LUCAS CAETANO GROSCHE

LUCAS CAETANO GROSCHE

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Physicochemical and radiological characterization of flue gas desulfuration waste samples from Brazilian coal-fired power plants
2023 - FUNGARO, D.A.; GROSCHE, L.C.; SILVA, P.S.C.
Flue gas desulfurization (FGD) waste is an industrial by-product generated during the flue gas desulfurization process in coal-fired power plants. This by-product contain trace quantities of naturally occurring radionuclides and elements such as As, Ba, Co, Cr, Zn. The characteristics of FGD waste are important for its reuse and are mainly depend on the desulfurization process. In this work, two types of FGD materials collected from three coal-fired power plants using semi-dry and wet processes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XFR) and particle size analysis. The radioactive content of 238U, 232Th, 228Th, 226Ra, 228Ra, 210Pb and 40K and trace elements were also determined using Neutron activation analysis and Gamma-ray spectrometry. The major constituents for all samples were Ca, Si, S, Al and Fe. Wet FGD by-product presented also high magnesium content. The wastes contain mainly semi-hydrate calcium sulfite and calcium sulfate. The particle size of FGD from semi-dry process was lower than that from the wet process. The average activity concentration of 238U, 232Th, 226Ra, 210Pb, 228Ra, 228Th and 40K varied between were 50-71, 33-42, 28-52, 113-150, 26-33, 33-39, 161-390 Bq kg-1 , respectively. According to the results of leaching and solubilization tests, FGD samples were classified as non-hazardous and non-inert. The obtained data are useful for evaluation of possible applications of FGD by-products
Avaliação dos níveis de radioatividade natural produzidos na atividade carbonífera e em amostra de clínker
2022 - FUNGARO, DENISE A.; SILVA, PAULO S.C.; IZIDORO, JULIANA C.; GROSCHE, LUCAS C.; BIBIANO, RAMIRO H.N.
Os Produtos de Combustão de Carvão são materiais produzidos em usinas termelétricas que contêm radionuclídeos de ocorrência natural derivados da matriz de carvão, enriquecidos em até uma ordem de magnitude em relação aos níveis originais. A avaliação do impacto radiológico dos ambientes circundantes das usinas termelétricas é de fundamental importância para monitorar os níveis de radiação, a qual as pessoas estão expostas direta ou indiretamente, visto que níveis aceitáveis podem ser ultrapassados com essas atividades. A análise de ativação de nêutrons foi usada para determinar 238U e 232Th e a espectrometria de raios gama para determinar os conteúdos de 226Ra, 228Ra, 210Pb e 40K presentes no carvão, nas cinzas sílico-aluminosas, nos materiais zeolíticos sintetizados a partir de cinzas e em amostras de solo coletadas nas proximidades de Usina termelétrica de Figueira, localizada no Paraná. As concentrações de atividade foram comparadas com a média mundial das diferentes amostras. A análise de ativação de nêutrons também foi utilizada para avaliar os riscos radiológicos decorrentes da presença de cinzas sulfatadas e clínquer em materiais de construção. As cinzas sulfatadas podem substituir o gesso natural em matrizes cimentícias.
Synthesis of calcium silicate hydrate compounds from wet flue gas desulfurization (FGD) waste
2020 - FUNGARO, DENISE A.; GROSCHE, LUCAS; IZIDORO, JULIANA de C.
In this study Calcium silicate hydrate based products (CSHP) were synthesized from wet flue gas desulfurization waste (FGD) by alkali fusion followed by hydrothermal treatment. The effect of various factors on the formation of products, such as mineralizing agent, fusion temperature and time, crystallization time and addition of Ca and Si were studied as well as the conditions optimized. The FGD and synthesized materials were characterized by using X-Ray (XRD), Scanning Electron Microscope (SEM), X-ray fluorescence (XFR), among other methods. A fusion temperature of 600 °C with NaOH, fusion duration of 1 h, and a subsequent hydrothermal temperature of 100 °C for a reaction of 24 h were found to be the optimal conditions. In these synthesis conditions, CSHP containing tobermorite and Al-tobermorite was the major phases. The synthesized CSHP revealed high selective uptake for Cs+ in water. The maximum adsorption capacity of Cs+ onto the synthesized material, as calculated from the Langmuir model, was 1949 µmol g-1. The performance on the Cs+ removal in the presence of high Na+ contents was also evaluated. The adsorbent material showed a high Cs+ adsorption capacity in deionized water and a decrease of 56% and 62% in saturated media with the Na+ ions and seawater, respectively. Therefore, CSHP as a higher value-added product can be obtained from a by-product of a coal-fired power plant, which has wide range applications, including for Cs+ removal from wastewater.
Alkaline hydrothermal treatment of the waste produced in the semi-dry flue gas desulfurization system
2017 - GROSCHE, LUCAS C.; FUNGARO, DENISE A.
Semi-dry flue gas desulfurization ash (SDA) is a byproduct generated from the desulfurization system of coal-fired power station. The beneficial reuse application for SDA material is relatively undeveloped and this residue is underutilized. SDA was used as raw material for the synthesis of zeolitic material by alkaline hydrothermal treatment. Different experimental conditions, such as, reaction time, temperature, alkali hydroxide concentration and solid/liquid ratio were studied. Raw ash material and synthesis products were characterized by XRD, XRF, particle size analyzer, TG-DTG-DTA and SDA was classified according to Brazilian Environmental Regulations. The results show that SDA has a higher CaO and SO3 content. The major minerals present in SDA are hannebachite, anhydrite, calcite, portlandite, gehlenite and sodium carbonate. The size of SDA particles is around 0.399-355.656 μM with median diameter of 7.63 μM. Thermal behavior of SDA was characterized by the existence of six and four stages under air and inert atmosphere, respectively. SDA can be classified as Class II A (non-dangerous/ non-inert) materials. The presence of zeolite hydroxysodalite confirms successful conversion of SDA into zeolitic material after activation in NaOH solutions. Along with the zeolitic product katoite, hydrocalumite and Al-substituted tobermorite were obtained. All the compounds formed present ionic exchange capacity. SDA utilization minimizes the environmental impact of disposal problems and further enables application for treatment of wastewater.
Síntese de material de valor agregado a partir de coproduto da combustão de carvão
2019 - GROSCHE, LUCAS C.
O presente projeto se insere na sugestão encontrada no "Roadmap tecnológico para a produção e uso limpo do carvão mineral nacional: 2012 a 2035" quanto às ações necessárias para que seja estabelecido um ambiente favorável ao maior uso do carvão mineral no Brasil. Isso se dá no que tange ao desenvolvimento de tecnologia considerada prioritária para o setor da geração termelétrica, a saber: aproveitamento de coprodutos da combustão de carvão (PCC). Neste contexto, o projeto envolveu o desenvolvimento de processos capazes de sintetizar material de valor agregado a partir de PCC, como fonte alternativa de silício e alumínio. O material escolhido, proveniente da queima do carvão foi o resíduo de dessulfurização de gases de exaustão, e os nanomateriais sintetizados são considerados produtos de alto valor agregado por possibilitar inúmeras aplicações. O presente trabalho foi dividido em duas etapas; a primeira etapa tratou da síntese e caracterização dos nanomateriais obtidos a partir de diferentes condições da reação de ativação alcalina buscando aperfeiçoar o processo de síntese. Os resíduos de dessulfurização foram coletados de três localidades diferentes, que no início do projeto representavam todas as localidades onde a tecnologia de dessulfurização já estava sendo aplicada na geração de energia elétrica a partir do carvão. Quanto a caracterização dos resíduos, embora existam diferenças envolvidas nos processos que originam as amostras gerando muitas vezes materiais com formas cristalinas diferentes, foram encontrados em todas as amostras os elementos cálcio, alumínio e sílicio. As amostras das três localidades de amostragem foram submetidas ao processo de ativação hidrotérmica alcalina formando principalmente materiais zeolíticos (Sodalitas), tobermoritas e outros compostos do tipo hidrotalcitas. A segunda etapa do trabalho foi direcionada ao uso dos materiais no tratamento de água contaminada com césio, com este objetivo o resíduo de dessulfurização que indicou maior presença de tobermoritas e hidrotalcitas foi selecionado para otimização do processo de síntese hidrotérmica por duas etapas incluindo fusão previa do resíduo. E o material com os melhores resultados de acordo com os materiais cristalinos obtidos foi testado quanto a sua capacidade de remoção de íons de césio em solução, assim como sua seletividade em relação ao sódio presente em certos meios como, por exemplo, na água do mar, em soluções salinas sintéticas e também em uma amostra de água marinha. A capacidade de adsorção do Cs+ sobre o material adsorvente foi de 1949 μmol g-1, indicando que o adsorvente sintetizado pertence ao grupo de materiais com alta capacidade de adsorção de césio quando comparado com outros materiais estudados na literatura, além de apresentar seletividade para o íon de césio em relação à água do mar. Por fim entende-se que o material tem grande potencial para aplicações em remediações em acidentes como o de Fukushima, onde césio radioativo foi liberado na água do mar. Especialmente devido ao material como o resíduo de dessulfurização ser produzido em larga escala e não possuir aplicação na indústria sendo destinado a aterros onde pode se tronar passivo ambiental.
Assessment of natural radioactivity levels in flue gas desulfurization gypsum and clinker samples
2019 - FUNGARO, DENISE A.; SILVA, PAULO S.C. da; GROSCHE, LUCAS C.; BIBIANO, RAMIRO H.N.
Coal Combustion Products (CCPs) are the by-products generated from burning coal in coal-fired power plants. which includes fly ash, bottom ash, boiler slag and flue gas desulfurization wastes. These by-products contain trace quantities of naturally occurring radionuclides from the uranium and thorium series, as well as other naturally occurring radionuclides such as 40K derived from the original coal matrix that tend to become enriched in the ashes. Flue gas desulfurization gypsum (FGD gypsum) is the hydrated calcium sulphate produced when SOx is removed from gases produced during the combustion of coal. FGD gypsum can be used as an alternative material to natural gypsum as retarder additive for Portland cement. In this work, analysis of the radioactive content in FGD gypsum samples were performed to determine if beneficial uses of this CPP in building materials could be of radiological concern. Analysis of clinker sample was also performed. The FGD gypsum samples were collected at Presidente Médici thermoelectric power plant, located in Candiota, RS. The radioactive content of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K was determined using Neutron activation analysis and Gamma-ray spectrometry. The specific activities (Bq kg−1) were compared to results from literature studies including different building materials and coal ashes specific activities.
Alkaline hydrothermal treatment of the waste produced in the semi-dry flue gas desulfurization system
2018 - GROSCHE, LUCAS C.; BERTOLINI, THARCILA C.R.; FUNGARO, DENISE A.
Semi-dry flue gas desulfurization (FGD) material is a byproduct generated from the desulfurization system of coal-fired power station. The beneficial reuse application for dry FGD material is relatively undeveloped. FGD was used as raw material for the synthesis of value-added materials by alkaline hydrothermal treatment. Different experimental conditions, such as, reaction time, temperature, alkali hydroxide concentration and solid/liquid ratio were studied. Raw material and synthesis products were characterized by XRD, XRF, particle size analyser, TG-DTG-DTA, and FGD was classified according to Brazilian Environmental Regulations. The results show that dry FGD has a higher CaO and SO3 content and the major minerals present in material are hannebachite, anhydrite, calcite, portlandite, gehlenite and sodium carbonate. The size of dry FGD ash particles is around 0.399-355.656 μm with median diameter of 7.63 μm. Thermal behaviour of FGD was characterised by the existence of six and four stages under air and inert atmosphere, respectively. FGD can be classified as Class II A material (non-dangerous/non-inert). The presence of zeolite hydroxysodalite confirms successful conversion of FGD into zeolitic material after activation in NaOH solutions. Along with the zeolitic product were obtained katoite, hydrocalumite and Al-substituted tobermorite. All synthesised materials present ionic exchange capacity and could be used as a low-cost adsorbent. FGD utilisation minimises the environmental impact of disposal problems and further enables an application for treatment of wastewater.
Aplicação de zeólitas sinterizadas a partir de cinzas de carvao na remoção de corante em água
2007 - GROSCHE, LUCAS C.; FUNGARO, DENISE A.
Surfactant-modified zeolites from coal fly and bottom Ashes as adsorbents for removal of crystal violet from aqueous solution
2015 - BERTOLINI, THARCILA C.R.; IZIDORO, JULIANA de C.; ALCANTARA, RAQUEL R.; GROSCHE, LUCAS C.; FUNGARO, DENISE A.
Estudos cineticos da adsorcao de azul de metileno sobre zeolita de cinzas de carvao
2007 - FUNGARO, DENISE A.; GROSCHE, LUCAS C.; BRUNO, MARIZA