RESUMO Minas Gerais tem um enorme desafio relacionado com a destinação de bilhões de toneladas de rejeitos da mineração de ferro. Neste contexto, a inovação é elemento fundamental para encontrar alternativas técnicas e economicamente viáveis para fazer frente a este problema. Neste trabalho, avalia-se a tentativa de implementação de rede colaborativa para gerar as inovações necessárias para a destinação de rejeitos no estado de Minas Gerais. Trata-se da Plataforma R3 Mineral, uma rede colaborativa para o desenvolvimento de soluções para a destinação dos rejeitos. Para a compreensão dos obstáculos que levaram ao encerramento foram realizadas entrevistas com atores que participaram da Plataforma. As redes colaborativas internacionais da mineração, AMIRA (Austrália) e CEMI (Canadá) são apresentadas como parâmetros para a análise da Plataforma R3 Mineral. De forma geral, observou-se que a falta de uma estrutura organizacional formal foi determinante para a dispersão dos membros da plataforma e para o seu insucesso. ferro contexto problema trabalho avaliase avalia se Tratase Trata R Mineral Austrália (Austrália Canadá (Canadá geral observouse observou insucesso

ABSTRACT Minas Gerais faces the challenge of disposal billions of tons of iron mining tailings. Innovation is a fundamental key in the search of technically and economically viable alternatives for solving this problem. In this paper, is presented and evaluated an attempt to implement a collaborative network to foster innovations for the disposal of tailings in the state of Minas Gerais. This is the Plataforma R3 Mineral, a collaborative network for the development of solutions for the disposal of mining waste. In order to understand the obstacles that led to the end in its operations, interviews were conducted with actors who participated in the Platform. International collaborative mining networks, AMIRA (Australia) and CEMI (Canada) are presented as parameters for the analysis of the Plataforma R3 Mineral. It was observed that the lack of a formal organizational structure was decisive for the dispersion of the platform members and for its failure. problem paper R Mineral waste operations Platform networks Australia (Australia Canada (Canada failure

In this article, it is described the main aspects to be considered during the process of scaling up hard sciences technologies developed in the Science and Technology Institutes aiming at industrial application. Based on the experience of our group in scaling up, pre-acceleration, and acceleration of different technologies, a methodology was developed and divided into four main stages: Step 1, which involves basic research, Step 2 with a focus on product development, and Step 3 with a focus on process development, all on the laboratory scale and the last one, Step 4 focused on pilot plant development. The most important aspect of this article is to show that many critical questions can be answered even in the laboratory phase. In this way, the risks of Step 4 are minimized. Step 4 is a complicated, lengthy, and expensive process of construction and operation of a pilot plant. Aspects such as proof of concept, technical and economic feasibility studies, minimum viable product, capital expenditures, and operating expenses of pilot plants are approached in a simplified way to serve as a basis for researchers who wants to know the long path to be followed by technology before reaching the industry, consequently the market.

Resumo Neste trabalho, estudou-se em escala piloto a pirólise de três diferentes rejeitos de borracha do setor de mineração, i.e. peças de moinho de composição nominal de borracha estireno e butadieno (SBR), peneiras e correias transportadoras com composição nominal à base de borracha natural e butadieno (NR/BR) e pneus offroad de composição complexa (mistura de borracha natural, nitrílica, butadieno e estireno-butadieno) em temperaturas de 450, 600 e 800°C. As reações realizadas a 450°C mostraram uma pirólise incompleta, sendo que a 600 e 800°C os rejeitos de borracha se convertem totalmente em três produtos: 15-25% de gás, 42-44% sólido e 34-45% de líquido. Análises por cromatografia gasosa (CG) dos produtos gasosos mostraram majoritariamente a presença de hidrocarbonetos C1-C4 com valores de poder calorífico inferior (PCI) iguais a 8.496 e 7.325 kcal kg-1, similares ao gás liquefeito de petróleo (GLP). Análise dos sólidos obtidos por análise elementar de carbono, hidrogênio e nitrogênio (CHN), espectrômetria de emissão atômica com plasma induzido (ICP-AES) Spectro Ciros CCD para a determinação de enxofre, análise térmica gravimétrica e diferencial (TG/DTA), carbono fixo, cinzas, voláteis mostraram a presença de 72-89% de carbono com 2% de enxofre. Análises dos produtos líquidos por cromatografia gasosa acoplado a espectrometria de massas (CG-EM) indicaram a presença de misturas complexas de hidrocarbonetos majoritariamente até C20. As amostras NR/BR e pneu produzem líquidos com concentração de compostos aromáticos próxima a 50%, enquanto a amostra SBR resulta na formação de um líquido de concentração próxima a 87%. A mistura dessa fração líquida obtida pela pirólise (sem qualquer purificação) com um diesel comercial nas proporções de 0,5, 1 e 3 vol% mostrou que nenhum parâmetro de qualidade de combustível definido pela ANP (Agência Nacional do Petróleo, Gás Natural e Biocombustíveis) foi alterado significativamente.

Abstract In this work, the pyrolysis of three different rubber wastes used in the mining industry, i.e. milling (based on styrene butadiene rubber, SBR), sieves and conveyor belts (based on natural and butadiene rubber, NR/BR) and offroad waste tires (based on complex mixture of nitrile, butadiene, styrene and natural rubber) was investigated in a pilot plant at 450, 600 and 800°C. Reactions at 450°C showed incomplete pyrolysis whereas at 600 and 800°C the rubber wastes were completely converted into three products:15-25% gas, 34-45% liquid and 42-44% solids. The gas products analyzed by gas chromatography (GC) showed mainly the presence of C1-C4 hydrocarbons with LHV (Low Heating Value) values between 8496 and 7325 Kcal kg-1, similar to liquefied petroleum gas (LPG). The solid products analyzed by elemental analysis of carbon, hydrogen and nitrogen (CHN), atomic emission spectrometry with inductively coupled plasma (ICP-AES) Spectro Ciros CCD for the determination of sulfur, thermogravimetry and differential thermal analysis (TG/DTA), fixed carbon, ash and volatile compounds showed the presence of 72-89% carbon and 2% sulfur. The liquid products analyzed by gas chromatography applied mass spectrometry (GC-MS) indicated the presence of complex mixtures of hydrocarbons containing mainly compounds up to C20. The NR/BR and waste offroad tire samples produced ca. 50% aromatics whereas SBR rubber resulted in the formation of near 87% aromatics. The mixtures of these liquids products (without any purification) with a commercial diesel fuel at 0.5, 1 and 3 vol% did not significantly change the fuel quality parameters defined by the ANP (Agency National Petroleum, Natural Gas and Biofuels).

In this work, chemists with experience in different areas of industry and academy raised some important issues in career planning to help undergraduate chemistry students to get prepared for the future professional life.

In this work, it is proposed a simple experiment in polymer science for undergraduates, involving the glycerol polymerization catalyzed by H2SO4 to produce different materials, e.g. from oligomers to crosslinked polymer. The students can investigate the reaction conditions such as time, temperature and catalyst concentration, thus controlling the extent of polymerization and its kinetics. This experiment stimulates students to see polymer science in a broader context, involving diverse topics, such as biodiesel, and processing of a co-product of low value in polymeric materials with potential industrial application.

In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al2O3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields.

Os livros didáticos, pela disponibilidade e acesso, são uma fonte importante de pesquisa para o professor de Ensino Médio, ao selecionar conteúdos e preparar suas aulas. Na tentativa de se adaptarem às novas tendências educacionais, esses livros vêm inserindo textos e assuntos que discutem os problemas vivenciados pela sociedade em geral. Nos livros de Química, um assunto que se faz presente é o Efeito Estufa. Analisou-se, neste trabalho, o tratamento e o aprofundamento dado a esse tema. Uma visão muito simplista do fenômeno foi percebida e, por isso, algumas sugestões foram incorporadas neste trabalho.

Widely available textbooks are an important source of research for high school teachers for both content selection and class preparation. As an attempt to adapt to new educational trends, these textbooks have introduced texts and subjects relevant for the discussion of current problems of the modern society. In the chemistry textbooks the Greenhouse Effect is one of these subjects. The aim of this work is to analyze the elements and discussion given in the textbooks on this topic. It was observed in general a simplistic treatment given to greenhouse effect and in order to improve the texts analyzed some suggestions are made.

A series of activated carbons (AC) were prepared from waste of the olive oil production in the Cuyo Region, Argentine by two standard methods: a) physical activation by steam and b) chemical activation with ZnCl2. The AC samples were characterized by nitrogen adsorption at 77 K and evaluated for natural gas storage purposes through the adsorption of methane at high pressures. The activated carbons showed micropore volumes up to 0.50 cm³.g-1 and total pore volumes as high as 0.9 cm³.g-1. The BET surface areas reached, in some cases, more than 1000 m².g-1. The methane adsorption -measured in the range of 1-35 bar- attained values up to 59 V CH4/V AC and total uptakes of more than 120 cm³.g-1 (STP). These preliminary results suggest that Cuyo's olive oil waste is appropriate for obtaining activated carbons for the storage of natural gas.

In this work two perovskites were prepared: LaMn1-xFe xO3, and LaMn0.1-x Fe0.90Mo xO3. XRD and Mössbauer spectroscopy suggest the formation of pure phase perovskite with the incorporation of Fe and Mo in the structure. The catalytic activity of these materials was studied in two reactions with H2O2: the decomposition to O2, and the oxidation of the model organic contaminant methylene blue. The perovskite composition strongly affects the catalytic activity, while Fe decreases the H2O2 decomposition Mo strongly improves dye oxidation.

In this work, controlled reduction of perovskites supported on Al2O3 was used to prepare thermally stable nanodispersed iron catalysts based on Fe0/La2O3/Al2O3. The perovskites composites LaFe0.90Mn0.08Mo0.02O3(25, 33 and 50 wt (%)) /Al2O3 and LaFe0.90Mn0.1O3(25 wt (%)) /Al2O3 were prepared and characterized by XRD, BET, TPR, SEM and Mössbauer spectroscopy. XRD for unsupported perovskite showed the formation of a single phase perovskite structure. The Mössbauer spectra of the perovskites were fitted with hyperfine field distribution model for the perovskite. Supported perovskites on Al2O3 showed a decrease of the hyperfine field in respect to unsupported perovskite, due to decrease of particle size and dispersion of the Fe3+ specimens on the support. Also showed broaden lines and relaxation effects due to the small particle size. To produce the Fe0 catalyst, the composite perovskite(25%)/Al2O3 was reduced with H2 at 900, 1000 and 1100 °C for 1 hour. XRD data indicated the formation of Fe0 catalyst with particles sizes of ca. 35 nm. The Mössbauer spectrum showed the formation of metallic iron and doublets corresponding to species of octahedric Fe2+ and Fe3+ sites dispersed on Al2O3. These catalysts showed improved stability towards sintering even upon treatment at 1000 and 1100 °C under H2.

In this work highly dispersed Ru-Sn bimetallic catalysts have been prepared from organobimetallic Cp(PPh3)2Ru-SnX3 (X = Cl or Br) complexes. These single source precursors can be easily impregnated in high surface area supports, such as activated carbon and sol-gel SiO2, and upon controlled thermal treatment the ligands are released as volatile products resulting in the formation of the bimetallic system Ru-Sn. Catalytic reactions, such as hydrodechlorination of CCl4 and chlorobenzene and TPR (Temperature Programmed Reduction) experiments carried out with these RuSn catalysts suggested a strong interaction between Ruthenium and Tin. Mössbauer measurements showed that these materials when exposed to air are immediately oxidized to form Sn (IV). It was shown that upon controlled reduction conditions with H2 it is possible to reduce selectively Sn to different oxidation states and different phases. The Sn oxidation state showed significant effect on the catalytic hydrogenation of 1,5-cyclooctadiene. The use of these single source precursors with a controlled decomposition/reduction procedure allows the preparation of unique catalysts with an intimate interaction between the components ruthenium and tin and the possibility of varying the Sn oxidation state around the Ru metal.