In Brazil, heavy mineral sand deposits are still barely exploited, despite some references to Brazilian reserves and ilmenite concentrate production. The goal of this project is to characterize and investigate the potential recovery of heavy minerals from selected Brazilian placer occurrences. Two areas of the coastal region were chosen, in Piaui state and in Bahia Provinces. In all samples, the heavy minerals of interest (ilmenite, monazite, rutile, and zircon) were identified by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques and also quantified by X-ray fluorescence spectrometry (XRF) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The total heavy minerals (THM) in the Piaui samples were 6.45% and 10.14% THM, while the figure for the Bahia sample was 3.4% THM. The recovery test of the Bahia sample, using only physical separation equipment such as a shaking table and magnetic separator, showed valuable metallurgical recoveries at around or greater than 70% for each stage, and the final concentrate of pure ilmenite was composed of up to 60.0% titanium dioxide after the differential magnetic separation. Another aim is to compile accessible information about Brazilian heavy mineral main deposits complemented with a short economic overview.

The lithium market has been expanding due to the high demand for lithium-ion batteries, which are essential for electric and hybrid vehicles as well as portable devices. This has driven the search for new lithium ore deposits and the development of more efficient extraction and processing technologies. The main methods used for lithium extraction from hard rock ores include the acid process, the alkaline process, and chlorination roasting. This study investigated a chlorination process applied to α-spodumene extracted in Brazil for lithium chloride (LiCl) production. The ore underwent thermal treatment in the presence of calcium chloride (CaCl₂) and magnesium chloride (MgCl₂), followed by water leaching at 90 °C. The thermodynamics of the α-Li₂O·Al₂O₃·SiO₂ system, combined with calcium and magnesium chlorides, was analyzed using HSC 5.1 software. The main objective of this study was to produce lithium chloride from alpha spodumene and avoid decrepitation of the ore to the beta phase before mixing with the reagents, making the process faster and less expensive compared to traditional extraction methods. Pyrometallurgical tests were conducted in a muffle furnace, varying the molar ratio between chlorides (MgCl₂:CaCl₂) at 1:0, 0:1, 1:1, 2:1, and 1:2 and the mass ratio of spodumene to chlorides at 1:4, 1:6, and 1:8. The best lithium extraction result was approximately 95%, the conditions for obtaining the result were a spodumene:chloride ratio of 1:6 and a molar ratio between chlorides of 2:1. The results provide a better understanding of the chlorination roasting process and demonstrate the potential of the chlorination technique as a viable alternative to conventional lithium extraction methods.

In the industrial production of aluminum through the Bayer process, two main pollutants are generated, red mud and carbon dioxide (CO₂). Conventional processes for treating polluting waste include the neutralization of red mud with hydrochloric acid (HCl) and the capture of CO₂ with ethanolamine (CH₂(NH₂)CH₂OH). However, the CO₂ generated can be used to neutralize the red mud, allowing the simultaneous treatment of two harmful substances and reducing the amount of HCl required to neutralize the red mud. The solvent present in red mud is the residual alkaline liquor from the Bayer process, which absorbs CO₂ in a secondary stage, but is not yet considered as a pollutant treatment process. From this perspective, the treatment of two polluting substances (red mud and CO₂) can be carried out in aluminum production plants with lower energy consumption. In the present study, bench and pilot-scale tests were carried out to verify the efficiency of CO₂ adsorption by red mud at a temperature of 25 °C. Among the results of bench tests, 84.05% CO₂ absorption by red mud was obtained. And on a pilot scale, using a bubble column and continuous flow, an efficiency of 96.80% CO₂ absorption was observed with red mud. The study also found that among the most significant variables in this type of treatment are the solid content and mechanical speed.

The objective of the present study is to evaluate the fluid dynamics of a flotation column (2" in diameter and 6 m in height) based on gas hold-up measurements and, in particular, by applying the liquid-phase RTD (residence time distribution) technique. Additionally, a comparative study is performed between different methodologies used to determine RTD hydrodynamic parameters such as fitting of tanks-in-series and axial dispersion models to the experimental data. The evidence indicates that the axial dispersion and tanks-in-series models agreed well with the experimental data, with a slight advantage of the first model, in terms of obtaining the fluid dynamic parameters. It was proven that the axial dispersion model parameters (Pe or Nd) can be obtained with good precision (R2 > 0.99) within the evaluated ranges from correlations that use the number of tanks in series (N) values estimated by the tanks-in-series model.

O lítio é um metal de grande importância para matriz energética mundial devido a sua aplicação na produção de baterias para veículos elétricos e equipamentos de portabilidade (celulares, notebooks, smartphones, ferramentas, etc.). Os produtos de lítio de maior interesse econômico são o carbonato e o hidróxido de lítio, sendo o hidróxido de alta pureza o composto chave principal dos novos projetos de lítio em desenvolvimento no mundo, função de seu uso na fabricação de catodos para as baterias Li-íon com maior potencial energético, que são utilizadas em veículos elétricos (EVs) e sistemas de armazenamento de energia de grande porte (grid storage). As reservas brasileiras de lítio são provenientes de pegmatitos litiníferos, mais especificamente os minerais espodumênio e ambligonita. A indústria nacional utiliza a rota ácida para a produção de carbonato de lítio, a qual está estabelecida desde a década de 40, mas com custo operacional alto, devido à utilização de barrilha e ácido sulfúrico, insumos caros e importados e que são descartados durante a obtenção do hidróxido. Com o intuito aumentar a sustentabilidade do processo e a competitividade da indústria brasileira no mercado global, fornecendo um produto de maior pureza e menor custo, percebeu-se a necessidade do desenvolvimento de novas rotas de obtenção deste composto, o hidróxido. Foi desenvolvida uma rota alternativa, partindo-se das etapas iniciais do processo ácido e concluindo-se com a rota alcalina, cujo princípio baseia-se na caustificação do sulfato de lítio, até a obtenção do hidróxido de lítio. A recuperação metalúrgica de lítio, nessa etapa do processo, foi superior a 98%. O hidróxido de lítio monohidratado obtido possui uma pureza de 55,07%, superior a do produto produzido pela indústria nacional.

The present study aimed to estimate the contribution of the mining and mineral processing steps of lithium concentrate production in Brazil to the Global Warming Potential (GWP100) using an LCA perspective. No previous national study was identified that quantified national GHG emissions in mining and beneficiation operations for lithium ores. This study is considered original and aims to contribute to filling this gap. The functional unit was 1 ton of lithium carbonate equivalent (LCE) in the mineral concentrate. The contribution to GWP100 was estimated at 1220 kg of CO_2eq per ton of LCE, of which 262 kg originated from foreground processes. In the background processes, the largest contribution was 456 kg of CO_2eq from emissions in the production of ammonium nitrate, used in the manufacture of mining explosives. An analysis of substituting electricity sources in the product system showed a reduction of 22.7% and 14.7% in the estimated global warming impact when using wind or solar power, respectively.