1. purposes

In order to prolong the service life of rotary kiln lining, reduce the consumption of energy and refractories, protect the safety of equipment and improve the economic benefits of cement production, this standard is formulated.

2. scope of application

This standard is applicable to the construction of refractory materials in the production department.

3. reference standards

"Rules for the Use of Refractory Materials for Cement Rotary Kilns (Trial Implementation)" promulgated by the State Building Materials Bureau and implemented on August 21, 1995

4. terms

4.1 dry lining

The construction method without using fire clay to build refractory bricks is called dry masonry.

4.2 wet masonry

The construction method of using fireclay to build refractory bricks is called wet masonry.

5. technical requirements

5.1 the construction of refractory materials shall be classified into firebrick masonry and castables.

5.2 General requirements for masonry of refractory bricks:

5.2.1 Refractory bricks are classified into four categories according to the size and operation of cracks and the degree of fineness of cracks. The type and size of cracks are classified as follows: Class I, <0.5mm; Class II, <2 mm; Class IV, <3 mm.

5.2.2 when the firebrick is used for wet mortar, the design of the gray joint should be less than 2mm. Or according to the specific requirements of refractory bricks for construction. The mortar in the seam of the lining of the immovable equipment should be full, and the joints between the upper and lower layers should be staggered.

5.2.3 Principles to be followed in the preparation of refractory slurry for bricklaying; pre-test of various slurries before bricklaying shall be carried out to determine the bonding time, initial setting time, consistency and water consumption of different slurries; different instruments shall be used for the preparation of different slurries and timely cleaning; clean water shall be used for the preparation of slurry, and the water quantity shall be accurately weighed and adjusted. Be uniform and follow suit. The water-hardened and air-hardened muds that have been adjusted shall not be used again arbitrarily, and the muds that have been initially set shall not be used continuously.

The 5.2.4 vault and barrel lining should be constructed by girth, and the straight wall and inclined plane should be constructed with wrong joints. In masonry, we should strive for straight brick joints, smooth arc surfaces and dense masonry. When lining bricks with immovable equipment, the slurry fullness is required to reach more than 95%, and the cracks on the surface of the bricks should be hooked with the original slurry, but the excess slurry on the surface of the lining bricks should be scraped off in time.

When 5.2.5 brickwork, wooden hammers or rubber hammers are used.

5.2.6 Fire-resistant and heat-insulating composite lining for masonry fixed equipment should be layered and segmented. Mixed layer masonry is strictly prohibited. Masonry insulation lining also requires full slurry seam, when encountering holes and anchor weldments to process bricks or boards, cracks filled with mud. It is forbidden to arbitrarily paving, leaving gaps or mud free. In the thermal insulation layer, refractory bricks should be used for masonry where they are under anchor bricks and behind arch-foot bricks, around holes and in contact with expansion joints.

The expansion joints in the 5.2.7 refractory bricks must be reserved according to the design and must not be omitted. Negative tolerance should not occur in the width of expansion joint, no hard lumps and sundries should be left in the joint, and the joint should be filled with refractory fibers. To avoid the phenomenon that the outside is full of the inside, expansion joints can not be generally set in the thermal insulation layer.

5.2.8 The lining of important and complex parts of the exterior shall be precast to use castable lining for linings of complex structures and bricks with too much processing.

Exposed metal parts in 5.2.9 brick lining. Including supporting slabs, baffles and other parts to be sealed with special-shaped bricks, castables or refractory fibers, not directly exposed to the use of hot kiln gas.

5.2.10 anchorage bricks are brick masonry structures. They should be designed according to the design and must not be omitted. No crack anchorage bricks should be used around hanging holes, and metal hooks should be put flat. Hanging holes and hooks can not be stuck, and the gap can be filled with refractory fibers.

5.2.11 When masonry top bricks, joint bricks and bend bricks are used, if the original bricks can not meet the sealing requirements, the bricks should be finely processed by a brick cutter, not by hand. The dimension of the bricks should be no less than 70% of the original bricks under the rotary kiln and the supporting slab, and no less than 1/2 of the original bricks in the plane joint bricks and bend bricks. The original brick must be locked. The surface of the brick should not be directed towards the inside of the furnace.

Masonry of 5.3 lining brick for rotary kiln

　　Before the 5.3.1 brick lining is built, the kiln shell should be thoroughly checked and cleaned.

The laying of 5.3.2 brick lining should be done before construction. The vertical datum line of the kiln should be placed along the circumference of the circle per 1.5m, and each line should be parallel to the axis of the kiln. A circular datum line is placed every 10m and a construction control line every 1m. The circular datum line should be parallel to each other and perpendicular to the axis of the kiln. Whatever masonry method is adopted in the masonry, the masonry shall be strictly carried out according to the datum line, and bricklaying without line is strictly prohibited.

5.3.3 The basic requirements for bricklaying in kilns are: the lining of bricks is close to the shell, the brick and the brick are tight, the cracks of the bricks are straight, the circles are accurate, the bricks are locked firmly, the bricks are not dislocated, and the bricks do not hang and fall off. To ensure that the lining brick and kiln body are reliably concentric in the kiln operation, the stress in the lining brick should be evenly distributed throughout the lining and on each lining brick.

5.3.4 must strictly select bricks. When the ring is laid, the length of the bricks should be equal. In the staggered construction, the thickness of the small head of the selected brick is homogeneous.

5.3.5 brick joints should be horizontal and vertical. In the case of staggered masonry, the deviation of longitudinal joints per meter is allowed to be less than 2 mm, and that of a construction section (usually 4-6 m) is allowed to be less than 10 mm.

5.3.6 The thickness of the jointed steel plate for dry masonry is generally 1-1.2 mm. It is required to be flat, without curling, distortion and burr. The width of each plate should be less than 10mm of the width of the brick, and no steel plate sounding and bridging can occur. At most, only one piece of steel is allowed in each seam. Adjust the narrow steel plate as little as possible. The cardboard used for expansion joints should be placed according to the design.

When 5.3.7 locks the bricks, it should be locked with the whole brick, and the 1~2 blocks should be staggered in the opposite ring. The middle end of the processing Brick ring should be built in advance of 1~2 ring. The last lock brick of the whole kiln should be carefully processed. It is strictly forbidden to lock the brick with castable alone, and no more than one steel plate should be allowed in the lock joint.

5.3.8 After the brick lining of the whole kiln is completed, the brick lining of the whole kiln should be cleaned and tightened thoroughly before ignition. Check by ring, tighten the ring and keep the kiln clean. After fastening, it is not suitable to turn to kiln.

5.4 preheater system, masonry of refractory lining of kiln door cover

5.4.1 There are a lot of technological holes in the preheater calciner and the rising flue, which should be checked one by one, carefully constructed and not omitted.

5.4.2 The cone part should be constructed in sections, the slope of the inclined wall surface should be accurate, and the lining surface should be smooth, so as to ensure the smooth cutting of materials in production and operation.

5.4.3 The whirlwind part of the cyclone cylinder should be built strictly according to the design size, and be filled with processed bricks or castables to avoid the occurrence of steps or gaps, so as to ensure the smooth operation of the air flow.

5.4.4 The linings of pipes or equipment which are small in space, thin in lining, highly sealed, difficult to operate and can not be operated after installation shall be prefabricated or constructed on the ground (or platform) before or after installation, and then hoisted and installed.

The upper half dome of the 5.4.5 kiln door cover should be scribed on the hood when laying the refractory lining. The allowable error of circumferential seam in full length is less than 8mm. Masonry shall not be skewed, void and ramp. The insulation bricks and firebricks should be staggered and masonry. Finally, the locking bricks can be located at the special holes at the top of the cover. When there is no special hole, a rectangular small hole should be cut along the direction of brick ring. The last brick should be inserted from the top of the cover and locked with steel plate.