The current increase in the use of photovoltaic (PV) energy demands the search for solutions to recycle end-of-life modules. This study evaluated the use of a mechanical pre-treatment in the thermal recycling of c-Si crystalline PV modules, which were submitted to recycling routes to separate and concentrate the materials of interest. The first route was constituted by only thermal treatment, and the second route was constituted by a mechanical pre-treatment to remove the polymers from the backsheet, and subsequent thermal treatment. The exclusively thermal route was performed at 500°C, varying dwell times between 30 and 120 minutes in the furnace. In this route, the best results were obtained in 90 minutes, with a maximum degradation of 68% of the polymeric mass. In route 2, a micro-grinder rotary tool was used to remove the polymers from the backsheet and, subsequently, thermal treatment performed at 500°C, with dwell times in the furnace ranging between 5 and 30 minutes. The mechanical pre-treatment removed about 10.32 ± 0.92% of the mass of the laminate PV module. By this route, only 20 minutes of thermal treatment were needed for the total decomposition of the polymers, that is, a reduction of 78% in the oven time. With route 2, it was possible to obtain a concentrate with 30 times more silver than the PV laminate and 40 times more than a high-concentration ore. Furthermore, with route 2 it was possible to reduce the environmental impact of heat treatment and energy consumption.

This work investigated the thermal treatment to separate and concentrate economically valuable materials from laminates of crystalline silicon photovoltaic modules (i.e., photovoltaic modules without the aluminum frame and the junction box). Chemical characterization of the metal content was performed by X-Ray Fluorescence (XRF). The polymers of the backsheet were also characterized by Fourier Transform Infrared Spectroscopy (FTIR). The influence of the atmosphere (oxidizing and inert) on the decomposition of the backsheet was investigated by Thermogravimetric Analysis (TGA). Moreover, non-comminuted samples were tested for 4 thermal time lengths (30, 60, 90, and 120 min) in the furnace under ambient air. The degradation of the polymers was measured and 3 material fractions were obtained: silicon with silver and residual polymers (SS), glass and copper ribbons. Furthermore, there was no statistical difference between the mass losses of the samples submitted for 90 (13.62 ± 0.02 wt.%) and 120 min at 500 °C (p-value = 0.062). In the SS fraction, silver was 20 times more concentrated than in the ground photovoltaic laminate and 30 times more concentrated than high silver concentration ores. The SS fraction (about 6 wt.%) also presented low copper concentration and a high concentration of lead (hazardous metal). About 79 wt.% glass was obtained, as well as 1% copper ribbons (55.69 ± 6.39% copper, 23.17 ± 7.51% lead, 16.06 ± 2.12% tin). The limitations of the treatment and its environmental impact are discussed, and suggestions for industrial-scale application are given.

Recent increases in the demand for automotive lithium-ion batteries (LIBs) have led to higher needs for critical materials like lithium, cobalt, nickel, and graphite. Consequently, recovering materials from spent batteries has gained importance. This study aimed to (1) develop a mechanical pretreatment method for separating and concentrating materials from spent NCM₈₁₁ cells and (2) evaluate the economic, environmental, and shortage potentials of these fractions. The pretreatment involved grinding and granulometric separation, producing six particle-size fractions. The main novelty of the study was the assessment to identify the particle size fractions which are priorities for recycling for decision-making by recycling companies, optimizing their resources and efforts. Analysis showed that the finest fraction (n < 0.5 mm) had 85% of lithium, 77.4% of cobalt, 75.1% of manganese, and 68.5% of nickel. This fraction represented 40.4% of the processed mass and had the highest economic value (USD 3669/ton NCM cell). This fraction was also prioritized for recycling due to its superior environmental impact (103,788 kg CO₂-eq/ton NCM cell) and scarcity considerations. Furthermore, the black mass of NCM was the priority for recycling and had greater economic, environmental, and supply risk potential than the black mass of LFP cells.

In 2022, global solar energy capacity reached 1 TW and is expected to double by 2026. Predictions suggest that photovoltaic waste, which contains environmentally harmful elements such as lead and cadmium, could exceed 70 million tons by 2050. Therefore, this study aimed to assess the hazardous nature of four photovoltaic module technologies: polycrystalline silicon (p-Si), cadmium telluride (CdTe), amorphous silicon (a-Si), and copper indium gallium selenide (CIGS). This work involved chemical characterization and leaching tests for solid waste classification. The leaching procedures strictly adhered to American (TCLP 1311), European (EN 12457-2), and Chinese (HJ/T299) standards. Results indicated that the p-Si module was deemed hazardous as it exceeded the Pb tolerance limits of both the TCLP 1311 (8.69 mg/L) and HJ/T299 (7.35 mg/L) standards. The CdTe module was considered hazardous as it surpassed Cd tolerance limits in all the studied standards: TCLP 1311 (1.01 mg/L), EN 12457-2 (1.86 mg/L), and HJ/T299 (4.74 mg/L). The CIGS module was identified as hazardous according to the EN 12457-2 standard, exceeding a Se tolerance limit of 0.56 mg/L. The a-Si module did not exceed the maximum concentration levels set by the standards for the analyzed elements, although traces of toxic metals were observed in the leachate.