Preparation method of mineral insulated magnesium oxide for heating cable

The invention discloses a preparation method of mineral insulated magnesium oxide for a heating cable, and belongs to the technical field of magnesium oxide production, and the preparation method comprises the following steps: performing crushing processing and high-temperature calcination on mineral fused magnesium oxide to obtain high-temperature calcined magnesium oxide powder, uniformly mixing the high-temperature calcined magnesium oxide powder, kaolin and a solid waterproof material, and performing extrusion molding to obtain the mineral insulated magnesium oxide for the heating cable. And calcining the mixture at a low temperature to obtain the mineral insulated magnesium oxide for the heating cable. In the mineral insulation magnesium oxide prepared by the method, the content of MgO is greater than or equal to 94%, the content of CaO is less than or equal to 2.0%, the content of Fe2O3 is less than or equal to 0.8%, the content of Al2O3 is less than or equal to 0.5%, the content of SiO2 is less than or