firebrick by brick joints size and operating the fine degree is divided into four categories. The categories and brick joints size respectively is: class I, class II, less thanless than or equal to 0.5mm; 1mm; class III, IV, is less than or equal to 2mm less than or equal to 3mm. System of rotary kiln refractory lining with fire clay masonry, the mortar joints should be less than 2mm, the construction should be strictly controlled. Realequipment lining mortar joint fire clay should be full, and the upper and lower inner and outer brick joints shall be staggered.