Syfte och frågeställning: Detta arbete syftar till att utvärdera en metod för att mäta kraftverkan kvantitativt av slag och spark med avseende på validitet och reliabilitet med målet att svara på frågan: Går det att mäta kraftverkan i slag- och sparkartekniker (genomförande av slag- eller sparkrörelse) på ett enkelt och tillgängligt sätt med god validitet och reliabilitet med den valda metoden? Metod: Detta arbete innehåller flera delar. En litteraturstudie som syftade till att få en bild över forskningsläget kring ämnet. Mätutrustning anskaffades, testutrustning och testmiljö byggdes. Därefter testades validiteten och reliabiliteten i mätutrustningen. Mätutrustningen som användes i den här studien var en vattenvattenfylld droppformad slagsäck med en sensor, Aqua Training Bag (ATB säck), som mätte kraft i slagen. För att kunna mäta validiteten i mätutrustningen användes en mätpåle. Mätpålen bestod av en träbalk med en kalibrerad mätsensor som mätte kraften vid sammanstötningen med slagsäcken. I första delen av testerna släpptes mätpålen likt en vagga (slagvagga), upphängd i taket med snören, mot fyra olika träffområden på slagsäcken. Slagvaggan släpptes från tre olika höjder mot respektive träffområde. I andra delen av testerna utdelades slag med varierande kraft med mätpålen mot ATB säcken. Fem 30 sekunders slagserier genomfördes med mätpålen. Mätvärden från slagsäcken och mätpålen jämfördes med varandra. Resultat: Resultaten visar att det finns en signifikant korrelation mellan uppmätta variablerna maxkraft och impuls från mätpålen och mätvärdena från ATB säcken. Det finns en hög positiv linjär korrelation mellan uppmätta variablerna maxkraft och impuls från mätpålen och kraften i ATB säcken. Höga värden på determinationskoefficienten visar att variationen i kraften i ATB säcken kan förklaras av ändringar i variablerna maxkraft och impuls från mätpålen. Slutsats: Efter att ha validerat metoden med en kalibrerad mätpåle går det att dra slutsatsen att det går att mäta kraftverkan i slag- och sparkartekniker med god validitet och reliabilitet med ATB säcken. Metoden är enkel och tillgänglig då det finns på kommersiella marknaden.

The main objectives of this study were to investigate (i) anovel wetland treatment technology and (ii) selected bed filtermedia for the removal of contaminants from landfill leachate. Areview of the literature concerning experiences of the use ofconstructed wetlands (CW) for the removal of nitrogen fromlandfill leachate, showed that at least three groups oftreatment systems are in practice: sub-surface flow wetlands,hybrid systems (a combination of vertical and horizontal flowwetlands) and, compact constructed wetland (CCW). Most of thesetypeswere generally effective in reducing nitrogen (N,e.g.NH4-N, dominant N species in leachate) down toeffluent concentrations of about 10 mg L-1. Unfortunately, very little evidence ofresponsible mechanisms for the removal of N was presented,although some data indicated denitrification. The treatmentperformance of a compact constructed wetland (CCW) applied atthe Tveta Landfill, Södertälje, Sweden, wasevaluated. Chemically purified leachate and untreated leachatewere applied in periods of 7 day submergence and 7 day drainageto different sections of the CCW. The removal efficiency variedbetween 40 and 82%, and a mass removal rate of up to 5.1 g m2d-1was achieved. The chemical pre-treatment had adecisive role for the highest removal efficiencies obtained andit was unclear whether that treatment enhanced the efficiencybecause of lower toxicity and/or content of fewer competingcations. The possible combination of bed filter media and CCWas an ecotechnological treatment method for landfill leachatewas investigated by bench-scale laboratory column experiments.Reactive filter media (sorbents) was selected from their knownor suggested capacities for removal of heavy metals, nitrogenand phosphorus. Quartz sand or natural sand from an esker wasused as reference medium. Peat was used as an additionalcomponent in mixtures with the reactive media Polonite®(product from the bedrock opoka) and blastfurnace slag (BFS). A small column study also involved zeolite.Phosphorus was efficiently removed by Polonite®and NH4-N to some extent. Concerning metal removal, thebest performance was found as well for Polonite®, especially for Mn, Fe, Zn and Cu. The BFSshowed good removal efficiency for Cu, Ni and Mo. The removalof different elements was suggested to be a combination ofseveral factors,e.g.precipitation, ion exchange and adsorption. Priorto full-scale application of reactive filters at a landfillsite, matrix selection, filter design and operationalprocedures must be developed. Keywords:Blast furnace slag; Compact constructedwetland; Metals; Nitrogen; Polonite; Sorbents

Phosphorus (P) in stormwater runoff has detrimental effects on water quality and ecosystem health when it reaches surface waters and promotes algal blooms. Constructed wetlands (CWs) have been utilized to combat this problem by containing stormwater and removing excess nutrients. Including filter materials in the design of CWs has shown promise for increasing their capacity for nutrient removal. This mesocosm scale study was conducted outdoors over a 12-month period to evaluate the effectiveness of three filter materials in their ability to adsorb phosphorus, retain water, and support plant life. The filter materials examined were electric arc furnace (EAF) slag, engineered biochar, and sand. All treatments demonstrated positive plant response and the ability to retain water. The EAF slag and biochar removed significant amounts of P from effluent and appear to be suitable materials for integrating into CW design. Sand was found to be ineffective as a P filter.

No description available.

<p>Recent experiment in our laboratory demonstrates that an increase in slag foamingwith carbon injection rate is limited by slag volume. The current work has identified arelationship between foam height, carbon injection rate and slag volumes, whichpredicts the critical injection rate above which foaming become inefficient. Theprediction of critical injection rate employs an extension of understanding mechanismof bubble movement in the foam by estimating average/steady-state bubble size andwall thickness. The carbon gasification model developed in our laboratory by King etal., which has been extended to include greater consideration of gas bubble burstingwhen to predict bubble size, and further improvement for calculating how fast bubblecan burst instantaneously in carbon-gas-slag halo system, has found that has importantinfluence on the predicting foaming parameters in King’s model, which is crucial taskfor continuous development in future.</p> / Master of Applied Science (MASc)

<p>The local corrosion of refractories at the slag/gas interface is a serious problem that limits the life of the refractories.Although, there have been several studies focused on understanding the Marangoni effect on the refractory dissolution process, there is little quantifiable analysis available. The aim of this study is to establish a better fundamental understanding of refractory dissolution mechanisms, and develop appropriate models for predicting the extent and rate of slag-line dissolution.</p> <p>In the first part of this research, experimental studies using a high temperature dip technique were performed: MgO refractory in SiO₂-CaO-FeO_x-MgO slag and Al₂O₃- SiO₂-CaO-FeO_x-MgO. The experiments were conducted at varies temperature. There was significant evidence of a spinel phase formed at the slag/refractory interface for slags containing 20wt.% Al₂O₃. This existence of the spinel seems to have retarded the dissolution of the refractory. The decrease in erosion rate in the presence of spinel is in proportion to the decrease in the equilibrium MgO concentration at the slag/solid interface. The activation energy is calculated from the relationship of effective mass transfer coefficient vs. temperature and found in the range of mass transfer activation energy.</p> <p>The second part of this search is developing a numerical model to predict the slag-line dissolution. An effective algorithm for analysis of unsteady Marangoni convection in refractory slag line dissolution has been developed. The results show that the Marangoni effect plays a very important role in slag-line erosion at this condition; both the moving boundary condition and curved surface condition have significant effects on the slag-line erosion rate. The comparison of experimental and numerical results shows that the model can predict the refractory maximum corrosion distance caused by Marangoni flow at the slag line. However, the eroded material volume was predicted within 20~30% deviation</p> / Doctor of Philosophy (PhD)

<p><strong> </strong></p> <p><strong> </strong></p> <p>Considerable attention has been paid to the reaction between molten iron oxide containing slag and iron droplets or solid carbon due to the critical roles it plays in various metallurgical processes. However, during the last two decades, most of the studies have been carried out on iron droplets, for which the size remains constant. Another important phenomenon, that the droplet will swell has not been paid the same attention. Knowledge of the extent of droplet swelling is essential in predicting residence times in BOF steelmaking. The objective of this study is to develop the understanding for droplet swelling and produce a predictive model that predicts droplet swelling over the range of oxygen steelmaking conditions.</p> <p>Several workers have observed swelling of high carbon droplets when exposed to oxidizing slags. In the present work, the measurements on swelling rates were made using X-ray fluoroscopy. Comparing the swelling rate with the total volume of gas evolved during the reaction, it is shown that only a small percentage of the gas generated is retained in the droplet to contribute to swelling. The gas generation rate is shown to be controlled by the rate of nucleation of CO bubbles inside the droplet. The critical supersaturation pressure for nucleation is found to be two orders of magnitude less than predicted from theory, which is in keeping with many other studies on nucleation of gases in liquids. However, the effect of surface tension, temperature and saturation pressure shows quantitative agreement with theory.</p> <p>In order to predict the droplet swelling rate, CO bubble escape rate has to be known. In this research, the escape mechanism has been proposed; it is the film rupture around the iron droplet surface. The rupture rate is mainly influenced by viscosity, surface tension and bubble size. For a given experimental condition, the calculated film thickness is 1.5 μm at the maximum drop diameter, assuming the bubble radius is 0.3 mm. The CO escape rate is 2.51 cm³/s, it agrees well with 1 to 12 cm³/s when gas escapes from steelmaking slags considering the differences of surface tensions and viscosities between metal and slag.</p> / Doctor of Philosophy (PhD)

<p>The inclusions are harmful to the steel cleanliness; process parameters such as stirring and steel and slag oxidation must be controlled to obtain a final number of inclusions in the steel whose size is smaller than the critical size for each steel product.</p> <p>A simple mathematical model was developed to analyze the impact of bubbling, slag and initial oxidation level on inclusion distribution control (quantity and size of them) during the process in a Ladle Metallurgy Furnace (LMF).</p> <p>The initial inclusion size distribution is calculated and adjusted with the samples analyzed by SEM-EDAX, this initial distribution decreases by removal mechanisms such as bubbling and slag and they can increases by reoxidation.</p> <p>The model allows predicting the inclusion removal by bubbling mechanism as a function of gas flow rate and inclusion size and it proves which a softer stirring is better for removal inclusion than stronger one. An interesting point analyzed is the effect of stirring level on small and large inclusions.</p> <p>According to the inclusion number removal by slag, it is possible to appreciate like larger inclusions are removed easier than smaller ones. This mechanism is the most important to remove inclusions calculated by this model.</p> / Master of Science (MSc)

<p>Reaction kinetics of copper sulphide matte (Cu₂S) with an oxidizing slag was investigated. Silica-saturated fayalite (2FeO.SiO₂) slag was synthesized by melting powder mixtures of iron, silica and hematite with respective ratios of 1:2:3.6 at high temperatures. Experiments were performed in an inert atmosphere using a high-temperature furnace equipped with X-ray fluoroscopy and pressure transducer. The effect of temperature (1400 – 1475 °C) and matte droplet size (0.5 – 2 g) on desulphurization rate was evaluated. Chemical titration was performed on quenched slag samples synthesized at different temperatures in order to determine the amounts of Fe²⁺ and Fe³⁺ in the slags. Slag/matte samples quenched from high temperatures were extensively analyzed by means of optical microscope as well as scanning electron microscope (SEM), the latter equipped with an energy dispersive X-ray spectrometer (EDS). EDS analysis of the quenched samples showed that some areas of pure Cu were formed inside the matte droplets. It indicated that desulphurization reaction indeed has taken place and copper was formed as the product. In addition, EDS showed that some Fe-rich areas were formed inside the matte droplets. Gas halo formation around the droplets was confirmed by X-ray fluoroscopy observations. Additionally, it was seen that dome-like bubbles formed during high-temperature experiments on top of the matte droplets with mass equal to 0.75-gram or larger. In contrast to Fe-C metal droplets in contact with oxidizing slags, no droplet swelling was detected in this study. Reaction kinetics investigations showed that initial desulphurization rate increased with increasing temperature and matte droplet size. In fact, it was shown that rate increased linearly with matte droplet surface area. Finally, mass transfer in the slag phase and mass transfer in the gas halo formed around the droplet were found to be the rate-controlling mechanisms prior to and after gas halo formation, respectively.</p> / Master of Applied Science (MASc)

Low alloy steel electrodes have been electroslag remelted using alternating and direct current power sources. Changes in electrical contact between the furnace mould wall and mould base provided an improved understanding of the thermal ,and chemical processes characteristic of the remelting technique. 1m ion regeneration process has been postulated to account for current flow within the slag phase. Observed changes in furnace heating effects, electrode droplet sizes and in slag and metal compositions have be,en related to overtensions impressed on the slag/electrode and slag/ingot boundaries. The desulfurization reaction has been studied in detail. / Thesis / Doctor of Philosophy (PhD)