Micro Semi‐solid Manufacturing ‐ A New Technological Approach towards Miniaturisation

One of the most important prerequisites to meet the increasing demand for efficient technologies for micro‐part production is constituted by the ability to overcome existing process limitations by new innovative technological approaches. By the introduction of a new process variant based on a hybrid material condition between solid and liquid state, such an approach is presented. This micro semi‐solid manufacturing technology, so‐called Micro‐Thixoforming, was initiated, on the one hand, by being aware of the technological limits of existing micro‐forming and micro‐casting processes and, on the other hand, by a comprehensive understanding of the special rheological mechanisms of metallic materials in semi‐solid state finally establishing the desired potential to follow the trend towards miniaturisation with drastically reduced process restrictions. However, this promising potential can only be successfully exploited when the initial idea, which is based on phenomenological considerations, can be transferred to a process technology with sufficient practical relevance. Therefore, the presented new integrated process concept for Micro‐Thixoforming is particularly characterised by the application of unconventional solutions for the main process steps: raw material conditioning, thermal pre‐processing, semi‐solid forming and thermal post‐processing. To give an indication of the innovative character of the chosen practical solutions liquid metal jet technology, LASER‐induced plasma shockwaves and high pressure water jet should be mentioned. However, what is even more important in this context is the ability not only to realise a process concept but, beyond that, to recognise the further potential regarding new strategies for material design arising from the availability of this process. Such a strategy e.g. consists of utilising the well‐known segregation effect, which notably often is negatively associated with semi‐solid forming. However, for the envisaged technological approach, controlled segregation aims at a defined adjustment of functionally graded properties for the produced micro part.     

Development of New Combined Manufacturing Technologies ‐ Influence of the Cutting Process on Workpiece Properties

Properties of materials for high‐strength structure components are influenced by production processes. These influences can be augmented by a combination of two presently consecutively executed process steps. The presented work shows first results in the development of novel combined manufacturing technologies, which along with prospective tools use this effect to adjust the material properties locally, adapted to the requirements. The combination consists of a merging of the process steps ‘material separation’ (metal cutting) and ‘changing properties’ (rubbing, rolling) to one single process step. For this purpose novel combined tools have to be developed. For the estimation of the possibilities of properties changes by combined processes at first the influences of single processes have to be determined. This contribution presents results of a “material separation” process. The investigated material is the industrially important aluminium wrought alloy AI7075‐T6, the applied process is orthogonal turning, the process parameters varied are cutting speed and feed as well as the tool geometry. Cutting force and feed force are measured, and the process influences on surface and subsurface properties are determined.     

回转窑焙烧蒸硒工艺优化实践

介绍了贵溪冶炼厂阳极泥回转窑蒸硒工艺及存在的问题 ,提出优化方案 ,实践中取得了良好的效果     

镍红土矿RKEF法工艺进展

介绍了世界先进的镍红土矿火法冶炼RKEF法,对其工艺流程进行了详细的说明,对电炉和回转窑等主要设备的作用、工作原理进行了分析,以世界范围内先进RKEF法工厂的操作参数为依据对电炉和回转窑的现状和发展进行了分析.还对近年来出现的新熔炼工艺进行了探讨.     

Evaluation of a New Process for Ironmaking: a Productivity Model for the Rotary Hearth Furnace

In order to address the key issues of capital costs and CO₂ emissions in ironmaking operations, a new process was proposed combining a Rotary Hearth Furnace (RHF) and a Bath Smelter. This paper describes the construction of a productivity model for the RHF based on previous studies concerning the reduction behaviour of pellets of carbon and iron oxides. The model was used to estimate changes in RHF productivity according to the type of carbon used in the RHF pellets, numbers of layers of pellets, final metallization degree of the direct reduced iron (DRI) produced, and initial sizes of the pellets. The results indicate that productivity gains between 33 and 46% can be achieved replacing coal with wood charcoal, a carbon source virtually free of net CO₂ emissions. Also, the productivity of the RHF can be doubled by reducing the charge only up to 70% metallization. The model allows the study of changes in overall energy consumption due to changes in the extent of primary oxidation of the gas at the pellet level showing that the use of wood charcoal increases the total amount of carbon consumed by less than five percent relative to operations with coal.     

危险废物回转窑焚烧炉的工艺设计

结合工程的实际经验数据，给出了在确定危险废物回转窑焚烧炉的主要参数设计时应注意的问题。     

危险废物回转窑焚烧炉的工艺设计

结合工程的实际经验数据,给出了在确定危险废物回转窑焚烧炉的主要参数设计时应注意的问题。     

闪速炉预分散下料偏析模型实验的研究

在模型实验台上,选取了河沙和精矿粉对闪速炉预分散部位进行下料模拟实验。使用高速摄影仪拍摄物料在下料溜管与分布器通道内的流动情况,定性地分析了偏析程度;对筛分称重后的数据进行处理,定量地分析了偏析程度。实验结果表明:溜管与分布器通道交角处有很多颗粒,而接近通道外周圆几乎没有颗粒,存在明显的径向偏析和局部偏析;颗粒垂直碰撞通道隔板,存在明显的周向偏析;随着投料量的增大,周向和局部偏析增大,径向偏析的变化不明显。     

回转窑试生产过程中安全系统的完善

针对炭素回转窑试生产过程中发现的由于安全系统不完善而出现的故障现象,及时采取了相应处理方法,使重新投入运行的回转窑达到了设计产能,消除了煅烧系统的安全隐患。对以后回转窑的改造和新建提出了更高的设计要求。     

石煤旋窑焙烧工艺研究

目前的从石煤中提取钒的工艺普遍存在钒转化率低且不稳定的特点.对不同类型矿石进行了多因素旋窑焙烧条件试验,考察了添加剂的加入对钒焙烧转化率的影响.结果表明,矿石在旋窑中于800 ℃下焙烧2 h后,用4 g/L硫酸溶液在液固体积质量比3∶1条件下浸出,钒浸出率最高可达85%,并且可实现连续作业,烟气集中处理,改变了平窑焙烧不能连续作业及烟气无序排放难于处理的状况,对环境非常有利.     

转底炉工艺系统基本化学反应的热力学分析

转底炉工艺是直接还原中煤基还原的一种,其内部的热力学反应主要包括含碳球团的自还原反应、含碳球团与氧化性气体间的氧化反应、含碳球团的脱碳反应、含碳球团排出气体的燃烧反应及喷吹焦炉煤气对直接还原的影响等5个部分。对转底炉内部温度、气氛、配煤比的控制,是转底炉直接还原工艺的关键。     

回转式精炼炉炉口砌筑工艺改进

针对葫芦岛东方铜业有限公司120吨回转式精炼炉口出现炉口掉砖问题，对耐火材料及其砌筑工艺进行探讨和改进。     

基于热工及工艺参数的回转窑测温模型应用

工业生产过程中,回转窑的温度直接影响物料的煅烧质量,选择准确、实用的回转窑实时在线测温方法对保证回转窑正常生产有着重要意义。本文提出一种基于热工及工艺参数的回转窑测温数学建模方法,获得窑内温度。并通过在工业现场的大量实验,验证了模型的正确性及可行性。     

钢铁厂含锌尘泥转底炉炼铁工艺设计研究

因为环保和市场的需要,转底炉处理钢铁厂含铁尘泥及废弃物技术正在国内呈现出蓬勃的生命力。目前,国内已有多条转底炉直接还原生产线投入运行,转底炉技术能直接利用废弃粉尘中的碳还原氧化铁和氧化锌,金属化率达到70%,脱锌率达到80%,有效的解决了钢铁企业含锌粉尘的回收和利用。     

回转窑关键部件大型简体加工工艺设计

回转窑是一种大型圆筒类回转设备,简体是回转窑的重要组成部件,本文着重论述了回转窑简体在下料、钢板预处理、简体拼接、焊缝质量卷制、坡口设计、简体加工等方面关键部位的工艺保障措施,选择先进的新工艺、新方法解决回转窑生产过程中的技术难题,为回转窑的顺利生产提供了有效的技术支持和保障。     

摆辗机力能参数研究

介绍了摆动辗压工艺原理及基本特征。通过对摆辗力的实测实验找出摆辗力的分布规律。并根据此实验分析摆动辗压变形的两个阶段及摆辗力的分布特征，为今后摆辗机的理沦研究和结构设计提供依据。     

脱污剂CaO的回转炉蒸汽活化实验研究

在回转炉中通入蒸汽,研究了CaO在回转炉内的活化情况.研究表明,在蒸汽的作用下,对活化脱污剂的比表面积和比孔容积有一定改善.在450～650℃温度范围内,650℃蒸汽处理,样品累积比孔容积最大,比表面积最大,平均孔径减小.利用经过活化的脱污剂处理垃圾焚烧的烟气,期望能够吸附其中的二恶英等固态污染物;另一方面有利于回转炉蒸汽活化技术实现工业化.     

大型环形加热炉的设计

介绍了国内某无缝钢管集团258mm无缝钢管热连轧工程配套大型环形加热炉的设计特点,从设计计算、炉型结构、供热分配、燃烧系统、砌筑材料和节能降耗等方面探讨了大型环形加热炉的最优化设计方案。其中的一些设计特点和观念对以后类似工程有着重要的借鉴意义。     

回转窑基础大体积砼施工新技术

介绍直接还原铁回转窑基础大体积砼采用空腹结构的施工新技术温度应力分析、施工方法、防裂措施。