Covering powder for liquid steel and method for manufacturing same

摘要

Covering powder (I) comprises silicon dioxide (15-30 wt.%); alumina (10-25 wt.%); iron oxide (= 3 wt.%); calcium oxide (30-50); magnesium oxide (less than 5); carbon (less than 3 wt.%), where (I) has a basicity index of 0.6-1.3, and the basicity index is defined as the ratio of sum of calcium oxide and magnesium oxide/the sum of silicon dioxide and alumina. An independent claim is included for manufacturing (I) comprising: mixing alumina (5-20 wt.%) with wood ash and adding an organic or mineral binder.