid (H₂SO₄). It involves: (1) burning sulfur or roasting metal sulfides to form SO₂, (2) catalytic oxidation of SO₂ to SO₃ over a vanadium pentoxide catalyst at 450°C, and (3) absorption of SO₃ in concentrated H₂SO₄ to form oleum, then dilution with water. It is one of the most important industrial chemical processes.

Formula & Notation

2SO₂+O₂⇌2SO₃ (V₂O₅, 450°C); SO₃+H₂SO₄→H₂S₂O₇+H₂O→2H₂SO₄

Other Names / Synonyms: Sulfuric acid manufacturing process, V₂O₅ catalytic oxidation process

Properties & Characteristics

The Contact process is the industrial method for manufacturing sulfuric acid. Step 1: burn sulfur or roast sulfide ores to produce SO₂. Step 2: catalytic oxidation of SO₂ to SO₃ using V₂O₅ catalyst at 450-550°C (equilibrium favours SO₃ at lower temperatures; catalyst needed for adequate rate). Step 3: absorption of SO₃ in concentrated H₂SO₄ (oleum) then dilution. Overall yield >99.5% with double-absorption plants.

Uses & Applications

Sulfuric acid produced by the Contact process is the world's largest-volume industrial chemical, used in fertiliser manufacture (superphosphate, ammonium sulfate), petrochemical refining, metal processing (pickling), explosives, and battery electrolyte.

Safety Information

SO₂ and SO₃ are toxic and corrosive gases that cause severe respiratory damage. Concentrated sulfuric acid is highly corrosive with a high affinity for water (exothermic dilution — always add acid to water). Contact process plants require comprehensive gas containment and scrubbing systems.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Contact Process
Formula 2SO₂+O₂⇌2SO₃ (V₂O₅, 450°C); SO₃+H₂SO₄→H₂S₂O₇+H₂O→2H₂SO₄
Synonyms Sulfuric acid manufacturing process, V₂O₅ catalytic oxidation process

Frequently Asked Questions

The Contact Process is the industrial method for manufacturing sulfuric acid (H₂SO₄). It involves: (1) burning sulfur or roasting metal sulfides to form SO₂, (2) catalytic oxidation of SO₂ to SO₃ over a vanadium pentoxide catalyst at 450°C, and (3) absorption of SO₃ in concentrated H₂SO₄ to form oleum, then dilution with water. It is one of the most important industrial chemical processes.

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