Optimal Practices for Efficiently Reducing Sulfur Content in Steel: Calcium Carbide Particle Size, Temperature, and Addition Timing

In - depth Analysis of Calcium Carbide Desulfurization in Steelmaking

Calcium carbide (calcium carbide) plays a crucial role in steel desulfurization. Its high melting point ensures a stable reaction at high temperatures. In this guide, we will delve into the chemical reaction mechanism of calcium carbide desulfurization, analyze the key factors affecting desulfurization efficiency, and present practical cases and solutions.

Chemical Reaction Mechanism of Calcium Carbide Desulfurization

The desulfurization process using calcium carbide is based on a chemical reaction. When calcium carbide (CaC₂) reacts with sulfur (S) in molten iron, it forms calcium sulfide (CaS) and carbon monoxide (CO) gas. The chemical equation is as follows: CaC₂ + S = CaS + 2C + CO. This reaction effectively removes sulfur from the molten iron, thereby improving the quality of the steel.

Key Factors Affecting Desulfurization Efficiency

There are three key factors that significantly impact the desulfurization efficiency: temperature, particle size, and the timing of addition.

**Temperature**: Higher temperatures generally promote the reaction rate. However, excessive temperatures may cause the evaporation of calcium carbide. In practice, maintaining the temperature between 1350 - 1450°C can achieve a relatively high desulfurization efficiency.

**Particle Size**: The particle size of calcium carbide affects the reaction surface area. Smaller particles provide a larger reaction area, which can enhance the reaction rate. Generally, a particle size of 1 - 3 mm is considered optimal for desulfurization.

**Timing of Addition**: Adding calcium carbide at the right time is crucial. Adding it too early may lead to premature reactions, while adding it too late may not fully utilize its desulfurization potential. In most cases, adding calcium carbide when the molten iron temperature is stable and the sulfur content is relatively high is the best practice.

Case Study: A Steel Mill in Xinjiang

We introduce a case study from a typical steel mill in Xinjiang. Before parameter optimization, the desulfurization efficiency was only about 60%. After optimizing the particle size, temperature, and addition timing, the desulfurization efficiency increased to over 80%. The following table shows the comparison data:

Practical Recommendations and Problem - Solving

Based on the above analysis, here are some practical recommendations:

• Control the particle size of calcium carbide within 1 - 3 mm.
• Maintain the molten iron temperature between 1350 - 1450°C.
• Add calcium carbide when the molten iron temperature is stable and the sulfur content is high.

Industry Trends and Conclusion

The latest research in the industry shows that new desulfurization technologies are constantly emerging. However, calcium carbide desulfurization still has significant advantages in terms of cost - effectiveness and stability. Our high - purity calcium carbide products have been verified in many steel mills for their desulfurization effects. Click here to learn more about our technical support and supply solutions.