Maria Holuszko

Associate Professor

Relevant Thesis-Based Degree Programs


Graduate Student Supervision

Doctoral Student Supervision

Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.

Characterization and extraction of rare earth elements from metallurgical coal-based source (2023)

As global society moves towards a low-carbon economy, secure access to raw materials becomes the key bottleneck in achieving a green transition. Alternative resources such as coal-based materials have been evaluated for rare earth production in recent years to reduce import dependence and diversify production geographically. This study explores the possibility of using metallurgical coal-based materials from the East Kootenay coalfields in British Columbia as a source for rare earth elements (REEs). First, a characterization study was carried out to understand the target REEs and gangue mineralogy. The results showed that the concentration of REEs in the feed material varied between 230 to 314 mg/kg on an ash basis. When subjected to flotation, most of the REEs (by wt.%) were deported to waste streams such as middlings and tailings due to the inorganic (mineral matter) association of REEs. A mineralogical examination found that one of the rare earth-bearing minerals was monazite and indicated the presence of fine-sized multiple rare earth minerals in the sample. Feedstock materials were studied using different leaching techniques. Results demonstrated that acid baking followed by water leaching (ABWL) was the suitable method for extracting REEs for the samples studied. Acid dosages and bake temperature were found to be the most important process variables affecting REE extraction. The kinetic analysis showed that the process was controlled by interfacial transfer and diffusion through product layer, with an apparent activation energy of approximately 15 kJ/mol. The ability to recover REE ions from the leach solution was examined with a modified fruit peel. Results indicated that the new adsorbent was effective in adsorbing REE ions from the solution following the Langmuir isotherm model, with estimated equilibrium maximum adsorption capacities for Y³⁺, La³⁺, Dy³⁺, Er³⁺ of 34.99, 60.51, 65.08, and 66.79 mg/g, respectively. Further, an economic assessment of two process flowsheets examined for REE extraction showed that plant capacity, REE concentration in the feedstock, and price were key parameters affecting project economics. In addition to REEs, the co-production of other valuable elements from the feedstock has the potential to significantly improve the project’s viability on an industrial scale.

View record

Characterization of non-metal fraction of waste printed circuit boards to promote recycling (2021)

Electrical and electronic equipment has become an integral part of modern society. With the current technological advances, the life span of this equipment has been shrinking, leading to waste generation and issues related to end-of-life waste disposal. The circular economy model has been proposed to address the growing volume of e-waste. The model encourages reduction and reuse to decrease waste generation and encourages recycling to promote efficient natural resource usage.One of the challenges with promoting the circular economy model for e-waste is the insufficiency or absence of the recycling process for the non-metal fraction. The low value associated with the non-metal fraction increases its probability of being disposed of in landfills. This research explored the possibility of utilizing low-cost physical separation processes common in the mineral processing industry to recycle the non-metal fraction obtained from waste printed circuit board.The study showed that a density-based separation could theoretically be used to separate organic, inorganic, and residual metal streams from the non-metal fraction, thus increasing its reusability. The float-sink test and derived washability curves and washability indices showed that a conceptual three-product gravity separation process could produce an organic fraction with 47% yield at 86% organic content and a reject stream with a 35% yield at 72% fiberglass content. A gravity separation-based flowsheet was proposed for the recycling of non-metal fraction, and the potential applications of the recycled products were identified. Further test work at the pilot level would be required to estimate the process efficiency, related costs and understand the product characteristics for their proper application.This research also provided a simplified approach for determining the loss on ignition that can be used to estimate the separation efficiency. It also showed the applicability of advanced techniques such as inverse gas chromatography and micro-FTIR for analyzing the surface heterogeneity and polymeric identification of non-metal fraction components. Overall, the research used an interdisciplinary approach to provide a potential solution for the non-metal fraction to the recycling industry using tools and processes used in the coal and mineral processing industry.

View record

Investigating methods to improve the co-firing of biomass with coal using CFD simulations (2021)

Biomass as a renewable energy source can be burnt with coal in a coal-fired plant to reduce the impact of fossil fuel on the environment. The aim of this research is to investigate methods that can improve the co-firing of biomass with coal. Initially, a CFD model was validated by comparison with experimental data reported in the literature. Three mesh sizes were tested to prove that simulation results are mesh independent. The model was then applied to simulate the co-firing process with a 3:2 biomass-to-coal mixing ratio. Unsophisticated modifications of the furnace geometry near the inlet and the swirl angle were introduced to study their effect on co-firing. CFD simulations were extended to study the influence of particle shrinkage on co-firing due to biomass pelletization. Furthermore, fine coal tailings generated from coal processing (CT), raw biomass (RB), and torrefied biomass (TB) were characterized for subsequent CFD investigation on mono-firing and co-firing of the different fuels. Simulation results show that the modified furnace geometry with gradual expansion and a larger swirl angle leads to uniform temperature distribution (1650-1720 K) in the furnace vs. a more variant temperature profile (950-1500 K) for the original furnace geometry. Besides, an increase in the tangential component of gas velocity near the center from 1 m/s to 3 m/s with the modified furnace geometry results in a longer residence time of the particles and further reduction of unburnt fixed carbon by 55% from coal at the exit. With biomass pelletization, simulation outputs show that the compressed particles with particle density 1000 kg/m³ have slower volatilization rate and surface reaction, as well as a shorter residence time. This in turns causes a higher percentage of unburnt fixed carbon at the exit though NO emission is slightly lower. As for the co-firing of biomass with fine coal tailings, results indicate that CT alone, CT+TB, and CT+RB blended fuel are associated with 13%, 10% and 28% unburnt carbon, respectively. It may be concluded that co-firing coal tailings with torrefied biomass is better for co-firing since CT+TB also has the lowest NO emission among the different fuels.

View record

Master's Student Supervision

Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Assessment of dual-energy X-ray transmission image analysis process on sulphide ore and coal cases (2023)

Dual Energy X-ray Transmission (DE-XRT) technology has been widely used for hard rock ore sorting as well as for coal beneficiation purposes. Although there is an abundance of publications on research conducted using the DE-XRT system, there is a very limited number of publications discussing how the results are generated from the raw X-ray signal responses. Since the relative density values generated from the raw X-ray images could potentially alter the final DE-XRT result, it is important to study the image processing methods used to produce the relative density from raw X-ray images. In this thesis, the two known methodologies, the single curve method and dual material decomposition method (the name is used interchangeably with “dual curve method” in this study) were discussed and compared in two studies: a sulphide classification and sortability study (case 1) and a coal washability study (case 2). This thesis also attempts to use a more mathematical approach that takes into account all pixel values of the studied samples. In both case studies, the calibration curves used in single and dual curve methods are generated by evaluating the high and low pixel intensities on the H-L graph. The two sets of relative density results generated from the single curve and dual curve method are used to compare with the equivalent gold assay grades to classify rocks and perform sortability analysis in case 1. In case 2 they are used to compare with ash content and specific gravity (S.G.) plots to develop washability correlations. The results for case 1 show nearly identical performance on sulphide classification and sortability studies between the single curve and dual curve methods with the dual curve method slightly outperforming the single curve method. However, the DE-XRT results generated from both methods were not able to perform effectively “equivalent gold-grade” prediction. In case 2, although the dual material decomposition method outperformed the single curve method on all washability-related analyses, both methods were relatively effective at predicting ash content and S.G. and then could be effectively used for the prediction of washability curves.

View record

Preliminary assessment of hydrophobic-hydrophilic separation for pre-concentration of ree from coal tailings and alike material (2023)

No abstract available.

Application of acoustic measurements in fine coal processing (2022)

Metallurgical coal production is crucial for the world economy. It is the main ingredient in the steelmaking process, while steel is used in construction, infrastructure, transportation, new green renewable technologies, and everyday home appliances. Flotation has been commonly used to treat very fine ore and coal; however, flotation is a complex process requiring modern automation devices to be installed to maximize its efficiency. These sophisticated systems are usually cost intensive in terms of purchase and maintenance and require someone with qualified expertise to operate them. As a result, it is difficult for some companies to implement high-tech technology, so they must rely on manual sampling—resulting in costly decision-making delays. As a result, the main focus of this research was to find a suitable method to monitor the coal flotation process using acoustic monitoring as an alternative to other conventional approaches.The acoustic monitoring method was previously tested on ore and showed reasonable efficiency in monitoring froth in the flotation using coalescence phenomena as a process indicator. For the previous research, custom-made and industrial types of hydrophones were used in the experimental work, and their ability to monitor froth was confirmed in full-scale processing plants. For this research, it was decided to carry out a fundamental analysis to determine whether the sound signal could be directly correlated with solids content in the slurry and provide information on froth loading as an indicator of flotation efficiency.The commercially available acoustic equipment was acquired for the research; it met all the requirements from an efficiency point of view and had the flexibility to be used at the processing plant. This setup was shown to be fairly robust at the laboratory scale, and it had a reasonable response to changes in solids content in the tested coal samples. As a result, it was found that this type of monitoring approach could be used, and it will perform well since it does not require a high degree of qualifications or sophisticated skills to operate. In addition, the setup has the potential to be integrated into an automation system at an operating processing plant.

View record

Chemical composition of coal surface as derived from micro-FTIR and its effects on contact angle (2016)

In this study, in-situ image analysis, contact angle measurements, micro-FTIR spectroscopy and SEM are used to obtain information on the surface composition of coal. The heterogeneous coal surface is investigated with regard to the distribution of the chemical functional groups and its effect on hydrophobicity as derived from contact angle measurements. Contact angles obtained from sessile drop and captive bubble techniques are correlated with the semi-quantitative ratios from micro-FTIR spectroscopy. As part of the new methodology, image analysis and SEM are also applied in order to characterize and analyze for the petrographic composition of areas that are subjected to these measurements. An opposite trend between high rank coal and low rank coal is found in relation to the micro-FTIR semi-quantitative ratios versus contact angle. For lower rank coal, the increase in Aromaticity 1 and 2 led to an increase in the contact angle, while the increased quantity of aliphatic groups decreased the contact angle values. For high rank coal, the rising aliphatic groups increased the contact angle values and the increase in Aromaticity 1 and 2 led to smaller contact angle values. The newly introduced CHal/C=O was used to assess the abundance of aliphatic groups and oxygenated groups. The increased content of oxygenated groups in the high rank coal samples led to a decrease in the contact angle, which is consistent with the findings of previous studies. For low rank coal samples, although the correlation was less distinct, an opposite trend was observed.

View record

Current Students & Alumni

This is a small sample of students and/or alumni that have been supervised by this researcher. It is not meant as a comprehensive list.

If this is your researcher profile you can log in to the Faculty & Staff portal to update your details and provide recruitment preferences.


Discover the amazing research that is being conducted at UBC!