【作者】 康健；

【导师】 陈敏；

【作者基本信息】 东北大学 ， 钢铁冶金， 2008， 硕士

【摘要】 随着洁净钢需求的不断增加和人们对环境保护问题的关注,工业生产对引流砂使用性能的要求不断提高,不仅要求引流砂能使钢包自动开浇,还应减少引流砂带进的成分对中间包冶金过程的不利影响,对环境污染小。优质的引流砂应自然流动性好、热膨胀倾向小,与钢液接触后迅速在钢-砂界面形成致密的烧结层,以防止钢液的渗透和引流砂颗粒的上浮,且烧结后的引流砂强度较低,能被钢液的静压力冲破,达到自然开浇的效果。本研究针对引流砂使用中存在的问题,以镁砂、白刚玉和钾长石及石墨为原料,并添加一定量的方解石,利用方解石分解产生CaO和CO2的特性,使引流砂在高温下能够快速烧结,形成致密烧结层,而在低温区难以烧结,有利于实现钢包顺利开浇的目的。通过考察原料组成和烧结温度及保温时间对引流砂烧结性能及烧后线变化率的影响,确定了新型碱性引流砂的优化配料组成,并得出如下结论。(1)体系中引入方解石后,在高温条件下其分解产物CaO与体系中组分发生反应,通过促进低熔点液相的生成,促进了试样烧结性能的改善。添加6mass%和15mass%方解石的试样在1500℃保温2h后,显气孔率降至4%以下。(2)添加6mass%方解石的引流砂试样与添加15mass%方解石的试样相比,具有较好的烧结性能,可以在较短的保温时间内形成致密的烧结层。(3)在1500℃保温2h时,原料中镁砂与刚玉间发生的尖晶石化反应产生的体积膨胀补偿了因方解石分解和试样烧结引起的体积收缩,因此烧成试样不仅致密度高,且烧后收缩小。添加6mass%方解石和15mass%方解石的试样的径向收缩率均小于5%,与现场使用的引流砂相比,具备更好的体积稳定性,且添加15mass%比添加6mass%方解石的配料试样径向收缩率更理想。(4)添加6mass%方解石的试样具备较快烧结速度,添加15mass%方解石的试样具有较好的体积稳定性和较高的碱度。因此,根据实际应用条件,以这两个配料组成为基础,可以开发出高碱度新型引流砂。更多还原

【Abstract】 With development of clean steel manufacturing and attention paid on environment problems, highly qualified environment friendship packing sand are required, which not only ensure the free-opening of sliding-gate system for steel ladle, but also reduce its influence on the metallurgical process in tundish. Thus, high quality packing sand, with the properties of better flowability, smaller linear change as well as the sinterability are required, so that the sintered layer could be broken by the static pressure of molten steel.In this paper, an basic packing sand for sliding-gate systems for steel ladles was developed in the laboratory, which is composed of magnesia, corundum, calcite and potassium feldspar. The calcite added to the samples was used to make the packing sand fast sinter and form a compact sintering layer in high-temperature zone, moreover, not sinter in low-temperaure zone to avail the free-opening of sliding-gate system for steel ladle. The effect of composition, sintering temperature and holding time on sintering properties of packing sand was investigated, and the ingredient of high quality packing sand was determined. The following conclusions were obtained:(1) At high temperature, the liquid phase formed by the reaction between SiO2-Al2O3-MgO system and CaO derived from the composition of calcite added to samples accelerated the samples sintering. The apparent porosity of the packing sand samples added with 6mass% and 15mass% calcite and heated at 1500℃for 2h decreased to 4% below.(2) Compared with the sample with 15mass% calcite addition, the sample with 6mass% calcite addition and heated at 1500℃for 2h had better sinterability and can form a compact sintering layer in shorter time.(3) At 1500℃holding for 2h, the volume shrinkage of sintered samples caused by decomposition of calcite and sintering of samples was compensated by expension of spinel derived from reaction between magnesia and corundum. The sintered samples had high densification and small linear change. The radius shrinkage rates of samples with 6mass% and 15mass% calcite addition were lower than 5%. Comparing with in-situ packing sand, they had better volume stability. The radius shrinkage rate of sample with 15mass% addition was better than that of one with 6mass% calcite addition.(4) The sample with 6mass% calcite addition had faster sintering velocity, and the one with 15mass% calcite addition had better volume stability and higher basicity. Consequently, the two samples can be used to develop a new kind of highly basic packing sand.更多还原