In this work, iron ore tailing (IOT) was used for the production of two different materials: sodium silicate and geopolymers. Initially, reactions of IOT with NaOH were carried out by hydrothermal reaction in autoclave at 200 °C (1:1.5 and 1:2.5 SiO2:NaOH molar ratio) and reaction times of 4 and 8 h. X-ray fluorescence by dispersive energy (XRF), X-ray diffraction (XRD), Mössbauer spectroscopy, scanning electron microscopy (SEM-EDS) and titrations showed that IOT:NaOH ratios of 1:2.5 and reaction time 8 h completely dissolved the quartz from the IOT, obtaining a solid fraction consisting mainly of hematite and an aqueous phase of sodium silicate, which showed contents of ca. 23% SiO2 and 19% Na2O. This sodium silicate obtained was then combined with IOT (25 and 50 wt.%) to produce geopolimeric material with excellent physico-chemical properties, fast curing time and very good compressive strength results, which ranged from 41 to 58 MPa and many potential applications. work (IOT materials geopolymers Initially 20 C 11.5 115 1 1.5 5 (1:1. 12.5 125 2.5 2 1:2. SiO2NaOH SiONaOH SiO ratio Xray X ray XRF, XRF , (XRF) XRD, XRD (XRD) spectroscopy SEMEDS SEM EDS (SEM-EDS IOTNaOH ca 23 19 Na2O NaO Na O 25 (2 wt.% wt physicochemical physico chemical properties results applications 11 11. 15 1. (1:1 12 12. 2. 1:2 (XRF (XRD ( wt. (1: 1: (1

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

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

In this work, we describe a sustainable alternative to recover iron from two iron ore tailings (IOT) using hydrogen reduction at relatively low temperatures followed by magnetic separation. X-ray powder diffraction (XRD), inductively coupled plasma (ICP), atomic absorption (AA), Mössbauer, scanning electron microscopy (SEM/EDS), Raman and thermogravimetry (TG) analyses indicated that the Fe oxide present in the IOTs (sandy tailing (ST) and mud tailings (MT)), can be reduced with H2 at 500 ºC to produce α-Fe. Upon magnetic separation the mud tailing produced a 77 wt.% magnetic fraction increasing the Fe content from 19.2 to ca. 56 wt.% of Fe. On the other hand, the sandy tailing resulted in a 15 wt.% magnetic fraction increasing the Fe content from 19.2 to 70 wt.%. These results indicate that up to 86% of iron can be recovered from the IOT wastes already in the metallic form which can be very interesting for the steel industry.

Considering the bicentenary of Brazil’s Independence in 2022 and that this year was proclaimed by UNESCO as the International Year of Basic Sciences for Sustainable Development, in mid-2021 the Brazilian Chemical Society (SBQ) launched the “Post 2022 Chemistry Movement - Sustainability and Sovereignty”, with the main goal of promoting different activities so that chemistry contributes for the sustainable development and sovereignty of Brazil in the coming years. One of these activities is the proposal of an action plan, with goals to be achieved by 2030 and 2050. This article describes in detail how this action plan was formulated by a working group, with the help of an advisory council and interviews of 18 professionals from universities, the government, industries, the third sector and other organizations. Mimicking the Agenda 2030 SDGs, the resulting action plan is based on two broad Chemistry Sustainable Development Goals: promoting sustainability through chemistry in basic education, and promoting sustainability in the industry and university through science, technology, innovation, and education (STI&E) in chemistry. After the definition of three driving technological challenges in STI&E, they shall be successively implemented through different actions starting in 2023 yet.

Currently, approximately 1.4 billion tons per year of iron ore tailing wastes (IOT) are generated, mainly in Australia, Brazil, and China. This work describes the characterization and application of two typical IOT, i.e., fine and coarse wastes. The physicochemical characterization of these IOT by different techniques such as XRF (X-ray fluorescence), XRD (X-ray diffraction), Mössbauer spectroscopy, and granulometry, indicates for the fine tailing a composition of Fe2O3/FeOOH (10-55%), SiO2 (18-65%) and Al2O3 (up to 15%) with particles of 6-40 µm, whereas the coarse tailing presents 40-150 µm particles with the composition of 8-48% Fe2O3/FeOOH, 30-90% SiO2 and Al2O3 (up to 20%). The main IOT applications discussed in this review are related to civil construction (aggregates for concrete, mortar, Portland cement additives), ceramic industry, geopolymer, synthesis of new materials such as zeolites, mesoporous silica, carbon nanotubes, adsorbents, catalysts for different reactions, in batteries and in fuel cells. It was also carried out an analysis of patents related to IOT applications and the main technological and market barriers that hinder the industrial and commercial uses of these wastes.

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.

In this work, bio-oil (an organic matrix rich in oxygen functionalities) was used to efficiently dissolve and disperse Fe3+ which upon thermal treatment produced a carbon containing dispersed and encapsulated Fe oxide magnetic nanoparticles. These materials were prepared by dissolution of 8, 16 and 24 wt.% Fe3+ salt in bio-oil followed by treatment at 400, 450, 500 or 600 ºC in N2 atmosphere. X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopies (TEM), elemental analysis, thermogravimetric-mass spectrometry (TG-MS), potentiometric titration, Raman and Mössbauer spectroscopies showed that Fe3+ species in bio-oil is reduced to produce magnetic nanoparticles phases: magnetite Fe3O4 and maghemite γ-Fe2O3. At low temperatures, the iron phases were less protected, and the carbon matrix was more reactive, while in temperatures above 500 ºC, the iron phases were more stable, however, the carbon matrix was less reactive. Reaction of these magnetic carbon materials with concentrated H2SO4 produced surface sulfonic acidic sites (ca. 1 mmol g-1), especially for the materials obtained at 400 and 450 ºC. The materials were used as catalysts on esterification reaction of oleic acid with methanol at 100 ºC and conversions of 90% were reached, however, after 2 consecutive uses, the conversion decreased to 30%, being required more studies to improve the material stability.

In this work, a potassium magnesium silicate mineral based on phase K2MgSiO4 was prepared from serpentinite rock and studied as a potential K and Mg slow-release fertilizer. The material was prepared by impregnation of serpentinite/KOH and calcination at 700 °C to produce K2MgSiO4 phase, olivine and forsterite. The release patterns of K and Mg in the stirred-flow trial and leaching through the soil columns showed that K2MgSiO4-based materials released K on lower rates than KCl and MgSO4.7H2O, however, there was no evidence of Mg release. The extraction with 1 mol L-1 NH4OAc showed a considerable content of Mg and K for K2MgSiO4-based materials, due to exchange of NH4+ and Mg2+. X-ray diffraction (XRD) analysis of materials impregnated with K and calcined showed peaks relative to K2MgSiO4. After leaching, the peaks intensity diminished, supporting that part of K leached. Therefore, the samples showed great potential as slow-release K-fertilizers when compared with KCl source.

Serpentine is a versatile mineral family rich in Mg silicate with several polymorphic phases, mainly antigorite and lizardite, all of them with similar chemical composition (Mg3Si2O5(OH)4). Their structures are generally composed of octahedral layers rich in Mg[MgO2(OH)4]6- , attached to a tetrahedral silicate [Si2O5]2- sheet. The unique physicochemical properties of serpentinites and the existence of large reserves in Brazil create new important opportunities for research and technological applications. In this work, serpentinites structures and properties are reviewed, as well as its occurrence and literature describing its applications in construction/ceramics, agriculture, as a silica source, in steel production, as an additive/filler in polymers, in the production of composites, adsorption of cations and organics contaminants, CO2 capture and catalysis. The presence of harmful chrysotile associated with serpentinites, some of its properties and uses are also described.

In this work, efficient adsorbents for β-lactam antibiotics based on mesoporous iron oxide containing surface [FeOx(OH)y] sites were produced by controlled precipitation of iron hydroxide and thermal treatment at 150, 200, 300 and 450 ºC (150FeOH, 200FeOH, 300FeOH and 450FeOH, respectively). Mössbauer, X-ray diffraction (XRD), thermogravimetry-mass spectrometry (TG-MS), Fourier transform infrared spectroscopy (FTIR), Raman, Brunauer-Emmett-Teller method (BET), scanning electron microscopy (SEM) and elemental analyses showed that the temperature caused a gradual dehydroxylation process with a significant increase of the mesoporous surface area (e.g., 114-142 m2 g-1 with 46-59% mesopores, i.e., 0.04-0.09 cm3 g-1) and approximate compositions of FeO1.06(OH)0.89 for 150FeOH up to FeO1.38(OH)0.26 for 450FeOH. The material 150FeOH showed high adsorption capacities of ca. 42 and 58 mg g-1 for amoxicillin and ceftriaxone, respectively. Experiments assessing the effect of NO3-, Cl-, competitive PO43- adsorption and H2O2 decomposition suggest that the [FeOx(OH)y] surface sites located in the mesopores are involved in the efficient adsorption by complexation of the β-lactam antibiotics.

Solid state reaction of serpentinite Mg3Si2O5(OH)4 with NaOH was investigated to produce new NaMgSi oxide phases with basic properties for application in catalysis. X-ray powder diffraction (XRD) showed that NaOH impregnated on serpentinite, specially 20% sodium and treated at 700 ºC (20Na700), led to the formation of a new crystalline phase Na2Mg2Si2O7. This solid state reaction is discussed in terms of a first step involving Na+ diffusion and intercalation in the interlayer space of the serpentinite structure followed by a dihydroxylation and formation of the NaMgSi oxides. Temperature programmed reaction and desorption experiments with 20Na700 combined with XRD suggested a strong basicity with high CO2 uptake likely due to diffusion and interaction with the basic sites in the material structure. These materials were tested as catalysts for the transesterification of soybean oil with methanol. The obtained results are discussed in terms of a basic site Si-O-Na+ present in the in the Na2Mg2Si2O7 structure.

In this work, it is proposed a new strategy to improve the dispersion of inorganic fillers in polymeric matrices by producing surface carbon nanostructures. Clay/carbon nanofibers particles were prepared and used as fillers to improve the mechanical and thermal properties of ultra-high molecular weight polyethylene (UHMWPE). Thermogravimetry (TG), differential scanning calorimetry (DSC), elemental analyses, Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that chemical vapor deposition (CVD) with ethanol at different temperatures, i.e. 700, 800 and 900 °C with and without Fe catalyst, can be used to produce carbon (0.5-3.6 wt.%), mainly as nanofibers, on the clay surface. The use of these clay/carbon particles as fillers in UHMWPE at 1 and 3 wt.% produced an increase in the yield stress from 16 to ca. 20 MPa and Young modulus from 314 MPa for pure UHMWPE to values near 395-408 MPa. Moreover, the presence of the carbon/clay composites led to a strong improvement of the thermal properties of the UHMWPE increasing the decomposition Tonset (degradation start temperature) from 445 up to 472 °C. It was also observed by the crystallization enthalpies that the UHMWPE increased the crystallinity from 55 to 80-85% in the presence of the carbon composites. These results are discussed in terms of the strong interactions of the hydrophobic carbon nanostructures on the clay surface with the polymer hydrophobic chains.

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, composites based on carbon (1, 10 and 20 wt.%) interfaced with Fe3O4 (magnetite) have been studied as catalysts for the oxidation of aqueous sulfide. The composites were prepared by assembling cellulose nanocrystals surrounding Fe3O4 followed by a controlled thermal decomposition at 400, 600 and 800 ºC. Mössbauer, X-ray diffractometry (XRD), Raman, thermogravimetry (TG), elemental analysis CHN, scanning electron microscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR) and potentiometric titration indicated that at 400 and 600 ºC the cellulose nanocrystals decompose to different carbon forms, i.e., films, filaments and particles attached to the Fe3O4 crystals. At higher temperature, i.e., 800 ºC, this carbon on the magnetite surface further reacted to produce Fe0. UV-Vis, Raman and electrospray ionization mass spectrometry (ESI-MS) measurements showed that these composites catalyze the oxidation of aqueous sulfide to convert S2-aq to polysulfides Sn2- (where n = 2-9) and also oxygen containing polysulfides HOSn-. Simple kinetic experiments showed very low sulfide oxidation activities for pure Fe3O4 and pure carbon. On the other hand, the composites, especially with 10% C obtained at 600 ºC, were remarkably active. These results are discussed in terms of a possible participation of oxygen based redox groups present on the carbon surface and an electron transfer from the carbon to the Fe3O4 phase.