Evaluation of Soy Lecithin as Eco-Friendly Reagent for Iron Ore Tailings Thickening Iago Henrique Bernardes Peixoto, Michelly dos Santos Oliveira, Luís Alberto Silva, Natal Junio Pires, Mario Guimarães Junior Minerals, 2026 Managing tailings efficiently remains a critical significant challenge in the mining sector, affecting water usage, industrial process reuse, and environmental safety. Poor disposal practices can lead to water pollution, high infrastructure expenses, and the need for long-term monitoring. To address these challenges, thickening is commonly employed in tailings dewatering to improve particle aggregation and water clarity. In this regard, this study investigates the use of soy lecithin as a biodegradable alternative reagent for iron ore tailings thickening. Bench-scale tests assessed the impact of pH and reagent dosage on sedimentation speed and water clarity. Under optimal conditions (150 g/t at pH 5), there was a 110% increase in sedimentation rate and a 60% decrease in clarified water turbidity compared to untreated tailings. These findings highlight the potential of soy lecithin as a sustainable solution for mineral tailings treatment, providing both environmental and operational advantages, and fostering innovation in the mining industry.
Valorization of cardboard waste in the production of polyurethane biocomposites: A new and environmentally friendly material for civil construction Douglas Lamounier Faria, Laércio Mesquita Junior, Rafael Carvalho do Lago, Julio Soriano, Mário Guimarães Júnior, Natal Junio Pires, Augusto Cesar da Silva Bezerra, Juliano Elvis de Oliveira, Thiago de Paula Protásio, Maria Alice Martins, Leticia Catta Preta da Silva, Lourival Marin Mendes, José Benedito Guimarães Junior, Anand Ramesh Sanadi, Gustavo Henrique Denzin Tonoli Construction and Building Materials, 2025 Cardboard has been widely used in various applications and industry sectors, such as in civil construction as a formwork for concreting circular columns. In addition to the versatility of the product, a vast amount of waste is generated by the manufacturing process. The objective of this work was to determine the properties of green polyurethane matrix thermosetting composites reinforced with cardboard tube waste for application as thermal insulation in buildings. Preliminarily, alkaline solutions of NaOH and Ca(OH) 2 were applied to the residues to remove oils and waxes that affect the polymerization of vegetable polyurethane . The cardboard tube waste was characterized according to its chemical composition, basic density, infrared spectra, atomic force microscopy , X-ray diffraction, and surface SEM images. The composites were produced with 10 % (wt%) treated cardboard waste and without surface treatment to replace vegetable polyurethane through the hand lay-up method. Specimens were obtained from the composites to perform tensile tests , determine the bulk density, water absorption, and thermal conductivity , and visualize the matrix reinforcement interface via SEM. The data indicated that surface NaOH and Ca(OH) 2 treatments significantly increased the tensile strength of the composites by 76 and 187 %, respectively, compared with that of the polymer. For the composites, the use of cardboard waste significantly increased the thermal insulation , as proven by the thermal conductivity varying from 0.0607 to 0.0632 W/(m. K) and compatible with other insulating materials used in civil construction . Thus, composite polymers generated from cardboard tube waste are potential sustainable alternative construction materials.
Flotation performance of phosphate ore before and after dissolved air flotation water treatment Guilherme Henrique Ferreira Silva, Luís Alberto Silva, João Victor da Silva Alves, Natal Junio Pires, Michelly dos Santos Oliveira Revista Materia, 2024 Mineral flotation is a wet concentration operation that has a differentiating effect dependent on the surface properties of the minerals. Water quality is integral to the phosphate ore flotation, since the presence of certain ions in the solution can compromise the effectiveness of the operation. The objective of this study was to compare the effectiveness of phosphate ore flotation (dispersed air) before and after effluent treatment using coagulation, flocculation and dissolved air flotation (DAF) techniques. The mineral flotation tests were performed for new water (NW) and three effluents tailing dams (TD), simulated effluent with high concentrations of calcium and magnesium ions (SE) and simulated effluent after DAF treatment (SEDAF). The simulated effluent underwent two stages of aggregation followed by DAF for cation removal. The results showed that the proposed technique removed 91.6% of magnesium and 66.4% of calcium from the original simulated effluent (SE). The SEDAF presented better average values of mass recovery, content, and recovery of P2O5, confirming the effectiveness of the removing ions suggested as deleterious for mineral flotation. The flotation performance of the DAF-treated effluent was comparable to that of new water. This study underscores the significance of water quality management in optimizing mineral flotation processes.
Removal of methylene blue dye from aqueous solution using coffee silverskin biomass as a low-cost adsorbent André Ricardo Calciolari, Natal Junio Pires, Paulo Fernando Trugilho, Mario Guimarães Junior Revista Materia, 2022 RESUMO A busca por bioadsorventes eficazes e de baixo custo para a remoção de corantes de efluentes industriais tem despertado a demanda por novas pesquisas a fim de amenizar os impactos negativos causados ao meio ambiente. Nesse sentido, o objetivo do trabalho foi avaliar o potencial da pele prata de café (PPC) como bioadsorvente de baixo custo na remoção do corante azul de metileno (MB) de soluções aquosas por meio dos estudos de cinética e equilíbrio de adsorção. O resíduo foi submetido a caracterizações físico-químicas, área de superfície específica (BET), presença de grupos funcionais (FTIR), análise elementar (CHNS-O), ponto de carga zero (pHPCZ) e cristalinidade (DRX). Os resultados mostraram que a PPC apresentou estrutura preponderantemente amorfa composta por holocelulose (38,36%), lignina (34,97%) e minerais (potássio, cálcio e magnésio). A baixa área de superfície específica (0,383 m2/g) foi compensada pela diversidade de grupos funcionais de superfície contendo oxigênio, confirmados pela predominância de carbono (55,93%), oxigênio (32,91%) e hidrogênio (6,37%). A análise pHPCZ mostrou que o ponto de carga zero da PPC foi de 6,49. O processo de equilíbrio foi atingido em 24 h, propiciando uma cinética retratada pelo modelo Elovich (R2(aj.)= 0,999; χ2= 0,233), o qual apresentou valores de taxas de adsorção inicial (α) e dessorção (β), de 2,405 mg/g.min e 0,587 mg/g, respectivamente. A isoterma que melhor se ajustou aos dados de equilíbrio para o sistema foi a de Langmuir (R2(aj.)= 0,991; χ2= 99,176), indicando adsorção em monocamada. A adsorção de MB pela PPC foi favorável, apresentando fatores de separação (RL) entre 0,58 e 0,03. A capacidade máxima de adsorção da PPC (Qmax= 313,69 mg/g) foi superior a outros tipos de adsorventes de baixo custo relatados na literatura, demonstrando assim o seu potencial uso como bioadsorvente para a remoção de corantes catiônicos de solução aquosa.
Euler's criterion as a tool for the study and differentiation between state functions and process variables in chemical thermodynamics Paulo Ortega, Natal Pires, Cláudio Lima Quimica Nova, 2018 In this work, we present a little explored alternative for the study and classification of thermodynamic variables. Some methods in the theory of ordinary differential equations not only support the use and calculation of these variables but also assists the physicochemical interpretation. We explore the Euler's criterion as a resource to study and differentiate the state functions and process variables useful in chemical thermodynamics. For this purpose, we carry out the development of the differentials and their analysis in a simple, rigorous, and progressive way, in accordance with the level of the topics treated in graduate courses of physical chemistry and classical thermodynamics.
