The lining of the rotary refining furnace can be divided into four parts: the furnace barrel, the end wall, the furnace mouth, and the smoke exhaust port. The barrel has redox holes, sampling holes and other openings. End walls are divided into two types: flat end walls and dish-shaped end walls. The thickness of the furnace lining varies according to the size of the furnace, generally between 300~425mm.
1. Wall brickwork
(1) The flat end wall working surface shall be constructed using horizontal twist joint bricklaying method. A layer of 65mm thick standard clay refractory bricks is laid flat between the shell and the working layer. The working layer (magnesia chrome bricks) in the annular part of the end wall where the end wall contacts the cylinder lining should be retracted into the furnace face. 50mm (knotted 50mm magnesium grid ramming material). The slag line is semi-rebonded magnesia-chromium bricks, and the others are directly bonded magnesia-chromium bricks. Put horse manure cardboard in the vertical expansion joints to absorb the expansion of the bricks. The vertical joints of each layer should be staggered and should not be on a straight line. For horizontal expansion joints, according to the design requirements, put a layer of horse manure paper for every 5 to 6 layers. Absorb the expansion of bricks; fill the circumferential corner joints with magnesia-chromium ramming material.
(2) Dish-shaped end wall.
The working surface of the dish-shaped end wall is built using the horizontal bricklaying method. The masonry form is the same as for flat end walls. The brick material is the same as the flat end wall, and the masonry method and expansion joint treatment requirements are the same as the flat end wall. The difference is that the shape of the brick is different, the inner surface is smooth, and there are no wrong teeth.
2. Furnace barrel
Before laying bricks on the cylinder, use brine magnesia ramming material to pound a 50mm thick permanent furnace lining in the steel shell, or lay a layer of 65mm thick standard clay refractory bricks flatly. Magnesia-chromium bricks at the redox holes and sampling holes are built with straight joints to facilitate local repair and replacement.
The brick type is specifically designed according to the furnace specifications (cylinder diameter). The brick size of Φ4530mm cylinder bricks is: 380mm×150mm×115/91mm and 75/59mm. The width of the staggered bricks at the ends is 225mm and the thickness is 115/91mm and 90/70mm. Finally, tighten it with a locking brick.
Expansion joints should be set according to masonry design requirements. Brick lining of the refining furnace: circumferential seams, insert a 2mm thick horse manure cardboard every 15 bricks; longitudinal seams, insert a 2mm thick horse manure cardboard every two bricks. The shape and dimensions of the cardboard are the same as the cross-sectional dimensions of the vertical wedge-shaped bricks being laid.
3. Brick laying at the furnace mouth
The brickwork at the refining furnace mouth is the weakest part of the entire furnace lining structure, especially the intersection between the furnace mouth and the circular cylinder, which has a complex shape. Therefore, the joint between the furnace mouth locking bricks, the furnace mouth brickwork and the cylinder brickwork , you must be careful when building masonry. When the masonry is laid to the furnace mouth, it must be done symmetrically from both sides to the center at the same time. The radial joints of the arch bricks should coincide with the radius direction, otherwise there will be misaligned teeth or corner joints. When laying bricks, pre-laying should be used first to determine the amount of locking bricks to be processed.
Lock refractory bricks should be distributed symmetrically and evenly according to the center line of the vault. Lock brick 2 should be put in at the same time as bricks 1 and 3 on both sides, and then driven in with a wooden hammer, not with an iron hammer. Expansion joints should be set according to masonry design requirements or according to the expansion amount provided by the refractory material supplier.
4. Masonry of the copper outlet
There are two types of copper outlet bricks: single drilled type and combined type, as shown in Figure 4. In the figure, 1, 2, and 3 are built with 6 composite bricks, or they can also be built with a single drilled brick. No matter which form of brick masonry is used for the copper outlet, it must be ensured that the center of the copper outlet is aligned with the center of the copper outlet of the shell to ensure the angle required by the design and the error is not greater than 2mm, otherwise it will be unqualified.
5. Air outlet
The air outlet is constructed of two air outlet refractory bricks and 8 surrounding large bricks. Due to the influence of the cold wind during restoration, the tuyere bricks have a shorter lifespan than the furnace barrel bricks and often need to be replaced, so the masonry requires easy disassembly and assembly.
