Manganese silicon alloy is an alloy composed of manganese, silicon, iron, carbon and other elements. It is a kind of electric furnace ferroalloy with wide application and large output. Its output occupies the second place in ferroalloy products. In the process of smelting silicon manganese alloy, the most important thermal equipment is the submerged arc furnace. The submerged arc furnace is mainly composed of furnace shell and furnace lining. The furnace shell is steel shell and the furnace lining is made of refractory materials, including clay brick, carbon brick, carbonized cinnamon brick and electrode paste; Thermal insulation materials: asbestos board, asbestos rope, clay particles, slag cotton.
The requirements for furnace building materials are as follows: ① it has high fire resistance and does not change greatly in shape and volume at high temperature. ② Sufficient mechanical strength at high temperature. Good slag resistance and high chemical stability at high temperature. ③ It has low conductivity and thermal conductivity (thermal insulation and thermal insulation). ④ It has high oxidation resistance at high temperature. ⑤ The size of refractory brick is accurate, with little deformation, no cavity or crack, no missing edge and corner. Handle carefully, store and keep properly and avoid moisture. ⑥ All refractory materials shall be kept clean and tidy without dust, soil and oil stain.
How to construct refractory bricks for manganese silicon alloy submerged arc furnace?
Specific construction process of refractory brick
Clean the furnace shell. Lay a layer of 10mm asbestos board at the bottom of the furnace and tamp it with a wooden hammer to make it close to the steel plate at the bottom of the furnace. The joints of the asbestos board shall be tight. A layer of 80 ~ 100mm thick clay particles is paved on the asbestos board as an elastic layer. Survey, set out and start masonry. Seven layers of clay bricks, four layers of flat bricks (65mmx4) and three layers of side bricks (115mmx3) are laid on the elastic layer.
For the first time of flat laying of clay bricks, dry laying is required for easy leveling (the horizontal tolerance shall not exceed ± 5mm). After passing the inspection, the next layer can be laid, and the second, third and fourth layers can be laid wet. The brick joint shall not exceed 2mm, the slurry shall be full, and the filling shall be solid. Three layers of dry laying shall be laid on the side, and the joint shall be filled with clay powder. The vertical joints of each two layers of bricks shall be staggered by 30 ° ~ 50 °. While laying the clay bricks at the bottom of the furnace, put the asbestos board on the furnace wall, leave an elastic layer space of 80 ~ 100mm, and fill the clay particles once after smashing the second layer of clay bricks.
After laying the clay brick layer at the bottom of the furnace and the clay brick layer of the carbon brick enclosure, leave 8 ~ 10 vent holes in the vertical direction in the enclosure, with a section of 50mmx80mm, evenly distributed on the circumference. The vent holes lead from the first layer of the enclosure to the edge of the furnace wall. Leave an 80 ~ 100mm annular space outside the enclosure to fill with clay particles and elastic layer. Place carbon bricks in the enclosure, leave a 50mm gap between the carbon bricks and between the carbon bricks and the enclosure, and tamp and fill with joint filler (electrode paste: bottom paste = 2:1).
Before placing the carbon brick, lay a horizontal paste (graphite powder: water glass = 2:1) 10 ~ 15mm thick. Place the carbon brick in the right place. After placing it stably, remove the extruded horizontal paste and fix it with a wooden wedge. The joint filling paste shall be well heated (evenly heated, the particle size is suitable, and shall not be overburned. The temperature shall be controlled at 110 ~ 1501. Pour the carbon brick into the vertical joint. The pouring thickness shall not exceed 100mm each time. It shall be compacted in layers. Each brick joint shall be filled, leveled and tamped.
The masonry method of the second and third layers of carbon bricks is the same as that of the first layer. The joints of the two layers of carbon bricks shall be staggered by 30 ° ~ 45 °, and the vertical joints of the third layer of carbon bricks shall be 30 ~ 50mm higher than the brick surface. The arrangement direction of the third layer of carbon bricks must be parallel to the center line of one side of the taphole, and the middle row of tapholes protrudes 100mm. After the completion of the laying of carbon bricks at the furnace bottom and passing the inspection (the horizontal tolerance shall not exceed ± 5mm), an elastic layer of 80 ~ 100mm shall be reserved between the laying of carbon brick enclosure of furnace wall (65mmx20), wet laying, asbestos board of furnace wall, clay brick and asbestos board. Every 3 ~ 5 layers of bricks shall be filled with clay particles. After the enclosure is dry, clean the enclosure soil and the surface of furnace bottom carbon brick. Set out, determine the center of the furnace bottom, and draw the furnace circumference and the center line of the two tapholes. Place the carbon bricks on the furnace wall and pay attention to placing them correctly and stably. The carbon bricks on the furnace wall of the iron outlet must be aligned with the iron runner. All the carbon bricks are placed, the spacing is adjusted evenly, fixed with a wooden wedge, sealed with a wooden board, measured inside the vertical joint, and firmly supported with a wooden square. Check and remove the falling objects in the vertical joints of carbon bricks, and clean all the vertical joints with compressed air.
Pour the heated joint filling paste into the vertical joint of carbon brick and tamp it in layers (about 10mm for each layer). It is required to be filled and tamped until it is 30 ~ 50mm higher than the upper surface. The horizontal tolerance of the surface of the furnace wall is about 8mm, the joint with the carbon brick at the furnace bottom is less than 5mm, the inner side of the vertical brick joint is about 40mm, and the outer side is about 70mm. The three groups of silicon carbide bricks at the tap hole are made into an electrode paste layer with the enclosure. The enclosure has clay bricks laid flat along the asbestos board of the furnace wall, and the two sides are laid into brick stacks to block refractory particles. The tap hole is made of special-shaped bricks, the arch thickness is 115mm, the space under the arch is sealed with refractory bricks, and the round hole in the silicon carbide brick is threaded with an iron pipe containing coke powder, Left in rammed electrode paste and 115mm thick clay brick. Clay bricks are laid on the carbon bricks of the furnace wall, which shrink into a ladder shape layer by layer towards the furnace shell, and no elastic layer is left outside the top three layers of bricks. Cover the vent hole on the wall with brick.