As one of the most abundant elements on earth, iron is nearly always present in metal concentrates. This is specifically true for zinc sulphide concentrates, which can contain up to 18% iron (marmatite). Today more than half of these concentrates are treated in hydrometallurgical- or combined hydrometallurgical¬pyrometallurgical circuits. In hydrometallurgical circuits, iron is solubilised (either in a roast-Ieach-, a direct leach- or bacterial leach circuit) along with zinc and must be removed from the zinc¬rich solution before the electrowinning- or solvent extraction step. Various iron removal processes were developed to address the iron problem in hydrometallurgical circuits. The better known of these include the jarosite-, goethite- and hematite processes also used in the zinc industry. Zincor (Zinc Corporation of South Africa) patented an iron removal process (Zincor Process), which was generally considered to be very similar to the so-called "para-goethite" iron removal process used only in two other zinc smelters notably Porto Vesme (Italy) and Pasminco Hobart (Tasmania). However, since the Zincor Process was patented in 1976, various changes have been made such as a change from a batch parallel to a continuous series process, a change in precipitation pH-profile and the introduction of a pH controlled acid wash in the second tank. The introduction of a weak acid leach step and vacuum belt filters at Zincor's residue treatment plant in the near future and an iron removal process that is not clearly understood, necessitated this further study of the Zincor iron removal process. The study has been conducted in three parts. The first part of the study has focused on the characterisation of the Zincor iron residue and the Zincor process. The second part of the study has been concerned with the definition of an optimum operating window in terms of the filterability of the residue and the third part investigated the use of neutralisation reagents other than zinc calcine to control the pH during iron precipitation. The distribution of iron in the Zincor iron precipitate, which usually contains between 35% and 40% iron, has been found to be as follows: approximately 45% as schwertmannite, 5% as ferrihydrite, 20% as jarosites, 25% as franklinite, trace amounts of pyrite as well as 5% of an unknown phase. This confirmed that goethite is not present in the Zincor iron residue and that iron is mainly removed in the form of amorphous intermediate iron phases such as schwertmannite and ferrihydrite. Of these two phases, schwertmannite was the least expected as most work up until now were done on samples taken from natural environments. The following description of the conditions that promote iron removal, mainly as schwertmannite, is viewed as an expansion of the available literature data, which was gathered at ambient conditions. In terms of the main operating parameters, optimum filterability was achieved under the following conditions: pH of 3.0, temperature as high as possible (70°C) and at least 25 kg/m3 seeding. A retention time of at least 4 hours at a pH of 3.0 and 60°C was required, which decreased by more than 50% at a temperature of 70°C. As these conditions mainly impact on the soluble zinc loss encountered during iron removal, an effort was made to further reduce the insoluble zinc loss, which is the inherent weakness in the Zincor process, and similar processes where zinc calcine is used for pH control, by investigating the use of alternative neutralisation reagents. This study showed that iron can be successfully removed with Ca(OH) 2, a basic zinc sulphate and zinc oxide mixture as well as chemically precipitated CaC03 produced in the paper and pulp industry. Of these alternatives, CaC03 appeared to be the most promising, with filtration rates an order of magnitude higher than the zinc oxide options (calcine and basic zinc sulphate mixture), due to better overall economics than with the use of Ca(OH) 2. Utilisation CaC03 as an alternative neutralisation agent might increase the overall zinc recovery figure at Zincor by up to 1.5%. Based on the findings, it can be concluded that the Zincor process in its current form has a very distinct character compared to what was historically considered to be the very similar patented para-goethite iron removal process, as practiced at the Porto Vesme and the Pasminco Hobart hydrometallurgical zinc plants. / Dissertation (MEng (Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / unrestricted

Este trabalho avaliou a deposição úmida de duas localidades da cidade de São Paulo (Universidade Presbiteriana Mackenzie localizada na região central e no IAG/USP localizado na zona oeste de São Paulo) e uma localidade pertencente ao município de Cubatão (CEPEMA), na Baixada Santista. O período de estudo compreendeu os meses de julho/2009 a agosto/2010 para o IAG/USP e Cubatão; enquanto que o conjunto amostral no Mackenzie é referente ao período de julho de 2002 a outubro de 2008. A partir da comparação com dados climatológicos verificaram-se para ambas as regiões que o ano de 2009 teve um inverno anomalamente chuvoso; e o ano de 2010 apresentou um verão seco. Observaram-se diferentes faixas de concentrações médias ponderadas por volume (MPV) dos íons majoritários para cada região: Cubatão, onde os íons dominantes foram: cloreto (60,3 mol L-1), sódio (51,4 mol L-1), sulfato (24,0 mol L-1), amônio (23,3 mol L-1) e nitrato (17,4 mol L-1); enquanto que na região do IAG/USP os íons dominantes foram: amônio (25,5 mol L-1) e nitrato (16,3 mol L-1). Obtiveram-se valores médios de pH em água de chuva de 4,8 e 5,3 em Cubatão e São Paulo respectivamente. Registraram-se 12 eventos (em 99) de chuvas ácidas em Cubatão e apenas um entre 59 eventos no IAG/USP. Estimou-se a contribuição marinha para os íons Ca2+, Na+, Mg2+, K+, Cl- e SO42-, observou-se que o íon de referência mais adequado para tal estimativa em São Paulo foi o sódio, entretanto para Cubatão o íon mais adequado foi o magnésio. A partir destas premissas pode se destacar que os íons potássio, cálcio e sulfato apresentaram baixa influência marinha em ambas as regiões (<11%), entretanto, o íon cloreto apresentou grande contribuição marinha (>63%) para os dois municípios. A análise estatística multivariada para São Paulo destacou o papel da relação entre o íon amônio com sulfato e nitrato no processo de neutralização da acidez da atmosfera; além da relação da brisa marítima com as concentrações dos íons sódio e cloreto, principalmente no período chuvoso. Ressalta-se também que a contribuição de sódio e cloreto não foi unicamente oceânica e que processos antrópicos e/ou naturais continentais desconhecidos contribuíram para estas concentrações. / This study evaluated the wet deposition of two localities in São Paulo city (University of Mackenzie in the central region and the University of Sao Paulo, IAG/USP, in the west area) and one in Cubatão (CEPEMA), both in Sao Paulo State. The sampling period happened from July 2009 to August 2010 in the IAG/USP and CEPEMA; while the samplings in the Mackenzie were from July 2002 to October 2008. The climatological data analysis showed that the year 2009 had an abnormally rainy winter, and 2010 presented a dry summer for both regions. The major ion volume weight mean (WMV) concentrations for Cubatão were: chloride (60.3 mol L-1), sodium (51.4 mol L-1), sulfate (24, 0 mol L-1), ammonium (23.3 mol L-1) and nitrate (17.4 mol L-1), while in the IAG / USP the dominant ions were: ammonium (25.5 mol L-1) and nitrate (16.3 mol L-1). The average rainwater pH values in CEPEMA and in IAG/USP reached 4.8 and 5.3 respectively. The acid rain events were recorded in 12 samples of Cubatão (from 99 totals) and only one (from 59 total samples) in the IAG/USP. The marine contribution were estimated for Ca2+, Na+ / Mg2+, K+, Cl- and SO42- and was observed that the most appropriate reference ion for this estimative in Sao Paulo was the sodium, however to Cubatão the most appropriate ion was magnesium. From these premises it is emphasized that the potassium, calcium and sulfate showed low marine influence in both regions (<11%), however the chloride ion showed large marine contribution (> 63%) for the two regions. Multivariate statistical analysis to Sao Paulo rainwater has highlighted the role of the relation between ammonium with sulfate and nitrate in the process of neutralizing the acidity of the atmosphere, besides of the relation of sea breeze with the concentrations of sodium and chloride ions, especially in the rainy season. The results also emphasized that the contribution of sodium and chloride was not natural oceanic only and anthropogenic and/or natural unknown sources on the continent contributed to these concentrations.

Este trabalho avaliou a deposição úmida de duas localidades da cidade de São Paulo (Universidade Presbiteriana Mackenzie localizada na região central e no IAG/USP localizado na zona oeste de São Paulo) e uma localidade pertencente ao município de Cubatão (CEPEMA), na Baixada Santista. O período de estudo compreendeu os meses de julho/2009 a agosto/2010 para o IAG/USP e Cubatão; enquanto que o conjunto amostral no Mackenzie é referente ao período de julho de 2002 a outubro de 2008. A partir da comparação com dados climatológicos verificaram-se para ambas as regiões que o ano de 2009 teve um inverno anomalamente chuvoso; e o ano de 2010 apresentou um verão seco. Observaram-se diferentes faixas de concentrações médias ponderadas por volume (MPV) dos íons majoritários para cada região: Cubatão, onde os íons dominantes foram: cloreto (60,3 mol L-1), sódio (51,4 mol L-1), sulfato (24,0 mol L-1), amônio (23,3 mol L-1) e nitrato (17,4 mol L-1); enquanto que na região do IAG/USP os íons dominantes foram: amônio (25,5 mol L-1) e nitrato (16,3 mol L-1). Obtiveram-se valores médios de pH em água de chuva de 4,8 e 5,3 em Cubatão e São Paulo respectivamente. Registraram-se 12 eventos (em 99) de chuvas ácidas em Cubatão e apenas um entre 59 eventos no IAG/USP. Estimou-se a contribuição marinha para os íons Ca2+, Na+, Mg2+, K+, Cl- e SO42-, observou-se que o íon de referência mais adequado para tal estimativa em São Paulo foi o sódio, entretanto para Cubatão o íon mais adequado foi o magnésio. A partir destas premissas pode se destacar que os íons potássio, cálcio e sulfato apresentaram baixa influência marinha em ambas as regiões (<11%), entretanto, o íon cloreto apresentou grande contribuição marinha (>63%) para os dois municípios. A análise estatística multivariada para São Paulo destacou o papel da relação entre o íon amônio com sulfato e nitrato no processo de neutralização da acidez da atmosfera; além da relação da brisa marítima com as concentrações dos íons sódio e cloreto, principalmente no período chuvoso. Ressalta-se também que a contribuição de sódio e cloreto não foi unicamente oceânica e que processos antrópicos e/ou naturais continentais desconhecidos contribuíram para estas concentrações. / This study evaluated the wet deposition of two localities in São Paulo city (University of Mackenzie in the central region and the University of Sao Paulo, IAG/USP, in the west area) and one in Cubatão (CEPEMA), both in Sao Paulo State. The sampling period happened from July 2009 to August 2010 in the IAG/USP and CEPEMA; while the samplings in the Mackenzie were from July 2002 to October 2008. The climatological data analysis showed that the year 2009 had an abnormally rainy winter, and 2010 presented a dry summer for both regions. The major ion volume weight mean (WMV) concentrations for Cubatão were: chloride (60.3 mol L-1), sodium (51.4 mol L-1), sulfate (24, 0 mol L-1), ammonium (23.3 mol L-1) and nitrate (17.4 mol L-1), while in the IAG / USP the dominant ions were: ammonium (25.5 mol L-1) and nitrate (16.3 mol L-1). The average rainwater pH values in CEPEMA and in IAG/USP reached 4.8 and 5.3 respectively. The acid rain events were recorded in 12 samples of Cubatão (from 99 totals) and only one (from 59 total samples) in the IAG/USP. The marine contribution were estimated for Ca2+, Na+ / Mg2+, K+, Cl- and SO42- and was observed that the most appropriate reference ion for this estimative in Sao Paulo was the sodium, however to Cubatão the most appropriate ion was magnesium. From these premises it is emphasized that the potassium, calcium and sulfate showed low marine influence in both regions (<11%), however the chloride ion showed large marine contribution (> 63%) for the two regions. Multivariate statistical analysis to Sao Paulo rainwater has highlighted the role of the relation between ammonium with sulfate and nitrate in the process of neutralizing the acidity of the atmosphere, besides of the relation of sea breeze with the concentrations of sodium and chloride ions, especially in the rainy season. The results also emphasized that the contribution of sodium and chloride was not natural oceanic only and anthropogenic and/or natural unknown sources on the continent contributed to these concentrations.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-04-26T20:42:12Z No. of bitstreams: 1 Caroline_Ribeiro_2018.pdf: 4186138 bytes, checksum: e15fcfac07f7fe535fcafad4cba066dd (MD5) / Made available in DSpace on 2018-04-26T20:42:12Z (GMT). No. of bitstreams: 1 Caroline_Ribeiro_2018.pdf: 4186138 bytes, checksum: e15fcfac07f7fe535fcafad4cba066dd (MD5) Previous issue date: 2018-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work focused on the characterization of an effluent of a recycling and recovery industry of automotive batteries and on the feasibility evaluation of different materials, a biosorbent (fish scales - FS), a mineral (dolomite - DL) and a commercial material (cationic resin - CR) combined use in the removal of heavy metals. The studied materials were physico-chemically and morphologically characterized (pHpzc, MEV-EDS, FTIR and XRD) before and after their use in the removal processes in order to understand the structural modifications of the materials. In addition, the elemental composition of the liquid and solid phases after the treatment process were evaluated by TXRF analysis. The effluent presented an extremely acidic characteristic (pH = 1) and the incidence of heavy metals above the legislation discharging limits (Fe, Zn and Pb). Due to the structural characteristics and its respective functional groups, each adsorbent material presented different functional groups and different behavior in solution, which led to different removal and neutralization capacities. The CR presented the highest removal capacity of the metallic ions, mainly governed by an ion exchange process. Whilst the FS and DL presented lower removal capacities following complex simultaneous phenomena such as dissolution, complexation, precipitation and adsorption. On spite of that, the FS and DL presented a great neutralization capacity (i.e. pH elevation of the extremely acidic medium), related to the leaching of its alkaline constituents. By considering the generation of chemical sludge as a key factor in the work, aiming its mitigation and the better quality of the treated effluent, it was verified that the sequential application of these materials in hybrid process could be a promising and feasible alternative, by taking advantage of the particular characteristics of each material both in the neutralization and heavy metals’ removal. In this way, the use of DL, FS and CR in combined hybrid processes was evaluated, initially in batch system. Amongst the evaluated ones, the DL-CR hybrid process, in which the dolomite was used for the effluent neutralization up to pH = 5 followed by CR for the metallic ions removal presented better results. Therefore, the DL-CR hybrid process showed the highest percentages of metal removal (99, 73 and 100%, respectively, for Fe, Zn and Pb), as well as the lowest generation of chemical sludge by the end of the processes. In addition, the pre-neutralization (pH = 5 achieved by the DL) provided greater chemical stability of the CR. Subsequently, the DL-RC hybrid process was employed in fixed bed, evaluating the possibility of adsorption-desorption cycles aiming at the resin reuse and recovery of heavy metals. Different affinities of each metal ions by the RC for the multicomponent system (Pb> Fe> Zn) were identified, which were associated with the properties of each species as radius of hydration, valence and electron affinity. The possibility of the RC use in recycle was verified, in which similar removal capacities to the previous cycle and compatible with the levels of disposal of legislation - in terms of concentration of heavy metals as well as pH - was reached. These results demonstrate the potential of the hybrid treatment process, however, the fixed bed operating conditions such as bed height and volumetric flow still can be optimized in order to maximize mass transfer efficiency in the bed. Therefore, considering that the DL-RC hybrid process was able to overcome the treatment drawbacks of such type of effluent, due to its extremely acidic character and the complex multicomponent composition of heavy metals in solution, the process can be considered viable in technical and operational terms. In general, the cooperative use between DL and RC in hybrid process presents a remarkable potential in the neutralization and treatment of heavy metals from the battery recycling industry. / Este trabalho enfocou na caracterização de um efluente de uma indústria de reciclagem-recuperação de baterias automotivas e na avaliação de viabilidade de utilização combinada de diferentes materiais, um biossorvente (escamas de peixe - ES), um mineral (dolomita - DL) e uma material comercial (resina catiônica - RC) na remoção de metais pesados. Os materiais estudados foram caracterizados físico-química e morfologicamente (pHpzc, MEV-EDS, FTIR e DRX) antes e após sua utilização nos processos de remoção visando compreender as modificações ocorridas na sua estrutura. Além disso, a composição elementar das fases líquida e sólida após o processo de tratamento foram avaliadas por análise TXRF. O efluente apresentou caráter extremamente ácido (pH=1) e presença de metais pesados acima dos limites da legislação de descarte (Fe, Zn e Pb). Devido às características estruturais e seus respectivos grupos funcionais, cada material adsorvente apresentou comportamentos distintos em solução, o que levou a diferentes capacidades de remoção e neutralização. A RC apresentou a maior capacidade de remoção dos íons metálicos, governada majoritariamente por um processo de troca iônica. enquanto que a ES e a DL apresentaram menores capacidades de remoção seguindo fenômenos simultâneos complexos como dissolução, complexação, precipitação e adsorção. Por outro lado, a ES e a DL, apresentaram uma grande capacidade de elevação do pH dos meios extremamente ácidos, relacionado à lixiviação dos seus constituintes alcalinos. Ao considerar a geração de lama química como um fator chave no trabalho, visando sua mitigação e o a melhor qualidade do efluente tratado, verificou-se que a aplicação desses materiais de forma sequencial em processo híbrido poderia ser viável e promissora, considerando as características particulares de cada um desses materiais, tanto na neutralização quanto para remoção de metais pesados. Neste sentido, avaliou-se o uso da DL, ES e RC em processos híbridos combinados em sistema batelada, sendo o processo híbrido DL-RC, o qual empregou a dolomita na neutralização do efluente até o pH = 5 seguido pela RC para remoção dos íons metálicos a combinação que apresentou melhores resultados. O processo híbrido DL-RC apresentou as maiores porcentagens de remoção dos metais (99, 73 e 100%, respectivamente, para Fe, Zn e Pb), bem como a menor geração de lama química ao final dos processos. Além disso, a pré-neutralização (pH = 5 alcançado pela DL) proporcionou uma maior estabilidade química da RC. Posteriormente, empregou-se o processo híbrido DL-RC em leito fixo avaliando-se, ainda, a possibilidade de ciclos de adsorção-dessorção visando a reutilização da resina e recuperação dos metais pesados. Identificou-se diferentes afinidades de cada íon metálico com a RC para o sistema multicomponente (Pb > Fe > Zn), associadas às propriedades de cada espécie como raio de hidratação, valência e eletroafinidade. Verificou-se a possibilidade do uso da RC em reciclo, atingindo-se capacidades de remoção similares ao ciclo anterior e compatíveis com os níveis de descarte de legislação em termos de concentração de metais pesados bem como de pH. Tais resultados evidenciam o potencial do processo híbrido de tratamento, no entanto, as condições operacionais do leito fixo como a altura do leito e vazão volumétrica ainda podem ser otimizadas visando a maximização da eficiência de transferência de massa no leito. Desta forma, considerando-se que o processo híbrido DL-RC foi capaz de contornar a problemática do tratamento de tais efluentes dado seu caráter extremamente ácido e a complexa composição multicomponente de metais pesados em solução o processo pode ser considerado viável em termos técnico-operacionais. No geral, o uso cooperativo entre DL e RC em processo híbrido apresenta notável potencial na neutralização e tratamento de metais pesados provenientes da indústria de reciclagem de baterias.

The purpose of this study was to simulate the liquid flow rate distribution in the etching modules and find the optimal setup in order to achieve a distribution as homogenous as possible. The commercial software Matlab 2015a has been employed for all the numerical simulations. The optimization has been carried out varying several parameters, i.e. spray cross sections of the nozzles, the oscillation parameters, the rotating angle of the nozzles within etching module 1 and the nozzle arrangement inside the modules. Furthermore, the optimization has been carried out separately along the two directions of the modules. The results achieved computationally have been validated via experimental procedures. During this study a specific experimental setup has been developed in order to be able to compare experimental and computational results. The validation process has shown that the computational method matches the experimental results to a good extent. The experimental liquid distribution in etching module 2 widely matches the simulations to a quantitative extent, while the one in etching module 1 provides the same qualitative but different quantitative results.