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Iron is one of the most abundant chemical elements in the Earth's crust and is found in nature in the form of ores. Obtaining it in its pure state involves the exploration, extraction and processing of these minerals. The production of iron is of fundamental importance, given the scope of its use, which ranges from the production of steel—its main application—to the most diverse industrial applications. It is due to its physical and chemical properties that iron has such a wide range of industrial uses. Thus, knowing the behavior of iron in different structures and environments is necessary. Currently, one of the forms of iron that has attracted attention because of its most diverse applications is zero-valent iron (ZVI), which is the subject of many studies, especially on its uses in soil remediation and effluent treatment on account of its physical and chemical properties. These properties can be enhanced when it is on a nanoscale, in the form of nanoscale zero-valent iron (nZVI). nZVI—given that it is easily obtainable, affordable, and has a toxic effect that is considered irrelevant—has environmental uses that are accepted by many regulatory agencies, and its applications have deserved attention. Thus, this chapter will provide a general review of the subject of iron ore and, in particular, will analyze the properties and applications of nZVI. It will also discuss its synthesis methods and the treatments that it can be submitted to in order to improve its efficiency in applications of interest.

It was made a technic-economic analysis of the feasibility of implementing a pyrolysis plant for the production of fuel oil (FO) from plastic fractions of Municipal Solid Waste (MSW). The catalytic pyrolysis process is carried out in a fixed bed reactor with a capacity of 4 m³ loaded with crushed and dry plastic waste (volumetric mass of 500 kg/m³), which is heated at a rate of 2 °C/min until the reaction temperature reaches 270 and 350 °C. Then, the pyrolysis process is then maintained at the established temperature for 6 hours. The retention time of the pyrolysis gases is 90 minutes. Each batch operation cycle lasts an average of 9 hours. It was evaluated production of FO from different plastic fractions resulting from MSW sorting in a medium-sized municipality. In scenario 1 (reference scenario), 1.04 and 3.63 ton/day of plastics of the MSW (PSW) are sent to recycling and landfill, respectively. Three alternative scenarios were defined and analyzed to implement plastic pyrolysis: scenario 2, 3.63 ton/day, the fraction of non-recycled PSW is considered for processing by pyrolysis; scenario 3, it is considered the recycling of PET and PVC, and the remaining PSW represents 4.36 ton/day, and it is considered for processing by pyrolysis; scenario 4, it is maintained the 4.36 ton/day of PSW as valorized by pyrolysis, and it is assumed that an additional 0.64 ton/day of PSW comes from an external source. The FO production costs were estimated at 1.50, 1.29, and 1.13 R$/L, approximately 41%, 49%, and 56% lower than the FO sale price (2.55 R$/L), for scenarios 2, 3, and 4, respectively. Costs of production per unit of energy (GJ) in FO are between 40.88 and 29.67 R$/GJ. The Net Present Value (NPV) of the solution, considering scenarios 2 to 4, increased from R$ 6.72×106 to R$ 11.29×106. The positive NPV for the scenarios 2 to 4 indicates the economic viability of the pyrolysis plant. The pyrolysis system would need to operate between three and four years to recover the invested capital. The costs of the municipality with the destination of MSW can be reduced in 54.75%, from 139.48 to 63.12 R$/ton MSW, between the reference scenario and scenario 4.

The pulp and paper industry has been researching different treatments for the degradation of adsorbable organohalogens (AOX). In this work, two agitation processes (mechanical and ultrasound) were analyzed in the AOX degradation of the bleaching wastewater using nano zero valent iron (nZVI). The work used different variables for the AOX removal process, such as pH, time, nZVI, and hydrogen peroxide (H 2 O2) concentration. Results show an increase in AOX degradation when a higher nZVI concentration is used. The optimal combination of variables for the treatment with mechanical agitation was found in the ratio 2:5 (nZVI : H 2 O2), degrading 85% of AOX in 60 min, with acid pH. Ultrasound treatment consisted of half process time and less degradation than mechanical agitation treatment. The 2:5 ratio in ultrasound agitation degraded 55% of AOX within 30 min at the end of the process. Both methods of the homogenization process of zero valent iron nanoparticles in the bleaching wastewater of the paper and cellulose industry are efficient. However, the mechanical stirring process has a more significant potential for AOX degradation. The variables (pH, concentration of nZVI and H 2 O2 and duration of the process) used in the bleaching wastewater treatment process must be considered for future implementation in the pulp and paper industry.

In this study, we evaluated the environmentalcompatibility of glass–ceramic materials produced from galvanic sludge and soda–lime glass to understand the occurring phenomena in the investigated ceramic system and to find an environmentally compatible way to recycle the materials. The formulated compositions were homogenised (with 1, 5, 10, and 20 wt% of galvanic sludge), compacted, and fired at various temperatures (750–1050 °C). The chemical composition, particle size, thermal behaviour, structure (via X-ray diffraction (XRD), and microstructure (via SEM) of the raw materials, samples, and obtained glass–ceramic materials were evaluated. The ceramic materials were submitted to leaching and solubilization assays. We successfully produced environmentally compatible ceramic bodies using the formulations with 1 and 5 wt% galvanic sludge. Harmful elements could be successfully immobilised. The findings are significant mainly when extended to the industrial scale where the strategic reuse of this waste type is a concern.

The metallurgic industry, especially foundries, is a significant source of waste. For this reason, alternatives that involve reuse and recycling are necessary to minimize waste disposal in landfills and recover matter and energy. The feasibility of elaborating ceramic matrix composites with the incorporation of foundry waste was investigated in this study. Two types of residues were used to elaborate the composites. Green sand and grit blasting powder, in formulations with concentrations that ranged from 5.0 to 10.0% (m/m). The specimens were molded by uniaxial pressing, and a thermal treatment at 1000 °C was performed. The materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), particle size determination, linear retraction, water absorption, mechanical strength, leaching and solubilization. The results indicate that the incorporation of waste to the ceramic mass enables the processing of specimens with properties of industrial interest, such as mechanical strength and water absorption.

Óxido de zinco (ZnO) nanoestruturado foi obtido por síntese de combustão em solução (SCS) utilizando nitrato de zinco e ácido cítrico. Morfologia, perda de massa, transformação de fases e tamanho de cristalito foram caracterizados por microscopia eletrônica de varredura (MEV), análises termogravimétrica (ATG) e termodiferencial (ATD), e difração de raios-X (DRX). A atividade fotocatalítica foi avaliada através da degradação de uma solução de alaranjado de metila. Investigou-se a influência de diferentes razões molares combustível/oxidante na microestrutura e na atividade fotocatalítica do ZnO. Os resultados indicaram maior cristalinidade e desempenho fotocatalítico para os produtos obtidos com deficiência em combustível na reação. Nanostructured zinc oxide (ZnO) was obtained by combustion synthesis in solution using zinc nitrate and citric acid. Morphology, weight loss, phase transformation and crystallite size were characterized scanning electron microscopy (SEM), thermal gravimetric (TGA) and thermal differential (DTA) analysis, and X-ray diffraction (XRD). The photocatalytic activity was evaluated by the degradation of a solution of methyl orange. We investigated the influence of different fuel/oxidant molar ratios in the microstructure and in the photocatalytic activity of ZnO. The results showed a higher crystallinity and photocatalytic performance for the products obtained with disabilities fuel in the reaction.

The main purpose of this work was the investigation of the immobilization of chromium ion present in the ash from the incineration of chromium-tanned leather shavings (ACS) by means of vitrified ceramic bodies. To achieve the immobilization samples were initially produced adding soda-lime glass to ACS. After that, new formulations were produced with the addition of pure oxides, TiO(2) and MgO, to the soda-lime glass and ACS sample. These samples were conformed by pressing and fired in an eletrical furnace, at temperatures of 750, 800, 950 and 1000 degrees C. The ceramic bodies were evaluated with respect to their physical properties and mineralogical composition by X-ray diffraction and energy dispersive spectroscopy (EDS) mapping. The chromium immobilization was characterized by leaching tests according to Brazilian Regulations (NBR 10005). The results confirmed the immobilization of the chromium ion within the allowed limits of Brazilian Regulations, NBR 10004 (5mg/L), with the use of glass and vitrification/densification agents such as titanium and magnesium oxides.

Óxido de zinco (ZnO) nanoestruturado foi obtido por síntese de combustão em solução (SCS) utilizando nitrato de zinco como oxidante e ureia como combustível. O material foi caracterizado por difração de raios X (DRX); método Branauer, Emmet e Teller (BET); análises termogravimétricas (ATG) e termo diferencial (ATD) e microscopia eletrônica de varredura (MEV). A influência de diferentes razões molares combustível/oxidante na microestrutura do ZnO foi investigada. As amostras com maior razão molar apresentaram menor tamanho de cristalito e maior área superficial. As imagens de MEV mostraram placas irregulares e placas finas com pontas alongadas que se assemelham a flores. Nanostructured zinc oxide (ZnO) was obtained by combustion synthesis in solution (CSS) using zinc nitrate as oxidant and urea as fuel. The material was characterized by X-ray diffraction (XRD), Branauer, Emmet and Teller method (BET), thermal gravimetry (TGA) and thermal differential (DTA) analysis, and scanning electron microscopy (SEM). The influence of different fuel/oxidant molar ratios on the microstructure of ZnO was investigated. The ZnO powders produced using the highest molar ratio presented the lowest crystallite size and the highest surface area. The SEM images showed irregular plates and thin plates with elongated ends that resemble flowers.

In this study, the viability of using electrostatic painting residues - paint sludge - as a raw material to the red clay industry was investigated. Red clay-based ceramic masses containing electrostatic paint residues were formulated during the study. The clays were obtained from the Rio do Rastro deposit, in Gravataí, and were of the standard formulation used in industry. Different ceramic mass formulations with additions of 0.5, 1.0, 2.5 and 5.0 wt.% electrostatic painting residue in addition to a formulation with no residue addition (standard formulation), were evaluated. The samples were uniaxially pressed in a double-effect press and were fired in an electric oven at 900, 950 and 1000°C. The firing at constant temperature lasted 8 h, and heating rate was 150 K h-1. After processing the samples were characterized in terms of their physical and mechanical properties. Environmental compatibility was also considered by the evaluation of gaseous emissions and leaching and solubilization tests according to the Brazilian standards NBR 10.005 and NBR 10.006, respectively. The results showed that it was possible to produce ceramic materials containing electrostatic painting residues within their formulations.

The leather tannery industry produces a significant amount of solid and hazardous wastes. Chromium-containing wastes like tanned shavings used to be incinerated in order to recover energy. The incineration process generates ashes that must be disposed of. This paper is a report on the results of the evaluation of technological properties and environmental compatibility of products made of alumina and ashes from incinerated chrome tanned shavings. The raw materials, tannery ashes and alumina were mixed together in different proportions. The ceramic bodies were molded using a hydraulic press and fired with a heating rate of 100 K/h until 1400 °C for 4 h in a muffle furnace. The ceramic specimens were characterized regarding physical, mechanical and thermal properties. Leaching tests, according to Brazilian, German and Dutch regulations, were performed on ceramic bodies containing different additions of ash. Results show that the ceramic materials produced are acceptable for refractory applications.

This paper is a report on the results of a feasibility study on the immobilisation of tannery sludge by producing a ceramic product. The main purpose of this work was to test the clays used in the manufacture of a ceramic that could incorporate tannery sludge. The raw materials, tannery sludge and clay, were mixed together in different proportions. The ceramic specimens were characterised with respect to water absorption, porosity, linear shrinkage and transverse rupture strength. Leaching tests, in accord with the Brazilian and German regulations, were done on ceramic bodies made with different additions of sludge. In order to evaluate the possibility of air contamination during the firing process, preliminary studies of air emissions were carried out The mechanical properties of the samples evaluated were similar to those specified for ceramic bricks. All the leaching tests have shown that the main sludge contaminant i.e. chromium, could be immobilised within a finished ceramic product. The studies of air emissions have shown that zinc and chlorine are mainly collected from gas emissions and hence are not immobilised by the ceramic system. The study shows that the properties of the ceramic materials produced are acceptable for applications such as bricks for the building industry.

Nanostructured CrC-30wt%NiCr powders were synthesized by high energy ball milling in a planetary ball mill. Two ball-to-powder ratios, four milling times and two milling speeds were used. Morphology, average grain diameter, and phase transformation of the powders were characterized by scanning electron microscopy (SEM), particle size analysis, and X-ray diffraction (XRD). Crystallite size and mean diameter decrease with increase in BPR, milling time and speed. The results show that with the use of a ball-to-powder weight ratio of 1:20, a milling time of 1h and a milling speed of 500 rpm, the average particle size and crystallite size were respectively 5.6µm and 8.3nm.

Foram realizados experimentos objetivando selecionar materiais e revestimentos com propriedades antiincrustantes para o controle do bivalve Limnoperna fortunei no sul do Brasil, em duas localidades: no canal principal do rio Jacui, Porto Alegre, RS, e no reservatorio da UHE Ibitinga, medio rio Tiete, SP. Os materiais testados foram: aco galvanizado, aco carbono, aco cobreado e cerâmica. Os revestimentos utilizados foram tintas: basica sem oxidos; basica com oxidos em concentracao de 5% como: ZnO nanometrico, particulas de ZnO convencional, Cu2O nanometrico, particulas de Cu2O convencional; e as tintas comerciais R e antibacterias. Corpos de prova com e sem revestimento (seis replicas de cada), foram submersos na coluna d’agua dos dois locais selecionados para os experimentos, entre outubro de 2006 e fevereiro de 2007. Quanto aos materiais metalicos, o cobre metalico, o aco galvanizado e aco carbono revestido com tinta comercial R e tinta antibacterias se demonstraram promissores no controle de incrustacoes do mexilhao dourado. Quanto ao material cerâmico, o revestimento de tinta base com ZnO comercial apresentou os melhores resultados. Nos materiais com e sem revestimentos, com elevadas densidades do bivalve, foi verificado que existe uma relacao com a alta incidencia de biofilmes, corrosao do material metalico e deterioracao do revestimento.

Foram realizados experimentos objetivando selecionar materiais e revestimentos que tenham características antiincrustantes contra o bivalve invasor Limnoperna fortunei, para uso em usinas geradoras de energia. Diferentes tipos de materiais foram utilizados como corpos-de-prova: aço carbono, aço cobreado, aço inoxidável, aço galvanizado e acrílico. Sobre os corpos-de-prova em aço carbono, foram também testados diversos tipos revestimentos à base de óxidos em diferentes concentrações. Foram utilizados o óxido de cobre, o óxido de zinco e a combinação dos mesmos. Os corpos-de-prova foram submersos na coluna d’água, por um ano entre outubro de 2007 e setembro de 2008, no reservatório da Usina Hidrelétrica de Ibitinga, Estado de São Paulo, Brasil. Os seguintes materiais e revestimentos apresentaram as menores densidades de mexilhões incrustados: aço carbono revestido com tinta a base de resina epóxi poliamina com adição de óxido de zinco convencional 5%, aço carbono revestido com tinta a base de resina epóxi poliamina com adição de óxido de cobre convencional 10%, aço carbono revestido com tinta a base de resina epóxi poliamina com adição de óxido de zinco nanométrico 10%. Estes materiais são recomendados para a utilização no controle da incrustação do mexilhão dourado, após a realização de estudos complementares sobre a solubilidade, lixiviação e ecotoxicidade, temas que serão abordados em nova fase da pesquisa. Experiments were carried out aiming to select materials and coatings with antifouling properties against the exotic bivalve Limnoperna fortunei at power plants. Different kinds of materials were used as sample: carbon steel, metallic copper, stainless steel, galvanized steel and acrylic. Tests were also performed with several kinds of oxide based coatings at different concentrations on carbon steel samples. Copper oxide, zinc oxide and a combination of them were used. The samples were immersed in water column along a year, from October/2007 to September/2008, at Ibitinga Hydroelectric Power Plant Reservoir in São Paulo State, Brazil. The following materials and coatings showed the lower densities of golden mussel fouling: carbon steel coated with epoxy-polyamine resin based ink with addition of conventional zinc oxide 5%, carbon steel coated with epoxy-polyamine resin based ink with addition of conventional copper oxide 10% and carbon steel coated with epoxy-polyamine resin based ink with addition of nanometric zinc oxide 10%. These materials are recommended for use in golden mussel fouling control, after complementary studies about solubility, lixiviation and ecotoxicity, issues that will be considered in the new stage of the research.

Resumo O presente trabalho avaliou os efeitos da adição de resíduos de vidro sodo-cálcico e de erva-mate sobre a absorção de água, porosidade e resistência mecânica de um material cerâmico. Os pós homogeneizados foram compactados por prensagem uniaxial e submetidos a queima de 900 e 1100 °C a 2 °C.min-1. Os resultados mostraram que a adição de vidro e erva-mate à argila produziu materiais cerâmicos com retração linear entre 0,3 e 6%, absorção de água entre 5,3 e 34%, porosidade aparente de até 41% e resistência mecânica entre 0,5 e 20 MPa. Os materiais queimados a 1100 °C foram os que obtiveram as melhores combinações de propriedades, podendo ser aplicados na produção de blocos, telhas ou revestimento cerâmico de acordo com as necessidades específicas da aplicação.