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Chapter “Sintering of iron ores and concentrates” is focusing on the study of theoretical, thermodynamic and experimental results in the production of sinters from iron ores and concentrates. The authors of the chapter have long been interested with the production of sinter from iron ores and have recently also focused on the use of biomass as a substitute for a part of coke breeze in the production of iron sinter. Important characteristics of the chapter include the characteristics of iron ores and concentrates used to produce sinter including physico-chemical, mineralogical and metallurgical properties. Predicting the influence of the properties of iron ores and concentrates on the final quality of the sinter and on the production of pig iron is another part of the study. These properties are a key factor in achieving the highest possible agglomerate quality for pig iron production. The sintering process requires mathematical and physical modeling. For this reason, the authors created thermodynamic models of sintering including material-heat balance of sinter production. In the final part of chapter is the use of traditional and alternative carbonaceous fuels in the production of sinters, mainly in the context of replacement of coke breeze with biomass.

Capillary water absorption of materials is a very important factor in the process of pre-treatment of fine-grained materials. Materials that are in a moisturized state capable of forming a firm, compact pellet are, thanks to this particular physical property, suitable for utilisation in sinter charge preparation within the process of sintering iron-ore raw materials. The pelletising ability of coke dust is generally known and coke dust exhibits good pelletisability. From the ecological point of view, an alternative to coke dust is currently biomass, which has a great potential for industrial applications, including use in the agglomeration process. Understanding of how biomass behaves during pre-pelletisation is very important and for the sintering process, it is essential. The purpose of pre-pelletisation of the sinter charge is to achieve its optimal permeability in the sintering process. The experiment described in the article was carried out using wood biomass&mdash, oak and pine sawdust, as well as plant biomass&mdash, Miscanthus sinensis and Lavandula angustifolia. The evaluation was carried out by applying the capillary water absorption test and the free-fall drop test. As different types of biomass have different chemical compositions, heating capacities, grain morphologies, and chemical and physical properties, the testing was carried out with several types of biomass. The capillary water absorption was examined in terms of different granulometries, and the impact of the type of liquid medium was analysed. It was observed that different types of biomass differ in their ability to absorb liquids. Another finding was that the type of a liquid medium had a significant effect on the pelletising ability of biomass, which was determined by the surface tension and the ability to form liquid bridges between the grains. Research results indicate an excellent pelletising ability of the Miscanthus sinensis grass. The wettability of oak and pine sawdust determines its application in the pelletising process. It may be concluded, based on the research, that Lavandula angustifolia is not a suitable alternative to coke dust due to its low ability to form pellets.

The use of lignin can be one of the methods of coke powder substitution in the agglomeration process. This article specifies the material research of lignin and the technological and ecological parameters of the agglomeration process in laboratory conditions using biomass lignin. The methodology of the Raman and infrared spectroscopy, representing a new approach in the analysis and assessment for the purposes of material characteristics for the agglomeration process, was applied to study the structure of carbonaceous matter. The material research of lignin has determined that its calorific value corresponds to ca. 80% of the calorific value of coke powder, while its reactivity is higher than that of the coke. Although the substitution of coke powder using different types of waste biomass (e.g., wood sawdust) in the production of the agglomerate is limited to the maximum of 8&ndash, 15%, in case of lignin, more than 20% can be substituted, while the standard properties of the produced agglomerate are maintained. The lower emissions of sulfur and nitrogen oxides as well as the reduction of carbon footprint in the agglomeration process as a result of the so-called zero CO2 balance in the formation and processing of the biomass represent its positive aspects. Based on the laboratory research of lignin, up to a 50% substitution of coke powder with this type of biomass can be predicted for the technology of agglomerate production in real operation.

This paper specifies the mathematical and physical modelling of the iron sintering process in laboratory conditions. The aim is to get the simplest approach (using thermodynamic software &ldquo, HSC Chemistry&rdquo, version 9, Outokumpu Research Oy, Pori, Finland) that allows one to predict the output parameters based on the initial composition analysis. As a part of the application of mathematical modelling, a mass and thermal balance of combustion of carbonaceous fuels (including biomass) and a mass and thermal balance of high-temperature sintering of an agglomeration charge were determined. The objective of the paper was to point out the advantages of modelling using thermodynamic software and apply the results into a simulation of the sintering process. The outcome of mathematical modelling correlates to the outcome of physical modelling for fuel combustion and the agglomerate production in a laboratory sintering pan. The energy required to reach the desired sintering temperatures and acquire the standard quality of agglomerate was calculated using 4.97% of coke breeze. In a real experiment with the laboratory sintering pan, 4.35% of coke was used. When a biomass fuel with a lower calorific value (lignin) is used in the agglomeration charge, the amount of fuel has to be increased to 5.52% (with 20% substitution of coke). This paper also aimed at predicting methodological tools and defining thermodynamic conditions for creating an interactive simulation. In addition, kinetics should be considered to improve the predicting capabilities of the current model and therefore in further research it will be required to optimise the computational program pursuant to the results of the kinetics experiments.

During the iron ore sintering process, two types of particles are present in the sinter bed: (1) fines, which are actively taking part in melting and the formation of secondary phases, and (2) coarse ores, which are partially interacting with the surrounding melt. The quality of the final sinter is particularly determined by the secondary phases and their bonding ability. Due to chemical differences between the fines and coarse particles, knowing the overall chemical composition of the sintering blend is not sufficient to estimate the final sinter microstructure. In this study, different ore types were used to prepare iron-rich, high-alumina, and high-silica blends, which were sintered in a laboratory sinter pot to investigate the behavior of fine as well as coarse particles. As a result, very different sinter matrices formed depending on the useful basicity in each sinter. The density, mineral nature, and the gangue of the ore affected coarse ore assimilation.

The article presents the results of the research on the reduction of the high-copper slags produced in the single-step Outokumpu blister copper production process, carried out by KGHM Polska Miedz. The company is the fifth largest blister copper producer in the world. The tested slags containing 12–16 wt%. Cu

The use of iron ores with high gangue content in industrial sintering leads to varying sinter quality; this also applies when formation of calcium-ferrites is optimized to enhance sinter strength. In this study, pot sinters containing calcium-aluminosilicoferrites as a matrix phase were tested for their mechanical properties. It was found that the presence of the ferrite matrix had a positive effect on sinter strength, which was also influenced by the chemical compositions of the ferrites. Nanoindentation measurements on custom-synthesized calcium-aluminosilicoferrite crystals revealed a correlation between the alumina content of the ferrite phase and its mechanical properties, which ultimately also controls sinter strength. Both the modulus and the hardness of the SFCA phase increased with further incorporation of Al2O3. However, with increasing hardness the SFCA phase became more brittle, and this is a cause of bulk sinters becoming weaker. There was however no detectable effect of silica or other minor components on the mechanical properties of the ferrites.

Charcoal is becoming an alternative source of energy to traditional fossil fuels such as coal and coke. In theoretical studies, some types of biomass have been identi ed as alternative sources of fuel to coke. The use of charcoal for sintering applications has been evaluated in separate experiments in the world. These experiments indicate that charcoal can replace a portion of the coke breeze (approximately 20-30%). The aim of this thermodynamic study was to evaluate the possibilities of charcoal utilization in iron-ore sintering process. Thermodynamic analysis has shown that the main factors determining the composition and properties of sinter are chemical composition of input materials (including fuels), thermodynamics of fuels burning, and oxidation potential of the gaseous phase (CO2/CO ratio). The main objective of this work was to determine the e ects of coke substitution by charcoal in the laboratory sintering process with respect to combustion e ciency and sinter quality. The coke substitution and energy requirement provided by charcoal was in range of 8 to 86%. The use of charcoal fuel resulted in a decrease in sintering time and the replacement of coke with charcoal may lead to increase in sinter productivity. Overall, the results from the laboratory scale tests suggest that replacement of coke breeze energy with an equivalent amount of energy from charcoal in the iron-ore sintering process is possible and has no negative influence on technological and ecological parameters.

The present work deals with thermal degradation and kinetic study of chosen types of biomass in order to evaluate their usefulness as a supplementary fuel in the iron ore sintering process. The thermal stability and degradation of sawdusts and walnut shells were studied by TG/DTG coupled with differential thermal analysis (DTA) under air from 40 to 700 °C. The kinetic experiments were performed at different heating rates 5, 10, 15 °C min–1. From the thermogravimetric experiments of each sample, it was found that the mass loss characteristics under air atmosphere showed similar combustion profiles. However, the thermal degradation temperature of walnut shell was higher than sawdust samples and the residual mass was lowest, what indicated that the higher combustion was found at the walnut shell sample.

The effort to minimize CO2 emissions leads the existing integrated steel plants to implement alternative biomass-based fuels that dispose of equilibrium carbon balance. The fuel is a key factor in the iron ore sinter production, so it is essential to know its impact not just on mechanical properties of the finished sintered ore but also on the mineral composition as the mineral phases together determine all observed sinter properties. For this purpose the samples prepared by replacing a part of coke breeze with charcoal or walnut shell substitute were subjected to the observation under the light microscope, also using etching, to the phase identification by chemical EDX analysis on the scanning electron microscope and to the phase composition quantification by X-Ray diffraction analysis. The studied microstructure areas in the vicinity of the pores left by fuel grains were neither characterized by different phases nor by changed chemical composition of these phases even thought mineral matter of the used fuels were substantially different in terms of the chemical composition. The only feature of the burned substitute fuels were ash particles arranged in characteristic shapes. The main reason of variation in ratios of respective mineral phases of samples appeared to be thermal conditions that were reflected in the content of unreacted non-ferrous phases. Coke substitution in the sinter mixture has no negative impact on the phase composition of the produced sinters, which confirms the prospective use of biofuels in the sintering process.

The work deals with examination of the influence of the ratio between iron ore concentrate and iron ore on quality of produced iron ore sinter. One of the possibilities to increase iron content in sinter is the modification of raw materials ratio, when iron ore materials are added into sintering mixture. If the ratio is in favor of iron ore sinter, iron content in resulting sintering mixture will be lower. If the ratio is in favor of iron ore concentrate and recycled materials, which is more finegrained, a proportion of a fraction under 0.5 mm will increase, charge permeability property will be reduced, sintering band performance will decrease and an occurrence of solid particulate matter in product of sintering process will rise. The sintering mixture permeability can be optimized by increase of fuel content in charge or increase of sinter charge moisture. A change in ratio between concentrate and iron ore has been experimentally studied. An influence of sintering mixture grain size composition, a charge grains shape on quality and phase composition on quality of the produced iron sinter has been studied.

Coke breeze is a special type of fossil fuel that significantly contributes to environmental pollution. Therefore, ways and opportunities to reduce its negative impact on climate change are being sought. Alternative fuels constitute one of the opportunities where biomass can play an important role. Biomass represents a new fuel for the sintering process and an attractive way to decrease CO2 emissions. Today, biomass is not considered for complete substitution of coke. Opportunities for its partial substitution are instead being sought. Each type of fuel is characterized by different properties and thus also by an appropriate scope of its substitution in an agglomeration mixture. This study covers the available options and the potential impact of this substitution on the structural and mineralogical composition of the agglomerate. These experiments were carried out by substituting coke breeze with biomass (hydrolyzed lignin). To perform the experimental sintering, a sintering apparatus&mdash, laboratory sintering pan (LSP)&mdash, was used, which was fully equipped with measuring devices and analyzers. The samples of agglomerates prepared by substituting 0%, 20%, 50% and 86% of coke breeze with biomass (hydrolyzed lignin) in dried form were analyzed by chemical and microscopic analysis-The representation of individual minerals in agglomerates was determined by powder X-ray diffraction analysis. Based on the results of the study regarding the impact of partial coke substitution with biomass on the mineralogical composition of the agglomerate, it can be stated that it is possible to substitute about 50% of coke with lignin in the sintering process. When lignin was used to substitute up to 50% of coke, agglomerates with minimal variations in the chemical and mineralogical composition were produced.

Worldwide laboratory research proves that replacement of coke breeze by solid biomass in the process of agglomeration is possible [1,2,3]. One possibility of solid biomass use is the charcoal. Literature indicates that coke breeze can be replaced by charcoal up to 40% based on calorific value [4]. This paper deals with the poblems of coke breeze substitution by charcoal in laboratory conditions sintering and the impact of such substitution on the resulting agglomerate properties, i.e. microstructure. Agglomerate microstructure consists of mineralogical phases; hematite, magnetite, calcium and aluminum silico-ferrites, and silicates. Substituting coke breeze for charcoal up to 40% in the process of agglomeration, slight changes occur in the volume fractions of individual phases of the agglomerates. Volume fractions of agglomerate phases change significantly above 40% substitution by charcoal. Phase composition has an effect on the quality characteristics of the produced agglomerate. The amount of calcium and aluminum silico-ferrites influences the strength of the agglomerate [5].

At present, the powder XRD is widely used analytical method for iron ore sinter mineralogy determination. In many types of research, diffraction data for SFCA and SFCA-I phases were not available, and diffraction data for other calcium ferrites were used instead. Therefore, the aim of this paper is to bring a comparison between the evaluation of diffractograms, when SFCA/SFCA-I, and, other calcium ferrites, respectively, are considered. As a result, the quantification of phases is quite comparable, when minerals are collected into groups, i.e. hematite, magnetite, calcium ferrites, silicates and non-assimilated non-ferrous phases. Only in the case of silicates, a comparison tends to be dissatisfactory.

This article contains characteristics of selected types of biomass, which can be considered as an alternative fuel in the production of iron ore agglomerate. Selected types of biomass were evaluated by chemical analysis, X-ray phase analysis and microscopic analysis using the camera on microscope Olympus BX 51. Biomass was characterized according to its structure, chemical composition and chemical composition of ash. The obtained data were confronted with the data for coke breeze and based on the results, conclusions were made about the possible use of selected types of biomass as an alternative fuel in the process of iron ore agglomerate production.

Paper presents the results from the study of the effect of materials with titanium addition on the strength properties of the iron ore sinter. The sinters with TiO2 addition or without TiO2 addition prepared in laboratory were applied in this research and were compared based on the structural and phase composition. Exploited was the method of the X-ray diffraction and method of elemental EDX analysis applying the electron raster microscope with the energo-dispersion analyser. Confirmed was the relationship between the sinter structure and its strength. Higher strength of the sinter without TiO2 addition is the result of the different phase composition of the compared sinters. In the sinter production considered should be not only the chemical composition of the entry components of the charge and the chemical composition of the final product but also its structural and phase composition.

The work is focused on studying the influence of the ratio of concentrate to iron ore on the phase composition of the iron ore agglomerate. The concentrate has significantly higher iron content than used iron ore, and is a determining factor, which influences the richness of the batch and consequently, the richness of the agglomerate. The increased iron content in the agglomerate can be achieved by adjusting the raw material ratio in which iron ore materials are added to the agglomeration mixture. If the ratio is in favor of iron ore this reflects in lower iron content in the resulting agglomeration mixture. If the ratio is in favor of a concentrate, which is finer, the fraction share of less than 0.5 mm will be increased, the permeability of the batch will be reduced, the performance of the sintering belt will decrease and the presence of solid pollutants will increase. The possibility of concentrate replacement by iron-rich iron ore with granulometry similar to that of concentrate was experimentally verified. The effect of the concentrate replacement by the finer iron-rich ore was tested in a laboratory sintering pan. There were performed six sinterings, with gradually changing ratio concentrate/iron ore (C/O). The change in the ratio of concentrate to iron ore, does not cause the occurrence of new phases, only the change in their prevalence, which does not bring a significant change of the qualitative indicators of the compared agglomerates. Concentrate replacement by iron ore up to 50% was optimal from technological, quality, and environmental aspects.

Sintering is thermal process used in the iron and steel industry to transform fine particles of iron ore and concentrate into porous product known as sinter. Sinter is input material for the blast furnace process. In the sintering process fuel is in the form of coke breeze (or in the form various types of biomass) used for production of iron-ore sinter. Temperature measurement and monitoring is very important in the iron sintering process. Temperature can be a very good indicator of the behavior of the sintering process. The present work contains the findings, which were obtained from analysis of the results, obtained by experiments with the laboratory sintering pan. The simulation conditions on this laboratory sintering pan are sufficiently close to those present in the sintering layer. This paper primarily presents temperature measurement in iron sintering process with infrared thermography. During the sintering, the laboratory sintering pan was monitored by thermovision camera and movement of the combustion zone in direction of airflow was recorded. The information provided by the measurement system can be used to control many parameters of the sintering process (homogeneity and dimension of combustion zone, temperature profile in sintering bed, etc.). The experiment results were analyzed and summarized in the present paper.

An investigation was carried out into the use of saw-dust form oak wood as a supplementary fuel in the iron ore sintering process. The primary fuel was coke breeze and total heat output of all the tested raw blends was the same and was calculated as 3.8 wt. % coke breeze. The coke substitution and energy requirement provided by saw-dust from oak wood (SDOW) was in the range of 8 - 44 %. Experimental tests were made by using a laboratory sinter pot (LSP) with charge capacity of around 70 – 90 kg per run. The main objective of the work reported here was to determine the effects of substituting coke with saw-dust from oak wood in the iron ore sintering process with respect to combustion efficiency and sinter quality. The use of SDOW fuel up to 20 % as a partial substitution of coke resulted in a decrease in the sintering time but on the other hand with the increasing of SDOW the bed temperatures were reduced. A substitution of coke with SDOW more than 20 % may lead to decrease in permeability of mixture and consequently it may lead to achieve low temperature profile of bed. Explain in more detail and interpretation of results is described in the paper.

This paper deals with assessing the impact of substitution fuel charcoal on the technological parameters of sintering and agglomerate quality. Changes in the quantity and qualitative parameters of fuel in the process of agglomeration affect the maximum sintering temperature and productivity. The maximum temperature varies with calorific value, the amount of fuel and gas-dynamic conditions in the sintered layer. When replacing fuel by solid biomass, an important parameter is also quantity of volatile substances that affect the process of agglomerate formation. Agglomerate quality is determined by its chemical composition, its physical and metallurgical properties. Effect of charcoal, as fuel substitution, on agglomerate quality indicators is evident. It was confirmed that the replacement of fuel by charcoal is only possible to a certain percentage level regarding agglomerate quality. Small amount of charcoal in the agglomeration process favorably affects the quality of agglomerate.

This work was focused at identification and percentage share of semifusinite in coking coal. Coal itself had different random reflectance of vitrinite and carbon content (content of volatile matter). Petrographic analysis (determination of vitrinite, liptinite and inertinite) was extended to inertinite macerals group. Semifusinite determination was carried out by measuring the random reflectance and by observation of its morphology. Subsequently, semifusinite was categorized into three groups according to the theory of boundary equations as fusible, partially fusible and infusible semifusinite based on random reflectance. The overall content of semifusinite in samples of coal was also considered. The results of petrographic analysis were graphically evaluated as fusible semifusinite content versus coal light reflectance plot. According to the above results, the amount of fusible semifusinite accounted for 29 – 44 % of total semifusinite in observed types of coal. This research was part of a larger study of coal types with the requirement for extension of the classical petrographic analysis.