Multi purpose furnace refers to the continuous production of thermal equipment with multi-layer hearth, also known as rake furnace or multi chamber furnace. It is used for burning municipal solid waste, roasting nonferrous metal ore powder, light burning magnesium hydroxide filter cake and natural magnesite ore powder. Due to its complex structure, difficult maintenance and low thermal efficiency, the equipment has been gradually replaced by suspension furnace and fluidized bed furnace in the production of magnesia refractories.

Working principle: the furnace body is equipped with multi-layer hearth, which is divided into drying, preheating, roasting and cooling zones from top to bottom. The vertical shaft in the center of the furnace drives the rake arm and rake teeth of each hearth to rotate. The material is added from the charging holes around the top of the furnace. The discharging ports of odd number hearth are located in the center of the furnace, and several discharging ports of even number hearth are evenly arranged around the furnace. Due to the different orientations of the rake teeth of odd and even number hearth, under the turning and pushing action of the rake teeth, the material falls from top to bottom layer by layer in an "s" shape, and meets with the hot flue gas from the combustion chamber countercurrent for heat exchange.