calcium carbide cas 75-20-7

Calcium carbide is a chemical compound primarily used to produce acetylene gas and as a key industrial chemical for organic synthesis and metalworking.

Chemical Properties

Calcium carbide (CaC2) is an inorganic compound appearing as a white crystalline powder in pure form, while industrial-grade material is typically gray, yellow-brown, or black solid with a purple hue on fresh fracture surfaces 
CaC2 + 2H2O → C2H2 + Ca(OH)2 + heat 
It also reacts with gases and chemicals such as chlorine, hydrogen chloride, sulfur, phosphorus, and alcohols at elevated temperatures, demonstrating its high chemical reactivity 

Production

Industrial calcium carbide is produced via the electric furnace reduction method, the only widely used industrial process. In this method, calcium oxide (CaO) is mixed with coke and heated to 2000–2200°C in a closed electric furnace, producing molten calcium carbide and carbon monoxide:
CaO + 3C → CaC2 + CO
The molten carbide is then cooled, crushed, and packaged. This process is energy-intensive, historically consuming 10–11 GJ per ton of carbide, and modern production uses large, closed furnaces to reduce heat loss and improve carbon monoxide recovery 

Applications

1. Acetylene Production: The primary use of calcium carbide is generating acetylene gas, which serves as a fundamental raw material in organic chemical synthesis 
2. Organic Synthesis: Acetylene derived from calcium carbide is used to produce PVC, polyvinyl alcohol, vinyl acetate, chloroprene rubber, and other chemicals 
3. Metal Cutting and Welding: Calcium carbide is used in oxy-acetylene torches for cutting and welding metals 
4. Agriculture: Calcium carbide reacts with nitrogen to form calcium cyanamide, which is used as a fertilizer and plant growth regulator 
5. Lighting: In areas without electricity, carbide lamps use calcium carbide to generate acetylene for illumination