Non-metallic inclusions (NMI) are small impurities that can always be found in steel and other materials. NMIs are of great importance because they may negatively impact various properties of the steel, depending on their composition, morphology and numbers. In the oil and gas industry, one of the most concerning property that can be affected by the NMIs is corrosion resistance. In this report, certain aspects of NMIs were investigated, such as size or composition and effect which they have on the corrosion resistance. To accomplish this, two different steel alloy samples from pipelines were analyzed using electrolytic extraction,a scanning electron microscope (SEM) and a software called ImageJ. The results showed that only Niobium-Titanium carbides (NbTi-C) which were found on one of the samples had the potential to be dangerous, due to them causing pits ranging from 1 to 12.5 times their inclusion size. It was also found out that the size of the inclusions did not affect the size of the pitting that they caused. / Icke metalliska inneslutningar (NMI) är små föroreningar som alltid finns i stål och andramaterial. NMI:er är mycket viktiga eftersom de kan negativt påverka olika egenskaper hos stål, beroende på deras komposition, morfologi och antal. I olje -och gasindustrin är en särskilt oroande egenskap som kan påverkas av NMI:er deras korrosionsmotstånd. I denna rapport undersöktes hur olika aspekter hos NMI:er, som storlek eller komposition, påverkade korrosionsmotståndet i rostfritt stål. För att utföra detta analyserades två olika stållegeringsprovbitar från pipelines med elektrolytisk extraktion, ett svepelektronmikroskop (SEM) och ett program som kallas ImageJ. Från resultatet framkom det att baraNiob-Titankarbider (NbTi-C) som fanns på en av provbitarna hade potentialen att vara farlig, då den orsakar gropar som är 1 till 12.5 gånger större än sin egen storlek. Det framkom också att storleken på inneslutningarna inte påverkade storleken på deras gropar.

Nickel-based superalloys have a wide range of applications, mainly in gas turbines for power generation and aircraft propulsion. They are superior to competing alloys in maintaining excellent mechanical properties for extended durations at extreme temperatures and loads, all while resisting corrosion and oxidation. Haynes 282 is a new age-hardenable nickel-based superalloy that is reported to have a remarkable combination of creep strength, thermal stability, weldability and formability that gives it potential for new applications. Additive manufacturing (AM) is often referred to as 3D printing and the term comprises a number of techniques with the commonality of producing components layer-by-layer with a 3D CAD model as basis. The AM methods allow for unprecedented design freedom and the possibility of replacing complex multi-part components with single part components. The AM methods also enable shorter lead times in many cases and repairs where only part of a component can be replaced instead of replacing the whole component. Selective laser melting (SLM) is a metal AM method that involves a metal powder bed and a laser beam that fuses the powder by melting it according to the predefined geometry. The aim of this project was to evaluate the effect of different heat treatments for Haynes 282 components produced by SLM and it was done by microstructural studies and mechanical testing. Comparisons were made between literature reports on the conventionally produced material, the as-manufactured SLM material and three different heat treatments of 1120-2h-WQ+1010-2h-AC+788-8h-AC, 1170-8hWQ+1010-2h-AC+788-8h-AC and 1170-8h-WQ+1010-4h-AC+788-8h-AC. The first one is recommended by Haynes for conventionally produced material. The microstructural studies focused on identifying occurring phases and their distribution. The grain boundary carbide precipitation after heat treatment was shown to be rather different from the conventionally produced material both in terms of carbide types and their distributions. Grain boundary carbide networks were formed after all the heat treatments. A fine intragranular distribution of a titanium-rich phase that could not be identified was found in all examined SLM specimens. The mechanical testing consisted of tensile testing at room temperature and 600°C, impact testing and hardness testing. The heat treated specimens exhibited remarkable strength but significant embrittlement that was believed to be caused by the grain boundary carbide networks.

This thesis investigates the influence of pulsing on the mechanical properties of PVD TiAlN coatings. The thesis focuses on defects caused by droplets during the arc-evaporation technique by altering the duty time, which affects mechanical properties. The coatings' properties and performance depend on the microstructure and morphology, which, in turn, depend on the process parameters of the PVD process. The methodology used to analyze the coatings included microscopy techniques such as SEM and EDS. The study found that coatings produced using pulsed bias exhibited a considerably higher number of droplets, i.e. the rounded topography, than those produced using DC bias. The duty cycle of the pulsed bias may play a significant role in determining the surface characteristics of the coatings, where pulsed bias coatings with a 10% duty cycle resulted in rougher surfaces, while a 20% duty cycle resulted in smoother surfaces. The surface composition of the coatings exhibits high consistency, characterized by an even distribution of titanium and elevated concentrations of aluminum and nitrogen on droplets from both methods. A higher duty cycle also led to more cracks in the coating. / Den här arbetet undersöker påverkan av pulsering på de mekaniska egenskaperna hos PVD TiAlN-beläggningar. Studien fokuserar på defekter orsakade av droppar under arc-förångning genom att ändra dödtiden, vilket påverkar de mekaniska egenskaperna. Beläggningarnas egenskaper och prestanda beror på mikrostrukturen och liknande karaktärsdrag, som i sin tur beror på processparametrarna för PVD-processen. Metodologin som användes för att analysera beläggningarna inkluderade mikroskopitekniker som SEM och EDS. Studien visade att beläggningar som producerades med pulserad bias hade betydligt fler droppar än de som producerades med likströmsbias. Pulserad bias arbetscykel kan spela en betydande roll för att bestämma ytegenskaperna hos beläggningarna, där beläggningar med en duty cycle på 10% resulterade i grövre ytor, medan en duty cycle på 20% resulterade i jämnare ytor. Ytkompositionen hos beläggningarna uppvisar hög konsekvens, kännetecknad av en jämn fördelning av titan och förhöjda koncentrationer av aluminium och kväve på droppar från båda metoderna. En längre arbetscykel ledde också till fler sprickor på beläggningen.

Novel solar cells are being synthesized from sustainable, non-toxic, and economic materials. All metal oxide semiconductors are one such class of these materials. Synthesis of different combinations of p and n type MO semiconductors heterojunctions as well as high throughput characterization is crucial to improve their applications in fields such as solar cells. A Cu2O/TiO2 Nanorods heterojunction is synthesized on a fluorine doped tin oxide substrate. The TiO2 Nanorods are synthesized via a two-step, solvothermal method. The Cu2O is deposited conformally on the TiO2 NRs via a physical vapor deposition method known as RF magnetron sputtering, with thicknesses of 100, 50 and 25 nm. Characterization methods are used to first determine that the correct materials were synthesized and deposited. Scanning electron microscopy demonstrated that nanorods were made of length, 750 nm, and width, 45 nm. Optical measurements were taken, including: absorbance, transmittance, and reflectance; trends followed the optical data as the thickness of the p-type material increased. From the absorbance data, the bandgap of the materials could be calculated from the generated Tauc plot. The bandgap of TiO2 was calculated to be 3.0 eV which agreed with literature values. The bandgap of Cu2O was calculated to be 2.76 eV which is not in agreement with literature values. X-ray diffraction demonstrated that TiO2 rutile phase was grown, with diffraction angles at: 36.45, 62.747 and 69.766 with their lattice planes being (011), (002) and (112) respectively. Raman spectroscopy demonstrated TiO2 in the rutile phase with Raman shifts at both 447 cm-1 (Eg) and 609 cm-1(A1g). There is a minor peak at 522 cm-1 (T2g) which correlates to Cu2O. Macro-electrical measurements were taken to plot a current vs voltage curve (IV curve), under dark and light conditions. From the macro-electrical measurements Isc, Voc and η (photoconversion efficiency) were calculated: 2.38 E-09 A, -0.18 V, 7.25E-07 respectively (under light, 1 sun equivalent). Atomic force microscopy (AFM) was used to attain topographical images, force/deflection curves, IV curves/maps, and surface potential maps. Conductive-AFM (c-AFM) and Kelvin Probe Force Microscopy (KPFM) were the specific AFM techniques used. From the KPFM measurements it was possible to measure the work functions of TiO2 NRs and Cu2O/TiO2 NRs by using highly oriented pyrolyzed graphite as a reference. The work function for TiO2 NRs was: 4.24 eV and 4.14 eV under dark and light conditions respectively. The work function of the 100 nm Cu2O/TiO2 NRs heterojunction was 4.44 eV and 4.35 eV under dark and light conditions respectively. The apparent work functions that were calculated via this KPFM method were not in agreement with literature values of the respective materials. This thesis has proved that Cu2O/TiO2 Nanorod Heterojunctions can be synthesized using previously known solvothermal synthetic methods. Furthermore these Cu2O/TiO2 Nanorod Heterojunctions have an increase in current under illumination. This current response under illumination has been studied on the nanoscale, using KPFM and C-AFM, as well as on the macroscale. Further investigations on the nanoscale are to be done, which can shed light on how and why these all metal oxide nanorod heterojunctions are functioning as solar cells.

This thesis work aimed to contribute to the development of online characterization techniques for non-metallic inclusions in steelmaking. The study focused on assessing the precision and accuracy of the optical emission spectroscopy pulse distribution analysis (OES/PDA) technique using asreference light optical microscope (LOM) and scanning electron microscope(SEM). Steel samples were collected from three different routes at SSAB Oxelösund steel mill, including vacuum degassing with aluminium or silicon as deoxidizers, and a direct route using magnetic stirring. The precision study compared the inclusion index obtained from each burn spot within the same sample. The precision study includes two parts, the first one compared the dispersion of a set of samples when testing four and eight burn spots, and the second part all the samples were tested to determine the overall dispersion using four burn spots. This study revealed that samples with eight burn spots exhibited higher dispersion and higher average inclusion index, indicating potentially higher inclusion content in the middle section of the sample. Overall, the precision of PDA/OES was found to be satisfactory, with the possibility of further improvement by eliminating outliers. The particle size distribution (PSD) and volume fraction of inclusions obtained from OES/PDA and LOM was compared, and it was observed that OES/PDA yielded higher values in most samples, suggesting limited agreement between the two techniques. Comparing the results of OES/PDA with scanning electron microscopy (SEM) for PSD and volume fraction of inclusions showed relatively better agreement, although accuracy could not be described as entirely accurate. The comparison of the B-factor indicated that OES/PDA generally provided lower values than SEM. SEM was more effective in capturing additions during the steelmaking process, while OES/PDA exhibited lower sensitivity. Finally, the comparison of inclusion chemical composition between OES/PDA and SEM indicated significant disagreement, emphasizing that OES/PDA should not be utilized for this purpose. The limited gathered data from the seven sampled heats indicate that OES/PDA is a precise tool that need more development to be consider accurate to be consider as a monitor tool during secondary metallurgy. / Detta examensarbete syftade till att bidra till utvecklingen av online-karakteriseringstekniker för icke-metalliska inneslutningar i ståltillverkning. Studien fokuserade på att bedöma precisionen och noggrannheten hos OES/PDA-tekniken (Optical Emission Spectroscopy Pulse Distribution Analysis) med hjälp av ljusoptiskt mikroskop (LOM) och svepelektronmikroskop (SEM)som referens. Stålprover samlades in från tre olika produktionsvägar vid SSAB Oxelösundsstålverk, inklusive vakuumavgasning med aluminium eller kisel som deoxidationsmedel, och en direkt produktionsväg med magnetisk omrörning. Precisionsstudien omfattar två delar, den första jämförde spridningen av en uppsättning prover vid testning av 4 och 8 brännfläckar, och den andra delen testades alla prover för att bestämma den totala spridningen med 4 brännfläckar. Denna studie visade att prover med 8 brännfläckar uppvisade högre dispersion och högre genomsnittligt inkluderingsindex, vilket tyder på potentiellt högre inkluderingsinnehåll i den mellersta delen av provet. Precisionen för PDA/OES var överlag tillfredsställande, med möjlighet till ytterligare förbättringar genom att eliminera avvikande värden. Partikelstorleksfördelningen (PSD) och volymfraktionen av inneslutningar som erhållits från OES/PDA och LOM jämfördes, och det observerades att OES/PDA gav högre värden i de flesta prover, vilket tyder på begränsadöverensstämmelse mellan de två teknikerna. Jämförelsen av resultaten från OES/PDA med svepelektronmikroskopi (SEM) för PSD och volymfraktion av inneslutningar visade relativt bra överensstämmelse, även om noggrannheten inte kunde beskrivas som bra. Jämförelsen av B-faktorn visade att OES/PDA i allmänhet gav lägre värden än SEM. SEM var mer effektivt för att fånga upp tillskott underståltillverkningsprocessen, medan OES/PDA uppvisade lägre känslighet. Slutligen visade jämförelsen av den kemiska sammansättningen mellan OES/PDA och SEM på betydande oenighet, vilket understryker att OES/PDA inte bör användas för detta ändamål. De begränsade data som samlats in från dem sju utvalda härdarna indikeraratt OES/PDA är ett exakt verktyg som behöver utvecklas ytterligare för att ansesvara korrekt som ett övervakningsverktyg under sekundärmetallurgi.

Chalcopyrite (CuFeS2) is the most abundant and the most economically important copper mineral. Increasing worldwide demand for copper accompanied by exhaustion of copper resources necessitate the development of new processes for treating lower-grade copper ores. Heap (bio)leaching of copper oxides and secondary sulphides (covellite (CuS) and chalcocite (Cu2S)) is a proven technology and a convenient process due to its simplicity and relatively low capital investment requirement. As a result, the technology appears to be an attractive process option for treatment of low-grade chalcopyrite ores as well. However, chalcopyrite is recalcitrant to leaching and bioleaching in conventional heaps: its dissolution is slow and it halts on a low level of copper extraction usually unacceptable for a commercial practice. Slow dissolution of chalcopyrite is attributed to the formation of compounds on the surface of the mineral during its oxidative dissolution, often termed “passivation”. There is still no consensus about the nature of the passivation layer. There are, however, four proposed candidates suggested in the literature: metal deficient sulphides, polysulphides, jarosite and elemental sulphur. This project was aimed to further investigate the chalcopyrite dissolution and its passivation.In this thesis, dissolution of a pyritic and a pure chalcopyrite concentrate was studied in stirred tank reactors in the absence and presence of moderately thermophilic microorganisms. The abiotic experiments were performed under accurately controlled redox potential conditions to reproduce the same oxidising conditions recorded during the bioleaching experiments. The results showed that the microorganisms did not have any effect in the copper leaching efficiency other than oxidation of ferrous ions to ferric ions. Comparing the copper dissolution rates in the experiments where bulk elemental sulphur was formed with those experiments where the elemental sulphur was oxidised to sulphate due to microbial activity showed that the bulk elemental sulphur did not hinder the dissolution. The same phenomenon was observed in case of bulk jarosite. Under otherwise identical leaching conditions, the presence of bulk jarosite did not decrease the leaching efficiency compared to those experiments were bulk jarosite was not formed. It was also shown that surface spectroscopic methodologies such as X-ray photoelectron spectroscopy (XPS) cannot be applied on powder leached samples due to interfering data from the bulk precipitated species. As a result, massive natural chalcopyrite samples were II prepared and used in the leaching experiments for XPS measurements. Different samples in different stages of leaching were extracted from the biotic and abiotic experiments and analysed by XPS. Results indicated that the surface elemental sulphur was not oxidised by bacterial activity. The data revealed that the common phases on the surface of the samples leached biotically and abiotically for different durations were elemental sulphur and iron-(oxy)hydroxides. The surface elemental sulphur was rigidly bound to the surface and did not volatise in the room temperature XPS measurements. Jarosite was observed in only one sample from the abiotic experiment, but no correlation between its presence and the slow dissolution could be made. Other minor surface compounds such as iron-sulphate was also observed in some samples with no contribution to the leaching behaviour. It was concluded that a multi-component surface phase consisting of mainly sulphur and iron-hydroxides were responsible for the slow chalcopyrite dissolution.

Recycling of secondary raw materials by non-ferrous metal producers is steadily increasing. These materials inevitably introduce various impurities to the production furnaces, which can change the chemical composition, and thereafter, the physical and chemical properties of the products and by-products.Alumina is one of the most common and significant impurities that enters the furnaces in different ways. Finding a balance between the recycling advantages and possible adverse effects of the increased alumina content in the process is of great interest to the metals industry.In the current work, effects of alumina on two of important properties (melting and leaching behaviours) of an actual industrial fayalite slag, from a Swedish copper producer, is investigated.A reference slag sample, devoid of alumina addition, and three different mixtures of slag with 5, 10, and 15 wt-% alumina addition were prepared. After homogenization (re-melting) of the mixtures, in an induction furnace, the materials were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). A standard single stage leaching test was used to study the leaching behaviour of the samples. Differential scanning calorimetry (DSC), Pt-Rh pans, was applied to investigate the melting and solidification properties of the mixtures.Results show that, olivine, spinel, and augite based solid solutions are the three main constituents of the samples. Addition of alumina to the slag increases the amount of spinel solid solution and changes its composition from iron rich to aluminum rich. The slag shows an alumina saturation limit between 5 and 10 wt-% alumina additions. Chemical composition of the major phases does not change above the saturation and excess amount of aluminum is consumed for formation of a new aluminum containing phase, anorthite. Below the saturation limit, alumina addition causes a relatively sharp increase in the melting temperature of the slag, and at the same time, an increase in the leached amounts of the elements is seen. Alumina addition, close to the saturation limit of the slag, lowers the leachability considerably, while the melting characteristics are not changed dramatically. However, above the saturation limit, a more complex transition occurs as the partial melting and leached amounts of most of the elements increase. In order to achieve an appropriate melting and leaching characteristics, the total alumina content of the slag must be close to its saturation limit. The grounds and influential parameters on such behaviours are thoroughly discussed.

Comminution test methods used within mineral processing have mainly been developed for selecting the most appropriate comminution technology for a given ore, designing a grinding circuit as well as sizing the equipment needed. Existing test methods usually require comparatively large sample amounts and are time-consuming to conduct. This makes comprehensive testing of ore comminution behavior – as required in the geometallurgical context – quite expensive. Currently the main interest in the conduct of comminution test lies in the determination of particle size reduction and related energy consumption by grindability test methods, which provide the necessary information about mill throughput. In this procedure mineral liberation is regarded as a fixed parameter due to missing this information in ore characterization as well as a lack of suitable comminution models. However, ignoring the connection between particle size and mineral liberation prevents the scheduling and controlling of the production process from being optimal.For these reasons new comminution tests need to be developed or alternatively the existing test methods need to be suited to geometallurgical testing where the aim is to map the variation of processing properties of an entire ore body. The objective of this research work is on the one hand to develop small-scale comminution test methods that allow linking comminution behavior and liberation characteristics to mineralogical parameters, and on the other hand establish a modeling framework including mineral liberation information.Within the first stage of the study the comminution of drill cores from Malmberget’s magnetite ore, classified by modal mineralogy and texture information, have been investigated. It was found that there is a direct correlation between the mechanical strength of the rock, as received from unconfined compressive or point load tests, and the crusher reduction ratio as a measure for crushability. However, a negative correlation was found between crushability and grindability for the same samples. The grindability showed inverse correlation with both magnetite grade and the magnetite’s mineral grain size. The preliminary conclusion is that modal mineralogy and micro-texture (grain size) can be used to quantitatively describe the ore comminution behavior although the applied fracture mechanism of the mill cannot be excluded.With crushed ore samples from Malmberget also grindability tests and mineral liberation analyses were conducted using laboratory tumbling mills of different size. Starting from the dimensions of the Bond ball mill a modified test method was developed where small size samples of approximately 220 g were pre-crushed and ground in a down-scaled one-stage grindability test. Down-scaling was done by keeping similar impact effects between the mills. Mill speed and grinding time were used for adjusting the number of fracture events in order to receive similar particle size distributions and specific grinding energy when decreasing mill size by the factor 1.63. A detailed description of the novel geometallurgical comminution test (GCT) is given.With respect to ore crushability and autogenous and semiautogenous grinding (AG/SAG) also drop weight tests were conducted. For a more accurate and precise measurement of the energy transferred to the sample a novel instrumented drop weight was used. Initial tests with fractions of drill cores and pre-crushed ore particles showed that the simple energy calculation based on potential energy needs to be corrected. For the future work these tests will be extended to other ore types in order to investigate the effects of mineralogy and to include mineral liberation in comminution models suitable for geometallurgy.

Geometallurgy is a team-based multidisciplinary approach aimed at integrating geological, mineralogical and metallurgical information and yielding a spatial quantitative predictive model for production management. Production management includes forecast, control and optimization of the product quality (concentrates and tailings) and metallurgical performance (e.g. recoveries and throughput); and minimization of the environmental impact. Favourable characteristics of an ore body calling for geometallurgical model are high variability, low mineral grades, complex mineralogy and several alternative processing routes or beneficiation methods.Industrial application of geometallurgy is called a geometallurgical program. This study undertook a critical review and evaluation of methods and techniques used in geometallurgical programs. This evaluation aimed at defining how geometallurgical program should be carried out for different kinds of ore bodies. Methods applied here were an industry survey (questionnaire) along with development and use of a synthetic ore body build-up of geometallurgical modules. Survey on geometallurgical programs included fifty two case studies from both industry professionals and comprehensive literature studies. Focus in the survey was on answering why and how geometallurgical programs are built. This resulted in a two-dimensional classification system where geometallurgical program depth of application was presented in six levels. Geometallurgical methods and techniques were summarised accordingly under three approaches: traditional, proxy and mineralogical. Through the classification it was established that due to similar geometallurgical reasoning and methodologies the deposit and process data could be organized in a common way. Thus, a uniform data structure (Papers I, II) was proposed.Traditionally the scientific development in geometallurgy takes place through case studies. This is slow and results are often confidential. Therefore, an alternative way is needed; here a synthetic testing framework for geometallurgy was established and used as such alternative. The synthetic testing framework for geometallurgy consists of synthetic ore body and a mineral processing circuit. The generated digital ore body of a kind is sampled through a synthetic sampling module, followed by chemical and mineralogical analyses, and by geometallurgical and metallurgical testing conducted in a synthetic laboratory. The synthetic testing framework aims at being so realistic that an expert could not identify it from a true one while studying data it offers. Important and unique aspect here is that the geological ore body model is based on minerals. This means that synthetic ore body has full mineralogical composition and properties information at any point of the ore body. This makes it possible to run different characterisation techniques in synthetic analysis laboratory.The first framework built was based on Malmberget iron ore mine (LKAB). Two aspects were studied: sampling density required for a geometallurgical program and difference in the prediction capabilities between different geometallurgical approaches. As a result of applying synthetic testing framework, it was confirmed that metallurgical approach presents clear advantage in product quality prediction for production planning purposes. Another conclusion was that optimising the production based solely on head grade without application of variability in the processing properties gives significantly less reliable forecast and optimisation information for the mining value chain.For the iron ore case study it was concluded that the number of samples required for a geometallurgical program must vary based on the parameters to be forecasted. Reliable recovery model could be established based on some tens of samples whereas the reliable concentrate quality prediction (e.g metal grade, penalty elements) required more than 100 samples. In the latter the mineralogical approach proved to be significantly better in the quality of prediction in comparison to the traditional approach based on elemental grades. Model based on proxy approach could forecast well the response in magnetic separation performance with the help of Davis tube test. But the lack of geometallurgical test for flotation and gravity separation caused that in total the proxy approach forecast capability was worse than in mineralogical approach. This study is a part of a larger research program, PREP (Primary resource efficiency by enhanced prediction), and the results will be applied to on-going industrial case studies.

Coal used in metallurgical processes can participate in reduction reactions to produce metals and alloys from oxides. Base metals production leads to generation of slag, which contains valuable metals that can be recovered and recycled. There are several options to treat the slag, depending on the metal content in the slag. One is slag fuming, which is a well-established process that is traditionally used to vaporize zinc from zinc containing slags, mainly lead blast furnace slag, but is applied in a few plants for copper smelting slags. In this process reduction is achieved using pulverized coal, lump coal or natural gas. Conventionally pulverized coal injected to the furnace is utilized both to participate in reduction reactions and also to supply heat. On the other hand, the amount of possible alternative reducing agents such as residue plastic material is increasing steadily and the issue of sustainable disposal management of these materials has arisen. As carbon and hydrogen are major constituents of the residue plastic-containing materials, they have the potential to be an auxiliary source of reducing agents, to partially replace conventional sources such as coal. Shredder Residue Material (SRM) is a plastic-containing residue material after separation of main metals. Utilization of SRM as an alternative reducing agent, would lead to not only decreased dependency on primary sources such as coal but also to an increase in the efficiency of utilization of secondary sources. This calls for systematic scientific investigations, wherein these secondary sources are compared with primary sources with respect to e.g., devolatilization characteristics, gasification characteristics and reactivity. As a first step, devolatilization characteristics of SRM are compared with those of coal using thermogravimetric analysis. To study the reduction potential of the evolved materials, composition of evolved off-gas was continuously monitored using quadrupole mass spectroscopy. To gain a better understanding of possible interaction of plastics in a mixture, the devolatilization mechanisms and the volatile composition of three common plastics; polyethylene, polyurethane and polyvinylchloride and their mixture have been studied. Furthermore, gasification characteristics and reactivity of char produced from SRM is compared with coal char. The effect of devolatilization heating rate on gasification rate of char was investigated. Proximate analysis has shown that SRM mainly decomposes by release of volatiles, while coal shows high fixed carbon content, which is reported to contribute to reduction reactions. The composition of volatiles shows H2, CO and hydrocarbons which are known to have reduction potential. Therefore, it is essential that SRM be used in a process that could utilize the evolved volatiles for reduction. The results confirm the interaction between the plastics within the binary and ternary mixtures, which suggests that similar phenomenon may occur during devolatilization of SRM. Although the char produced from SRM contains lower amounts of fixed carbon compared to coal char, it has a porous structure and high surface area, which makes it highly reactive during gasification experiments. In addition to physiochemical properties, the catalytic effect of ash content of SRM char contributes to its higher reactivity and lower activation energy value compared to coal char. Moreover, the gasification reactivity of char produced at fast devolatilization heating rate was highest, due to less crystalline structure of produced char.