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[en] CHARACTERIZATION AND CHEMICAL PROCESSING, USING CHLORINE AGENTS, OF ELECTRIC ARC FURNACE DUST / [pt] CARACTERIZAÇÃO E PROCESSAMENTO QUÍMICO POR MEIO DE REAGENTES CLORETANTES DE UM RESÍDUO INDUSTRIALFELIPE SOMBRA DOS SANTOS 01 November 2018 (has links)
[pt] Este trabalho aborda um estudo alternativo voltado para o tratamento de um resíduo industrial gerado durante a fabricação de aço nos fornos elétricos, através do uso reagentes cloretantes. O resíduo analisado quantitativamente apresenta os seguintes resultados em relação aos seus principais constituintes:
29 por cento de Fe e 16 por cento Zn. Tem-se como principal objetivo uma recuperação do zinco contido e o simultâneo enriquecimento do resíduo em Fe2O3, que permitiria, então, o reaproveitamento do resíduo pela indústria e a conseqüente diminuição do impacto ambiental. Foram utilizados diversos métodos de análise de caracterização, tais como difração de raios-X, microscopia eletrônica de varredura, difração e fluorescência de raios-X e espectroscopia de massa (ICPMS). Observou-se que o zinco encontra-se presente na amostra na forma de ferrita de zinco (franklinita). As análises prévias dos clássicos diagramas energia livre de Gibbs versus T em variadas opções de tratamentos químicos indicaram que algumas
ustulações, tais como aquelas com Cl2 e CaCl2, seriam capazes de viabilizar a remoção seletiva do zinco, enriquecendo assim o resíduo em ferro, a fim de que possa ser usado novamente na alimentação do forno. Os resultados experimentais da ustulação com cloreto de cálcio confirmaram tal possibilidade ao mostrar que quando a reação é conduzida a 1100 graus Celsius durante 30 minutos com um excesso de 40 por cento de reagentes, o teor de ferro no resíduo aumenta ligeiramente (com remoção de 21 por cento), enquanto o teor de zinco decresce de 16 por cento para 1 por cento (remoção de 94 por cento), sugerindo estudos complementares onde a seletividade fosse otimizada. / [en] This work is related to an alternative chemical treatment of an electric furnace dust. The residue containing 29 percent of Fe and 16 percent of Zn, most of it in a zinc ferrite (ZnFeO4) structure, was submitted to chlorine containing reagents. The main idea was to separate the zinc from the iron through a selective chloride formation of the former followed by its volatilization. In this case, the residue, without the zinc presence, could be reused in the industrial plant, minimizing the environmental impact. Some characterization analyze methods was used as Xray diffraction, scanning electronic microscopy, diffraction and X-ray fluorescence and mass spectroscopy (ICP-MS). The zinc observed in the sample was present
as zinc ferrite (franklinite). Preliminary thermodynamics studies have shown that chlorine and calcium chloride roasting could act selectively on the residue, then producing the volatile zinc chloride and leaving behind the iron oxide. Experimental work has proved that possibility showing that when the reaction happened at 1100 degrees Celsius, with 40 percent the reagents excess, for 30 minutes, the iron content increase slowly (with 21 percent removed) while that the zinc conten decrease the 16 to 1 percent (94 percent removed), proposing complementaries studies to optimize the selectivity.
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Modelling and simulation of unsteady state heat and mass transfer in the roasting of meatSingh, Neera January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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Vikingatida stavar och deras funktioner : En komparativ studie om stavar funna i SkandinavienOlsson, Oskar January 2016 (has links)
Abstract: This essay is a comparative study conducted on several iron staffs and a few staffs made of wood believed to be either roasting spits, measurement rods or staffs of sorcery. The aim of the study is to distinguish if all the staffs can be perceived as staffs of sorcery or which of them should not be considered as such. Also if there is a standard type of staffs of sorcery. Furthermore the study will also contain the question, if the ritual specialization of “volur” could be a role in which an ordinary matron would be able to perform as. Another question is if the Sami shamanism share features with the Nordic ritual of “seidr”, if so, is there reason to believe the staffs also might share features with shamanism.
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Poboljšanje kvaliteta napitka kafe izborom optimalnih uslova prženja i odnosa različitih vrsta kafe / Improvement of coffee beverage quality by selecting optimal roasting conditions and optimal ratio of different coffee speciesOdžaković Božana 01 February 2016 (has links)
<p>Na našim prostorima napitak crne kafe veoma je cijenjen i ima dugu tradiciju pripreme i konzumiranja. Izborom optimalnih parametara procesa prženja u industrijskim uslovima proizvodnje i definisanjem recepture, nastoji se postići odgovarajući kvaliteta, odnosno najprihvatljivija senzorska svojstava napitka kafe. Da bi kafa na određenom tržištu zadovoljila želje i očekivanja porošača, potrebno je definisati parametre kvaliteta kafe za potrebe svakog ciljnog tržišta. Primjenom deskriptivne senzorske analize moguće je dati precizan opis arome, ukusa i boje napitka kafe, kao najvažnijih senzorskih svojstava, sa značajnim uticajem na kvalitet i prihvatljivost kvaliteta.<br />Cilj ove doktorske disertacije je postizanje optimalnog senzorskog kvaliteta napitka crne kafe definisanjem parametara procesa prženja kafe u industrijskim uslovim proizvodnje i definisanjem optimalnog odnosa kafe vrste Arabika i kafe vrste Robuste, kao i definisanje senzorskog profila i sistema senzorskog ocjenjivanja napitka crne kafe koji se priprema na tradicionalan način.<br />Da bi se definisali parametri procesa prženja, neophodno je odrediti optimalnu temperaturu prženja, koja će omogućiti razvoj i formiranje prijatnih senzorskih svojstava u zrnu kafe. Za pripremanje napitka crne kafe na tradicionalan način obično se koriste dvije vrste kafe, Arabika i Robusta u različitom odnosu.<br />Na osnovu rezultata dobijenih hemijsko-fizičkim analizama uzoraka različitih vrsta kafa i mješavina na različitim temperaturama prženja i senzorskom analizom napitka kafe pripremljenog od ispitivanih uzoraka kafe na tradicionalan način, sa ciljem poboljšanja kvaliteta napitka kafe izborom optimalnih uslova prženja i odnosa različitih vrsta kafe može se zaključiti da uzorci napitka kafe pripremljeni od uzoraka proizvedenih prema proizvođačkoj specifikaciji nemaju očekivani kvalitet napitka kafe, kao i da proizvodnjom uzoraka pojedinačnih vrsta kafe pržene na 167°C i 175°C i njihovih mješavina nije postignut optimalni kvaliteta napitka kafe. Takođe je zaključeno da je uzorak napitka kafe pržene na 171°C N1 ocjenjen kao uzorak najboljih senzorskih svojstava (82,35%). Odnos kafa Arabika II klasa, Arabika I klasa i Robusta je bio 34,28%:51,42%:14,30%. Vrijednost titracione kiselosti iznosila je 128,86, sadržaj hlorogenske kiseline 3,77%, sadržaj kofeina 2,29%, sadržaj proteina 13,79%, sadržaj slobodne masti 14,37%, odnosno sadržaj ukupno zasićenih masnih kiselina 42,65%, a sadržaj ukupno nezasićenih masnih kiselina 57,36%, vrijednost pH 5,35 i aktivnost vode 0,102. Antioksidativna aktivnost je iznosila 235,57 μmola TE/g uzorka (DPPH) i 217,62 μmola TE/g uzorka (ABTS).<br />Uzorak U1 napitka kafe pripremljen na tradicionalan način od mješavine kafe pržene na 171°C, sitno mljevene okarakterisan je kao veoma prijatan za konzumiranje, sa najskladnijim aromatskim profilom, usaglašene gorčine i kiselosti, prijatne i umjerene punoće ukusa i blagog i harmoničnog utiska u ustima. Odnos kafa Arabika II klasa, Arabika I klasa i Robusta u ovom uzorku je bio 34,28%:51,42%:14,30%.</p> / <p>Consumption of black coffee prepared in a traditional way is very popular in our region. By selecting the optimum parameters of roasting in industrial conditions and defining ratio of the individual species of coffee, it aims to achieve the appropriate quality, and the most acceptable sensory properties of a coffee beverage. In order to fulfill consumers expectations, it is necessary to define the parameters of quality coffee for the needs of each target market. Using descriptive sensory analysis it is possible to give a precise description of the aroma, taste and color of coffee beverage, as the most important sensory characteristics, with significant impact on the quality and acceptability of quality.<br />The aim of this PhD thesis was to achieve optimal sensory quality black coffee beverage, by defining the parameters of the coffee roasting within the industrial conditions and defining the optimal ratio of coffee Arabica and Robusta species, as well as defining a sensory profile and the system of sensory analysis black coffee beverage which was prepared on traditional way.<br />In order to define the parameters of the roasting process, it is necessary to determine the optimum temperature of roasting, which will enable the development and formation of pleasant sensory properties of coffee beans. For the preparation of coffee beverage in the traditional way, usually used two species of coffee, Arabica and Robusta in different ratio. Based on the results of chemical and physical analysis of coffee samples (different species and blends) at different roasting temperatures and results of sensory analysis of a coffee beverage prepared from coffee samples in the traditional way, with the aim of improving the coffee beverage quality, by determining optimal conditions of roasting and ratio of different species of coffee, it could be concluded that the samples of coffee beverage prepared from samples produced according to the production specification do not had the expected quality of coffee beverage. It also could be concluded that by production of individual species of coffee samples roasted at 167 and 175° C, and their blends was not reached optimal quality of coffee beverage. It was also concluded that the coffee beverage of sample roasted at 171C, N1 was rated as the sample of the best sensory properties (82.35%). The ratio of coffee Arabica Class II, Arabica Class I and Robusta was 34.28%: 51.42%: 14.30%. Value of titratable acidity was 128.86, chlorogenic acid content was 3.77%, caffeine content was 2.29%, protein content was 13.79%, the content of free fat was 14.37%, total content of saturated fatty acids was 42.65%, and total content of unsaturated fatty acids was 57.36%, pH value was 5.35 and aw value was 0.102. The antioxidant activity was amounted 235.57 μmol TE/g sample (DPPH) and 217.62 μmol TE/g sample (ABTS).<br />Coffee beverage prepared in the traditional way from a sample U1 roasted at 171 °C, finely ground, was characterized as very pleasant, with the most harmonious aromatic profile, pleasant bitterness and acidity, pleasant and moderate body and gentle and harmonious impression in the mouth. The ratio of coffee Arabica Class II, Arabica Class I and Robusta in this sample was 34.28%: 51.42%: 14.30%.</p>
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Determining the impact of roasting degree, coffee to water ratio and brewing method on the sensory characteristics of cold brew Ugandan coffeeSeninde, Denis Richard January 1900 (has links)
Masters of Science / Department of Food, Nutrition, Dietetics and Health / Edgar Chambers IV / In today’s market, there is a growing demand for high-quality coffee with distinctive sensory characteristics. An example of such coffees is the cold brew which has become quite popular. Despite the increasing prevalence of cold drip/brewed coffee, little-published research exists on the factors that impact the sensory characteristics of cold brew coffee. The objectives of this study were to determine the impact of a) degree of roasting, b) coffee to water ratio (C2WR) and c) brewing methods on cold brew coffee from d) Ugandan coffee beans. Four distinct coffee samples, sourced from different lowland and mountainous regions in Uganda, were roasted and tested using a factorial design that allowed comparison of all main factors (a-d) and their interactions. The samples were evaluated by a highly trained sensory panel based on 42 attributes from a previously published coffee lexicon. Results showed that all aspects studied (Ugandan variety, roast degree, C2WR, and brewing method) had an impact on most of the attributes. For example, Robusta coffees generally had a more bitter taste than Arabica coffees and the Dark roast samples generally were more bitter than the Medium roast coffees. In addition, coffee samples that were brewed using a higher coffee to water ratio (C2WR) generally were more bitter than the coffees that were brewed using a lower C2WR. However, although most of the main effects had a significant impact, their effects were mitigated by their interaction with other factors. For example, Medium roast Robusta that was slow-dripped with a high C2WR had a more bitter taste than the corresponding Arabica samples however when the Medium roast Robusta was steeped with a high C2WR it had a similar bitter intensity with the corresponding Arabica samples. Thus, although major impacts are critical, individual sample combinations must be considered when evaluating coffee samples for their impact on the sensory characteristics.
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[en] CHEMICAL PROCESSING OF A HIGH CARBON FECR ALLOY FINES AIMING TO OBTAIN CHROMIUM OXIDE / [pt] PROCESSAMENTO QUÍMICO DE FINOS DE UMA LIGA FECR ALTO CARBONO VISANDO A OBTENÇÃO DO ÓXIDO DE CROMODOUGLAS MARTINS TORRES 16 April 2019 (has links)
[pt] Ligas ferrosas são importantes insumos nos processos de obtenção de aços especiais. A obtenção de ligas Fe-Cr se dá principalmente por meio de dois processos, empregando-se como agentes redutores C ou Si, sendo o primeiro associado à síntese de ligas FeCrAC, e o segundo às ligas FeCrBC. Neste contexto, ligas do sistema Fe-Cr, com teor de Cr típico variando entre 45 a 95 por cento em massa, apresentam destaque, principalmente na fabricação de aços inoxidáveis. Durante processo de obtenção das referidas ligas, há considerável produção de finos, os quais podem ser reaproveitados mediante tratamento químico (piro e hidrometalúrgico) apropriado. No presente trabalho investigouse a extração de cromo de finos gerados durante a produção de uma liga Fe-Cr com alto teor de C. Para tanto foram realizadas ustulações nas temperaturas de 700, 800, 900 e 1000 graus Celsius com excessos de 100, 200, 300 e 400 graus Celsius NaOH e estequiométrico, 125, 150 e 200 graus Celsius de excesso de Mg(OH)2 em atmosfera oxidante, seguida de solubilização em meio aquoso e redução com H2O2 em diferente valores de pH, seguido-se da precipitação com NaOH em pH alcalino. Matéria prima, intermediários e produtos foram caracterizados por MEV/EDS, FTIR, DRX e ICP-OES. As recuperações de Cr em solução máximas alcançadas foram da ordem de 98 por cento, e a etapa de redução e precipitação em aproximadamente 95 por cento sugerindo que a rota de processamento químico proposta foi satisfatória no que tange à extração do cromo inicialmente presente. / [en] Ferrous alloys are important inputs in the process of obtaining special steels. The obtained Fe-Cr alloy is mainly by two processes, employing reducing agents such as C or Si, the first being associated with the synthesis of FeCrAC alloy and the second alloy to FeCrBC. In this respect, alloys of Fe-Cr system with varying Cr content typically between 45 to 95 percent by weight show prominence, particularly in the manufacture of stainless steel. During the process of obtaining these alloys, there is considerable production of fines which can be reused by appropriate chemical treatment (hydro-and pyro). In the present work we investigated the extraction of chrome fines generated during the production of a Fe-Cr alloy with high content of C. For both ustulações were performed at temperatures of 700, 800, 900 and 1000 Celsius degrees in excess of 100, 200, 300 and 400 percent stoichiometric NaOH and 125, 150 and 200 percent excess of Mg (OH) 2 in an oxidizing atmosphere, followed by solubilization in an aqueous medium and in H2O2 reduction with different pH values was followed by precipitation with-NaOH alkaline pH. Raw materials, intermediates and products were characterized by MEV/ EDS, FTIR, XRD and ICP-OES. The recoveries of Cr on maximal solution achieved were of the order of 98 percent, and the stage of reduction and precipitation by about 95 percent suggesting that the route of chemical processing proposal was satisfactory with regard to the extraction of chromium initially present.
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Hantering av inköpsrisk vid svenska kafferosterier : när smaken får avgöra En studie av hur riskhantering kan integreras i inköpsprocessen / Supply Risk Managment within Swedish Roasting-Houses : when taste is everything A study of how risk management can become an integral part of the purchasing processBerlin, Jenny, Leidstedt, Hanna January 2004 (has links)
<p>Background: The strategic importance of purchasing departments is increasing, yet supply risks are rather uncharted. The procurement of coffee involves supply risks and the purchaser needs to be able to handle these to enable the roasting-house to produce coffee as specified. </p><p>Purpose: To chart risks in connection with the procurement of coffee as well as the possibilities of handling these. The thesis also examines if general risk management theories are applicable on the supply risk present within Swedish roasting-houses and can become an integral partof the purchasing process. </p><p>Method: A qualitative case study of the purchasing process of Swedish roasting- houses. </p><p>Result: An a priori-model, which can serve as the basis for evaluation of the purchasing process and risk management of a business, elaborated to fit the Swedish roasting business.</p>
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Hantering av inköpsrisk vid svenska kafferosterier : när smaken får avgöra En studie av hur riskhantering kan integreras i inköpsprocessen / Supply Risk Managment within Swedish Roasting-Houses : when taste is everything A study of how risk management can become an integral part of the purchasing processBerlin, Jenny, Leidstedt, Hanna January 2004 (has links)
Background: The strategic importance of purchasing departments is increasing, yet supply risks are rather uncharted. The procurement of coffee involves supply risks and the purchaser needs to be able to handle these to enable the roasting-house to produce coffee as specified. Purpose: To chart risks in connection with the procurement of coffee as well as the possibilities of handling these. The thesis also examines if general risk management theories are applicable on the supply risk present within Swedish roasting-houses and can become an integral partof the purchasing process. Method: A qualitative case study of the purchasing process of Swedish roasting- houses. Result: An a priori-model, which can serve as the basis for evaluation of the purchasing process and risk management of a business, elaborated to fit the Swedish roasting business.
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Hydrometallurgical Extraction Of Nickel And Cobalt From Caldag Lateritic OreOzdemir, Veysel 01 September 2006 (has links) (PDF)
In this study, an attempt has been made to hydrometallurgical extraction of cobalt and nickel by atmospheric pressure sulphuric acid leaching and a pug-roast-leach process using two stage roasting for lateritic ore. The ore used in the study was obtained from Ç / aldag Lateritic Ore, Manisa, Turkey. The metal contents of the ore are 2.1 % Ni, 0.12 % Co, 32.45 % Fe, 1.01 % Mn, 2.58 % Cr, 0.78 % Mg and 1.01 % Al. The reserve of lateritic ore deposit is approximately 40 million tonnes.
In the study, first sulphuric acid leaching was applied at atmospheric pressure for leaching the Ç / aldag lateritic ore. The effect of various parameters, such as leaching time, leaching temperature, particle size, pulp density and acid strength on Ni and Co extractions were determined. By leaching at 80oC for 40 wt % H2SO4 addition of ore, 1/3 pulp density, Ni and Co extractions were found 44.49 % and 53.03 % respectively, yielded a pregnant solution containing 3.11 g/L Ni and 0.12 g/L Co. But the result of atmospheric pressure sulphuric acid leaching was considered insufficient from the recovery point of view.
In the pug-roast-leach process, which is consisted of a two stage roasting followed by water leaching, decomposition temperature differences of sulphates of cobalt, nickel and iron are exploited. In this process, amount of acid, sulphatization and decomposition temperature, sulphatization and decomposition time, leaching temperature and time, solid/liquid ratio, and the effect of water addition during pugging were optimized. Under the optimized conditions (sulphuric acid: 25 wt % of ore / moisture: 20 wt % of ore / sulphatization temperature: 450oC / sulphatization time: 30 minutes / decomposition temperature: 700oC / decomposition time: 60 minutes / leaching temperature: 70oC / leaching time: 30 minutes and solid-liquid ratio: 1/4 by weight), Co and Ni extractions were found 91.4 and 84.4 percent, respectively. A pregnant solution containing 3.084 g/L Ni and 0.185 g/L Co was obtained. These results were considered sufficient for the leaching of lateritic nickel ores.
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Optimization Of Roasting Conditions Of Hazelnuts In Microwave Assisted OvensUysal, Nalan 01 February 2009 (has links) (PDF)
The main objective of this study was to optimize the roasting conditions of hazelnuts in microwave-infrared and microwave-convective heating combination ovens by using response surface methodology. It was also aimed to construct regression models for the prediction of quality parameters of hazelnuts as a function of processing conditions. The independent variables were microwave power (10, 30, 50, 70 and 90%), upper-lower infrared power (10, 30, 50, 70 and 90%) and roasting time (2, 3, 4, 5 and 6 min) for microwave-infrared combination roasting. Microwave power (70, 140 and 210W), air temperature (90, 150 and 210° / C) and roasting time (5, 15 and 25 min) were the independent variables of microwave-convective heating combination oven. As control, hazelnuts roasted in conventional oven at 150° / C for 20 min were used. The quality parameters were L* value, a* value, fracture force and moisture content of the hazelnuts for both microwave assisted ovens.
The optimum roasting conditions of microwave-infrared combination oven were determined as 2.5 min of roasting time at 613.8W microwave power, 1800W upper infrared power, and 300W lower infrared power. Hazelnuts roasted at the optimum condition had comparable quality with the conventionally roasted ones. When micro-
wave infrared combination oven was used, conventional roasting time of hazelnuts was reduced by 87.5%. Optimum roasting conditions of microwave-convective heating combination oven were 140 W microwave power, 150° / C air temperature and 20 min roasting time. High regression coefficients were calculated between the experimental data and predicted values showing that RSM is capable in predicting quality parameters of hazelnuts during microwave assisted roasting.
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