Influence the life of the crucible furnace refractory lining the main, ovens and other aspects of technology and the use of technology, to be introduced below.
1, refractory lining
Refractory lining quality and performance quality of life of the furnace to play a fundamental role.
(1) refractory brickwork should have a very high refractoriness, resistance to high-temperature thermal load is applied, not softened, not melted. But also has a high volume stability, resistance to high-temperature thermal load is applied, the volume does not shrink and is only uniform expansion.
(2) refractory component. Refractory impurities at high temperatures to form a low melting point compounds, thereby reducing the refractories refractoriness. Therefore, to ensure the lining sand quartz content, strict control of impurities, sand lining composition control as follows: ω (SiO2) ≥98.0%; ω (Al2O3) ≤0.5%; ω (Fe2O3) ≤0.5%; ω (TiO2) ≤ 0.05%; ω (H2O) ≤0.5%.
(3) refractory size ratio. Refractory reasonable size ratio, furnace building process can easily form a high density refractory layer, in the course less prone to defects. Here is a group of more reasonable proportion: 3.35mm ~ 5mm, 0.85mm ~ 1.70mm, 0.1mm ~ 0.85mm, 0.1mm or less proportion were 17%, 33%, 20%, 30%.
2, oven technology
Ovens order process to obtain a sintered layer sintered layer directly affects the quality of the life of the stove, the oven is an important part. After building the oven cavity, the oven should be carried out immediately; front oven, check the electrical equipment, cooling water system is normal; in strict accordance with the process proceeds oven oven. Oven oven process is a key factor in the process, specific points: ① to control the heating rate, especially early oven, if heated too fast, too lining the water discharges are susceptible to cracking, the life of the furnace greatly shortened. When ② When the lining is heated to 573 ℃ quartz phase transition process will likely lead to expansion cracks or excessive flaking, thus heating to 600 ℃ at 400 ℃, heating rate should slow down, but should be incubated at 870 ℃ 1h ~ 2h so that it can slow and complete phase transition. ③ oven insulation final stage of sintering, the sintering temperature varies depending on the specific refractory, generally hoping to get 30% of the thickness of the lining of the sintered layer thickness, and therefore, the sintering temperature is generally higher than the temperature of the iron 50 ~ 100 ℃.
3, with the furnace process
Various process furnaces use the service life of the furnace it is also very important to have a variety of improper operation may reduce the life of the furnace. Therefore, in the course of the following points should be noted.
(1) Since the new furnace sinter layer is thin, and therefore the use of the new furnace process is very important. The new furnace effluent of the first furnace should be 50% of that is feeding melted, so that it can avoid feeding lining after all effluent and quench cracks and other defects; new continuous smelting furnace as much as possible, to avoid interruption caused by melting hot and cold crack, should generally be continuous melting one week.
(2) melting process to avoid melting temperature. At elevated temperatures, lining will be the crucible of molten iron to react with the following equation: SiO2 + 2C → Si + 2CO, the higher the temperature, C is higher, the lower Si, lining erosion will increase, especially when a new furnace more It is clear, therefore melting in ensuring water temperature to avoid high temperatures.
(3) Avoid lining overheating. Due to very fast frequency furnace heating, smelting workers do not pay attention when that charge a "bridging" phenomenon leaving a partial lining temperature even more than the lining of the refractoriness, this has the potential to melt and lining erosion.
Leaving for lining crack damage the lining (4) during use, when other reasons due to a fault shutdown takes a long time, should be emptied of liquid iron furnace, molten iron to avoid condensation.
(5) The use of the process, especially when you try to use a clean new furnace charge.
(6) When the shutdown cooling, in order to avoid lining quenching air furnace should be cooled, as well as to avoid lining upper and lower temperature in the cooling process is too large cracks, should cover the lid, so that even lining up and down during the cooling, in order to ensure the life of the furnace.
(7) Since the inevitable emergence of vertical cracks furnace cold, so cold oven start, should be low oven, then melted, so that the crack can be bridged to avoid infiltration of crack crack when hot metal melt so further expansion.
(8) The use of the process furnace furnace conditions to observe, observe good furnace conditions is on the kind of protection of the furnace hearth measured every three days, every day we have to observe the furnace wall furnace, in order to protect the lining of security.
(9) of the electric equipment maintenance and repair, such as regular purge coil, coil cleaning debris to prevent the coil breakdown, thereby avoiding due to equipment failure caused the demolition of furnaces, effectively raising the crucible life.
