furnace working area

March 15, 2022

The selection of refractory materials in the working area (furnace wall, furnace top) in the furnace is divided into two areas, one is the refractory bricks in the molten pool area (especially the slag line area), and the other is the refractory bricks in the meteorological area.

  

(1) The molten pool area in the furnace

  

The refractory bricks in the molten pool area (especially the slag line area) will be eroded and washed by the molten slag. The composition of the lead smelting slag is relatively complex, and the high-alumina refractory material will participate in the slag-forming reaction, so high-alumina refractory bricks are selected. It is not suitable, and magnesia-chromium refractory bricks should be used. At the same time, considering the slag erosion resistance and erosion resistance of refractory bricks, magnesia-chrome bricks with electrofusion and recombination should be selected.

  

The bricks of this material are superior to semi-recombined magnesia-chrome bricks in slag corrosion resistance. The increase of Cr₂O₃ content can improve the slag corrosion resistance of bricks, so try to choose magnesia-chromium refractory bricks with higher Cr₂O₃ content.

 

(2) Meteorological area in the furnace

 

The refractory bricks in the meteorological zone will not be eroded by slag, but only by the splash erosion of a small amount of slag and the erosion of dusty smoke. Therefore, magnesia-chromium refractory bricks with lower Cr₂O₃ can be selected. The magnesia-chrome bricks used in the lead smelting reduction furnace of a domestic factory used direct-bonded magnesia-chrome bricks with high Cr₂O₃ in the early stage of production, and the surface of the magnesia-chrome bricks in the meteorological area was free of metal and slag. The bricks are broken into two sections and the structure is loose. According to the analysis results, it is judged that Fe³﹢ and Fe²﹢ in the refractory bricks are reduced to elemental Fe in a large amount, which leads to the loose structure of the brick body.

 

Therefore, in the maintenance, the fused recombined magnesia-chrome brick with lower Cr₂O₃ was used (Cr₂O₃ content is 12%). The main reason for this improvement is that the apparent porosity of the fused magnesia-chrome brick is low, and the content of Fe³﹢ and Fe²﹢ in the refractory brick is reduced, so that it is more suitable for the strong reducing atmosphere in the meteorological area and prolongs the service life. After switching to this type of electrofusion combined with magnesia-chrome bricks, the use time has been greatly extended and good results have been achieved.

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