The development of electric heating kilns is constrained by the high price of electricity, therefore, large-scale commercial production rarely uses electric rotary kilns. Electric rotary kilns are only used in laboratories and some special occasions, where "special occasions" refer to situations where extremely high temperatures are required for the preparation of certain materials. Regarding the "material thermal preparation technology of some red star techniques", it includes the "discharge plasma sintering" technology of materials, the "hot isostatic pressing preparation" technology of materials, the "microwave sintering" technology of materials, the "self propagating high-temperature synthesis" technology of materials, and other "material reaction sintering technologies", "explosive sintering technology" of materials, etc. In addition, a solar furnace that uses solar energy to focus and generate high temperatures is also a promising type of rotary kiln. Its drawback is that it is greatly influenced by climate and meteorological conditions.