Magnesite:  These refractory are basic in nature. Some properties are

• High refractoriness and thermal conductivity
• Great resistance to basic slag

Silicon carbide

SiC content exceeds 85% in these type of refractories. Some of the important properties are

Properties: 

• High thermal conductivity and high refractoriness
• Resistance to thermal spalling and temperature load bearing capacity is high
• Inert to acid slags and
• Light weight