In the earth's crust, iron is the fourth most abundant element, and Brazil is characterized by having reserves with a high iron content, generating a quality ore, ensuring the country stands out in the world market as the second largest in iron production.Updating information about production and mineral reserves is crucial for better planning, use and technological development of reserves, especially considering the current context, where reserves of high grades are running out.Project Bloco 8, under the responsibility of Sul Americana de Metais S/A (SAM), is located in the northern region of the state of Minas Gerais, and estimates a production capacity of 27.5 million tons per year of pellet feed.To this end, the project seeks to work with innovations in the sectors of beneficiation, dams and water recirculation so that low-grade mining is used satisfactorily.

The use of antioxidants in biodiesels, especially the synthetic TBHQ, has been an efficient way of maintaining the oxidative stability of biofuel during storage for a longer period. Considering other types of products, the use of several natural antioxidants, such as Eugenol, has been promising to increase oxidation stability and conservation of foods, with few studies on biodiesel conservation. This study aimed to evaluate the antioxidant action of Eugenol and TBHQ in commercial biodiesel produced from soybean oil and animal fat blend in order to evaluate the efficiency of these antioxidants. Thus, the samples of pure commercial biodiesel (without antioxidant), enriched with the antioxidant TBHQ and Eugenol were prepared and stored in an oven at constant temperature of 43 degrees C for 150 days. Periodically, the samples were characterized by ultraviolet absorption spectroscopy and oxidation stability (Rancimat method). They were also chemically characterized concerning the acidity, peroxide and iodine amounts. The results showed higher efficiency of the antioxidant Eugenol in relation to the TBHQ, considering that the oxidation stability was within the standard legislations.

ResumoOs sistemas de óxidos cerâmicos são frequentemente investigados para os mais diversos propósitos, sejam como refratários, pigmentos, cerâmicas eletroeletrônica ou semicondutores fotocatalíticos, entre várias outras aplicações. Muitos deles, como a alumina, a sílica, a zircônia e a titânia, acabam por se tornar ótimas matrizes adsorventes e de catalisadores, mas podem ter seus desempenhos significativamente melhorados com a modificação como outros tipos de óxidos não refratários, mas com excelentes propriedades adsortivas, como o cobre, molibdênio, vanádio, cério, entre outros. No entanto, materiais heterofásicos de sistemas ternários ou quaternários de óxidos metálicos são de difícil controle morfológico e estrutural e poucos métodos são mais adequados para a obtenção deste tipo de material do que o Método Sol-Gel. Um destes sistemas é TiO2-CeO2-V2O5, investigado neste trabalho, do ponto de vista das alterações morfológicas e estruturais que ocorrem ao longo do processo de tratamento térmico, sofrendo transições de fases e coalescência de poros. Palavras-chave: Cerâmica. Morfologia. Cristalização. Refratário. Equilíbrio de fases. AbstractCeramic oxide systems are frequently investigated for the most diverse purposes, whether as refractories, pigments, electro-electronic ceramics, or photocatalytic semiconductors, among many other applications. Many of them, such as alumina, silica, zirconia and titania, end up becoming excellent adsorbent matrices and catalysts, but their performance can be significantly improved with the addition of non-refractory oxides, but with excellent adsorptive properties, such as molybdenum, copper, molybdenum, vanadium, cerium, among others. However, heterophasic materials from ternary or quaternary systems of metal oxides are difficult to control from a morphological or structural point of view and few methods are more suitable for obtaining this type of material than the Sol-Gel Method. One of these systems is named TiO2-CeO2-V2O5, as investigated in this work, and a sample of this system was investigated from the point of view of the morphological and structural changes that occur throughout the heat treatment process, undergoing phase transitions and significant pore coalescence. Keywords: Ceramics. Morphology. Crystallization. Refractory. Phase balance.

ResumoOs materiais cerâmicos semicondutores possuem amplo espectro de aplicações e alguns sistemas quaternários de óxidos metálicos costumam ser bem versáteis. Um destes sistemas é composto majoritariamente por óxidos de titânio, cério e vanádio TiO2-CeO2-V2O5. Neste trabalho, foi obtida uma amostra de óxido misto com 80 mol% de titânio IV, 10 mol% de cério IV e 10 mol% de vanádio V através do método Sol-Gel, investigando alterações morfológicas e estruturais em função do tratamento térmico. A obtenção do material envolveu como reagentes de partida o tetraisopropóxido de titânio IV, nitrato de cério IV e metavanadato de amônio, com massa e volumes calculados com base na estequiometria referente aos compostos. O procedimento foi iniciado a partir de misturas específicas de ácido acético em um recipiente contendo uma barra magnética. Primeiramente foi feita adição de tetraisopropóxido de titânio IV e aguardada a complexação por tempo específico em agitação. Após incluiu-se na mistura o isopropanol como solvente, fato que reduziu consideravelmente a concentração da solução. Depois de outro intervalo de tempo para que ocorresse a homogeneização foi dissolvido o nitrato de cério IV e o metavanadato de amônio em água, em volume tal que foi produzida concentração específica para o experimento. Esta solução, em sua natureza aquosa, foi adicionada a solução alcoólica mediante agitação, permanecendo em homogeneização por tempo específico antes do processo de gelificação forçada com ação de uma sonda de ultrassom por tempo determinado. Palavras-chave: Cerâmica. Morfologia. Cristalização. Refratário. Equilíbrio de Fases. AbstractThe Semiconductor ceramic materials have a wide spectrum of applications and some quaternary metallic oxide systems are usually quite versatile. One of these systems is composed mostly of titanium oxides, cerium and vanadium TiO2-CeO2-V2O5. In this work, a mixed oxide sample was obtained with 80 mol% titanium IV, 10 mol% cerium IV and 10 mol% vanadium V using the Sol-Gel method, investigating morphological and structural changes as a function of the heat treatment. The material was obtained by using titanium IV tetralopropoxide, cerium IV nitrate and ammonium metavanate as starting reagents, with mass and volumes calculated on the basis of the stoichiometry of the compounds. The procedure was initiated from specific acetic acid mixtures in a container containing a magnetic bar. First titanium IV tetralopropoxide was added and the complexation was awaited for a specific time in agitation. After that, isopropanol was included as a solvent in the mixture, which considerably reduced the concentration of the solution. After another interval of time for the homogenization to occur, the cerium nitrate IV and ammonium metavanadate were dissolved in water, in such volume that specific concentration was produced for the experiment. This solution, in its aqueous nature, was added the alcoholic solution by agitation, remaining in homogenization for a specific time before the process of forced gelation with the action of an ultrasound probe for a specific time. Keywords: Ceramics; morphology; crystallization; refractory; phase equilibrium.

imperativo nos comandos descritos no texto (4), ( 5), (6) e conseguimos evidenciar a presença de dois pontos principais que foram abordados no módulo 1 e que vão de encontro à problematização inicial, que são a leitura de rótulo e a mistura de PL (5).

ResumoO semicondutor dióxido de titânio é usado como fotocatalisador de oxidação avançada para descontaminação de água. Vários processos de síntese do material são usados, mas o controle de fases e a cristalinidade desempenham papeis fundamentais na eficiência. A fase tetragonal de baixa simetria denominada anatase é mais eficiente quando apresenta reduzida quantidade de feitos estruturais, o que pode conseguir promovendo o ordenamento estrutural do material. Entretanto, no limite deste ordenamento, que ocorre geralmente logo acima de 600 °C, também começa a ocorrer uma transição de fases irreversível, formando uma nova fase tetragonal de maior simetria, denominada rutilo, com reduzida eficiência fotônica para aplicações em fotocatálise. Neste trabalho, buscou-se demonstrar como as técnicas de Espectroscopia Raman e Difratometria de Raios X são utilizadas para entender o ordenamento estrutural deste material obtido pelo Método Sol-Gel e submetido a tratamento térmico em várias temperaturas. Como suporte para este entendimento, foram também utilizadas as técnicas de Análise Térmica e de Espectroscopia de Refletância Difusa no UV-Vis. Palavras-chave: Semicondutor. Ordenamento estrutural. Transição de fase. Fotônica. AbstractTitanium dioxide semiconductor is used as advanced oxidation photocatalyst for water decontamination. Several synthesis processes are used, but the phase control and crystallinity play fundamental roles in the efficiency. The tetragonal phase with low symmetry called anatase is more efficient when almost absent of structural effects, which it can achieve by structural ordering of the material. However, at the limit of this ordering, which generally occurs just above 600 °C, an irreversible phase transition also begins to occur, forming a new tetragonal phase with high symmetry and reduced photonic efficiency for applications in photocatalysis, called rutile. In this work, we sought to demonstrate how the techniques of Raman Spectroscopy and X-ray Diffractometry are used to understand the structural ordering of this material obtained by Sol-Gel Method and undergone to heat treatment at various temperatures. As support for this understanding, the techniques of Thermal Analysis and UV-Vis Diffuse Reflectance Spectroscopy were also used. Keywords: Semiconductor. Structural ordering. Phase transition. Photonic

There are several purposes for investigating hydrotalcite clays and one of them is due to its importance as an anionic adsorbent and ion exchanger, which make them capable of removing various pollutants from water. The most common hydrotalcite structure is based on double lamellar hydroxide of magnesium and aluminum, containing carbonate anions in the interlayer space. However, it is common to investigate the co-substitution of aluminum with other trivalent cations, especially transition metal cations, due to their binding properties. In this work, it was investigate the co-substitution of chromium (III) and aluminum in a sample of magnesium-aluminum carbonated hydrotalcite, comparing it with the same composition without this co-substitution. Thermal stability, crystallinity and morphology were investigated, showing that chromium contributes to the adsorptive capacity at low temperature.

Structural concretes must have a set of chemical characteristics to present a satisfactory resistance to the degradation in environment conditions. Besides the several types of mineralogical compositions, the calcium-rich sulfates, silicates and aluminates phases appear as majority components, but the gypsum one seems to play the most important rule in morphological changes during the concrete cure. In this work, it was carried out several characterizations in commercial Portland cement and the structural concrete sample. Nitrogen adsorption isotherms at 77 K for Portland cement showed the thermal treatment at 500 oC does not undergo significant decreasing in surface area due the high content of porous silicates and aluminates components. The additional resistance to the corrosion of structural concretes exposed at environment conditions can be associated to presence of slag metallic aggregates, which could be characterized successfully by thermal analysis. The amount of embedded metallic component in concrete sample was detected by typical weight gain originated form oxygen incorporation above 700 oC.

How to improve our school playground? Based on the school plan and the surrounding area, it was decided to promote scientific activities in the playground by sharing scientific knowledge. In these activities, 20 pupils and 4 teachers participated as organizers, covering a community of 244 pupils (ages 3-10), 18 teachers and 11 other school staff. We chose a set of scientific questions, connected with the knowledge of space, the influence of the Sun in our lives, and with the protection of bats. We promote the questions through two tools: a conference and an exhibition, both organized by the students. The conferences were prepared in small groups, by exploring and using reliable scientific sources such as Ciência Viva science centres and ESERO Portugal. In the exhibition, scientific knowledge was offered at the school playground, in an experimental, interactive and dynamic approach, where we were the facilitators and guides of the other students and the educational community.