L’auto-cicatrisation des fissures des matériaux cimentaires présente un intérêt important pour améliorer leur durabilité (propriétés de transfert par exemple). L’impact du laitier de haut-fourneau sur ce phénomène a été peu étudié bien qu’il ait été observé sur des ouvrages du Génie Civil. Dans cette étude, la cinétique et l’amplitude de l’auto-cicatrisation ont été suivies par des essais non destructifs : la tomographie aux rayons X et la perméabilité à l’air, pour une fissuration créée à 7 jours et à 28 jours. Les résultats montrent que le laitier de haut-fourneau possède un potentiel d’auto-cicatrisation intéressant pouvant dépasser les résultats obtenus pour les formulations de référence sans laitier. Ce bon potentiel dépend des caractéristiques physicochimiques des matériaux brutes et du potentiel d’hydratation de la formulation au cours du temps. De plus pour suivre l’auto-cicatrisation, un nouvel essai a été mis en place afin de fissurer les éprouvettes de mortier par retrait gêné et d’étudier l’auto-cicatrisation d’une fissure naturelle. Cet essai s’est avéré efficace sur la formulation de référence. Une caractérisation des produits de cicatrisation par MEB-EDS témoigne de la formation de nouveaux produits dans les fissures et de l’impact important des conditions de stockage sur le type de produits formés: des C-S-H pour un stockage sous eau et des carbonates de calcium pour un stockage en chambre humide (CO2 + eau). Les résultats de migration aux chlorures de nano-indentation montrent que ces produits de cicatrisation possèdent de bonnes propriétés de durabilité et des propriétés mécaniques à l’échelle microscopique intéressantes (pour le carbonate de calcium). Enfin, une modélisation du phénomène d’auto-cicatrisation est proposée au moyen du code de calcul de géochimie PHREEQC. L’étude a révélé le potentiel intéressant de PHREEQC pour modéliser l’auto-cicatrisation et en faire un outil de prédiction du phénomène. / Self-healing of cementitious materials presents great interest to improve the durability of concrete structure (transfer properties for example). The impact of blast-furnace slag on this phenomenon is not yet clear even if the self-healing of concrete with blast-furnace slag was observed in building sites. To understand the blast-furnace slag influence, non-destructive methods were used to follow self-healing: X-ray tomography and gas permeability test. All specimens were cracked at 7 days and 28 days. The results show that the blast furnace slag has an interesting self-healing potential that can exceed the reference formulation results. This good potential depends on the physico-chemical characteristics of the raw materials and the hydration potential of the formulation over time. In addition to follow the self-healing, a new trial was set up to crack mortar specimens by restrained shrinkage and study the self-healing of a natural crack. In addition to follow the self-healing, a new trial was set up to crack mortar specimens by restrained shrinkage and study the self-healing of a natural crack. This test has proven effective over the reference formulation.The SEM with EDS analysis showed the formation of new products in the crack and the impact of storage conditions on these products : C-S-H for specimens stored in water and calcium carbonate for specimens stored in a damp chamber (CO2 + water). Migration chlorures and nano-indentation tests results showed that self-healing products had interesting durability properties and micro-mechanical properties (for calcium carbonate). Finally, self-healing modelling is proposed by means of geochemistry PHREEQC calculation code. The study revealed interesting potential PHREEQC to model self- healing phenomenon and make it a of predictive tool.

[pt] O alto forno é um reator metalúrgico cujo objetivo consiste na produção de ferro-gusa. O consumo de combustível/redutor no processo de redução de minério de ferro em altos fornos, representa mais de 50 por cento do custo do gusa. No sentido de aumentar a produtividade e reduzir o consumo de combustível/redutor são empregadas técnicas de injeção de combustíveis auxiliares pelas ventaneiras dos altos fornos. A combustão de gás natural (GN) injetado nas ventaneiras produz grande quantidade de hidrogênio, esse gás é melhor redutor se comparado ao monóxido de carbono, pois ele possui velocidade de reação maior com os óxidos de ferro e, além disso, a geração de CO2 no processo de redução é diminuída quando comparado ao uso do carvão pulverizado (PCI), que é atualmente o material de injeção mais usado no Brasil. Este trabalho propõe a simulação da combustão de GN injetado pelas ventaneiras de um alto forno, utilizando o software CHEMKIN. As simulações provenientes deste software são amplamente utilizadas para otimização da combustão, sendo possível explorar rapidamente o impacto das variáveis de projeto sobre o desempenho do processo. Os resultados provenientes dessa simulação computacional em condições típicas de alto forno permitiram a previsão da temperatura de chama adiabática e a quantificação dos gases redutores de óxidos de ferro: H2 e CO. A partir da variação dos parâmetros de processo foi possível obter resultados úteis para a tomada de decisão, visando controlar e otimizar o processo. / [en] The blast furnace is a metallurgical reactor whose goal is to produce pig iron. The fuel / reductant in the reduction of iron ore in the blast furnace process, represents more than 50 percent of the cost of the iron. In order to increase the productivity of the blast furnace and reduce fuel consumption / reducer injection techniques are employed by tuyeres of materials that act as fuel / reducer. The combustion of natural gas injected into the tuyeres produces large amounts of hydrogen, which replaces part of the carbon monoxide as reducing gas in the tank. The hydrogen gas is better compared to the reductant carbon monoxide, because it has reaction rate with the iron oxides and, moreover, the CO2 generation in the process of reduction is decreased when compared to the use of pulverized coal (PCI), which is currently the material most commonly used injection by tuyeres in Brazil. This paper proposes the simulation of combustion of natural gas injected into the tuyeres of a blast furnace, using the CHEMKIN software package. Simulations from this software are widely used for optimization of combustion, which can quickly explore the impact of design variables on the performance of the process, using accurate models of chemical kinetics. The computer simulation results from the combustion of natural gas at typical conditions of blast furnaces allowed the prediction of the adiabatic flame temperature and the reaching of the reducing gases of iron oxides: H2 and CO. From the variation of process parameters was possible to obtain useful results in order to control and optimize the process.

yes / Test results of thirty six ground granulated blast-furnace slag (GGBS)-based mortars and eighteen fly ash (FA)-based mortars activated by sodium silicate and/or sodium hydroxide powders are presented. The main variables investigated were the mixing ratio of sodium oxide (Na2O) of the activators to source materials, water-to-binder ratio, and fine aggregate-to-binder ratio. Test results showed that GGBS based alkali-activated (AA) mortars exhibited much higher compressive strength but slightly less flow than FA based AA mortars for the same mixing condition. Feed-forward neural networks and simplified equations developed from nonlinear multiple regression analysis were proposed to evaluate the initial flow and 28-day compressive strength of AA mortars. The training and testing of neural networks, and calibration of the simplified equations were achieved using a comprehensive database of 82 test results of mortars activated by sodium silicate and sodium hydroxide powders. Compressive strength development of GGBS-based alkali-activated mortars was also estimated using the formula specified in ACI 209 calibrated against the collected database. Predictions obtained from the trained neural network or developed simplified equations were in good agreement with test results, though early strength of GGBS-based alkali-activated mortars was slightly overestimated by the proposed simplified equations.

The steel industry is aiming to reduce CO2 emissions by different means; in the short-term, by replacing fossil coal with highly reactive carbonaceous material like bio-coal (pretreated biomass) and, in the longer term, by using hydrogen. The use of bio-coal as part of top charged briquettes also containing iron oxide has the potential to lower the thermal reserve zone temperature of the Blast furnace (BF) and, due to improved gas efficiency, thereby give a high replacement ratio to coke. In order to select a suitable bio-coal to be contained in agglomerates with iron oxide, the current study aims at investigating the devolatilization behavior and related kinetics of different types of bio-coals. In addition, the aim is to investigate the self-reduction behavior of bio-coal-containing iron ore composite under inert condition and simulated blast furnace thermal profile. In the BF the temperature of the top-charged material will increase rather quickly during the descent in the upper part. Ideally, all the carbon and hydrogen contained in the top-charged bio-coal should contribute to the reduction. The devolatilization of bio-coal is thus important to understand and to compare between different types of bio-coal. To explore the devolatilization behavior for different materials, a thermogravimetric analyzer equipped with a quadrupole mass spectrometer was used to monitor the weight loss and off-gases during non-isothermal tests for bio-coals having different contents of volatile matter. The samples were heated in an inert atmosphere up to 1200°C at three different heating rates: 5, 10 and 15°C/min. The thermogravimetric data were evaluated by using the Kissinger–Akahira–Sonuse (KAS) iso-conversational model and the activation energy was determined as a function of the conversion degree. Bio-coals with both low and high content of volatile matter can produce reducing gases that can contribute to the reduction of iron oxide in bio-agglomerates. Bio-coals containing a higher content of catalyzing components such as CaO and K2O will enhance the devolatilization and release of volatile matter at a lower temperature.  The self–reduction of composites was investigated by thermogravimetric analyses in argon atmosphere up to 1100°C and evolved gases were monitored by means of quadrupole mass spectroscopy. Composites with and without 10% bio-coal and sufficient coke breeze to keep the C/O molar ratio equal to one were mixed and Portland cement was used as a binder. To explore the effect of added bio-coals, interrupted vertical tube furnace tests were conducted in a nitrogen atmosphere at temperatures selected based on thermogravimetric results, using a similar thermal profile as for the thermogravimetric analyzer. The variation between fixed carbon, volatile matter contents and ash composition for different types of bio-coal influences the reduction of iron oxide. The results showed that the self-reduction proceeds more rapidly in the bio-coal-containing composite and that the volatile matter could have contributed to the reduction. The self-reduction of bio-coal-containing composites started at 500°C, while it started at 740°C with coke as the only carbon source. The hematite was successfully reduced to metallic iron at 850°C with bio-coal present as a reducing agent, but not until 1100°C when using coke. Use of bio-coal with high content of volatile matter but low content of catalyzing elements as potassium, sodium and calcium in bio-agglomerates for the BF can be recommended because it enhances the self-reduction of iron oxide, e.g., wustite was detected by XRD analysis in samples treated up to 680°C. Bio-coal with low content of volatile matter, low alkalis, low phosphorous and high content of fixed carbon will also be suitable to use in the BF.

Expansive clays undergo a large swell when they are subjected to water. Thus, expansive clay is one of the most abundant problems faced in geotechnical engineering applications. It causes heavy damages in structures, especially in water conveyance canals, lined reservoirs, highways, airport runways etc., unless appropriate measures are taken. In this thesis, Granulated Blast Furnace Slag (GBFS), GBFS - Lime combinations and GBFS Cement (GBFSC) were utilized to overcome or to limit the expansion of an artificially prepared expansive soil sample (Sample A). GBFS and GBFSC were added to Sample A in proportions of 5 to 25 percent. Different GBFS-Lime combinations were added to Sample A by keeping the total addition at 15 percent. Effect of stabilizers on grain size distribution, Atterberg limits, swelling percentage and rate of swell of soil samples were determined. Effect of curing on swelling percentage and rate of swell of soil samples were also determined. Leachate analysis of GBFS, GBFSC and samples stabilized by 25 percent GBFS and GBFSC was performed. Use of stabilizers successfully decreased the amount of swell while increasing the rate of swell. Curing samples for 7 and 28 days resulted in less swell percentages and higher rate of swell.

O presente trabalho tem como objetivo a caracterização do carvão da mina de Leão IIcamada inferior, com a finalidade de gerar carvão pulverizado para a injeção nas ventaneiras do alto-forno na indústria siderúrgica. Esta prática visa diminuir o custo do coque, através do aumento da taxa de substituição do coque por carvões brasileiros de baixo rank. Para o estudo foram realizados ensaios de beneficiamento, análise imediata e elementar, poder calorífico, análise petrográfica e índice de inchamento livre. Na 1ª etapa de ensaios de beneficiamento, usaram-se densidades entre: 1,3-2,4g/cm3, com intervalo de diferença de 0,1 e 0,2 para as densidades de 1,3-1,9 e 2,0-2,4 g/cm3, respectivamente.Verificou-se que a fração de densidade 1,3 g/cm3 apresentou uma menor recuperação (2,0%) e um teor de cinzas de 4,3%. As maiores massas foram obtidas nas densidades de 1,4; 1,5 e 2,4 g/cm3, com recuperação de 11,1%;14,3% e 22,2% e teores de cinzas de 14,9%; 24,3% e 83,4%, respectivamente. Foram escolhidas as frações de densidades 1,4 e 1,5 g/cm3 com maior recuperação na 1ª etapa e com teor de cinzas em torno de 12 a 18%, conforme as curvas lavabilidade. Na 2ª etapa foi flutuado o carvão nas densidades de interesse escolhidas para o PCI e obtiveram-se recuperações mássicas de 13,11% e 27,00%, respectivamente. Assim as recuperações das médias ponderadas corresponderam a 22,46% para os carvões de interesse com alto teor de matéria carbonosa enquanto para as frações indesejadas obteve-se 80,45% em massa. A partir da análise imediata foram obtidos os teores das frações densidades flutuadas de 1,4 e 1,5 g/cm3, obteve-se os seguintes teores: U%- 14,45%; Cz(%bs)-15,22%;MV(bs)-36,04%; MV(bsic)- 42,51%; CF(bs) -50,54% e CF(bsic)- 59,6%. As médias da análise elementar obtida das duas frações foram: enxofre total-0,54%, hidrogênio total-5,44% e carbono total-56.74%, respectivamente. O poder refletor da vitrinita médio foi de 0,46 a 0,48% Ro, sendo classificado como sub-betuminosoB de acordo com a ASTM. O valor do poder calorífico médio foi de 5462 kcal/kg. A fração FL 1,4 é levemente aglutinante com 0,5 de perfil de inchamento, pois concentrou mais vitrinita e perfil zero (0) para fração de FL 1,5g/cm3 e NB, não sendo aglutinante. A partir dos resultados o carvão de leão II apresenta altos voláteis, bom poder calorífico superior; baixo S<1% e teores de cinzas e umidade razoáveis após beneficiamento em densidade de 1,4 a 1,5g/cm3. Assim pode ser usado para PCI, mas há necessidade de se fazer a devida mistura com carvão de médio e/ou alto rank para ajustar algumas propriedades de interesse de acordo com as exigências de cada alto-forno. / The present study concerns itself with the characterization of coal from the mine of Leão II (lower layer), for use in the steel industry with the purpose of generating pulverized coal for injection in the blast furnace. This practice is intended to reduce the cost of coke, by increasing the rate of replacement of Coke by Brazilian low-rank coals. For the study, were carried processing trials, proximate(%) and ultimate(%) analysis, calorific value, petrographic analysis and free swelling index. In the first step of processing tests, it was used density in between densities: 1.3-2, 4 g/cm3, with range of difference of 0.1 and 0.2 to 1.3 densities-1.9 and -2.0 2.4 g/cm3, respectively. It was found that the fraction of 1.3 g/cm3 density showed a minor recovery (2.0%) and an ash content of 4.3%. The biggest masses were obtained in 1.4; 1.5 and 2.4 g/cm3 densities, with 11.1%; 14.3% and 22.2% recovery and 14.9%; 24.3% and 83.4% ash content, respectively. There were chosen the fractional density 1.4 and 1.5 g/cm3 with greater recovery on the first step and with ash content around 12 to 18%, as the washability curves. The second stage was floated coal in densities of interest chosen for PCI and led to mass recalls of 13.11% and 27.00%, respectively. So recoveries of weighted averages corresponded to 22.46% to the coals with high carbon content while the unwanted fraction was 80.45% by mass. From the immediate analysis were obtained the contents of the fractions of floated densities of 1.4 and 1.5 g/cm3, the following levels: U%- 14.45%; as (% bd)- 15.22%; VM (bd)- 36.04%; VM (daf)- 42.51%; FC(bd)- 50.54% and FC (daf)- 59.6%. The averages of the elemental analysis obtained from two fractions were: total sulphur- 0.54%, total hydrogen- 5.44% and total carbon- 56.74%, respectively. The vitrinite reflector medium power was of 0.46 to 0.48% Ro, being classified as Sub-bituminous B in accordance with the ASTM standard. The value of the calorific average was of 5462 kcal/kg. The fraction FL 1.4 is slightly binder with 0.5 swelling profile because it obtained more vitrinite and focused profile of zero (0) for FL1.5 g/cm3 fraction and NB not agglutinative. From the results the Leão II coal has it was obvious presenting high volatile, good upper calorific value; low levels of S<1% and ashes and humidity reasonable after processing in density of 1.4 to 1.5 g/cm3. So it can be used for PCI, but there is need to do proper mixture with medium carbon and/or high rank to set some properties of interest according to the requirements of each blast furnace.

The reduction behaviour of the olivine iron ore pellet MPBOwas studied in laboratory scale at KTH as well as in the LKABexperimental blast furnace. Initially, a newreduction-under-load, or so-called reduction/softening/melting,test equipment was developed. Experiments using differentreducing conditions, corresponding to different radialpositions of the blast furnace, were conducted. The experimentsincluded different temperature profiles, reducing atmospheresand mechanical loads applied on the sample bed to simulate thevarying conditions in the blast furnace process. The progressof reduction was investigated, as well as the processes ofsintering and contraction during reduction. A model of thecarburisation (pick-up of carbon by the reduced iron) andmelt-down process during rapid contraction was presented. Laboratory testing of MPBO pellets was compared with resultsfrom the LKAB experimental blast furnace. The reduction of ironore pellets in the experimental blast furnace was surveyed by adissection of the furnace after quenching. The high temperaturephenomena occurring when reducing the MPBO pellet, with limitedsoftening and a short temperature range of the melting process,resulting in a thin cohesive zone, were found to be the same inlaboratorytests and in the experimental blast furnace. Thereduction down through the burden of the experimental blastfurnace was similar, but not identical to the results of theRUL experiments. The differences were found to be due todifferent reducing conditions. Therefore, it was concluded thata simulation of the reduction occurring in the blast furnacecan be performed in laboratory scale, provided the experimentalconditions are correctly chosen. Finally, a modification to further improve the properties ofthe MPBO pellets was examined. With the aim to improve theblast furnace process, coating of blast furnace pellets wasinvestigated in laboratory scale, as well as in the LKABexperimental blast furnace. Olivine, dolomite and quartzitewere used as coating agents. In laboratory scale the stickingprevention action of the different coating materials wasverified, in established test methods as well as in new testmethods, modified for blast furnace conditions. Testing of thecoated pellets in the experimental blast furnace revealedseveral advantages; significantly reduced blast furnace fluedust generation, improved gas utilisation and a smoother blastfurnace operation with a potential for a lowered fuel rate. <b>Keywords:</b>Olivine, pellets, pellet testing,reduction/softening/melting, MPBO, blast furnace, reduction,quenching, dissection, coating, sticking, coated pellets.

During the last decade, power quality has been recognised asa global problem. Among different types of power qualityproblems, voltage sags have been identified to be one of themost severe problems for different process industries. The mostcommon reason to voltage sags is lightning strikes in powerlines. Protection equipment, usually located at switchyards,disconnect faulted power lines as soon as possible, which isapproximately 100 ms. Thus, the duration of voltage sags areapproximately 100 ms. The sensitivity to voltage sags ofelectrical equipment in process industries can be observed asfor instance malfunction, automatic turnoff or damages. This thesis gives an overview of three metals processes withfocus on the sensitivity to voltage sags and interruptions. Theinherent energy in the process is used to find the sensitivity.This energy may also be used to obtain "ride-through" for theprocesses. The three metals processes are a blast furnaceprocess, a hot rolling mill process and a cold rolling millprocess. The main attention in this thesis is paid to the blastfurnace process, which is powered by a line-operatedsynchronous machine. The thesis shows that the protection equipment forelectrical machines can be adjusted to avoid unnecessaryshutdowns. It is also explained why there are high torque andcurrents during voltage sags as well as after voltage sags. Itis shown that the first peak torque and current during thevoltage sags is almost proportional to the voltage change, thatis the voltage magnitude before the voltage sag minus thevoltage magnitude during the voltage sag. The first peak torqueand current after the voltage sag depends sinusoidal-like onthe duration of the voltage sag and almost proportional to thevoltage change during the voltage sag. There is no fluxsaturation during voltage sags, however after voltage sagssaturation is very likely to occur. The thesis explains why andalso how the flux is changed during and after voltage sags. The duration of voltage sags is in many cases set by theprotection equipment located in switchyards. It is shown thatthe durations of voltage sags can be changed to durations thatwill cause less peak torque and current after voltage sags forline-operated AC-machines. It is also shown how this istheoretically achieved. <b>Keywords:</b>Rolling mill, Blast furnace, Power Quality,Synchronous machine, Asynchronous machine, Voltage sag, Voltageinterruption, Ride-through, Process disturbances, Simulation,Modelling

In recent years, there has been a growing trend for the use of industrial by-products in the production of blended cements because of economical, environmental, ecological and diversified product quality reasons. Granulated blast furnace slag, a by-product of the transformation of iron ore into pig-iron in a blast furnace, is one of these materials which is used as a cementitious ingredient. The aim of this study is to investigate the properties of Portland slag cement (CEMII/B-S) by using separate grinding and intergrinding of granulated blast furnace slag and Portland cement clinker. For this purpose, granulated blast furnace slag was used as mineral admixture replacing 30% of the clinker. Clinker and granulated blast furnace slag were ground to four different Blaine fineness values of 3000 cm2/g, 3500 cm2/g, 4000 cm2/g and 4500 cm2/g by intergrinding and separate grinding in a laboratory ball mill. Then, eight Portland slag cement mixes and four Portland cement control mixes were prepared, in order to determine and compare 2-, 7-, 28-, and 90-day compressive and flexural strengths, normal consistencies and setting times. It was found that for the Blaine fineness values of 3000 cm2/g, 3500 cm2/g and 4000cm2/g, the 2-, 7-, 28-, and 90-day compressive strength of the interground Portland slag cements had higher values than the separately ground Portland slag cements. However, for the Blaine fineness values of 4500 cm2/g, separately ground Portland slag cement specimens had slightly higher 2-, 7-, 28-, and 90-day compressive strength values than the interground ones.

<p>The reduction behaviour of the olivine iron ore pellet MPBOwas studied in laboratory scale at KTH as well as in the LKABexperimental blast furnace. Initially, a newreduction-under-load, or so-called reduction/softening/melting,test equipment was developed. Experiments using differentreducing conditions, corresponding to different radialpositions of the blast furnace, were conducted. The experimentsincluded different temperature profiles, reducing atmospheresand mechanical loads applied on the sample bed to simulate thevarying conditions in the blast furnace process. The progressof reduction was investigated, as well as the processes ofsintering and contraction during reduction. A model of thecarburisation (pick-up of carbon by the reduced iron) andmelt-down process during rapid contraction was presented.</p><p>Laboratory testing of MPBO pellets was compared with resultsfrom the LKAB experimental blast furnace. The reduction of ironore pellets in the experimental blast furnace was surveyed by adissection of the furnace after quenching. The high temperaturephenomena occurring when reducing the MPBO pellet, with limitedsoftening and a short temperature range of the melting process,resulting in a thin cohesive zone, were found to be the same inlaboratorytests and in the experimental blast furnace. Thereduction down through the burden of the experimental blastfurnace was similar, but not identical to the results of theRUL experiments. The differences were found to be due todifferent reducing conditions. Therefore, it was concluded thata simulation of the reduction occurring in the blast furnacecan be performed in laboratory scale, provided the experimentalconditions are correctly chosen.</p><p>Finally, a modification to further improve the properties ofthe MPBO pellets was examined. With the aim to improve theblast furnace process, coating of blast furnace pellets wasinvestigated in laboratory scale, as well as in the LKABexperimental blast furnace. Olivine, dolomite and quartzitewere used as coating agents. In laboratory scale the stickingprevention action of the different coating materials wasverified, in established test methods as well as in new testmethods, modified for blast furnace conditions. Testing of thecoated pellets in the experimental blast furnace revealedseveral advantages; significantly reduced blast furnace fluedust generation, improved gas utilisation and a smoother blastfurnace operation with a potential for a lowered fuel rate.</p><p><b>Keywords:</b>Olivine, pellets, pellet testing,reduction/softening/melting, MPBO, blast furnace, reduction,quenching, dissection, coating, sticking, coated pellets.</p>