Furnace lining

March 15, 2022

Before masonry, thoroughly clean and dehumidify the bottom of the furnace, open 6 small exhaust holes in the bottom of the furnace, calculate and mark each layer at the corresponding position of the furnace shell according to the drawings, especially the position of the furnace mouth. 

 

1) Furnace bottom refractory brick masonry

 

From bottom to top, there are two insulating layers of asbestos boards, which play the role of insulation and heat insulation. On the insulating layer, high-alumina aggregate with a thickness of 80mm is laid as an elastic layer. After the elastic layer at the bottom of the furnace is tamped and leveled, the center line of the furnace body is determined. The 31.5MVA manganese-silicon alloy submerged arc furnace adopts 12 layers of refractory bricks at the bottom of the furnace. The order of masonry from bottom to top is: 7 layers of LZ-55 high-alumina bricks, 2 layers of LZ-65 high-alumina bricks Layer, LZ-75 high alumina brick 3 layers. The brick type adopts G-2 type (dimensions: 345mm×150mm×75mm), the masonry method is dry-laying method, the brick layers are cross-shaped, and each layer is staggered by 300~45. Press the brick seam. The brick joints are less than or equal to 2mm, and each layer of brick joints is filled with high-alumina fine powder. A 100mm wide gap is reserved for the refractory brick layer of the furnace bottom and the insulation layer of the furnace wall as an elastic layer and filled with high-alumina aggregate. The dry lining method has less moisture, which is beneficial to the oven, but the filler porosity is large and the lining is loose, which is not conducive to ensuring the integrity of the lining. In contrast, the wet masonry method uses refractory mud to build brick joints, which is beneficial to improve the integrity of the furnace lining, but due to excessive moisture, more heat is consumed during the oven, which is not conducive to temperature stability.

 

2) Furnace wall refractory brick ring

 

The refractory bricks of the furnace wall are built by the heat preservation method, and the inner wall of the furnace shell is covered with two layers of asbestos boards, which are pasted with high-alumina phosphate refractory mud. The elastic layer of the reserved gap of about 80mm is filled with high-alumina aggregate. The ring-laying bricks are wet-laid with high-alumina phosphate fire mud. The inner and outer rings are made of LZ-65 high-alumina bricks. The ratio of 2:1 is the base masonry matching radian (G-1 brick size: 230mm×150mm×75mm; G-3 brick size: 230mm×150mm/135mm×75mm)). There are 33 layers of ring-laying bricks in total. When the refractory-brick layer of ring-laying bricks reaches a certain height, the furnace bottom carbon bricks are ready to be laid.

 

3) Furnace bottom charcoal brick masonry

 

The carbon brick manufacturers design, manufacture and process according to the drawings. After pre-assembly, they are numbered and built on site according to the number. There are three layers of charcoal bricks at the bottom of the furnace. From bottom to top, two layers are laid flat first, and then the third layer of charcoal bricks is built after the completion of the charcoal brick laying around the furnace wall. Before laying each layer of carbon bricks, clean them up, evenly coat the bottom with carbon cement, pre-build according to the number of carbon bricks, and use a wide joint (50mm) masonry method, with staggered joints between adjacent carbon bricks. Wrong 30 ° ~ 45 ° stacking, the gap is first covered with wooden wedges, after all the carbon bricks are stacked, then fine-tune the brick joints, and finally fill with rough seam paste and tamping and smoothing, the cross-sectional size of the carbon bricks is 410mm × 400mm, two Two grooves with a width of 60mm and a depth of 30mm are machined on each side, and the height of each groove is the same, so that the contact between the bricks after knotting the rough seam paste and furnace bottom sintering is more firm.

  

4) Tap hole charcoal bricks and furnace wall charcoal bricks

  

The taphole carbon bricks are made of semi-graphite silicon carbide bricks and pre-baked carbon block combination bricks. There are four combined bricks. Clean up and apply carbon cement evenly between each block, and lay them according to the number. After the construction is completed, the short chute outside the taphole of the furnace wall is built, and the LZ-65 high-alumina brick wet laying method is adopted. When the furnace hole brick is built, it needs to be well debugged and connected with the hole opening and plugging machine. The refractory bricks with a width of about 750mm on both sides of the tap hole carbon bricks are built with single-ring masonry, and the gaps of about 750mm×350mm×1800mm do not leave an elastic layer, and are poured and tamped with corundum castables.

  

After the two layers of charcoal bricks at the bottom of the furnace are built, the ring-laying of the charcoal bricks on the furnace wall shall be carried out. The masonry method adopts seamless masonry. Before masonry, clean the bottom of the carbon bricks and evenly apply carbon cement, and then place them according to the number. There is a 50mm gap between the ring-laid charcoal bricks and the refractory bricks on the furnace wall. The ring-laid charcoal bricks are placed on the inside. The gap is first covered with wooden wedges. , Ring-laying carbon brick size: l800mm×400mm/370mm×400mm, the trapezoidal section ensures the radian of the ring-laying, and the two tap holes divide the entire ring-laying into two sections. Place two charcoal bricks in numbers, each section is built from both sides of the taphole charcoal bricks to the middle, until finally there will be an opening of an irregular size in the middle - the closing door. The end of the charcoal brick ring.

 

5) The third layer of carbon bricks at the bottom of the furnace

  

After the charcoal bricks are laid around the furnace wall, the third layer of charcoal bricks at the bottom of the furnace is laid, and the masonry method is the same as the first two layers. This layer of carbon bricks is built symmetrically on both sides of the center line of the tap hole. The surface of the third layer of carbon bricks is paved with a thickness of 100mm with rough seam paste and leveled. The role of this layer of rough seam paste is to protect the carbon bricks from being oxidized during the oven.

  

6) Masonry with refractory brick layer on the upper part of the furnace wall

 

The high-alumina castables and the ring-laid carbon bricks are leveled on the ring-laid refractory brick layer, and then the upper refractory bricks of the furnace wall are laid. LZ-55 high-alumina bricks are used. The gap between the masonry is filled with elastic layer high-alumina aggregate, and the lower part of the furnace mouth flange about 600mm begins to close. High alumina bricks and clay bricks use G-1, G-2, G-3, G-4 with flat laying (G-1 brick size: 230mm×150mm×75mm; G-2 brick size: 345mm× 150mm×75mm; G-3 brick size: 230mm×150mm/135mm×75mm; G-4 brick size: 345mm×150mm/130mm×75mm), the masonry method is wet laying method, with high alumina phosphate fire mud pressing seam masonry.

 

7) Masonry of furnace bottom and furnace wall protective layer

 

After the refractory bricks on the upper part of the furnace wall are completed, the furnace bottom and furnace wall protective layer are built. The furnace bottom protective layer is a layer of PN-40 clay bricks flatly laid on the 100mm thick rough seam paste, and the furnace wall protective layer is one layer. PN-40 clay brick adopts vertical laying + side laying, wet laying method, and the brick type is T-3 type (230mm×114mm×65mm).

 Home  Whatsapp  Mail  Inquiry