Eutectic Freeze Crystallization Of Boron Compounds

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2016Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2016Boron birleşikleri, özelikle boraks ve borik asit, çeşitli endüstriler için istenilen ve önemli hammaddelerdir. Tarımdan nükleer reaktörlere kadar çok sayıda uygulamaları bulunmaktadır. Boraks ve borik asidinin ana kullanım alanları borosilikat cam, seramik sır ve deterjan üretimidir. Genel olarak boraks ve borik asit ürünleri, tinkal ve kolemanit minerallerinden üretilmektedir. Türkiye tinkal (35.5% B2O3) ve kolemanit (50.8% B2O3) kaynaklarıyla dünya lideridir. Türkiye’de 803 milyon ton bor rezervi bulunmakta ve günde tonlarca bor atığı endüstriyel süreçlerde oluşmaktadır. Bor üretim tesislerinden çıkan atıklar genellikle ince boyutlu katı veya pülp halindedir. Çevre duyarlılığı ve bilinci gelişmeden önce, bu atıklar direkt çevreye atılıyordu. Günümüzde endüstriyel atıklar, yeniden kullanılmak üzere zenginleştirmekte veya kullanılmayan kısımları çevresel ve ekolojik etkilerinden dolayı uygun şekilde imha edilmektedir. Gelişmiş ülkeler başta olmak üzere, Dünya'nın birçok ülkesinde araştırmacılar ve işletmeler bu konuda yoğun çaba harcamaktadır. Başta çevresel ve ekonomik koşullar göz önüne alındığında, bor atıklarının değerlendirilmesi konusunda yeni bir yönteme ihtiyaç duyulmaktadır. Bor içeren atıkların yönetiminde üç temel seçenek mevcuttur: • bor minerallerinin atıktan geri dönüştürülmesi, • bor atıklarının çevreye zarar vermeden imha edilmesi, • bor atıklarının seramik ve inşaat sektöründe hammadde olarak kullanılmasıdır. Bu durum, sürdürülebilir proses ve teknolojileri, hammadde gelişimi, -atık su geri kazanılımı ve enerji verimi gibi- proses optimizasyonlarına yönlendirmiştir. Günümüzde bu amaca “Ötektik Dondurma Kristalizasyon” (ÖDK) teknolojisi hizmet etmektedir. Bu teknoloji özellikle atık suyunun arıtılması için uygundur. Ötektik dondurma kristalizasyonun temeli ötektik noktanın bulunmasına dayanır. Ötektik nokta, tuz-su karışımı faz diyagramında karakteristik bir noktayı ifade eder. Bu sıcaklıkta buz, tuz ve çözelti arasında belirli bir konsantrasyonda denge oluşmaktadır. Böylece, ötektik dondurma kristalizasyonu prosesi değersiz ve/veya tehlikeli atık çözeltilerini temiz su ve değerli katı tuz ürünlerine dönüştürülmektedir. Ayrıca, ÖDK teknolojisi saf buz ve tuzu son derece düşük maliyet ve yüksek verimde işlemektedir. Bu tezde, temel amaç boraks-su (Na2B4O7-H2O) ve borik asit-su (H3BO3-H2O) sistemlerinin ötektik noktalarının araştırılmasıdır. Birinci atık çözelti, sentetik boraks sistemi, 1 litrelik ÖDK deneysel düzeneğinde ötektik noktanın araştırması için kullanılmıştır. Bu çalışmada, tüm deneyler başlangıçta ağırlıkça 2% boraks sulu çözeltisi kullanılarak yapılmıştır. Karıştırcı 200 rpm devire ve soğutma makinası -10 ºC’ye ayarlanarak kesikli uygulama süreçlerinde ötektik noktası bulunmuştur. Şekil 4.3’te boraks-su çözünürlük grafiği verilmiştir. Yapılan 11 tane deney sonucunda ötektik nokta 1.06% Na2B4O7 ve -0.74 ⁰C olarak tayin edilmiştir. Ötektik Dondurma Kristalizasyon prosesi uygulandıktan sonra, buz ürün saflığı tespit edilmiştir. Bu çalışmadan elde edilmek istenilen bir diğer veri ise ötektik noktaya ulaştıktan sonra soğutucu akışkan (etilen glikol) ve boraks çözeltisi arasındaki süper doygunluk sıcaklığı (sürücü güç buzun safsızlık içeriğidir. Ötektik noktada, ΔT= 6 ºC’lik sürücü güç altında 60 dakika büyümesi sağlanmış, ve Na2B4O7∙10H2O tuz kristallerinin yoğunluk farkıyla birbirinden ayrılması sağlanmış (Şekil 4.4), ardından süzme ve yıkama işlemleri yapılmıştır. Süzme işlemi cam filtre yardımıyla vakum filtrasyonu gerçekleştirilmişti. Toplamda iki yıkama gerçekleştirilmiş ve her yıkama sonrası buzun ve alttaki çözeltinin ağırlıkları ölçülerek analiz için numuneler alınmıştır. Her birinden alınan numuneler titrasyon yöntemi ile analiz edilmiş. Sonucu olarak Şekil 4.5’de ötektik noktadaki tuz, buz, çözelti miktarları ve yıkamalar sonucu buzdaki safsızlık gösterilmiştir. Alınan tüm numuneler Otomatik Büret (schott titronic universal) ile analiz edilmiştir. Ötektik noktaya ulaşmış çözeltiden alınan 10 ml’lik numunenin boraks konsantrasyonu 0.1 N’lık NaOH çözeltisi ile yapılan titrasyonla belirlenmektedir. Ayrıca farklı ÖDK koşullarında süper-doygunluk ve değişik kesikli uygulama süreçlerinde, tuz kristal boyutunun ölçümü yapılmış ve büyüme hızı araştırılmıştır. Bu deneysel çalışmada, tuz ve buz kristalleri boyut ve görünüm özellikleri açısından Olympus BX51 marka mikroskop altında incelenmiştir. Mikroskop ile gözlemlenen kristallerin fotoğrafları mikroskopun 5X büyütme ile optik mikroskop ile çekilmiş ve Image-Pro Plus programı yardımıyla boyutlandırılmıştır. Deney sonrası, tuz kristalin kaydedilen görüntüleri kullanılarak, Image J programı yardımıyla kristal boyutunda meydana gelen değişimler hesaplanmıştır. Deneysel sonuçlar kısmında, boraks kristallerinin büyüme hızı ΔT ile değişimi grafiği ile ifade edilmiş ve Şekil 4.11’te gösterilmiştir. İkinci atık çözelti, sentetik borik asit sistemi, 1 litrelik ÖDK deneysel düzeneğinde ötektik noktanın araştırması için kullanılmıştır. Bu çalışmada, tüm deneyler başlangıçta ağırlıkça 2.5% borik asit sulu çözeltisi kullanılarak yapılmıştır. Karıştırcı 200 rpm devire ve soğutma makinası -10 ºC’ye ayarlanarak kesikli uygulama süreçlerinde ötektik noktası bulunmuştur. Şekil 4.3’te boraks-su çözünürlük grafiği verilmiştir. Ötektik nokta 2.57% H3BO3 ve -0.75 ⁰C olarak tayin edilmiştir. Ötektik Dondurma kristalizasyon prosesi uygulandıktan sonra, borakstaki gibi buz ürün saflığı tespit edilmiş ve sonucu Şekil 4.5’de gösterilmiştir. Ötektik noktada, ΔT= 4 ºC’lik sürücü güç altında 20 dakika büyümesi sağlanmış, ve H3BO3 tuz kristallerinin yoğunluk farkıyla birbirinden ayrılması sağlanmıştır (Şekil 4.14). Tuz ve buz kristalleri bir cam filtre yardımıyla vakum filtrasyonu yapılarak ayırmıstır. Daha sonra alınan çözelti numunesinin analizi aynı şekilde titrasyon ile yapılarak tuz, buz, çözelti miktarları ve yıkamalar sonucu buzdaki konsantrasyon belirtirilmişti (Şekil 4.15). Bu deneysel çalışmada, tuz ve buz kristalleri boyut ve görünüm özellikleri açısından da Olympus BX51 marka mikroskop altında incelenmiştir. Mikroskop ile gözlemlenen kristallerin fotoğrafları mikroskopun 5X büyütme ile optik mikroskop çekilmiştir. Ayrıca vakum filtrasyonu yapılarak tuz ve buz ayrılırtıktan sonra kütle dengesi kurularak ötektik noktadaki tuz, buz, çözelti miktarları ve yıkamalar sonucu dengesini sağlatmıştır. Detayli hesaplama Ekte gösterilmiştir. Bor içeren çözeltilerde deneysel araştırmalar ve ÖDK uygulama fizibilitesi, sonuç ve tartışmalar kısmında ele alınmıştır. Prosesin ayrıntılı hesabı ve mikroskobik görüntüleri Ekler kısmında verilmiştir.Boron compounds, especially borax and boric acid, are desired and important raw material in various industries. They have numerous applications from agriculture to nuclear reactors. Major usage of borax and boric acid includes borosilicate glass, ceramic glazes and detergent. Generally, borax and boric acid production is manufactured from tincal and colemanite minerals. Turkey is the world leader of tinkal (35.5% B2O3) and colemanite (50.8% B2O3) minerals. In Turkey, 803 million ton boron reserve exists, and every day several hundred to thousand tons boron waste is discharged in industrial processes. Before getting environmental awareness and consciousness, those wastes were disposed directly to the environment. Nowadays industrial wastes are enriched to reuse or wastes are discharged in appropriate way due to the negative environmental and ecological impacts. Three major options are available for the management of boron containing wastes: • recovery of boron minerals from tailings, • safe disposal of boron tailings without harming the environment, • utilization of boron tailings as raw materials in ceramics and cement industry. The continuous demand and consumption of raw materials and water in the world has increased significantly in the past decades. This leads to the necessity for sustainable processes and technologies in the development of raw material and for optimization of processes as regards recycling of wastewater, recovery of waste stream, and energy efficiency. This characterize the commonly known “Eutectic Freeze Crystallization” (EFC) technology in recent. This technology is in particular suited for the treatment of aqueous waste streams. The basis of eutectic freeze crystallization is the existence of eutectic point. The eutectic point refers to a characteristic point in the phase diagram of a salt-water mixture. At this temperature an equilibrium exits between ice, salt and a solution with a specific concentration. Thus, eutectic freeze crystallization process converts an invaluable and/or hazardous waste stream into clean water and valuable solid salt products. Besides, EFC has the biggest potential to treat aqueous streams at low cost and high yields. In this thesis, the primary purpose is to investigate eutectic points of borax-water (Na2B4O7-H2O) and boric acid-water (H3BO3-H2O) systems. The first stream, synthetic borax stream, was used for investigating the eutectic point in a 1 liter EFC experimental set-up. After crystallization process was conducted, ice product purity was detected. In addition, salt crystal size measurement was conducted for evaluating the salt crystal growth at different supersaturation process and different batch times. This aims to calculate the borax growth rates at different supersaturations under EFC conditions. In this experiment, microscopic studies were conducted by using Olympus BX51 microscope. The second stream, synthetic boric acid stream, was used for investigating the eutectic point in a 1 liter EFC experimental set-up. Similar to borax case, after crystallization process was conducted, the ice product pruty was detected. All experiments were done using starting compositions of 2 wt% borax aqueous, and 2.5 wt% boric acid aqueous solutions. The experimental investigations and feasibility of EFC applications for boron systems were discussed in result and discussion part. Detailed calculation of the processes and additional microscopic images were given in Appendices.Yüksek LisansM.Sc

Spatio-temporal modelling of dengue fever incidence in Malaysia

Previous studies reported significant relationship between dengue incidence rate (DIR) and both climatic and non-climatic factors. Therefore, this study proposes a generalised additive model (GAM) framework for dengue risk in Malaysia by using both climatic and non�climatic factors. The data used is monthly DIR for 12 states of Malaysia from 2001 to 2009. In this study, we considered an annual trend, seasonal effects, population, population density and lagged DIR, rainfall, temperature, number of rainy days and El Niño-Southern Oscillation (ENSO). The population density is found to be positively related to monthly DIR. There are generally weak relationships between monthly DIR and climate variables. A negative binomial GAM shows that there are statistically significant relationships between DIR with climatic and non-climatic factors. These include mean rainfall and temperature, the number of rainy days, sea surface temperature and the interaction between mean temperature (lag 1 month) and sea surface temperature (lag 6 months). These also apply to DIR (lag 3 months) and population density

Dissolution kinetics and mechanism of pandermite in acetic acid solutions

In this study, the dissolution kinetics and mechanism of pandermite mineral was investigated using a batch reactor employing the parameters of particle size, acid concentration, solid/liquid ratio, stirring speed and reaction temperature. From experimental data, it was determined that the conversion rate of pandermite to boric acid was increased with decreasing particle size, solid/ liquid ratio and increasing reaction temperature. Conversion rate increased up to 3 M, acid concentration then decreased with increasing acid concentration.It was observed that there was no important effect of stirring speed on the dissolution rate. Furthermore, it was observed that the dissolution mechanism was dependent on acid concentration due to restriction of dissolution in acetic acid solutions. The dissolution rate of pandermite mineral in acetic acid solution was examined according to homogeneous and heterogeneous chemical reaction model. It was determined from graphical and statistical methods that the reaction kinetics fitted to model in the form of first order pseudo homogeneous model [- ln (1 - X)] = kt and activation energy for the dissolution process was found to be 28.496 kj/mol. A mathematicalmodel, which indicated the dissolution process was established

Estimation of the Turkish Boron Exportation to Europe

Borate is an essential material to numerous industries and even to individual countries’ economies, defense, and politics. Almost all industries need borates for production, and almost everybody needs their products. Borate is a compound that contains or supplies boric oxide (B2O3). Among the minerals that contain boric oxide, there are only four minerals significant from an economic standpoint, namely borax (tincal), colemanite, ulexite, and kernite. Turkey has almost 70% of all known reserves in the world. Therefore, borates and their products could be one of the main topics for sustainable development in the whole world. The recent development and pursuit of new boron-consuming technologies and alternative products to existing borate-consuming products introduce additional uncertainty to the sustainability of boron minerals. Therefore, the European Union (EU) Commission also declared borate one of the 30 critical raw materials. Turkey is a prosperous country in terms of boron reserves, and it exports almost 96% of borates’ production. In order to better understand the relation between borate minerals and borate products, a material flow analysis (MFA) study has been carried out within the content of this work in order to update the data about the current status of boron. For this purpose, a system has been established that shows the flow of boron material. The extraction, enrichment, and refining processes of boron products are drawn. The results indicate that about 41% of extracted colemanite ore is converted into refined borate, about 31% of tincal ore is converted to refined borate, and 4% of tincal ore is converted to end-usage products, such as detergent. The correctness of the data and the sensitivity of the processes are all estimated values. The results can help in the development of boron sustainability and boron production strategies. The MFA study on tincal and colemanite ore may be an example of boron studies in different countries

Developing a communication plan for Leonor Silva Jewellery in order to create brand awareness in Portugal

The following research aims to create a communication plan for Leonor Silva Jewellery to create brand awareness in Portugal. This brand is an author jewellery company inserted in the luxury market. A research was made by focusing on customers’ behaviour and the main factors that influence their purchases, followed by an analysis of notoriety and the relationship between the decision­making process and brand awareness when talking about a product with high customer involvement, as well as the relationship between communication and notoriety; then it was decided to analyse the concept of cluster and the advantages that the latter can bring, and Porter's Diamond Model. The methodology used to answer the investigation question was to elaborate Depth Interviews, and it used the Gioia Methodology in order to analyse qualitative research. We are able to obtain a classification made of six dimensions: the characterisation of the market, Luxury brands' promise, position, consumer identity, distributional channels and communication strategies. Furthermore, in order to analyse each dimension in a more detailed way, some relevant secondary data was present. Due to the difficulty of creating notoriety in Portugal to Author Jewellery, an international benchmark was performed for other European markets. This analysis explains that the strategies used internationally are similar to those adopted by Portuguese brands. However, there is more dissemination in these countries regarding a more significant number of specialised trade fairs and events.A seguinte investigação pretende criar um plano de comunicação para a empresa Leonor Silva de forma a criar notoriedade em Portugal. Sendo esta uma empresa de joalharia de autor inserida no mercado de luxo. Assim sendo passou pela investigação sobre conceito de luxo, como é o comportamento do consumidor e quais os principais fatores que influenciam o comportamento de compra, seguido de uma análise sobre notoriedade e qual a relação entre o processo de decisão e de conhecimento da marca quando se fala de producto com alto envolvimento por parte do consumidor assim como a relação entre comunicação e notoriedade. De seguida decidiu­se analisar o conceito de cluster e as vantagens do mesmo assim como Modelo do Diamante de Porter. A metodologia utilizada para responder à investigação foi a elaboração de entrevistas estruturadas a joalheiros de autor com posterior utilização da metodologia de Gioia para se proceder à análise da pesquisa qualitativa. Foram identificadas 6 dimensões que são a caracterização do mercado, a promessa de uma marca de luxo, posicionamento, identificação do consumidor, canis de distribuição e estratégias de comunicação. Com o intuito de se proceder a uma análise mais detalhada adicionaram­se outras fontes de informação. Dada a dificuldade de a joalharia de autor criar notoriedade em Portugal procedeu­se a uma comparação com outros mercados europeus. Nesta análise concluiu­se que as estratégias utilizadas internacionalmente são similares às usadas pelas marcas portuguesas, no entanto, existe uma divulgação muito maior nestes países uma vez que há um maior número de feiras e eventos especializados

Evaluation of the Hydraulic Conductivity of Compacted Laterite-Metakaolin Mixtures for Solid Waste Leachate Containment

This paper presents the results of a study conducted to investigate the benefits of using metakaolin (MK) with laterite as liner material for containment of municipal solid waste (MSW). Laboratory tests were conducted on laterite specimens treated with MK at concentrations of 0 - 20 % by weight of the soil and compacted using four types of compaction energies. Hydraulic conductivity was determined based on permeation of the compacted laterite - MK mixtures with deionized water (DW) and municipal solid waste leachate (MSWL), respectively. Deionized water was the reference permeant fluid.  The results showed that hydraulic conductivity generally decreased with increase in the percentage addition of MK to the soil. From an economic and sustainability point of view, it has been found from the results that 5 % MK can be added to soil and compacted at moulding water content of 14.1 % using the West African Standard (WAS) compaction energy to achieve the regulatory hydraulic conductivity of less than or equal to 1 x 10-9 m/s for compacted soil liner. The natural logarithm of the hydraulic conductivity experimental results were computed and used to develop regression equations for estimating hydraulic conductivity given MK contents and compaction energies. The results of the two-way analysis of variance (ANOVA) test carried out at 5 % level of significance showed that calculated F-statistics are statistically significant and the measured values of hydraulic conductivity compare well with the predicted values. The developed models can therefore be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Therefore, the developed models can be used to give good estimates of hydraulic conductivity of soils having similar properties with the laterite investigated in this study. Keywords ­_ Deionized water, Hydraulic conductivity, Leachate, Metakaolin, Municipal solid waste

Continental evaporitic environments of Argentina

En Argentina los ambientes evaporíticos están representados en las facies del Mioceno desde Mendoza hasta Bolivia y en el Cuaternario desde la Puna hasta la Patagonia. La Puna constituye de por sí una “provincia evaporítica” con salares desarrollados hasta niveles profundos y donde además de las evapofacies comunes de yeso y halita ocurren los boratos que la distinguen e identifican. En esa región se registra sedimentación evaporítica desde el Mioceno hasta la actualidad. En la faja andina se reconocen también evapofacies miocenas donde abunda el yeso y puntualmente alcanza el estado clorurado sódico. Al menos dos momentos evaporíticos son reconocidos para el Mioceno medio y superior. Durante el Cuaternario, puede verse que gran parte del territorio argentino es árido y endorreico lo que facilita la formación de lagunas salobres y salinas. Puede distinguirse a grandes rasgos un ambiente pampeano entre Catamarca y la provincia de Buenos Aires, ocupando gran parte del norte, centro y Cuyo; y luego hacia el sur un ambiente patagónico. Se trata en general de salinas someras, sin desarrollo hacia profundidad, que dejan una costra evaporítica superficial que da lugar a explotaciones de sal de cosecha.Continental evaporitic environments of Argentina are represented by Miocene facies from the Bolivian border to the Mendoza province as well as Quaternary deposits from Puna to Patagonia. Puna is considered as an “Evaporite Province” with salars deeply developed. Together with gypsum and halite occurs borate, which is an exclusive facies of this region. Puna evaporite sedimentation is registered between Middle Miocene to Recent. Along the Andes eastern belt, the Miocene rocks contains facies of gypsum and eventually halite. At least two main evaporitic events are recognized in the middle and in the late Miocene. Today it is possible to distinguish that large surfaces of the interior of the country are arid and has internal drainage. This situation is favorable to the formation of salt lakes and playas. So, we can recognize two main saline environments: a) Pampean (between Catamarca and Buenos Aires), and b) Patagonian. In general, shallow saline deposits, with sodium chloride and sulfate are presents. Salt exploitation during winter seasons is common to several of these environments.Fil: Alonso, Ricardo Narciso. Universidad Nacional de Salta. Facultad de Cs.naturales. Escuela de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Correlación Geológica. Grupo Vinculado al INSUGEO- Centro de Estudios Geologicos Andinos; Argentin

Processing Tincal Ores using Ultrasonic Waves

ABSTRACT: In this study, effects of ultrasonic sound waves have been studied on the processing of tincal ores using ultrasonic baths producing 35 kHz frequency and 1.24 W/cm 2 intensity. Tincal ores (24.37 90B2O3) were processed in saturated solutions for 15 minutes and a concentrate containing 35.29 % B2O1 was obtained with 95.69 % recovery. During ultrasonic treatment boron minerals were found to corrode to a small extent. These findings showed that efficiency of dispersion process was proportional to directly treatment time and indirectly to the sample quantity, solids density and particle size

Prior knowledge of the data on the production capacity of boron facilities in Turkey

The element boron is widely used in many industrial fields (semiconductor industry, glass industry, etc.). In order to assess the environmental impact of industrial products containing boron from cradle to grave, it is necessary to consider the impact of borate minerals on the environment. The literature on this subject is quite poor and the inventory of data on the life cycle of boron mining is very scarce. This article presents a synthesis of a literature review on this topic and provides easy access to important data on boron use and production capacities of Turkish boron facilities. The scope of Turkey has been chosen because the country has the largest deposits of borate ores in the world. The literature review is based on the analysis of sixty-three theses and fourteen reports in the fields of mining engineering, geology and earth sciences, environmental sciences, and chemical engineering. The production capacities from 1985 to 2016 (most recent data) and supporting data for each facility were studied using bibliometrics analysis. The data were then evaluated by calculating a data quality matrix, the coefficient of dispersion, and the standard deviations. We have found that the data compiled is generally of good quality. The values of the production capacities ±2.3 tons have 95% chance to be the real values of the production capacities of the boron industry in Turkey. The data obtained constitute a basis for enriching models in the field of life cycle assessment (LCA), sustainability, and/or material flow analysis (MFA) applied to borate mineral processing