The grain size of chromite sand has an impact on the refractoriness？

The grain size of chromite sand has an impact on the refractoriness. The grain size of chromium ore can significantly affect its refractoriness. In the past, it was thought that the granularity was too coarse,
It will reduce the surface finish of the casting, but the surface of the sand mold and sand core made of chrome ore is usually sprayed with a certain thickness of paint to make
The surface finish of the casting is hardly affected by it.