Calcium Silicon
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Calcium silicon is a composite deoxidizer and desulfurizer for high-grade steel, and Calcium Silicon explains the alloy, its production and its role in secondary metallurgy.
Calcium silicon combines calcium and silicon for steel refining.
It deoxidizes, desulfurizes and modifies inclusions in the ladle.
Cored wire injection gives the highest calcium recovery.
Typical composition: about 28-32 percent calcium, 55-65 percent silicon.
Store dry; calcium reacts with moisture.
What Is Calcium Silicon?
Calcium silicon (CaSi) is an alloy of calcium and silicon, typically containing 28-32 percent calcium and 55-65 percent silicon, with iron as the balance. It combines the strong deoxidation of calcium with the fluidizing and deoxidizing action of silicon. It is supplied as lumps, granules or powder, and as cored wire for precise injection.
Production
Calcium silicon is produced by reducing a blend of quicklime and quartz with carbon in a submerged arc furnace, or by the silicothermic reduction of lime. The alloy is tapped, cast and crushed to the ordered size. Quality control focuses on the calcium and silicon contents, the calcium distribution within the lot, and the level of impurities such as aluminium and phosphorus.
Role in Steel Refining
In secondary metallurgy, calcium silicon is added to deoxidize and desulfurize the steel, and to modify non-metallic inclusions. Calcium turns solid alumina inclusions into liquid calcium aluminates that float out or deform harmlessly, improving steel cleanliness, castability and mechanical properties. It is especially important for aluminum-killed steels for pipelines, plates and engineering grades.
Application Methods
Calcium silicon can be added as lumps to the ladle, but the most efficient method is cored wire injection: a steel-sheathed wire containing CaSi powder is fed deep into the melt, giving high calcium recovery and consistent results. The injection rate and wire size are set by the steel grade, temperature and the target inclusion modification.
Quality and Ordering
Orders specify the calcium and silicon contents, the particle size or wire diameter, and the packaging. The certificate reports the analysis per lot, and because calcium is reactive, the product must be kept dry and used within a reasonable time after production.
Frequently Asked Questions
Deoxidation, desulfurization and inclusion modification in secondary steelmaking, and inoculation in cast iron.
About 28-32 percent calcium and 55-65 percent silicon, with iron as the balance.
As ladle lumps, granules, or most efficiently as cored wire injected deep into the melt.
Calcium turns solid alumina inclusions into liquid calcium aluminates, improving castability and final steel properties.
Chinese grades are defined in GB/T 34188 and similar specifications; the order should state the analysis and size per the applicable standard.
Dry storage in sealed packaging, because the calcium component reacts with moisture.
