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Solvent Extraction Preconcentration of Trace Metal Ions from Natural Waters with an Alkylated Oxine DerivativePavski, Victor 03 1900 (has links)
<p> A method for the simultaneous preconcentration by solvent extraction of a group of trace metal ions from natural waters has been developed. The procedure makes use of a proprietary "liquid cation-exchanger", Kelex 100, the primary component of which is an alkylated oxine (8-quinolinol) derivative, 7-(4-ethyl-1-methyloctyl)-8-quinolinol (HL). After purification of HL from the commercial mixture, the extraction of ten environmentally-significant trace metal ions from artificial seawater into toluene solution was studied as a function of pH. From these investigations, the optimal conditions for the extraction of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), Pb(II) and Zn(II) from natural waters were established. The conditions for quantitative back-extraction of the metal ions were then investigated. With the exception of cobalt, the metal ions were quantitatively back-extracted into a small volume of nitric acid, simplifying the matrix and providing additional analyte enrichment. The optimized forward- and back-extraction technique was subsequently applied to the determination of total (soluble) Cd, Cu, Mn, Ni and Pb in a coastal seawater reference standard by graphite-furnace atomic absorption spectroscopy (GFAAS). The quantitative recovery of the analytes and the uncomplicated matrix of analysis enabled quantitation to be carried out by external calibration. Compared to the method of standard additions, external calibration has advantages in overall analysis time and sample consumption. Satisfactory agreement was obtained between the experimental and reference values, although Cu(II) blanks were high due to trace Cu(II) contamination of HL and the stability of the Cu(II)-HL chelate.</p> <p> The lipophilicity of HL and its metal chelates provided high metal chelate distribution ratios which, in turn, permitted preconcentration factors of up to 500 in a single batch-extraction. Additionally, studies on the recovery of radiotracer spikes from lakewater and seawater suggested that HL is an effective extractant for stripping metal ions from variously-bound forms from natural waters.</p> / Thesis / Master of Science (MSc)
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Exploring Neoteric Solvent Extractants: Applications in the Removal of Sorbates From Solid Surfaces and Regeneration of Automotive Catalytic ConvertersSubramanian, Bhargavi 03 July 2007 (has links)
No description available.
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Solvent Extraction of Lipids from MicroalgaeAnthony, Renil J. 22 September 2010 (has links)
No description available.
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Bioraffinering av bark: En jämförelse mellan två extraktionsmetoder / Bark Biorefining: A Comparison between two extraction methodsAl-Bety, Salwa January 2021 (has links)
Intresset för användningen av material från förnybara råvaror ökar. Produktionen av vedmassa och material i skogsindustrin genererar dagligen stora mängder biprodukter, särskilt bark. Barken innehåller många värdefulla komponenter som kan förädlas och öka värdet för barken, men först måste de separeras. Målet med denna undersökning var att separera dessa genom att jämföra två olika typer av extraktionsmetoder. Den första metoden använde programmerbar utrustning som namnges accelerated solvent extraction (ASE) och den andra använde manuell teknik som namnges Soxhlet extraktion. Syftet med undersökningen var att avgöra vilken extraktionsmetod som kan användas till att utvinna bark komponenter mest effektivt. Metoden ASE omfattar acetonextraktion och varmvattenextraktion där trycket var 100 bar, temperaturen 100oC och tiden drygt en timme. Soxhletextraktion omfattade enbart acetonextraktion under atmosfäriskt tryck, kontinuerlig värme och tiden 90 minuter. ASE-metoden gav fyra extrakt; acetonextrakt vid 100oC samt varmvattenextrakt vid 100oC, 140oC och 160oC. Barken som studerades var uppdelad i två fraktioner, fuktig bark och torr bark. En beräkning av utbyte % utfördes efter varje extraktion. Extrakten från fuktig bark hade mörkare färg än extrakten från torr bark. Det uppmätes pH-värden för alla vattenextrakt och den som gav lägst pH var vattenextrakt som erhölls vid 160oC. Slutligen visade utbyteresultaten inga stora skillnader mellan de utförda ASE vattenextraktionerna exklusive extraktfärgen som kan vara en indikation till skillnad i extraherade molekyler. Användningen av sand under varmvattenextraktionerna gav inga förbättringar i extraktionsmetoden. / Interest in the use of materials from renewable sources is increasing. The production of wood pulp and materials in the forest industry generates large amounts of by- products daily, especially tree bark. Bark contains many valuable components which if separated can be used in various types of applications. The aim of this study was to compare two extraction methods. The first method used programmable equipment and is named accelerated solvent extraction (ASE) and the second used manual technology and is named Soxhlet extraction. The purpose of the study was to determine which extraction method can be used to extract bark components more efficiently. The ASE method included acetone extraction and hot water extraction where the pressure was 100 bar, the temperature 100oC and the time just over an hour. Soxhlet extraction involved only acetone extraction under atmospheric pressure, continuous heating, and a time of 90 minutes. The ASE method yielded four extracts: acetone extract at 100oC and hot water extract at 100oC, 140oC and 160oC. The bark studied was divided into two parts, undried bark and dry bark. Total calculation of yield% was performed after each extraction. The extracts from undried bark had a darker color than the extracts from dry bark. The pH values were measured for all water extracts and the one that gave the lowest pH was obtained at 160oC. Finally, the extraction results did not show any major differences between the ASE water extractions performed excluding the extract color which may be an indication of difference in extracted molecules. The use of sand during the hot water extractions did not improve the extraction method.
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Extraction and destruction of organics in wastewater using ozone-loaded solventTizaoui, Chedly, Slater, M.J., Ward, D.B. January 2004 (has links)
No / Originally developed as a heat exchange fluid, Volasil 245 (decamethylcyclopentasiloxane) has been found to dissolve 10 times more ozone than water does. This article proposes and investigates the extraction of wastewater contaminants to ozone-loaded Volasil 245 as a means of providing rapid treatment. In a series of bench-scale tests, the effectiveness of ozone-loaded Volasil 245 contact was compared with that of conventional gas contact. Tests were conducted with respect to a range of organic compounds: namely, phenol, 2-chlorophenol, 2,3-dichlorophenol, 1,3-dichlorobenzene, o-nitrotoluene, and nitrobenzene. Contact with the ozone-loaded solvent was suggested to be the more rapid technique, reducing aqueous concentrations by at least 85% within 30 s. In the case of 2-chlorophenol, Volasil 245 contact was shown to require just ~0.5 min to achieve a residual aqueous fraction of 5%, as opposed to ~4.5 min of gas contact. However, water/solvent interfacial mass transfer resistance was suggested to limit the degree of aqueous decontamination ultimately achieved.
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Utilization of predispersed solvent extraction for removal and enzymatic degradation of chlorinated solvents in ground waterYoung, Matthew J. 22 August 2008 (has links)
The feasibility of applying a recently developed liquid-liquid extraction method termed Predispersed Solvent Extraction (PDSE) in an <i>ex situ</i> pump-and-treat system to remove trace amounts of dissolved chlorinated solvents like perchloroethylene (PCE) and trichloroethylene (TCE) from contaminated ground water has been investigated. In PDSE, the solvent is comminuted into globules with diameters ranging from submicron to 100 microns, and stabilized by a surfactant film prior to contact with the aqueous feed. These stabilized globules, termed oil-core aphrons (OCAs), disperse readily in water since water is the continuous phase in systems where the oil-water phase ratios can be as high as 9. Due to their fine particle size and large surface area, high extraction mass-transfer rates are achieved with minimal mixing. OCA phase separation from water can be expedited with microbubble foam flotation. Experiments in this investigation focused on PDSE process development for this groundwater remediation application.
Distribution coefficients for PCE and TCE in possible OCA solvents were determined experimentally and agree with published calculated values. Various surfactant/solvent OCA formulations using the aforementioned solvents were examined with emphasis on creating a weakly stable dispersion which would maximize extraction efficiency yet destabilize sufficiently to permit rapid flotation with minimum losses in the raffinate.
Accelerating phase separation, hence solvent recovery, through dispersion chemical destabilization with salts, coagulants, and flocculants at varied pH was examined with and without microbubble flotation.
The presence of OCAs in the aqueous phase reduced vapor phase concentrations of PCE as much as 96% and was assessed through apparent Henry's Law constants.
TCE concentrated in dodecane OCA extract was degraded with a CO-dehydrogenase enzyme complex to cis 1,2-dichloroethylene, trans 1,2-dichloroethylene, and 1,1-dichloroethylene, and vinyl chloride as a possible means of destroying TCE dissolved in the extract.
Based on the implications of these experiments, the development of a PDSE <i>ex situ</i> pump-and-treat system appears technically feasible and a conceptual process layout has been provided. / Master of Science
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The thermodynamics of liquids in solution at 298 K and 1 atm.Naidoo, Rolandra D. January 2003 (has links)
For many years the problem of separating aliphatic and aromatic compounds has been at the
forefront of the petroleum and oil refining industries. This separation is often effected using
liquid-liquid extraction or extractive distillation. Both of these processes require the addition of a
solvent to bring about separation.
The aims of this work were to investigate the use of "mixed" solvents, such as those used in the
Arosolvan process, for their application in liquid-liquid extraction and extractive distillation as
well as to provide related thelmodynamic data for systems containing mixed solvents. In the last
part of this work, a computer program was developed to theoretically predict the effectiveness of
a number of solvents on a user-defined separation.
The solvents used for liquid-liquid extraction were chosen based on their similarities to those in
the Arosolvan process and were of the form, {N-methyl-2-pyrollidone (NMP) + glycerol, a glycol
or water} where the glycol was either monoethylene glycol (MEG), diethylene glycol (DEG) or
triethylene glycol (TEG). The additives were combined in various mixing ratios to NMP to
determine a mixing ratio for which the effect of the solvent is possibly optimized (a list of all
solvents and mixing ratios used are presented in this work).
Solvent selectivity and the range of compositions over which separation could occur determined
the effectiveness of the solvents. This work dealt with the separation of n-hexane and toluene. In
order to determine the selectivity and range of compositions, the liquid-liquid equilibria (LLE) of
systems containing n-hexane + toluene + solvent had to be determined. LLE was measured using
a simple equilibrium cell at 298 K and 1 atm. The phase separation boundaries (binodal curves)
were determined using a titration method.
The results obtained in this work showed an increase in the range of compositions over which the
mixture of n-hexane and toluene could be separated (i.e a larger range of mixing ratios over which
these components could be separated from each other) from the pure NMP solvent to the mixed
solvent cases. This implies that there is a The range of compositions over which separation could
be affected is given (for the solvents) in descending order:
NMP + 50% glycerol> NMP + 10% water > NMP + 30% MEG > NMP + 5% water > NMP +
30% glycerol> NMP + 10% glycerol > NMP + 10% MEG > NMP + 10% DEG > NMP + 10%
TEG > NMP + 5% DEG > 100% NMP.
The selectivities of the solvents showed a remarkable increase from the pure NMP case to the
mixed solvent cases. The maximum selectivity obtained for the NMP + 10% DEG system was
over 1200 compared to a maximum selectivity of just 6 for the pure NMP system. The maximum
selectivities obtained in descending order were as follows:
NMP + 10% DEG > NMP + 10% TEG > NMP + 10% glycerol > NMP + 10% MEG > NMP +
30% MEG > NMP + 50% glycerol > NMP + 10% water > NMP + 5% water > NMP + 30%
glycerol > NMP + 5% DEG > 100% NMP.
The binodal curves were modelled using the Hlavaty, ,8-density and log-y functions. The
maximum standard deviations obtained were 0.075, 0.078 and 0.05 for each of the functions
respectively. The equilibrium data was modelled using the UNIQUAC and NRTL
thermodynamic models and showed excellent agreement. This work showed better agreement to
the NRTL functions due to the fact that the non-randomness parameter, a ij , may be chosen
arbitrarily.
The results obtained in this work indicate that the use of mixed solvents greatly increases the
effectiveness ofNMP used for the separation of n-hexane and toluene. It is suggested that further
studies be performed on a wider range of aliphatic and aromatic compounds in order to determine
whether this is a generic behaviour or just true for n-hexane and toluene.
The effectiveness of each solvent for extractive distillation was determined by its separation
factor. In order to determine separation factors, the activity coefficients at infinite dilution
(IDACs) had to be measured. This was done using a gas-liquid chromatography technique. The
solvents employed in this study were NMP, Glycerol, MEG, TEG, NMP + 10% glycerol, NMP +
10% MEG, NMP + 10% DEG, NMP + 10% TEG. The solutes used were: pentane, heptane,
hexane, toluene and benzene.
The separation factors were determined for each alkane/aromatic pair per solvent. The pure
solvent cases were then compared to the mixed solvent cases. The mixed solvents did not show
results as promising for extractive distillation applications as they did for liquid-liquid extraction.
TEG displayed the best selectivities for each of the alkane/aromatic separations except for the
heptane/benzene pair, for which NMP + 10% glycerol proved to be the most effective solvent.
When compared to the results obtained from the original UNIF AC model, the IDACs obtained in
this work showed up to a 99% deviation. This is due to the fact that the model does not work well
for all types of molecules and does not predict the equilibrium of "unlike" molecules adequately.
It is suggested that other mixing ratios and different solvents be used to further investigate the
effectiveness of mixed solvents for extractive distillation applications. It is further recommended
that a computer aided data logging system be developed to determine residence times. This
would not only provide more accurate results, but also provide a database for future reference.
The computer program that was developed using the original UNIF AC method contains a
database of 28 commonly used industrial solvents. This program enables the user to compare
graphically the effectiveness of each of the solvents on the desired separation. Due to the
limitations of the original UNIF AC method, the program does not work well for all types of
molecules. However, the model can be changed without altering the prografnming structure to
include a modified version of the UNIFAC model depending on the users needs. The program
although written from an extractive distillation standpoint can be extended to include liquid-liquid
equilibrium predictions. The main benefit of such a program is to eliminate time-consuming
experimental work required to narrow down a long list of solvents required for a particular
separation by theoretically predicting the best solvents for the job. The solvent database can also
be expanded when new solvents become available or the user needs change / Thesis (M.Sc. Eng)-University of Natal, Durban, 2003.
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Citrus essential oil fractionation using ethanol with different water contents as solvents: phase equilibrium, physical properties and continuous equipment extraction / Fracionamento de óleos essenciais cítricos utilizando etanol com diferentes níveis de hidratação como solventes: equilíbrio de fases, propriedades físicas e extração em equipamento contínuoGonçalves, Daniel 17 July 2017 (has links)
Essential oils are featured commodities in the global market due their many applications in food and chemical industries, in different medicine areas, and as antibacterial, antifungal, and antioxidant agent. One of the phenomena accountable for the loss of essential oils quality may be associated with the degradation of terpene hydrocarbons by oxidation when exposed to air, light or heat, causing disagreeable odors. The procedure of terpenes content reducing, known as deterpenation, can be performed by diverse techniques, among which the liquid-liquid extraction can be highlighted since this process can be operated without the use of heating and pressure changes, causing low impact on the essential oil sensory qualities and low energy consumption. This research was focused on the fractionation process of citrus essential oils, by liquid-liquid extraction, using ethanol/water mixtures as solvents. Experimental liquid-liquid equilibrium data of model and real citrus systems were obtained. The aroma profile of the crude citrus essential oils (orange - Citrus sinensis and lime - Citrus aurantifolia) and the phases from the liquid-liquid equilibrium was also evaluated. Moreover, the crude citrus essential oils were fractionated in a continuous operation equipment (perforated rotating disc contactor, PRDC). It was verified that the water has an important influence over the fractionation performance, but not over the aroma profile of the phases. The experimental data from the model systems (citrus essential oil model mixture + ethanol + water) were used to adjust parameters of empirical and thermodynamic models, which provided satisfactory results on the calculation of physical property values and compositions of the phases from the real systems (crude citrus essential oil + ethanol + water). The fractionation of citrus essential oils by liquid-liquid extraction technology was technically feasible and can be accomplished into continuous apparatus such as PRDC column. The solvents employed provided extract phases enriched in oxygenated compounds. / Óleos essenciais são importantes produtos comercializados mundialmente devido às suas diversas aplicações em indústrias alimentícias e químicas, em diferentes áreas da medicina, e como agentes antibacteriano, antifúngico e antioxidante. Um dos fenômenos responsáveis pela sua perda de qualidade pode estar associado à degradação dos hidrocarbonetos terpênicos por oxidação, quando estes são expostos ao ar, luz ou calor, ocasionando odor desagradável. O procedimento para redução do teor de terpenos no óleo essencial, conhecido como desterpenação, pode ser realizado por diferentes técnicas, entre as quais a extração líquido-líquido se destaca uma vez que pode ser conduzida sem o emprego de calor e mudanças na pressão, o que atenua o impacto nas qualidades sensoriais e demanda menor gasto energético. Este estudo se concentrou no processo de fracionamento de óleos essenciais cítricos, pela técnica de extração líquido-líquido, empregando misturas de etanol e água como solventes. Foram obtidos dados de equilíbrio líquido-líquido de sistemas cítricos modelo e reais. O perfil de aroma dos óleos essenciais brutos (laranja - Citrus sinensis e lima ácida Citrus latifolia) e das fases provenientes do equilíbrio líquido-líquido também foram avaliados. Além disso, os óleos essenciais brutos foram submetidos ao processo de fracionamento em equipamento de operação contínua (coluna de discos rotativos perfurados, PRDC). Verificou-se que a água possui uma importante influência sobre o desempenho do processo de fracionamento, mas não afetou o aroma das fases. Os dados experimentais dos sistemas modelo (mistura modelo de óleo essencial cítrico + etanol + água) foram utilizados para o ajuste de parâmetros de modelos empíricos e termodinâmicos, os quais apresentaram bons resultados no cálculo de valores de propriedades físicas e da composição das fases oriundas dos sistemas reais (óleo essencial cítrico bruto + etanol + água). O fracionamento de óleos essenciais cítricos pela tecnologia de extração líquido-líquido mostrou-se tecnicamente viável e pode ser conduzido em equipamentos contínuos como a coluna de extração PRDC. Os solventes empregados permitiram a obtenção de fases extrato enriquecidas com compostos oxigenados.
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Estudo do fracionamento de terras raras a partir da monazita: separação do cério por oxidação e precipitação e do térbio por extração por solventes / Study of the rare earths fractionating form monazite separation of cerium by oxidation and precipitation and terbium by solvent extractionRenata Dias Abreu 29 August 2011 (has links)
Nenhuma / Este trabalho apresenta um estudo da separação dos elementos terras raras (ETR) cério (Ce) e
térbio (Tb) através de técnicas hidrometalúrgicas. Para a realização do estudo, a INB
Indústrias Nucleares do Brasil S.A., forneceu duas amostras; um licor sulfúrico proveniente
do processamento da monazita contendo principalmente os ETR leves (La, Ce, Pr e Nd) e um
carbonato dos ETR pesados contendo Tb, Dy, Ho, Er e Y também originado do
processamento do licor da monazita.
O estudo de separação do cério foi realizado em meio clorídrico. Para a preparação do licor
clorídrico os ETR presentes no licor sulfúrico foram precipitados na forma de sulfato duplo de
terras raras e sódio que foi convertido em hidróxido terras raras e então dissolvido em HCl. O
estudo de obtenção do Ce de elevada pureza foi dividido em duas etapas: precipitação seletiva
do cério e purificação do precipitado obtido. A separação do cério pela técnica investigada
compreende dois fenômenos: a oxidação do Ce (III) a Ce (IV) e a precipitação Ce (IV) como
hidróxido. Os oxidantes investigados foram: H2SO5, H2O2 e KMnO4. Devido ao fato do
KMnO4 ser mais estável em meio básico, este foi utilizado em solução contendo Na2CO3
evitando assim sua degradação e auxiliando no controle do pH de precipitação do Ce(OH)4.
Entre estes oxidantes, o KMnO4 se mostrou mais eficiente na oxidação do Ce. Após a escolha
do agente oxidante, investigou-se as seguintes variáveis de processo: pH final, excesso de
KMnO4, tempo de reação e razão molar KMnO4/Na2CO3. Os resultados indicaram a
necessidade de um excesso de 30 % de KMnO4 para se ter a completa oxidação do Ce (III) a
Ce (IV). Neste caso o Ce(OH)4 precipita juntamente com o MnO2. A purificação do cério foi
realizada pela dissolução da mistura de dióxido de manganês e hidróxido de cério com
solução de HCl e precipitação seletiva do cério mediante adição de solução de ácido oxálico
ou de hidróxido de amônia. Ambos, ácido oxálico e hidróxido de amônia, mostraram-se
eficientes na purificação do cério a partir da mistura de Ce/Mn. Após a purificação, os produtos obtidos apresentaram uma pureza entre 99 e 99,5 % de CeO2 com uma recuperação
de cério superior a 98 %.
A separação do térbio dos outros ETR pesados foi realizada usando a técnica de extração por
solventes. Foram realizados experimentos descontínuos e contínuos. Nos experimentos
descontínuos, investigou-se as seguintes variáveis de processo: tipo e concentração do agente
extratante, acidez da fase aquosa, relação volumétrica entre as fases, tempo de contato e
concentração do agente reextratante (solução de ácido clorídrico). Dez extratantes foram
investigados: três ácidos organofosforados (DEHPA, IONQUEST801 e CYANEX272);
uma mistura de DEHPA / TOPO (ester neutro), três extratantes quelantes (LIX63,
LIX984N e LIX612N) e três extratantes básicos - aminas (ALAMINE336,
ALIQUAT336 e PRIMENEJMT). Os extratantes organofosforados e extratantes quelantes
foram investigados em meio clorídrico e sulfúrico, o desempenho das aminas foi avaliado em
meio sulfúrico e a mistura de DEHPA / TOPO em meio clorídrico. Os melhores fatores de
separação para os elementos adjacentes foram obtidos com DEHPA e IONQUEST801. Para
DEHPA 1,0 mol L-1 em acidez inicial de 0,3 mol L-1 os fatores de separação foram: 2,5
Tb/Dy, 2,1 Dy/Ho, 1,9 Ho/Er, 2,0 Ho/Y e 1,1 Y/Er; para IONQUEST801 1,0 mol L-1 em 0,3
mol L-1 de H+ obteve-se 2,7 Tb/Dy, 2,4 Dy/Ho, 2,1 Ho/Er, 2,1 Ho/Y e 1,5 Y/Er.
Os experimentos contínuos foram realizados em um circuito de misturadores decantadores
composto das etapas de extração, lavagem, reextração e regeneração do solvente em sistema
contracorrente utilizando IONQUEST801 como extratante. Dez experimentos contínuos
foram conduzidos em 370 horas de operação, onde os ajustes pertinentes foram sendo
realizados, até que a pureza e o rendimento desejados fossem alcançados. Após otimização
das condições de processo, o circuito de extração por solventes foi constituído de 10 estágios
na etapa de extração, 15 estágios na etapa de lavagem, 10 estágios na etapa de reextração e 2
estágios de regeneração do orgânico. No processo de separação do Tb apresentado, tanto o
rendimento de separação como a pureza do produto obtido foram de aproximadamente 90 %. / This work presents a study of the separation of rare earth elements (REE) cerium (Ce) and
terbium (Tb) through hydrometallurgic techniques. For the accomplishment of the study, the
INB Indústrias Nucleares do Brasil S.A., supplied two samples: a sulphuric liquor from the
monazite processing containing mainly the light REE (La, Ce, Pr and Nd) and a heavy REE
carbonate containing Tb, Dy, Ho, Er and Y also obtained from the processing of the monazite
liquor.
The study of the separation of Ce was carried out in a hydrochloric medium. In order to
prepare the hydrochloric liquor, the REE present in the sulfuric liquor were precipitated as
sodium and RE double sulphate which was converted into RE hydroxide which was then
dissolved in HCl. The study of the accomplishment of high purity cerium was divided into
two steps: selective precipitation of cerium and the purification of the precipitated obtained.
The separation of Ce through the technique investigated comprises two phenomena: oxidation
of the Ce (III) into Ce (IV) and the precipitation of the Ce (IV) as hydroxide. The oxidant
agents investigated were: H2SO5, H2O2 and KMnO4. Amongst these oxidants, KMnO4
presented the best results. After choosing the oxidant agent, the following process variables
were investigated: final pH, KMnO4 excess, reaction time and the molar ratios of KMnO4 /
Na2CO3. KMnO4 was used in a mixture with Na2CO3 in order to keep the stability of the
solution. The results indicated that 30 % of KMnO4 excess was necessary to full oxidation of
Ce (III) into Ce (IV). In such case Ce(OH)4 was precipitated together with MnO2. The cerium
purification was carried out by dissolution of mixture of ceric hydroxide and manganese
dioxide with HCl and it was then selectively precipitated through the addition of oxalic acid
or an ammonium hydroxide solution. Both oxalic acid and ammonium hydroxide proved
efficient in the precipitation of the cerium present in the mixture of Ce/Mn. After purification the final products assayed between 99 and 99.5 % of CeO2. The cerium recovery yield was
greater than 98 %.
The separation of terbium from other heavy REE was carried out through the solvent
extraction technique. Non-continuous and continuous experiments were done. In the noncontinuous
experiment, the following process variables were investigated: type and
concentration of the extractants, acidity of the aqueous phase, aqueous / organic volumetric
ratio, contact time and the stripping agent concentration (chloridric acid solution). Ten
extractants were investigated: three organophosphorus acids (DEHPA, IONQUEST801 and
CYANEX272), a mixture of DEHPA/TOPO (neutral ester), three chelating extractants
(LIX63, LIX984N and LIX612N) and three basic extractants - amines (ALAMINE336,
ALIQUAT336 and PRIMENEJM-T). The organophosphorus extractants and chelating
extractants were investigated in hydrochloric and sulphuric media, the performance of the
amines was assessed in a sulphuric medium and the mixture of DEHPA/TOPO in
hydrochloric medium. The best separation factors for the adjacent elements were obtained
with DEHPA and IONQUEST801. For 1 mol L-1 DEHPA in an initial acidity of 0.3 mol L-1,
the separation factor was 2.5 Tb/Dy, 2.1 Dy/Ho, 1.9 Ho/Er, 2.0 Ho/Y and 1.1 Y/Er; for 1 mol
L-1 IONQUEST801 in 0.3 mol L-1 of H+ it was 2.7 Tb/Dy, 2.4 Dy/Ho, 2.1 Ho/Er, 2.1 Ho/Y e
1.5 Y/Er.
The continuous experiment was carried out in a mixer-settler circuit comprising extraction,
scrubbing, stripping and solvent regeneration steps in a counter-current system using
IONQUEST801 as extractant. Ten continuous experiments were conducted in 370 hours of
operation having their variables continuously adjusted in consecutive runs until the desired
yields and grades were achieved. The optimum operational circuit was composed of 10 stages
in the extraction step, 15 stages in the scrubbing step, 10 stages in the striping step and 2
organic regeneration stages. A terbium product attaining 90 % purity with a yield of 90 % was
obtained.Te
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Análise das perdas na produção contínua de extração de óleo de soja : estudo de caso no método de extração por solvente /Canizella, Rodnei. January 2012 (has links)
Resumo: As atividades de uma indústria com o sistema de produção contínua possuem características próprias dependendo do processo a que se dispõe a transformar uma matéria-prima, por isso este trabalho trata de analisar as perdas na produção contínua de extração de óleo de soja por solvente, apresentando a descrição do processo e as principais indicadores de desempenho, propondo sugetões de monitoramento para melhoria dos resultados. Essa abordagem é feita comparando-se resultados propiciados por alguns autores da área com dados da área com dados levantados de uma empresa no Brasil em dois períodos distintos, incluindo análise de evolução da planta, onde a alta gerência monitora a produtividade e a qualidade dos produtos, e trata as perdas no ambiente de transformação como consumo de solvente utilizado para extração do óleo de soja e consumo de combustível para a geração de energia térmica. Conclui-se que a indústria de extração de óleo vegetal, possui diversas variáveis de controle pelo conjunto de operações necessárias à transformação, ressaltando neste caso a perda de energia térmica como prioridade de atitudes de melhorias. Dado que a tendência de aumento da capacidade de processamento de soja é evidente, pela perspectiva de crescimento da produção de soja no Brasil, deve ser considerado neste contexto, o investimento em conhecimento para as pessoas exercerem as atividades operacionais em perfeita sincronia com as informações que ocorrem no processo, garantindo o objetivo da organização de minimização das perdas, e consequente aumento do lucro e crescimento / Abstract: The activities of the industry with a continuous production system have their own characteristics depending on the process that is willing to turn a raw material, so this work is to analyzed the losses in the continuous production of soybean oil extraction solvent, presenting the description of the process and key performance indicators and propose suggestions for the improvement of monitoring results. This approach is made comparing the results obtained by some authors in the field with data collected from a company in Brazil in two distinct periods, including examination of the plant, where top management monitors productivity and product quality, and treats losses the environment of use as processing solvent used to extract the soybean oil and fuel to generate heat energy. It is concluded that the industry of oil extraction plant has several control variables the operations required for processing, emphasizing in this case the loss of thermal energy as priority actions for improvements. Since the trend of increased processing capacity of soybean is evident from the perspective of growth of soybean production in Brazil, should be considered in this context, investment in knowledge for people to exercise operational activities in perfect synchrony with the information occur in the process, ensuring the organization's goal of minimizind losses, and consequent increase in profit and growth / Orientador: Manoel Henrique Salgado / Coorientador: José de Souza Rodrigues / Banca: Rogério Andrade Flauzino / Banca: Vagner Cavenaghi / Mestre
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