Academic literature on the topic 'Furnace slag-detection'

The refining process was investigated, it is the refining process about 100t LF refining furnace of an iron and steel group company, the refining effect was researched and systematic analyzed, by Through systematic sampling and detection to composition, slag, gas and inclusion of different refining period on LF furnace, the measures of process improvement have been proposed, to Optimization of production process and improve the quality of products.

The preparation in the jet mill of finely ground slag (FGS) from the waste of metallurgical production granulated blast-furnace slag, the obtaining of slag suspensions, and the behavior of FGS particles in an aqueous dispersion medium are considered in the paper. It was found that FGS particles in the suspension form micelles of two types with negative (micelle 1) and positive (micelle 2) charges of FGS surface. To increase the aggregative and sedimentation stability of FGS particles in suspensions, studies were carried out using ultrasonic dispersion. The results of investigations on the detection of optimal dispersion parameters for slag suspensions are presented. It was found that in the absence of temperature control, the process of coagulation of slag particles is accelerated and aggregative and sedimentation stability of suspensions of FGS is reduced. The slag particles in the suspension form aggregates that lead to a deterioration of the strength characteristics of the cement stone using suspensions of FGS. Optimal parameters of ultrasonic dispersion of slag suspensions are established: the frequency of ultrasonic vibrations is equal to 44 kHz; the dispersion temperature is 25 ± 2 °C; the dispersion time is 15 min. It was found that the application of ultrasonic dispersion to slag suspensions with the observance of dispersion conditions can increase the aggregative and sedimentation stability of FGS suspension by 2-3 times in comparison with the mechanical mixing of suspensions. The strength of samples with suspensions of FGS prepared using UST under the recommended dispersing conditions increased by 19 to 39% in the first day; for 28 days of hardening - by 19 - 36%, which allows using slag suspensions in the production of cement composite materials and concretes based on them.

Abstract The 5-day sodium carbonate-ammonium nitrate extraction assay (5-day method) has been recognized by the American Association of Plant Food Control Officials as a validated test method to identify fertilizers or beneficial substances that provide plant-available silicon (Si). The test method used the molybdenum blue colorimetric assay to quantify percentage Si; however, laboratories may use inductively coupled plasma optical emission spectroscopy (ICP-OES) for elemental analysis. To examine the use of either colorimetric or ICP-OES methods for Si determination, the 5-day method was performed on the following Si-containing compounds; wollastonite, sand, biochar, and a basic oven furnace (BOF) slag. Grow-out studies using Zinnia elegans were also performed using varying rates of the wollastonite, biochar, and BOF slag. Our results show using the 5-day method, wollastonite had the highest extracted amounts of silicic acid (H4SiO4) at 4% followed by biochar (2%), BOF slag (1%), and sand (0%). Extraction values calculated using either the molybdenum blue colorimetric assay or ICP-OES for detection of the H4SiO4 had a significant correlation, supporting the application of either detection method for this type of analysis. However, when extracted values were compared to amounts of Si taken up by the plants, the 5-day method overestimated both wollastonite and biochar. While this method is a valid indicator test for determining a soluble Si source, other plant species and methods should be perused to potentially provide more quantitative analyses for plant-available Si content of all materials.

This paper discusses the influence of fiber reinforcement on the properties of geopolymer concrete composites, based on fly ash, ground granulated blast furnace slag and metakaolin. Traditional concrete composites are brittle in nature due to low tensile strength. The inclusion of fibrous material alters brittle behavior of concrete along with a significant improvement in mechanical properties i.e., toughness, strain and flexural strength. Ordinary Portland cement (OPC) is mainly used as a binding agent in concrete composites. However, current environmental awareness promotes the use of alternative binders i.e., geopolymers, to replace OPC because in OPC production, significant quantity of CO2 is released that creates environmental pollution. Geopolymer concrete composites have been characterized using a wide range of analytical tools including scanning electron microscopy (SEM) and elemental detection X-ray spectroscopy (EDX). Insight into the physicochemical behavior of geopolymers, their constituents and reinforcement with natural polymeric fibers for the making of concrete composites has been gained. Focus has been given to the use of sisal, jute, basalt and glass fibers.

In addition to the desired plasticizing effect, superplasticizers used in high and ultra-high performance concretes (UHPC) influence the chemical system of the pastes and for example retardation of the cement hydration occurs. Thus, superplasticizers have to be chosen wisely for every material composition and application. To investigate the essential adsorption of these polymers to particle surfaces in-situ to overcome several practical challenges of superplasticizer research, fluorescence microscopy is useful. In order to make the superplasticizer polymers visible for this microscopic approach, they are stained with fluorescence dyes prior the experiment. In this work, the application of this method in terms of retardation and rheological properties of sample systems is presented. The hydration of tricalcium oxy silicate (C3S) in combination with different polycarboxylate ether superplasticizers is observed by fluorescence microscopy and calorimetry. Both methods can identify the retarding effect, depending on the superplasticizer’s chemical composition. On the other hand, the influence of the superplasticizers on the slump of a ground granulated blast furnace slag/cement paste is correlated to fluorescence microscopic adsorption results. The prediction of the efficiency by microscopic adsorption analysis succeeds roughly. At last, the possibility of high-resolution imaging via confocal laser scanning microscopy is presented, which enables the detection of early hydrates and their interaction with the superplasticizers.

Caricin Grad, Justiniana Prima, urban planning, fortification, settlement, aerial photography, geophysical surveys, LiDAR, photogrammetry, excavations, GIS. Thanks to the application of modern non-destructive sensing and detection methods, in recent years a series of new data on urban planning in Caricin Grad was obtained. For the most part, the current research programme studies the Upper Town?s northern plateau, wooded until recently and hence the only previously unexplored unit of the city. In the course of this programme, the classical research method - the excavations started in 2009 - is for the first time combined with the systematic application of airborne and terrestrial sensing and detection techniques. The analysis of historic aerial photographs and topographic plans proved to be very useful as well. Along with them, LiDAR-derived DTMs, photogrammetric DEMs, different geophysical and orthophotographic plans are stored in the GIS database for Caricin Grad and the Leskovac Basin. In this way almost 80 percent of the plateau area was defined, and the obtained plan is hypothetical only to a small extent, which particularly refers to the unexcavated northern rampart of the Upper Town. Each source provided relevant information for the reconstruction of both the rampart and the settlement, which points to the value of a holistic approach to documentation from various dates. The first source to be studied were archival aerial photographs of Caricin Grad from 1938 and 1947 (Figs. 1, 2.1). The latter one was originally processed by Aleksandar Deroko and Svetozar Radojci}, who drew the plan of the town after it, labelling the unexplored Upper Town?s northern plateau as ?a probable habitation area?. The route of the northern rampart was aslo rather precisely determined by the authors (Fig. 2.2). Recently, these photographs were rectified and georeferenced in the GIS. The 1938 shot reveals the position of some towers as well, and it is also indicative of the way of construction of certain buildings. From the spatial layout of whitish zones, originating from mortar scattered along the slope, it can be deduced which buildings were constructed in opus mixtum - the horreum and the so-called Building with Pillars east of it. Traces of mortar can be observed along the route of the rampart too. These archival images are particularly important because they record the topography of the site before it was filled with heaps of earth from the excavations. The topographic mappings of this area were conducted in 1981 and 2006 (Fig. 3). The first plan was drawn after an airborne stereophotogrammetric survey of Caricin Grad, and in 2006, after the wood was cut down, this whole area was surveyed with the total station, with a density of nine points per square meter. This survey also resulted in a 3D terrain model (Fig. 3.2) indicating the layout of the buildings, which was to be proved by geophysical surveys and archaeological excavations. In the course of the Serbian-French reaearch programme, in 2007 geomagnetic surveys were carried out by Alain Kermorvan of the University of Tours. Thanks to the application of this method the remains of collapsed stone structures could be observed, and in 2015, in cooperation with the Roman-Germanic Central Museum, Mainz, and the Ludwig Boltzmann Institute from Vienna, the middle and eastern parts of the plateau were scanned with GPR (Fig. 4.2). Precise plans of the buildings were obtained in the areas in which LiDAR scanning and photogrammetric and geomagnetic surveys failed to produce clear images. Within the framework of the ArchaeoLandscapes Europe project, in 2011 we managed to organise an airborne LiDAR survey of the wider area of Caricin Grad. With its density of some 20 points per square meter, this scanning proved to be crucial for our comprehension of the town. The standard DTM provided numerous important data, especially its version calculated in the focal statistics function of the ArcGIS software package (Fig. 5. 1-2). These models show not only the route of the Upper Town?s northern rampart, the position of its towers and the layout of the buildings, but also the line of the Outer Town?s western rampart. Visible only in the DTM, this entirely new aspect of the Caricin Grad fortification has been attested by the excavations. Highly important plans of the town, and of the northern plateau of the Upper Town in particular, were obtained by UAV photogrammetric surveys. The first drone survey was conducted in 2014 within the scope of the same project. It resulted in a cloud with up to 1,600 points per square meter (Fig. 6.1-2). Unlike the LiDAR technology, photogrammetry cannot penetrate vegetation; therefore the preliminary clearing of the ground proved to be a most important step. After the 2015 campaign was finished, the excavation area in the Upper Town was documented again in the same manner. Regular photogrammetric surveys make possible the control of the works and reliable visual monitoring of the progress of exploration (Fig. 9). After the wood was cut down in 2006 and enormous heaps of earth from twentieth-century excavations and restoration works were carefully removed by machinery in 2008 and 2010, without disturbing the original layers of debris, wide excavations could begin. At first only the humus layer was removed from fifteen-meter squares, which was followed by technical drawing. In 2009 and 2010 we did not explore the debris or the cultural layers (Fig. 7.1-2). The additional two squares were opened and documented in the same fashion in 2011, when previously recorded buildings 11 and 15C were explored in detail, together with the part of the corridor between them where a bread oven was found. These buildings were oriented south-north, cascading along the mild slope towards the northern rampart of the Upper Town. Fragments of pithoi and carbonised fruits were found in the buildings, allowing for an economic interpretation. Judging by coinfinds, the buildings ended in fire after the year 602. Some of the buildings on the northern plateau were oriented differently, following the route of the northern rampart of the Acropolis in the east-west direction. In 2012 building 18 was excavated, leaning on the rampart. Rectangular in plan and some 12 by 7.5 meters large, it had a storey and a 7 by 5.5 meters spacious paved atrium in the west. Parallel to building 18 is building 20, the only one on the northern plateau constructed in opus mixtum. The two buildings are separated by a four-meter-wide street, running from east to west. This street, corridor 4, was partly cut in the rock. In some sections it had a substructure of fragmented debris. Building 20 has been carefully excavated for several years now. After the initial documenting, the surface layer of debris was removed, but not the collapsed structures with characteristic construction details; to the east of the building a collapsed wall was uncovered, containing as many as eight successive rows of stone and brick. Beneath these layers are the occupation ones, so far investigated only to a small extent. Building 20 is rectangular in plan, covering 25 by 12.5 meters. In its central axis there is a row of masonry pillars, dividing the building into two naves. On its western side there was a vestibule with a pair of doors matching the main entrances to the building. In the back of the vestibule, between these entrances and in axis with the pillars, there was a staircase. Adetailed analysis of these features led us to conclude that building 20 was a horreum, the first such edifice to be discovered in Caricin Grad. Taking into account the details of its ground plan, pillars, parts of collapsed walls and especially arches, it will be possible to reconstruct the original form of the horreum. Judging by the existing estimate, although somewhat rough, it was 13.5 meters high. It could be observed that in its later phases the horreum was partitioned into several rooms, and some of its entrances were walled up. In the vestibule only these later occupation phases were documented, as the original brick pavement was removed from its northern part. This was followed by a significant accumulation of cultural layers, which were sealed by the debris stratum. South of the horreum there is a spacious courtyard connected with the western street of the Upper Town. The Upper Town?s northern rampart has never been graphically reconstructed, despite the fact that Aleksandar Deroko and Svetozar Radojci} published its accurate (although schematic) ground plan as early as 1950 (Fig. 2.2). This part of the town has gradually been left out of the research focus, mainly due to the vegetation growth. Upon employing all the methods described above, however, it is possible to undertake such an effort. The ideal reconstruction suggested here includes the rampart route, the disposition and the form of the towers, and the possible locations of the posterns. The line of the rampart can be traced following the trenches left by the locals dismantling the walls. Only the section of the northwestern rampart in front of the western postern of the Acropolis cannot be presented, being still covered by massive earth deposits. On the other hand, the recently discovered western rampart of the Outer Town can be traced to its full length in the LiDAR-derived DTM. Its form can be easily reconstructed on the basis of the results of the 2012 excavations and the section of the same rampart uncovered east of the main fortifications in 1955-56 (Fig. 8). Having studied the microtopography of the terrain, we were able to determine the position of a number of towers. They were clearly indicated by bumps, regularly distributed along the northern and northeastern sections of the rampart. The position of the tower below the Acropolis? western postern could be easily determined as well, unlike the position of the tower opposite to the horseshoe-shaped one of the Acropolis fortification. Yet, it is hard to imagine that a hundred-meter-long section of the rampart was left unprotected. The rectangular shape of the towers is suggested because almost all the towers of the town?s outer fortification were constructed in that way. On the other hand, at present we cannot exclude the possibility that some towers were different, horseshoe-shaped in plan, like the ones on the Acropolis rampart. The disposition of the towers along the northeastern rampart of the Upper Town, in the area where the northern street presumably met the fortification, is not clear. This part of the site still lies under massive heaps of earth, and even the 1938 and 1947 aerial photographs are not indicative enough in this regard. However, the tower(s) might have been erected there, not only because the eighty-meter-long stretch of the rampart would be left without protection in an opposite scenario, but because it is likely that the northern street ended in a gate, or at least a postern. It is already known that some of the posterns on the Caric in Grad fortifications were defended by towers. The average distance between the towers of the town?s main fortification extends from 20 meters on the southern to 40 meters on the western rampart of the Lower Town; in our reconstruction the average interval on the Upper Town?s northern rampart is 44 meters. Another argument is that this gate might have connected the Upper and the Outer Towns. The position of the second postern is determined thanks to a depression in the terrain following the axis of another communication route in the Upper Town, leading from corridor 4 and running towards the north along the rows of buildings. Finally, the 3.8 meter width of the rampart in the section adjoining the northern tower of the Upper Town?s eastern gate may only indicate a staircase, the last reconstructed fortification element. On the plateau stretching between the northern ramparts of the Acropolis and the Upper Town fortifications a settlement developed with its radially distributed rows of buildings cascading down the slope. In the eastern part of the plateau there is the horreum, adjoined from the east by another building - the storage called Building with Pillars. Larger than the other buildings and constructed in opus mixtum, the two buildings follow the route of the Upper Town?s northern street, all of which indicates that they belong to the initial construction phase. One should not exclude the possibility that this part of the town was originally conceived as an economic district with storages and similar edifices. By all appearances, the original concept was soon abandoned. Already at the time of Justinian a settlement of numerous smaller buildings was created. With their walls of stone and wattle and daub, the buildings were roofed with tiles. Yet one should underscore that this construction phase, although less sophisticated than the first one, was accomplished according to a previously prepared plan; the spread of the buildings speaks to that effect. Shortly afterwards, if not at the same time, buildings were erected along the outer face of the Acropolis rampart - a clear indication of abandoning urban planning (Fig. 9). Public space was turned into private, in spite of the legal proscriptions of that time. During the last phase of the town?s life the buildings described, whether public or private, were partitioned into small rooms, often with fireplaces and with some of their entrances walled up. Just like the edifices constructed in opus mixtum, some of the more modest buildings from the second construction phase were used to store food - namely buildings 11 and 15C. The plan of this part of the site points to an organised settlement, most probably inhabited by persons servicing a significant clergy and administration. On the other hand, except for some houses - such as building 18 - small buildings along the Acropolis fortification, facing the main street, corridor 4, might have served as shops and workshops. Traces of furnaces, slag and bone working were also encountered in this area. The parallel application of classical research methods and modern techniques of sensing and detection enabled the reconstruction of the northern rampart and the urban matrix of the Upper Town?s northern plateau. Until recently among the least known parts of the town, this unit can now be regarded as one of the best defined. This is important not only for our understanding of Caricin Grad (Justiniana Prima), but also for the study of Early Byzantine urban planning in general.

Image segmentation through neural networks and deep learning have, in the recent decade, become a successful tool for automated decision-making. For Luossavaara-Kiirunavaara Aktiebolag (LKAB), this means identifying the amount of slag inside a furnace through computer vision.  There are many prominent convolutional neural network architectures in the literature, and this thesis explores two: a modified U-Net and the PSPNet. The architectures were combined with three loss functions and three class weighting schemes resulting in 18 model configurations that were evaluated and compared. This thesis also explores transfer learning techniques for neural networks tasked with identifying slag in images from inside a furnace. The benefit of transfer learning is that the network can learn to find features from already labeled data of another context. Finally, the thesis explored how temporal information could be utilised by adding an LSTM layer to a model taking pairs of images as input, instead of one. The results show (1) that the PSPNet outperformed the U-Net for all tested configurations in all relevant metrics, (2) that the model is able to find more complex features while converging quicker by using transfer learning, and (3) that utilising temporal information reduced the variance of the predictions, and that the modified PSPNet using an LSTM layer showed promise in handling images with outlying characteristics.

碩士
國立中興大學
土木工程學系所
104
Because the lacks of environmental awareness in Taiwan, domestic waste disposal were almost buried under ground, it can also be funded in steel industry wastes. Under erosion after heavy rain, the steel industry waste material of Electric Arc Furnace (EAF) slag from underground may mix into the natural aggregates. In addition, the aggregate manufacturers would mix the EAF slag into the fine aggregates due to cost down. The EAF slag disadvantages the quality of fine aggregates. When the concrete mixes these kinds of imperfect goods, not only the appearance of the structure will be damaged but also be facing a huge penalty. This research is aimed to investigate the fast detected method of EAF slag that mixed in fine aggregates. Three methods were checked in this study, includes pH test, magnetic test and the digital electronic magnifier distinguished. When the fine aggregate arrives at the plant, fast detected before the concrete batching can easily find out whether the fine aggregates were unsuitable. On the other hand, through a fast mortar expansion test and compression test of mortar specimens, the mortar deterioration caused by the expansion of slag was observed. The result shows that the critical value of the pH of natural aggregates in Taiwan is 9.5 and the critical weight ratio of magnetic test is 1%. Fast detected method was not proper to be carried out on import aggregate of China due to the high level of alkalinity and metallic content. This research establishes a series of photos to help distinguish the source of fine aggregate. With a SOP method of this study suggested, the quality affected of fine aggregates caused by EAF slag can be easily tested within 3 hours, ensuring the quality control of fine aggregates.