合理的转炉废钢比探析

针对八钢铁水供应不足且铁水成分波动较大的问题,文中在现场冶炼数据采集的基础上,依据转炉冶炼的物料平衡、热平衡以及现场试验,研究了铁水成分、铁水重量、铁水温度、出钢温度以及留渣操作等工艺参数对废钢加入量的影响.通过采用留渣操作、适当提高铁水温度、减少辅料消耗以及适当降低转炉出钢温度等措施,转炉废钢比由16.4%提高到21.3%,脱磷率由79.3%提高到93.3%,同时石灰和白云石消耗量分别降低了3.3 kg/t钢和6.7 kg/t钢.      

废钢比对转炉钢液过氧化的影响及配料调优

转炉终点钢液过氧化不仅会造成合金收得率降低，冶炼成本增加，还会导致脱氧产物增多，钢液洁净度变差。因此，避免转炉终点钢液过氧化一直是工艺控制的重点。针对国内某特钢厂100 t转炉终点钢液过氧化严重的问题，本文通过数据统计发现，该厂平均废钢比高达26%，平均终点C含量仅有0.055%，平均终点温度为1 605℃。在未考虑炉内热平衡的前提下，采取高废钢配料导致了炉内热量不足，从而被迫采取补吹升温，引发终点碳、温度命中率低以及钢液过氧化现象。因此，本文基于该厂的原料条件，从优化炉料结构的维度出发，建立了最大废钢比计算模型，综合考虑原料条件来配加废钢，减少了需要补吹升温的炉次。模型应用后，转炉终点温度平均提高10℃，终点碳含量平均提高0.036%，钢液自由氧含量平均下降206.3×10^-6，降本提质效果显著。     

提高转炉废钢比实践

鞍钢集团朝阳钢铁有限公司炼钢厂为了保证转炉钢产量,采取了降低转炉造渣材料消耗、降低转炉出钢温度、提高铁水"一罐制"比例等措施。采取措施后,转炉废钢比由13.0%提高到21.5%,铁水单耗降低了60 kg/t。实践表明,当转炉铁水单耗为880 kg/t时,炼钢利润最佳。     

转炉底吹模型优化

研究了不同底吹强度对转炉终点w[C]w[O]积、炉渣w(TFe)、钢铁料消耗的影响关系,通过提高转炉底吹强度、改善熔池搅拌促进碳氧反应平衡、降低转炉终点碳氧积的效果,实现降低过钢钢水总氧、炉渣中w(TFe)、钢铁料目标。结果表明,转炉底吹强度由0.037 m³/(t·min)提高到0.06 m³/(t·min)后,实际生产过程中,转炉终点w(O)由713×10^-6降低到456×10^-6,转炉终点碳氧积由0.29×10^-6下降到0.26×10^-6,转炉渣中w(TFe)由27.21%降低到16.58%,钢铁料消耗降低1.78 kg/t。     

转炉炼钢废钢质量控制及结构优化

控制废钢质量、优化废钢结构有利于降低炼钢生产成本,减少环境污染,对转炉炼钢生产具有重要意义。通过理论计算和熔化试验,研究了不同废钢与转炉物料消耗及渣量之间的关系。结果表明,废钢质量对转炉钢铁料消耗和炉渣量具有显著影响。当转炉废钢比为20%时,废钢中杂质质量分数增加6%,钢铁料消耗量增加约为23 kg/t,带入渣量增加约为71.4 kg;锰的质量分数增加1%,产生钢水量约减少12.4 kg。质量较好的废钢带入转炉杂质少,利于降低钢铁料消耗和炉渣量;转炉中大量使用溢渣粉等废钢会引起钢铁料消耗和炉渣量显著增加。在此基础上,利用某企业120 t转炉进行废钢结构优化试验,研究了采用不同废钢配比冶炼对钢铁料消耗、炉渣量、终点磷含量和终点碳含量的影响。发现在该企业实际生产条件下,最优废钢配比(质量分数)为重型废钢33.3%、钢筋头16.7%、普通生铁26.7%、硫钢块6.7%和溢渣物16.6%。当120 t转炉采用最优废钢配比冶炼时,平均钢铁料消耗为1 052.9 kg/t,平均炉渣量为108.7 kg/t,冶炼铁损小;且转炉终点钢水平均w([P])、w([C])分别为0.030%、0.106%,满...     

150 t EAF-LF-VD-CC流程生产超低硫钢的工艺实践

生产超低硫0.20%～0.24%C钢时,在150 t EAF的炉料为40%铁水+优质低硫废钢,终点[C]0.03%～0.05%,电弧炉出钢平均[S]为0.046%,LF初始平均[S]为0.017%的条件下,控制精炼终点[O]≤2.5 X10^-6,终点(FeO+MnO)≤O.80%,控制渣量不小于22 kg/t_钢,铝消耗量1.85 kg/t_钢,氩气搅拌良好,成品钢中的硫含量≤0.001%。     

100t 转炉炉衬侵蚀因素的分析和长寿炉龄的工艺实践

通过分析了水钢100 t顶底复吹转炉炉衬的损坏机理和影响炉渣熔化性能的因素,得出每1%V₂O₅降低炉渣熔化温度27℃,每增加1%TiO₂含量,炉渣半球温度约降低5℃,当炉渣TFe含量在20%以上时,炉渣熔化温度在1 320~1 395℃。通过采取铁水捞渣工艺;建立转炉热平衡操作模式,提高拉碳率;铁水Si在0.6%~0.8%时,采用单渣操作,铁水Si>0.8%时,采用双渣操作;建立转炉最佳炉型及控制措施;优化钢水温度制度和优化脱氧合金化制度,降低出钢温度;在补吹提枪前加入适量焦丁,确保冶炼终点炉渣中FeO保持较低含量,提高溅渣护炉效果等工艺措施,结果使转炉炼钢的耐火材料消耗降到8.75 kg/t钢,转炉炉龄达到29 336炉。     

转炉半钢炼钢提高废钢比的工艺研究与应用

半钢炼钢条件下,以转炉炼钢物料平衡和热平衡为理论依据,制定出以焦丁为辅助热源的钢铁料新配比。通过试验证明,使用焦丁作为补热剂,在半钢条件稳定的前提下,1 t焦丁代替废钢4.93 t,并可降低石灰消耗2.06 kg/t,在保证终点技术指标得同时,废钢比(质量分数)由7.05%提高至13.54%,铁水消耗降低了40 kg/t,实现了降低钢铁料成本的目的。     

转炉炼钢工艺极限碳排放研究进展

中国钢铁行业发展取得长足进步,年钢产量连续多年位居全球第一,由此带来的CO₂排放等环保压力也日益凸显。降低钢铁行业CO₂排放至关重要。长流程炼钢工艺的吨钢CO₂排放量约为短流程炼钢工艺的3.5倍,如何降低长流程炼钢碳排放对钢铁工业的低碳发展具有重要意义。提出转炉炼钢极限碳排放工艺技术,从“低碳铁水”、“低碳冶炼”和“低碳原料”3个方面,研究分析长流程-转炉炼钢工艺的减排能力及潜力。在低碳铁水生产方面,依据现有可能实现的技术,铁水生产的碳排可由当前吨铁水碳排1.7 t/t降低至0.8 t/t;在低碳原料方面,转炉炼钢工序生产所需原辅料极限碳排放可由当前吨钢碳排197.5 kg/t降至61.7 kg/t;转炉炼钢工序采用低碳冶炼单元技术,吨钢碳排将显著下降,转炉采用20%废钢和50%废钢,吨钢极限碳排将降低至727 kg/t和466 kg/t。转炉炼钢工序使用50%废钢冶炼,喷吹生物质、采用绿电、低碳原料,转炉工序碳排放强度将从107 kg/t降至-186 kg/t,实现转炉工序“负碳炼钢”;精炼、连铸等工序着眼绿色低碳技术...     

马钢120 t转炉冶炼深脱硫铁水的冶金效果

马钢120 t转炉冶炼洁净钢时,采用≤0,002%S深脱硫铁水、冷料比17%,使用[S]≤0.020%低硫优质废钢,应用烟气分析动态控制技术,转炉终渣碱度3.2～3.5,出钢过程加活性灰600 kg,使终点[S]≤0.008%,提高了终点[C]和温度的命中率,终点钢水活性氧为556×10^-6,吹损喷溅下降,石灰等散装料消耗为≤90 kg/t,钢铁料消耗≤1104 kg/t。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

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。     

Results of treatment of cancer of the cardia

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.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

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)     

Comparison of rates of infection of two methods of emergency ventricular drainage

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.     

浅析《野草》的版画特征

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".     

四辊破碎机车刀架的改造

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。     

Effect of antibiotics of chemotaxis of human leukocytes

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.