The rotary kiln shell is made of steel plate such as boiler plate and Q235C plate, requiring highly on dimensional accuracy and geometric tolerances.

Due to transportation reasons, the rotary kiln is composed of shell segments. Because the outer circle of the kiln cylinder is not processed, the perpendicularity of the end face to the center of rotation cannot be directly measured. In the process design, the perpendicularity of the end face is converted into parallelism and the coincidence of the axes at both ends according to the structure of the cylinder.