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文章介绍了电石系脱硫剂、苏打粉系脱硫剂、石灰系脱硫剂和金属镁系脱硫剂等常用的铁水预脱硫剂的脱硫机理和特点,重点阐述了镁基脱硫剂的工艺及其在包钢炼钢厂生产中的应用.包钢炼钢厂采用镁-石灰二元复合喷吹脱硫工艺,在镁粉、石灰消耗量分别为0.40 kg/t和1.60 kg/t的条件下,可将高炉铁水脱硫量降至0.012%~0.013%,脱硫率在90%以上. 相似文献
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为了降低铁水预处理成本,对铁水预处理过程参数进行优化,包括喷粉速率、喷枪插入深度等参数,并且在不影响脱硫效率的前提下,采用低CaO含量的钝化石灰粉替代高CaO含量的钝化石灰粉进行喷吹脱硫尝试。结果表明,钝化石灰粉消耗减少0.963 kg/t铁,镁粉脱硫效率提高6.9%,低CaO含量的钝化石灰粉不影响脱硫率。 相似文献
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首钢京唐采用KR进行100%全量铁水脱硫预处理,从生产布局上可以同时满足脱磷炉和脱碳炉的生产需要。为了实现KR的高效脱硫,对影响脱硫的因素进行了分析和讨论,认为脱硫剂中添加一定量的CaF2可生成一定量的共熔晶体,提高了铁水中硫元素的传输和反应速率;铁水中加入一定量的铝渣可以降低铁水中的氧活度,提高脱硫反应速度;铁水温度应控制在1300~1380℃之间,温度太高会在石灰颗粒表面形成较多的液相,造成石灰颗粒聚团,减少铁水与脱硫剂的接触面积,降低了反应速率;良好的石灰质量和搅拌头形状也有利于KR脱硫。 通过以上措施,铁水经过KR脱硫预处理后w[S]≤0.002%比例达到98%以上,转炉终点平均硫质量分数为0.005%。 相似文献
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为了获得最佳的供氧和粉剂消耗与温度的关系。国内某钢厂采用专用炉顶吹氧+喷粉搅拌脱磷工艺为AOD炉提供优质的低磷铁水冶炼不锈钢,实现了新型一步法冶炼不锈钢工艺。生产实践表明,随着喷吹钝化石灰粉和铁皮球用量的增加,脱磷率逐渐升高,当石灰喷吹量为10~12 kg/t、铁皮球消耗量为25.0~37.5 kg/t、供氧量为300~400 m3时,脱磷率在85%以上;脱磷率随着钙氧比的增大而减小,当w(CaO)/w(Fe2O3)为0.8时达到最大值,钙氧比为0.8~1.4时脱磷率大部分在85%以上,钙氧比超过1.4时效果降低。 相似文献
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通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。 相似文献
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K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients. 相似文献
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Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies. 相似文献
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鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美". 相似文献
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针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。 相似文献
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The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed. 相似文献