Due to the rotation of the rotary kiln during operation, and the friction and mechanical stress of hazardous waste inside, it is required that refractories bricks should reserve a certain expansion space according to the expansion coefficient of the refractory bricks themselves during masonry, and the interior should be flat, smooth, without steps, and intact. To this end, strictly controlling the key points of masonry construction and optimizing the masonry method can reduce the thinning rate of refractory firebricks. The optimized masonry method includes:
(1) Center point calibration: Use a level and a plumb bob to locate 3 points to confirm the 2 axial center lines of the cylinder, and at the same time locate 5 circumferential reference lines and roundness to calibrate the center of the cylinder. Masonry based on the center of the cylinder can effectively detect the deformation of the cylinder and ensure that the annular gap of the fire bricks is uniform during masonry.
(2) Choose the pattern masonry method: During masonry, the horizontal brick joints are staggered by axial staggered masonry method, which effectively reduces the consistency of the relative sliding of each ring of refractory bricks, reduces the local stress of refractories bricks, and reduces the probability of brick corner damage. Do not choose the method of insufficient mortar fullness in masonry, because the masonry method will cause the brick joints to be consistent and prone to bending, which may cause the local stress of fire bricks to be large when they slide relative to each other, and increase the probability of damage to the local corner of the refractories bricks.
(3) Reserve expansion joints: Although refractory fire bricks are a kind of shaped refractory products sintered at high temperature, they will still expand to a certain extent due to heat in actual production and operation; during the masonry process of the "disposal center", a 5mm expansion joint is set in the circumferential direction of about 1 meter for every 5 rings of refractories bricks to release the thermal expansion of refractory fire bricks, thereby reducing the extrusion and fracture between refractory firebricks.
(4) It is strictly forbidden to use a hammer for bricklaying: Refractory bricks are fired at high temperatures. Although they are hard, they are still brittle and cannot withstand the impact of rigid materials. They must be laid with flexible tools such as wooden hammers and rubber hammers. If it is necessary to use a hammer for bricklaying, it is necessary to cushion it with wooden boards to avoid direct contact with the refractory fire bricks and cause damage.
(5) Locking bricks:
a. Refractories brick masonry is carried out in rings. The masonry work must be completed on the same day. The whole ring of brick locking and finishing work must not be interrupted in the middle, otherwise the mud will be squeezed due to inconsistent coagulation time.
b. In the actual masonry of the fire bricks with designed dimensions, due to the thickness deviation of refractory mortar and the allowable deviation size of refractory fire bricks, it is necessary to use processed bricks for the last part of the masonry. Generally, the estimation starts from the position of the last three to five refractory firebricks to seek the appropriate size of the last refractories brick.
c. When using processed bricks for locking bricks, when the processed size is less than 50% of the original size, the original brick structure may change and affect its actual strength. It may also be broken after being subjected to large forces during the rotation of the rotary kiln and unable to withstand the pressure, which will affect the integrity of the refractory bricks and cause safety risks such as falling off or collapse. Therefore, it is generally required that no more than 2 processed refractories bricks should appear in each circle of the bricks; the length of the processed refractory firebricks shall not be less than 50% of the original refractory firebricks, and the thickness shall not be less than 80% of the original refractory fire bricks; if 2 processed bricks are required, they need to be laid on both sides of one or two whole bricks, and 2 processed bricks cannot be laid adjacent to each other. The last locking brick of the whole kiln must be finely processed, and it is strictly forbidden to lock the brick with castables alone, but the last locking brick can be fixed with castables. The locking bricks must be firm and must not be misplaced.
By optimizing the refractory brick laying process and method, the quality of fire brick laying in the rotary kiln is effectively improved, and the operating efficiency of fire bricks is improved. During the masonry process, only qualified refractory firebricks are strictly used, and it is strictly forbidden to use defective bricks with broken corners or cracks. In order to avoid the erosion of hazardous waste on the gaps of refractory fire bricks, the flower masonry method is selected to build the hazardous waste incineration rotary kiln, and rubber hammers are used in the masonry to reduce the hard impact on the fire bricks; expansion joints are reserved according to the thermal expansion of the refractories bricks themselves to effectively avoid the refractory bricks from being broken by hard force; measurements are taken when locking bricks to ensure that the size of the final processed bricks is appropriate to avoid increasing the annular pressure due to excessive size and causing annular looseness due to too small size, which affects the overall structure of the masonry.
