Mathematical simulation of burden distribution in COREX 3000 shaft by discrete element method

The distribution of reducing gas in a shaft furnace dominates the temperature profile,gas utilization ratio,metallization degree and is the overwhelming factor for stable,high productivities and low-energy-consumption operation.At the same time,the distribution of gas flow is mainly determined by the position of gas inlet,the packed bed porosity distribution as well as its change due to the difference on the mode of top charge and bottom discharge.When injecting position of the process is fixed,the charg...     

Quick qualitative analysis of PCDD/Fs from the iron ore sintering process

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GC-TOFMS)was applied to the quick qualitative analysis of 17 types of polychlorinated dibenzo-p-dioxins and furans(PCDD/Fs)from the iron ore sintering process.The GC×GC-TOFMS parameters were evaluated and optimized to yield a complete separation for the 17 types of PCCD/Fs from interference and to the attainment of high sensitivity.After optimization,all the 17 types of PCCD/Fs were separated within 42.5 min.Th...     

Level and potential of cleaner production in Baosteel's sintering process

It is necessary for the sintering process to carry out cleaner production,which is also of great significance to the iron and steel enterprises of a long-flow process.According to the cleaner production standard recently issued by China's Ministry of Environmental Protection,the research detailed in this study has analyzed and estimated the level of cleaner production at Baosteel in the aspects of technical equipment,resource and energy utilization,product quality,emissions,recycling and environmental manag...     

Study on strip buckling in continuous annealing lines/hot galvanizing

In continuous annealing lines/hot galvanizing,strips are guided by upper and lower rolls in an alternate up and down vertical motion.This kind of process consisting of heating,soaking,and cooling furnaces(or zones) has several advantages in terms of productivity and product quality.Main problems encountered in continuous annealing lines are misguiding and formation of buckling.The strip buckling causes the strip to be rejected and,in the worst case,the strip breaks and the continuous annealing lines are ...     

铜绿山铜铁矿大直径深孔采矿技术试验研究

铜绿山铜铁矿采用大直径深孔采矿方法(VCR法)开采。多年来采场跨塌频繁,严重地影响了生产,并带来很大的采矿贫化损失。调查表明,岩性变差与凿岩爆破工艺不合理是采场跨塌的主要诱因。为此,将VCR法爆破改为后退式分段侧向多排微差控制爆破,并在不稳固地段和采场边孔采用不耦合装药方式实行减弱装药。对孔内爆轰波的试验研究表明,不耦合条状药包爆破的爆轰波传播距离可达6m以上,无需增加起爆弹可直接起爆下一分段的药包。为此将弱间隔的2段药包,合并为1段起爆。该法简化了装药结构,方便了减弱装药措施的实施。另外,为减少爆尘、减轻炮泥搬运负担,试验采用了水封爆破。该工艺在7313采场经过1a多的试验,获得了预期满意的效果,随后在全矿类似矿体推广应用,解决了矿山多年来因采场跨塌带来的负面影响。     

某商用车动力总成悬置系统隔振性能优化

为提升某商用车动力总成悬置系统的隔振性能,在试验获得某商用车动力总成惯性参数的基础上,利用能量解耦法计算获得了该系统的固有频率及各阶频率的能量分布,并针对其计算结果所表现出来的问题,运用Matlab编写程序对后悬置刚度进行了优化,获得了该悬置的理想刚度值,最后对新悬置系统的频率分布及解耦率进行了理论计算.计算结果表明:...     

厌氧消化泡沫形成的影响因素探究

针对污水处理厂厌氧消化工艺中易形成泡沫的问题,本文综述了厌氧消化泡沫形成影响因素的最新研究进展,阐述了表面活性剂、丝状菌、温度、有机负荷、搅拌和消化池构型等对于厌氧消化工艺中泡沫形成的影响。其中,表面活性介质累积、丝状菌过度增殖、温度波动、有机负荷过高、搅拌方式欠佳以及消化池构型差异,均能诱发厌氧消化池中泡沫的形成。为有效预防和控制厌氧消化工艺中泡沫形成,本文提出具体措施的同时并对其今后的研究方向进行了展望。通过温度、有机负荷、搅拌效率等参数调控监测,减少温度波动和表面活性物质积累,保持消化池混合适度等,可以针对性地控制厌氧泡沫的形成,提高厌氧消化工艺效率,降低厌氧工艺处理成本。此外指出,探明各影响因素诱发泡沫的机理以及各因素之间交叉作用对于厌氧泡沫形成的影响,同时研发新构型消化池,具有重要的理论和实用价值。     

70Cr3Mo钢支承辊超探不合格原因分析及改进措施

制造44800和19500 kg的两根70Cr3Mo钢支承辊大锻件。钢锭采用EAF+LF+VD+VC冶炼浇注,1锭锻制2件,锻后球化退火,出炉冷却后,毛坯进行超声波探伤检查。结果发现:小辊超探合格踩线,大辊在冒口端辊颈部分存在超标缺陷。为了探究锻造工艺合理性,切掉大辊两端辊颈部分,利用辊身合格的坯料改锻成小辊。改锻后的小辊经超声波探伤发现,除辊身外两端辊颈部分均存在超标密集缺陷。通过一系列试验,对孔洞缺陷和夹杂物进行了分析,确定了导致支承辊超探不合格的原因:铸锭缺陷中广泛分布的非金属夹杂物分割了钢基体的连续性,恶化了钢的性能,导致超探不合格。此外,分析了夹杂物的来源及其危害性,并提出了相应的工艺改进措施。     

基于SPSS的采煤工作面瓦斯涌出量预测模型研究

为了对矿井采煤工作面瓦斯涌出量进行有效预测,结合影响工作面瓦斯涌出量的各个因素,针对各因素间存在严重的多重共线性引起算法计算误差放大的问题,采用逐步回归算法进行优化。运用SPSS软件,综合多元主成分回归分析算法得出采煤工作面瓦斯涌出的主要影响因素,并建立PCR-SPA预测模型。将该模型的预测性能与多元线性回归预测、灰色关联度分析预测、BP神经网络预测结果进行对比分析。结果表明：该模型选取了三个主成分变量,有效地减少了计算量,具有较高的预测精度,可以对矿井工作面瓦斯涌出量进行有效预测。     

Effect of deformation twinning on the evolution of texture in TWIP steels during cold-rolling

Texture evolution of high-manganese twining-induced plasticity (TWIP) steels (Fe-16Mn-0.6C) during cold-rolling is studied by means of quantitative orientation distribution function (ODF)analysis.Thickness reductions of the specimens during cold-rolling are 10%,20%,30%,50% and 65%,respectively.Evolution of texture is of the Brass type,which is typical for low-stacking fault energy (SFE) materials.The contribution of deformation twinning to the development of texture is clearly illustrated by the monotonic increase of the twinned Cu component.In the present study,the deformation twinning was identified as significantly contributing to deformation up to the maximum reduction applied.These results are useful for the prediction and control of the texture in TWIP steels.