高炉炉底密封板上翘机理及预防措施

 国内一些高炉发生了高炉炉底密封板上翘现象，一些高炉炉底密封板上翘高度甚至达到了100～140 mm，出现炉底变形成锅底状、局部漏煤气、炉底冷却效果变差等现象，严重影响高炉的长寿和高效生产。通过建立高炉炉缸炉底温度场和应力场数学模型，分析砖衬异常膨胀、砖衬受热膨胀和炉底密封钢板厚度、膨胀缝及缓冲泥浆等因素对炉底密封板上翘高度的影响。结果发现，由于炉缸砖衬的异常膨胀，在风口组合砖位置产生较大的向上压力，最终导致高炉炉底密封板产生较大程度的上翘，而砖衬正常受热膨胀不会导致炉底密封板的明显上翘。碱金属、锌、铅等有害元素在高炉内富集、累积可以导致砖衬异常膨胀，是炉底密封板上翘的主要原因。炉底密封板厚度的增加会对炉底密封板上翘产生有效的阻碍作用。合适的膨胀缝和性能优良的缓冲泥浆可以吸收砖衬受热膨胀，但是不能解决砖衬较大的异常膨胀。为了抑制和减少高炉炉底密封板上翘现象，需要在风口组合砖与炉缸砖衬之间预留合适的膨胀缝；避免风口大套前端嵌入炉缸砖衬内部；严格控制有害元素入炉量，提高高炉排出有害元素的能力。

Mechanism and Preventive Measures of Upturned Blast Furnace Bottom Sealing Plate

The phenomena of the upturned bottom sealing plate were found from several blast furnaces (BFs) field surveys. The bottom sealing plates of some Blast Furnaces were even upturned 100-140 mm height, which led to bottom transformed into pot shape, the gas leaked from bottom and the bottom cooling effects weakened. It’s harmful for the longevity and efficient productivity of BF. The temperature field and thermal stress field mathematical model of hearth bottom was established and the effects of abnormal expansion, normal thermal expansion of lining bricks, thickness of bottom sealing plate, expansion joint and refractory cushion mortar on upturned height of bottom sealing plate were analyzed. Because of the abnormal expansion of lining bricks, big upward pressure at the tuyere combined bricks can be generated and the bottom sealing plate would be upturned finally. However, the normal thermal expansion of lining bricks could not result in the large upturned height of bottom sealing plate. The accumulation and enrichment of harmful elements such as alkalis, zinc and plumbum might lead to abnormal expansion of bricks and the upturning of bottom sealing plate. It can mitigate the transformation of bottom sealing plate with increasing thickness of bottom sealing plate. The appropriate expansion joint and good refractory cushion mortar can absorb the thermal expansion, but it can’t solve the large abnormal expansion. In order to restrain and reduce the phenomena of upturned bottom sealing plate, the enough expansion gap should be needed at the tuyere combined bricks and the front of tuyere-cooler casing should not be deep into the lining bricks. And also the charging amount of harmful elements should be controlled strictly and the discharging ability of harmful elements needs to be improved.