Cast iron insulating coverant is primarily used to extend the solidification time of metal liquid in the riser and serves the purpose of insulation and slag blocking. The appropriate time for its addition is when the steel liquid reaches 2/3 of the riser and before the casting process stops, or it can be added after casting has ceased. The entire addition process must be completed before a film forms on the riser's surface.

Using cast iron insulating agents can effectively reduce the heat loss of metal liquids, extend the solidification time of risers, enhance the feeding effect of risers, and also boasts the advantages of ease of use, minimal addition, and more.