The performance of fused magnesia  has a significant impact on refractory materials. Magnesia sand is produced by high-temperature calcination of magnesite ore, magnesite hydroxide, or magnesium hydroxide extracted from seawater. It is a general term for products produced by high-temperature treatment of magnesite and other magnesia materials to reach the sintering process. 

Magnesia sand can be produced through one-step or two-step calcination processes using high-temperature equipment such as vertical kilns or rotary kilns. Magnesia sand produced by calcining natural magnesite ore is called sintered magnesia sand, while magnesia sand produced by melting magnesite ore in an electric arc furnace and cooling it to a solid state is called fused magnesia sand. Magnesia sand produced from seawater extraction is called seawater magnesia sand.Magnesia sand is one of the important raw materials for refractory materials and is used to manufacture various magnesia bricks, magnesia-alumina bricks, ramming mixes, and repair materials. Magnesia sand with a higher impurity content is used for lining steelmaking furnace bottoms, among other applications.

Fused magnesia, specifically, plays a coating role in the decarburization annealing process of silicon steel. It prevents bonding during high-temperature annealing and forms a magnesium silicate layer with oxidation during the annealing process, which enhances the magnetic induction intensity. A coating solution consisting of fused magnesia sand is applied using a double-roll coating machine. The machine includes an upper coating roll, a lower coating roll, a tray, a circulating device for the fused magnesia sand coating solution, and a nozzle for spraying the coating solution onto the surface of the steel strip. The lower coating roll is immersed in the tray, and the excess coating solution flows into the tray through the spraying pipe. 

Fused magnesia sand primarily acts as an isolating agent,preventing the steel strip from sticking during the high-temperature annealing stage. It also removes impurities such as nitrogen and sulfur from the steel and reacts with the silicon dioxide on the surface of the silicon steel to form a good magnesium silicate insulation layer.

In summary, magnesia sand is a general term for products produced through high-temperature treatment of magnesite and other magnesia materials. It is an essential raw material for refractory materials and is used in the production of various magnesia bricks, magnesia-alumina bricks, ramming mixes, and repair materials. The impurity content of magnesia sand determines its application, with higher impurity content suitable for applications such as lining steelmaking furnace bottoms. Fused magnesia sand, in particular, plays a coating role in the decarburization annealing process of silicon steel, preventing bonding and enhancing magnetic induction intensity.