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Notes for Brick-laying in Rotary Kiln Construction
Running rate of rotary kiln has a close relationship with the quality of refractory bricklaying. The overall requirements for the refractory lining of cement rotary kilns are to be achieved: high corrosion resistance, thermal shock stability, and wear resistance. In addition, higher stress resistance, high-temperature strength, and heat preservation performance are also required. All these require scientific and reasonable brick type, precise brick size, and reasonable refractory brick lining.
The main refractory materials commonly used in the construction of rotary kiln are:
Magnesia-iron spinel bricks, magnesia-calcium bricks, magnesia zircon bricks, magnesia alumina spinel bricks, silica mullite wear-resistant bricks, anti-stripping high alumina bricks, alkali-resistant bricks, alkali-resistant castables, steel fiber reinforced refractory castables, Special castable for kiln mouth and coal injection pipe.
Strictly construct according to the technical requirements for refractory bricklaying. As follows:
Clean bricking and especially level the square timber location before construction.
Use the lead screw and square timber to tighten the bricking, confirm the part that need to change and tighten the reserve part with lead screw and square timber.
Remove the old bricks in the groove. Pay attention to protect the bricking and prevent the reserved bricking from sliding. After removing, weld small steel plate on the kiln shell to prevent bricking from sliding.
Check rotary kiln shell completely before refractory bricklaying and clean up inside kiln.
When laying firebricks, no matter adopt what kind of building ways, all shall strictly lay firebricks according to the base line. Strictly prohibit masonry without base line. Lay the base line before laying firebricks: lay one kiln base line along the circumference every 1.5m. Every line shall be parallel with axes of kiln. Every 10m lay one baseline along the ring direction. Ring ling shall be parallel and perpendicular each other to axes of kiln.
The basic requirement for laying brick in the kiln: bricking shall cling to kiln shell. Brickwork joint shall be straight. The circle shall be standard. Rider brick shall be tight without wrong position. Ensure that refractory bricks and kiln body keep the concentricity in the running. The bricking stress shall be distributed on the whole kiln lining and each brick evenly.
The way for laying firebricks includes two types of ring masonry and circle masonry. New kiln and kiln body with complete shape without badly change generally adopts ring masonry. Kiln body for traditional kiln with badly shape changed and the sued bricks with bad quality shape can adopt circle masonry on the position of high alumina brick and fireclay brick.
When ring masonry, ring joint deviation allows 2mm every meter. Construction division length allows 8mm at maximum. When circle masonry, vertical joint deviation allows 2mm every meter at maximum. But whole ring length allows 10 at maximum.
Push the last brick every circle (except for the last circle) in from one side of bricking (rotary kiln axes direction) to complete the whole circle masonry and pay attention to adjust brick type for avoiding continuous use. The joint steel board for drying masonry generally is 1~1.2mm. The width of steel board is less about 10mm than brick. Steel board shall not over the brick side. It is not allowed that steel board bridging.
Clean and tighten all the bricking completely after laying firebricks. It is not suitable to star turn the kiln after tightening over. Light the fire timely and bake the kiln according to the curve baking in kiln.
