contributing to the circular economy and sustainable solutions. KEYWORDS Montmorillonite, organoclay, PLA, packaging materials, bionanocomposites 1. INTRODUCTION During mining operations, the comminution process inevitably generates large volumes of fine particles, which can negatively impact subsequent beneficiation steps. However, these fines can be transformed from a potential problem into an opportunity to add value and improve overall process efficiency [Middea ET AL., 2024]. Bentonites, with their unique crystallochemical properties, have emerged as highly sought-after materials for obtaining higher-value-added products. Their chemical structure can be modified, making them suitable for various applications, including catalysis, water pollutant removal, and the production of nanocomposites for food packaging [Chokri ET AL., 2025]. The main mineral constituent of bentonites is montmorillonite, which co-exists with interstratified smectite minerals and associated phases [Guven, 2009]. The layered structure and ability of bentonites to exfoliate into nanoparticles make them an ideal raw material for bionanocomposites, particularly in food packaging. This approach promotes the reuse of clay fines as a circular economy alternative, reducing waste and promoting sustainability. The use of biopolymers, such as polylactic acid (PLA), as packaging materials is gaining attention due to their biodegradability, biocompatibility, and renewability [Lima ET AL., 2021]. The addition of organoclay to PLA improves its mechanical and barrier properties, making it a suitable material for food packaging [Prapruddivongs ET AL., 2014]. This research aims to develop packaging materials from fines generated in mineral beneficiation processes, promoting process innovation and resource recovery, and aligning with circular economy principles. The resulting nanocomposites were characterized using various techniques, including XRD, FTIR, TGA/DTADSC, SEM/EDS, and mechanical testing. 2. EXPERIMENTAL 2.1 Materials Bentonite samples were sourced from the Bravo mine in Boa Vista, Paraíba, Northeast Brazil, a region accounting for the country's highest production (Figure 1). Two types were obtained, classified according to the mining company's chromatic categorization: chocolate (brown) and bofe (beige). The clays underwent physical concentration at Embrapa and chemical treatment at CETEM/Brazil to facilitate cation exchange in the exfoliated lamellae with cationic surfactants [Morita et al., 2015]. Cetyltrimethylammonium bromide (CTAB) (MERCK, analytical grade) was used as received. Polylactic acid (PLA) (PURAPOL 175, Corbion Purac) was supplied by 2M3D (Novo Hamburgo, Rio Grande do Sul, Brazil).
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