Mineral extraction of coal in the carboniferous region of southern Santa Catarina (Brazil) plays a significant role in the regional economy. However, this activity has severe environmental impacts, with approximately 65% of the extracted mineral being discarded as a rejected material (deposited in landfills). The identification of the technological potential of these materials, based on the geological aspects of the extraction site and the beneficiation operations applied to obtain coal, provides the opportunity to add value to different residual fractions that can be reused. Thus, waste valorization, the main objective of this work, has recently become a strategy for the application of these minerals in the production of clay ceramics using a systematic approach named CPQvA, which means “classification, potentiality, quantity/viability, and applicability”. The use of these materials as secondary mineral sources can avoid the deposition of these materials in industrial landfills and help to reduce the pressure on landfills, which receive an average of four million tons of material annually. In this study, the residual fraction, part of the tailing from coal beneficiation, known as coal fines, was evaluated for formulation valorization in clay ceramics. This residual fraction was classified as non-hazardous (class II-A, non-inert). X-ray fluorescence spectrometry, X-ray diffraction, and thermogravimetric analysis were performed to characterize the moisture content, particle-size distribution, and coal content to be used in the development of different formulations using the residual fraction of coal tailings (ranging from 0 to 40%) that are of technological interest to the sector. Processing parameters, such as firing at different temperatures (750, 800, 850, and 900 °C), were also correlated with these formulations. The results were compared with those of a reference ceramic formulation from the local productive arrangement of Morro da Fumaça (Arranjo Produtivo Local Cerâmica Vermelha de Morro da Fumaça). The various relationships between the materials were characterized in terms of their thermal shrinkage, water absorption, and mechanical resistance. Leaching and solubilization environmental tests revealed that both the industrial standard formulation and formulations with the application of the residual fraction were classified as non-hazardous materials. Thus, the method of using a mining residual fraction in the formulation of clay ceramics proved to be beneficial for the circular economy in the regional mineral sector through productive and environmental gains; the primary mineral resource and energy consumptions and the impacts related to waste generation were reduced. The results of this study can be applied to similar situations in other parts of the world.

In order to obtain solutions to the coal mining region demand in southern Brazil for high-performance and low-cost technosols within a concept of mineral circularity and sustainable development of the coal sector, this study aims to evaluate the functional feasibility of the combined use of a residual fraction of coal tailing, waste from the rice and poultry agro-industry, as well as the cellulose industry, as raw materials for technosol development. Characterizations (XRF, LOI, ICP-OES, pH, XRD, and sulfur forms) were performed to adjust the waste proportions used in the constructed soil, as defined based on the clay content of the coal tailing, the organic carbon content of the poultry litter, and technical recommendations for the use of synthetic gypsum in agricultural soils. Based on the characterizations of the residues, a greenhouse experiment was designed, consisting of four technosol formulations (T1–T4). Initially, an ecotoxicity test was conducted with the treatments in contact with Allium cepa L. (onion) to determine the degree of technosol toxicity. Field tests were then carried out, which were replicated three times in a completely randomized block design, with the germination and growth of Lactuca sativa L. (crisp lettuce) as a bioindicator. The fertility of the treatments was analyzed eight weeks after the establishment of the experiment and compared to standard values for agricultural soils. The characterization performed with the individual wastes demonstrated the potential for application in technosols according to current regulations. The ecotoxicity tests showed that the soil was not toxic to the plant in any of the treatments studied. The field experiment demonstrated no difference in germination between the treatments. However, the development of lettuce seedlings occurred only in technosol formulations T2 and T3, highlighting the potential of the studied residues for the construction of technosols.

A ocupação do ambiente e o uso humano dos recursos hídricos levam a alterações químicas, físicas e biológicas dos corpos d’água, que refletem a qualidade ambiental das bacias hidrográficas. Este estudo objetivou avaliar a integridade ambiental da Bacia Hidrográfica do Rio Araranguá (BHRA), localizada no sul de Santa Catarina, sul do Brasil. A coleta de dados se deu em escala local e em escala da paisagem, a partir da aplicação de Protocolo de Avaliação Rápida de Integridade Ambiental (PAR), para analisar as relações entre as atividades antrópicas, a estrutura física e biótica dos rios. Foram definidos seis locais de análise ao longo da BHRA, um no terço superior, dois no terço médio e três no terço inferior, os quais foram avaliados no mês de abril de 2022 por oito pesquisadores devidamente familiarizados com a aplicação do PAR. Os resultados evidenciaram que dois trechos foram classificados como impactados, três como alterados e um natural. Observou-se que os núcleos urbanos e a agricultura extensiva, representada pela cultura do arroz irrigado, são os principais detratores dos recursos hídricos principalmente por levarem a redução nas matas ciliares e a degradação na qualidade física, química e biótica da bacia. O PAR se mostrou como um instrumento de avaliação rápida eficiente, passível de ser aplicado, inclusive pelo público leigo, desde que devidamente treinado. Não obstante sugere-se a realização de estudos que envolvam maior número pontos de amostragem, para uma análise mais pormenorizada da integridade ambiental da bacia hidrográfica avaliada.

The main focus of this study, from a sustainable perspective, was to develop mineral circularity actions for the minimization of environmental impacts, generated over decades by the processing of run-of-mine (ROM) coal in the Catarinense coal basin–Brazil (CCB–Br), from the use of potential residual fractions (candidate residues) as raw materials for the production of organo-mineral fertilizers, or OMFs (candidate products). Therefore, the objective was to assess the potential of the residual fractions, generated in the distinct phases of ROM coal processing, as candidate waste for valorization, contributing directly to the advancement of the Sustainable Development Goals (SDGs). The samples from ROM processing resulted in 24 waste fractions identified by geological characteristics and a sustainable processing methodology. These fractions were subjected to a systematic analysis using the criteria for waste valorization CPQvA (classification (C) of hazardousness, potentiality (P), quantities/viability (Qv), and applicability (A)). Two samples were identified with significant potential for valorization in the agro-industry as sustainable raw materials for the organo-mineral fertilizers. Both samples exhibited neutral stock pH values (7.0 and 7.1), low percentage Fe₂O₃ content (4.2% and 3.2%), low SO₃ content (0.5% and 1.2%), and low total sulfur content (1.0%). These characteristics qualified the studied ROM samples as raw materials suitable for the production of organo-mineral fertilizers (OMFs), and which comply with Brazilian legislation.

Resumo A reutilização de resíduos industriais é crucial para práticas sustentáveis na indústria da fundição. Este estudo caracteriza a areia descartada de fundição (ADF), comparando-a com a areia comum (CS) e avaliando seu comportamento temporal e variação dimensional em matrizes cimentícias. Foram realizados ensaios de granulometria, massa específica e unitária, índice de vazios, absorção de água, MEV, classificação do resíduo sólido, análise de fenóis no extrato lixiviado, perda ao fogo, TGA, FTIR, GC-MS, EDS e toxicidade aguda. A análise temporal mostrou uma redução nos valores de carbono com o tempo de armazenamento, atribuída à alteração química dos compostos orgânicos. Ensaios de perda ao fogo e TGA corroboraram as concentrações de fenol detectadas, enquanto análises por FTIR indicaram decomposição parcial da resina fenólica no processo industrial. A variação dimensional da argamassa no estado fresco foi avaliada, destacando a importância de utilizar moldes de 20 cm com discos indicadores para medição precisa. Os resultados sugerem que a ADF pode ser utilizada como matéria-prima na construção civil, conforme a legislação vigente.