The correct masonry of the kiln lining of the rotary kiln is related to whether the rotary kiln can run for a long time. What kind of work do we need to do before the lining is built? How to rotate the cylinder when the masonry is built, when the drum is rotated How should the inner material work? Today we will give a detailed explanation of these.
1. Acceptance of kiln shell process
Before lining the masonry, it should be verified whether the kiln equipment is in empty operation, whether the welding accessories in the casing meet the masonry requirements, and whether the temporary support is removed.
2. Masonry laying line
The kiln should be cleaned before laying the masonry.
Use the horizontal chord length drop method or the central axis hanging line method to find the control point of the longitudinal line. Four vertical lines are drawn on the inner wall of the kiln shell.
On the inner wall of the kiln shell, the circumferential line of the circular section centered at the center of the vertical axis is drawn at a certain distance (generally 5~6m), that is, the circumferential line. However, at the variable diameter of the kiln shell or at the design section of the lining, a circumferential line must be drawn. When the ring is built, draw a circle every 1m.
3. Lower semicircle lining masonry
The masonry of the rotary kiln body should be guided by the kiln shell, starting from the lower semicircle, and rotating the kiln body through the lining kiln and the supporting device. When laying bricks, the bricks should be close to the kiln shell.
(1) The lining of the lining of the lining should be carried out in sections. Each section must be started from the bottom of the kiln and simultaneously laid out on both sides in a circumferential direction until the lower semicircle is completed.
(2) The second row of bricks must be based on the longitudinal straight line. During the masonry process, the distance between the brick columns and the longitudinal straight line should be checked with a steel tape measure at any time.
(3) When the inner lining ring is built, the ring brick joints shall be laid according to the lateral circumferential line, and the brick rings shall be parallel to each other and perpendicular to the kiln axis.
(4) When the lining is more than 1~2 layers of bricks in the lower half circle, the masonry should be suspended and supported and strengthened according to the requirements of support reinforcement.
4. Lining method
(1) The inner lining should be wet and staggered. When wet, the thickness of the mortar and kiln should meet the design requirements.
(2) When using phosphate mud masonry, the phosphate mud must be in contact with the kiln shell, and the clay and high alumina refractory mud should be filled between the brick and the kiln shell.
(3) When lining the masonry products, it is advisable to use the dry-laying method, and the joint material should be thin steel or cardboard.
5. Support reinforcement
When the masonry of a section of kiln exceeds 1~2 layers of bricks in the lower half, the masonry should be suspended and supported and strengthened in the following order.
(1) Withdraw all raw materials, tools and equipment that affect support reinforcement.
(2) Use rafts with good texture, no decay and no cracks. The specifications of rafts should be determined according to the kiln diameter. The section should not be less than 150mm*220mm, and the length should be 1~1.2m. When the body diameter is greater than 4 m, the length of the raft is preferably 0.74~1m.
(3) The contact surface between the raft and the masonry should be properly trimmed. When cement refractory mud is used as the litter, the contact surface of the raft should be processed into a circular arc shape and basically conform to the arc of the masonry.
(4) Fill the contact surface of the raft mat with the masonry with a cement refractory mud slurry about 10 mm thick, press the support surface, and support the middle of the raft mat with a support screw. Before using the screw, check whether the accessories are complete and apply lubricant to the sliding surfaces of the screw, handwheel and rod end.
(5) First pull the handle by hand to position the screw. The position of the lead screw should be perpendicular to the wall of the casing, and the central axis of the screw should be horizontal. Then, the hand wheel handle is sleeved by the sleeve, and the operator uses the force at the same time, and repeatedly pulls the hand wheel to the screw bearing plate and the pin cone to fully tighten the pad, and the degree of the tightening should be checked by a special person.
6. The first turn to the kiln
After the support and reinforcement work of the lower semi-circular masonry of the kiln is completed, the first conversion kiln is carried out.
(1) Before turning the kiln, the personnel and materials in the kiln must be withdrawn, the lighting in the kiln should be cut off, and a special person should be set at each supporting wheel to prepare the locking (stopping) wooden wedge.
(2) The auxiliary kiln should be used for the rotary kiln, which should be operated by a special person and unified command.
(3) When the kiln body is rotated for 1/4 week, it should be stopped immediately, and the wooden wedge should be quickly inserted into the roller, or the wire rope at the waist of the kiln body, temporarily fixed on the foundation of the kiln.
(4) After the kiln is stopped and the anti-return measures are taken, the kiln should be checked to see if the supporting device and the masonry are loose, and the safety can be confirmed before entering the masonry.
7. Locking
(1) The lining of the kiln should be locked in the last 2~3 rows of bricks, and the locking bricks should have the correct wedge shape and flat surface.
(2) The locking bricks should be driven from the side, and the thin steel plate should be driven in time at the seam of the locking brick to lock it.
(3) When the last piece of locking brick can't be driven from the side, 1~2 bricks on the side of the locking mouth should be processed so that the upper and lower dimensions of the locking mouth are equal, and then the matching brick is used to drive the locking brick from above. And tighten the sides with steel plates.
(4) The last 1-2 blocks of bricks should be processed as follows.
(5) Hand-made bricks shall not be used for the door-to-door bricks of the dry-locking joints. Special joint-inserted bricks shall be used for the combined locking, and if necessary, the brick-cutting machine and the brick-grinding machine shall be used for processing.
(6) The last 7~8 bricks of the dry door shall be built together as the door bricks. The door brick and the steel plate should be combined and tested first. Finally, the gap is measured, and the steel plate of suitable thickness is selected to be sturdy.
8. Quality requirements
(1) Material quality The varieties and grades of refractory materials and products must meet the requirements of current national standards and design requirements. The type and grade of the mud and its mix must meet the design requirements. The consistency of the mud and its applicable masonry category must comply with the construction specifications.
(2) The gap between the kiln shell and the lining. The inner wall of the kiln shell should be cleaned. The refractory bricks must be close to the kiln shell (or sprayed layer) with a gap of no more than 3 mm and filled with mud.
(3) Processing of bricks. The brick shape of the processed brick should be correct, the surface should be flat, and the thickness of the processed brick should not be less than 2/3 of the brick thickness.
(4) The thickness of the brick joint, the allowable thickness of the brick joint, the longitudinal joint is not more than 2mm, and the transverse joint is not more than 3mm.
(5) The provisions of the sewed lining. The longitudinal brick joints should be in the same horizontal plane as the kiln axis. In the same masonry section, the twisting degree shall not exceed 20mm. The width of the locking brick row is basically the same, and the individual brick wrong teeth are not more than 3mm. The mud of the refractory masonry bricks must be full, the fullness should not be less than 90%, the stricter requirements for air tightness and the bottom and wall parts with molten metal or slag erosion should not be less than 95%.
(6) The provisions of the ring lining. The annular seams are parallel to each other and perpendicular to the axis of the kiln, and the wrong teeth of the individual bricks are not more than 3 mm.
