The growing volume of end-of-life (EoL) photovoltaic (PV) panels presents a significant challenge and an opportunity for sustainable resource recovery. This thesis investigates the application of Magnetic Density Separation (MDS) to recover and separate valuable non-ferrous metals, such as silicon, copper, zinc, tin, and silver, from crystalline silicon PV waste. The objective of the study is to evaluate the separation efficiency and recovery rates of MDS while addressing economic feasibility and process optimization challenges.
The experimental work involved the use of MDS to fractionate PV waste into light, medium, and heavy-density ranges based on particle size distributions: 200–500 µm, >500 µm–3 mm, and >3 mm-6 mm. X-ray fluorescence (XRF) was employed to analyze the elemental composition of the separated fractions, with leaching processes using hydrochloric acid (HCl) and citric acid applied to assess the purity of magnetic samples. Calibration and instrumental errors, as well as the effects of alloying and particle motion, were accounted for in the analysis. A financial assessment of the MDS process was conducted, examining revenues generated from metal recovery and associated costs, including the economic implications of contamination and refining. The results revealed that MDS achieved moderate separation efficiencies, with high recovery rates of silica (SiO2) in the form of glass and sand in the light fractions and silver (Ag) and copper (Cu) in the heavy fractions. However, significant contamination was observed due to overlapping densities of alloyed metals, such as Tin-silver-copper (Sn-Ag-Cu) and Zinc-copper (Zn-Cu), and particle agglomeration during feeding. A financial snapshot demonstrated that medium- and large-sized fractions contributed the most to revenue, driven by silver recovery, with a break-even point requiring the processing of at least 114 tons of PV waste. In conclusion, MDS shows significant potential as a low-energy, cost-effective solution for recycling EoL PV panels. However, achieving industrial viability requires addressing contamination issues and optimizing the separation process. Future work should focus on integrating complementary refining techniques and scaling up operations to meet purity standards and economic demands. The study also recommends the need for improved ferrofluid magnetization and alloy-specific calibration to enhance detection limits.

With the continued growth of the offshore sector and plans for new wind farm developments, shallow marine environments are becoming key areas for the renewable energy projects. As a result, the likelihood of encountering glauconitic sands is growing, posing challenges to the offshore wind infrastructure. Glauconite, or glauconitic sand, also known as ‘greensand’, refers to a soil containing peloidal sand-sized grains primarily comprised of mineral glauconite, an iron- and potassium-rich 2:1 interlayer-deficient mica. The tendency of glauconite to transform from sand to fine-grained soil with shearing creates uncertainties in site characterization and negatively impacts pile drivability to targeted depths. This thesis examines shearing behavior of glauconitic sands at soil-pile interface using two samples of Belgian glauconitic sands. With the final goal being the derivation of reliable interface shear strength parameters, the study aims to develop test procedures capable of capturing the transition of glauconitic sands from their natural uncrushed state to a reworked degraded condition, simulating the effects of shear-induced particle breakage during pile installation. To achieve this, a systematic experimental program was completed in two phases. The first part focused on glauconitic sands in their natural state and the second aimed to assess the degraded soil. Comprehensive material characterization, including geotechnical index tests, mineralogical analyses, and soil-steel interface direct shear tests under various conditions, was carried out to support each phase. The findings link the interface shear behavior and strength of glauconitic sands to their intrinsic properties, identify limitations in current experimental procedures, and offer recommendations for future research. New insights are provided into the behavior of Belgian glauconitic sands with the relatively low glauconite content and varying crushability potential. Interface roughness, shear rate, and normal stress effects are considered.