Magnesia-calcium sand refers to a magnesia-calcium refractory raw material prepared by a synthetic process at a given CaO/SiO2 ratio. Also known as high calcium magnesia. Converter magnesia carbon bricks are used to make magnesia-calcium bricks. With the increase of the calcination temperature, the C4AF can be distributed between the periclase crystal grains gradually accumulate to the corner gap between the periclase crystal grains, resulting in the increase of the high temperature strength of the brick. Although the calcium content of magnesia-calcium sand is much higher than that of ordinary magnesia brick sand, because there is no free CaO3, the brick making process is the same as ordinary magnesia brick, sulfite pulp waste liquid can still be used as binder