Purifying Molten Steel Steelmaking Metallurgy Alloying Additive Alloy Supplier Silicon Calcium Alloy Calcium Silicon Alloy

A binary alloy composed of silicon and calcium belongs to the category of ferroalloys. Its main components are silicon and calcium, and it also contains impurities such as iron, aluminum, carbon, sulfur and phosphorus in varying amounts. In the iron and steel industry, it is used as a calcium additive, deoxidizer, desulfurizer and denaturant for non-metallic inclusions. It is used as an inoculant and denaturant in the cast iron industry. On the basis of silicon-calcium alloy, other elements are added to form a ternary or multi-element composite alloy. Such as Si-Ca-Al; Si-Ca-Mn; Si-Ca-Ba, etc., used as deoxidizer, desulfurizer, denitrification agent and alloying agent in iron and steel metallurgy.

Calcium is an alkaline earth metal with an atomic weight of 40.08, an outer electronic structure of 4S2, a density (20°C) of 1.55g/cm3, a melting point of 839±2°C, and a boiling point of 1484°C. The relationship between the vapor pressure of calcium and temperature is

lnpCa=25.7691-20283.9T-1-1.0216lnT

Where pCa is the vapor pressure of calcium, Pa; T is the temperature, K. Silicon and calcium form three compounds, namely CaSi, Ca2Si and CaSi2. CaSi (41.2% Si) is stable at high temperatures. Ca2Si (29.5%Si) is a peritectic compound formed between Ca and CaSi at temperatures below 910°C. CaSi2 (58.36%Si) is a peritectic compound formed between CaSi and Si at temperatures below 1020°C. The phase composition of industrially produced silicon-calcium alloys is about 77% CaSi2, 5% to 15% CaSi, free Si < 20%, and SiC < 8%. The density of silicon-calcium alloy containing 30% to 33% of Ca and about 5% of Fe is about 2.2g/cm3, and the melting temperature ranges from 980 to 1200°C.