scholarly journals Optimizing Conditions for Scandium Extraction from Bauxite Residue Using Taguchi Methodology

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 236 ◽  
Author(s):  
Theopisti Lymperopoulou ◽  
Paraskevas Georgiou ◽  
Lamprini-Areti Tsakanika ◽  
Konstantinos Hatzilyberis ◽  
Maria Ochsenkuehn-Petropoulou
Keyword(s):  
Bauxite Residue ◽  
Modern Technology ◽  
Taguchi Methodology ◽  
Alumina Production ◽  
Recovery Method ◽  
Method Optimization ◽  
Potential Resource ◽  
Acid Molarity ◽  
Predicted Values ◽  
Solid Liquid

Bauxite residue is the voluminous by-product of alumina production after Bayer process. Its high alkalinity causes disposal problems and harmful environmental impacts. However, the residue contains significant amounts of valuable elements, such as rare earth elements, including scandium. Greek bauxite residue contains a high amount of scandium close to its main resources. Taking into account scandium’s limited availability coupled with its high demand in modern technology, bauxite residue could be considered as a potential resource for scandium recovery. In this study, the optimization of scandium extraction from bauxite residue with sulfuric acid is investigated using Taguchi methodology. Based on previous studies, acid molarity, leaching time, solid/liquid ratio, and reaction temperature were selected as control parameters for the selective Sc recovery. Method optimization targeted the highest concentration of scandium combined with the lowest concentration of iron without taking into account application constraints. Maximization of scandium concentration can be achieved only by reduced selectivity. The predicted values resulted from the Taguchi methodology were affirmed by a confirmation experiment conducted at optimal conditions. Regression analysis provided the respective equations to be applied on several conditions, depending on different applications.

scholarly journals Optimizing Conditions for Scandium Extraction from Bauxite Residue Using Taguchi Methodology

2019 ◽  
Author(s):  
Theopisti Lymperopoulou ◽  
Paraskevas Georgiou ◽  
Lamprini-Areti Tsakanika ◽  
Konstantinos Hatzilyberis ◽  
Maria Ochsenkuehn-Petropoulou
Keyword(s):  
Bauxite Residue ◽  
Modern Technology ◽  
Taguchi Methodology ◽  
Alumina Production ◽  
Recovery Method ◽  
Method Optimization ◽  
Potential Resource ◽  
Acid Molarity ◽  
Predicted Values ◽  
Solid Liquid

Bauxite residue is the voluminous by-product of alumina production after Bayer process. Its high alkalinity causes disposal problems and harmful environmental impacts. However, the residue contains significant amounts of valuable elements such as rare earth elements including scandium. Greek bauxite residue contains a high amount of scandium close to its main resources. Taking into account scandium limited availability coupled with its high demand in modern technology, bauxite residue could be considered as a potential resource for scandium recovery. In this study, the optimization of scandium extraction from bauxite residue with sulfuric acid is investigated using Taguchi methodology. Based on previous studies acid molarity, leaching time, solid/liquid ratio and reaction temperature were selected as control parameters for the selective Sc recovery. Method optimization targeted the highest concentration of scandium combined with the lowest concentration of iron without taking into account applications constraints. The predicted values resulted by Taguchi methodology were affirmed by a confirmation experiment conducted at optimal conditions. Regression analysis provided the respective equations to be applied on several conditions depending on different applications.

scholarly journals Preliminary Characterization of Three Metallurgical Bauxite Residue Samples

2021 ◽  
Vol 5 (1) ◽  
pp. 66
Author(s):  
Panagiotis Angelopoulos ◽  
Maria Georgiou ◽  
Paschalis Oustadakis ◽  
Maria Taxiarchou ◽  
Hakan Karadağ ◽  
...  
Keyword(s):  
Low Cost ◽  
Bauxite Residue ◽  
Raw Material ◽  
Morphological Observation ◽  
Critical Metals ◽  
Alumina Production ◽  
Preliminary Characterization ◽  
Fine Grained ◽  
Extraction And Separation ◽  
Bulk Chemical

Bauxite Metallurgical Residue (BR) is a highly alkaline and very fine-grained by-product of the Bayer process for alumina production. Its huge global annual production has resulted in increasing accumulation of BR, causing deposition problems and serious environmental issues. RM contains oxides and salts of the main elements Fe, Al, Ca, Na, Si, Ti, and rare earths—REEs (Sc, Nd, Y, La, Ce, Ds)—many of which have been categorised by EU as critical metals (CMs). The valorisation of BR as a low-cost secondary raw material and metal resource could be a route for its reduction, introducing the waste into the economic cycle. REEScue constitutes a research project that aims to instigate the efficient exploitation of European bauxite residues, resulting from alumina production from Greece (MYTILINEOS SA), Turkey (ETI Aluminium), and Romania (ALUM SA), containing appreciable concentrations of scandium and REEs, through the development of a number of innovative extraction and separation technologies that can efficiently address the drawbacks of the existing solution. The consortium consists of three alumina producers from Greece (MYTILINEOS SA), Turkey (ETI Aluminium), and Romania (ALUM SA) and two academic partners from Greece (National Technical University of Athens) and Turkey (Necmettin Erbacan University). We present preliminary characterization results of three different BR samples that originate from the three aluminium industries, in respect of bulk chemical analysis (XRF, ICP), mineralogical investigation (XRD), and morphological observation through microscopy.

scholarly journals The Future of Scandium Recovery from Wastes

2021 ◽  
Vol 5 (1) ◽  
pp. 55
Author(s):  
Olga Chernoburova ◽  
Alexandre Chagnes
Keyword(s):  
Rare Earth ◽  
Bauxite Residue ◽  
High Strength ◽  
Clean Energy ◽  
Industrial Wastes ◽  
Condensed State ◽  
No Production ◽  
Alumina Production ◽  
Energy Technologies ◽  
Critical Metal

With growing demand for renewable and clean energy technologies, the need in rare earth metals is increasing. Scandium, which is often considered a rare earth element (REE), is a critical metal mainly used in solid oxide fuel cells (SOFCs) and high strength aluminum alloys used in aerospace and 3D printing applications. Furthermore, scandium supply is limited due to its scarcity and the high cost of its production in Asia and Russia while Europe has no production of scandium. Therefore, scandium extraction from alternative resources such as secondary resources located in Europe is of great concern. Within this context, this work provides a condensed state-of-art review of the issue of scandium recovery from industrial wastes. Priority was given to addressing the technological and economic challenges associated with the recovery of scandium from the said residues, with particular emphasis on the bauxite residue from alumina production, which represents nearly 5 million tons on dry basis per year in Europe.

scholarly journals The Thermal Activation of Nsu Clay for Enhanced Alumina Leaching Response

2019 ◽  
Vol 16 ◽  
pp. 34-46
Author(s):  
Udochukwu Mark ◽  
Charles Nwachukwu Anyakwo ◽  
Okechukwu Onyemaobi ◽  
Chijioke Samson Nwobodo
Keyword(s):  
Activation Energy ◽  
Thermal Activation ◽  
Leach Solution ◽  
Kaolinite Clay ◽  
Alumina Production ◽  
Calcination Temperatures ◽  
Activation Conditions ◽  
Solid Liquid ◽  
Heating Up ◽  
Better Than

The thermal activation conditions for enhancing the leaching of alumina from Nsu clay from south-eastern Nigeria was investigated. The clay assayed 28.9% and 50.59% , comprising mainly kaolinite mineral (82.6%) and quartz (12.5%). Thermal activation rendered the alumina in the clay acid-soluble by transforming the clay from its crystalline nature to an amorphous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500, 600, 700, 800, and 900 °C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000 °C (holding for 60 minutes) were used in the control experiments. Leaching of alumina from the resulting clay calcines passing 300 μm sieve (-50 mesh) was done in 1M hydrochloric acid solution at room temperature using a solid/liquid ratio of 0.02g/ml and shaking speed of 100 rpm. The solubility data given by the fraction of Al ion taken into leach solution showed that the clay calcined at 700 °C (holding for 60 minutes) responded most to leaching. In general, it was observed that samples calcined for 60 minutes responded better than those held for 30 or 90 minutes. The activation energies for leaching the clay calcines were 29.50, 32.92, 26.71, 30.18, 29.18, and 33.24 kJ/mol for samples calcined for 60 minutes at 500, 600, 700, 800, 900, and 1000 °C, respectively. The activation energy of leaching for the uncalcined sample was 35.07 kJ/mol. Thus, calcines produced at 700 °C (holding for 60 minutes) had the highest leaching response for alumina and the lowest leaching activation energy of 26.71 kJ/mol. It is concluded therefore that Nsu kaolinite clay should be best calcined for alumina yield by heating up to 700 °C and holding for 60 minutes at that temperature. The clay deposit can be used as alternative resource for alumina production.

scholarly journals The beginning and the end of the aluminium value chain

2020 ◽  
Vol 108 (5-6) ◽  
pp. 506
Author(s):  
Leiv Kolbeinsen
Keyword(s):  
Value Chain ◽  
Bauxite Residue ◽  
Bayer Process ◽  
International Institute ◽  
Silicon Iron ◽  
Alumina Production ◽  
The World ◽  
Scrap Recycling ◽  
Negative Environmental Impact ◽  
Electric Cables

Metallic aluminium does not naturally occur in nature, and it was largely unknown, virtually a mystery, until 200 years ago. The modern aluminium production using a hydrometallurgical refining process for making alumina followed by electrolysis of this mineral was first developed in 1886 and, in principle, the same technology is still used to this day. About 90% of alumina refineries in the world use the Bayer process for refining Bauxite ore. It is very efficient, but it can only be used on high quality bauxite with low content of admixtures, especially silicon. The Bayer process also generates a Bauxite Residue (BR), maybe better known as Red Mud (RM) which is a thick red-brown, high-basicity paste consisting of silicon, iron, aluminium, titanium and others. The International Institute of Aluminium estimates that since 1886 almost a billion tonnes of aluminium were produced around the world with three fourths of this amount still being in use today, of which about 35% is located in buildings and structures, 30% in electric cables and equipment and 30% in transport. Aluminium scrap is collected all over the world. In the home, it mostly consists of aluminium beverage cans. It is claimed that 1 ton of recycled empty beverage cans save 8 tons of bauxite, 4 kg of various fluorides and 14 kWh of electricity. Additionally, recycling aluminium significantly reduces the negative environmental impact of ever-expanding RM landfills. As the idea of environmental responsibility is gaining more and more traction, separate household scrap recycling is becoming more and more popular around the world. How challenges related to such activity can be met will be the main topic of this paper alongside discussing new developments for alumina production without RM generation.

Application of a Tangential Flow Two Colliding Streams Cyclone Reactor in Solid-Liquid Reactions

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Morteza Sohrabi ◽  
Sohrab Fathi Pirkashani
Keyword(s):  
Time Distribution ◽  
Residence Time Distribution ◽  
Chemical Reactor ◽  
Reaction Systems ◽  
Tangential Flow ◽  
Liquid Reaction ◽  
Performance Capability ◽  
Predicted Values ◽  
Solid Liquid ◽  
Discrete Formulation

A tangential flow two colliding streams cyclone reactor (TFTCSCR) was employed as a chemical reactor in the implementation of a solid-liquid reaction. The reaction between barium sulfide particles and a sodium carbonate solution as a typical example of such reactions was considered. Higher conversions of BaS obtained in this reactor may indicate the better performance capability of TFTCSCR relative to those of conventional reaction systems. A stochastic model, based on the Markov chain discrete formulation has been developed for the TFTCSCR, which describes the flow pattern and the residence time distribution (RTD) within the reactor. The predicted values for BaS conversion have been compared with those determined experimentally. The degree of agreement was between 80-85%.

scholarly journals Extraction of Valuable Elements from Red Mud with a Focus on Using Liquid Media—A Review

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 38
Author(s):  
Dmitry Zinoveev ◽  
Liliya Pasechnik ◽  
Mikhail Fedotov ◽  
Valery Dyubanov ◽  
Pavel Grudinsky ◽  
...  
Keyword(s):  
Red Mud ◽  
Bauxite Residue ◽  
Environmental Risks ◽  
Environmental Damage ◽  
Acid Solutions ◽  
Liquid Media ◽  
Alumina Production ◽  
Advantages And Disadvantages ◽  
Complex Methods ◽  
Biological Organisms

Bauxite residue, known as red mud, is a by-product of alumina production using the Bayer process. Currently, its total global storage amounts to over 4.6 billion tons, including about 600 million tons in Russia. The total global storage of red mud occupies large areas, leading to environmental damage and increasing environmental risks. Moreover, it contains a significant amount of sodium, which is easily soluble in subsoil water; therefore, a sustainable approach for comprehensive recycling of red mud is necessary. The bauxite residue contains valuable elements, such as aluminum, titanium, and scandium, which can be recovered using liquid media. In recent years, many methods of recovery of these elements from this waste have been proposed. This paper provides a critical review of hydrometallurgical, solvometallurgical, and complex methods for the recovery of valuable components from red mud, namely, aluminum, titanium, sodium, and rare and rare-earth elements. These methods include leaching using alkaline or acid solutions, ionic liquids, and biological organisms, in addition to red mud leaching solutions by extraction and sorption methods. Advantages and disadvantages of these processes in terms of their environmental impact are discussed.

Carbonization processing of bauxite residue as an alternative rare metal recovery process

2020 ◽  
pp. 56-63
Author(s):  
I. N. Pyagay ◽  
◽  
E. A. Kremcheev ◽  
L. A. Pasechnik ◽  
S. P. Yatsenko ◽  
...  
Keyword(s):  
Red Mud ◽  
Raw Materials ◽  
Bauxite Residue ◽  
Target Component ◽  
Acid Activation ◽  
Rare Metals ◽  
Residual Moisture ◽  
Alumina Production ◽  
Carbonization Process ◽  
Pregnant Solution

A prerequisite for commercial production of rare metals is a continuous effort given to developing knowledge-intensive recovery and refining techniques. Commonly known natural raw materials and conventional processing techniques, which are based on initial acid activation and recovery of minerals, as well as selective recovery of the target component (i.e. by sorption and extraction) cannot always ensure sufficient productivity or cost-effectiveness. This paper considers certain aspects of continued research in this area, which would require novel techniques. Such techniques should be based on new approaches allowing for the use of alternative raw materials to produce valuable rare metals on a cost-effective basis. It is demonstrated that red mud, i.e. waste material generated by bauxite industry and rich in scandium and other rare metals, can serve as such alternative source material. The paper describes the results of a study that looked at finding an optimum carbonization process for red mud that would ensure a consistent and predictable complexing process with regard to certain components. The paper also examines the environment in which soluble carbonate complexes can be stabilized and concentrated in the pregnant solution before the primary scandium-bearing concentrate can be recovered. The authors identified target parameters that determine enhanced filtration properties of carbonized slurry to ensure complete separation of the pregnant solution from the dehydrated (to the residual moisture content of 18%) carbonized residue. The paper highlights some positive factors of the carbonization process which enable a comprehensive utilization of alumina production waste. They include a long-term sequestration of carbon dioxide in the air and modified physical and chemical properties of red muds. This makes carbonized muds more compactable and thus more suitable for transportation and minimizes waste disposal hazards. The experimental research was carried out in conformance with the governmental assignments of the Institute of Solid State Chemistry of the Ural Branch of the Russian Academy of Sciences and Saint-Petersburg Mining University.

scholarly journals Progress on the Industrial Applications of Red Mud with a Focus on China

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 773
Author(s):  
Hua Zeng ◽  
Fei Lyu ◽  
Wei Sun ◽  
Hai Zhang ◽  
Li Wang ◽  
...  
Keyword(s):  
Red Mud ◽  
Building Materials ◽  
Bauxite Residue ◽  
Industrial Applications ◽  
Utilization Rate ◽  
Oil Well ◽  
Alumina Production ◽  
Industrial Utilization ◽  
Develop Technology ◽  
Well Cement

Red mud (RM), also called bauxite residue, is a strong alkaline industrial waste generated during the alumina production process. The annual production of RM in China is large, but its average utilization rate is low (only 4%). High generation and low consumption make the disposal of RM mainly by stockpiling, which has caused serious heavy metal pollution and radioactive contamination. In this paper, the various industrial utilization methods of RM in China during the past 60 years have been introduced. Moreover, some recent industrial progresses were referred. The results show that RM can be widely used in building materials, valuable metals extraction, and some novel utilization methods, such as silica-calcium fertilizer, inorganic polymer material and desulfurizer. Most of the industrial utilization methods of RM have been used until now and some successfully applied to other aluminum plants, providing some feasible routes for a large amount utilization of RM. Some industrial utilization methods (such as oil well cement and calcium silicon fertilizer) have not been used due to some problems that cannot be ignored, but it provided a lot of valuable experience and was helpful for the subsequent RM utilization. Moreover, some novel and feasible RM utilization methods were proposed and successfully industrialized, which showed that RM has a broader application prospect. Many actual practices showed that the best way to safely dispose of RM was to develop technology that could consume large amounts of RM or transform it into secondary resources, which may need more time and effort.

Applications of bauxite residue: A mini-review

2017 ◽  
Vol 35 (10) ◽  
pp. 999-1012 ◽  
Author(s):  
Ajay S Verma ◽  
Narendra M Suri ◽  
Suman Kant
Keyword(s):  
Automobile Industry ◽  
Bauxite Residue ◽  
Glass Ceramics ◽  
Large Area ◽  
Alumina Production ◽  
Mineralogical Characteristics ◽  
Valuable Metals ◽  
High Alkalinity ◽  
Bauxite Ore

Bauxite residue is the waste generated during alumina production by Bayer’s process. The amount of bauxite residue (40–50 wt%) generated depends on the quality of bauxite ore used for the processing. High alkalinity and high caustic content in bauxite residue causes environmental risk for fertile soil and ground water contamination. The caustic (NaOH) content in bauxite residue leads to human health risks, like dermal problems and irritation to eyes. Moreover, disposal of bauxite residue requires a large area; such problems can only be minimised by utilising bauxite residue effectively. For two decades, bauxite residue has been used as a binder in cement industries and filler/reinforcement for composite materials in the automobile industry. Valuable metals and oxides, like alumina (Al2O3), titanium oxide (TiO2) and iron oxide Fe2O3, were extracted from bauxite residue to reduce waste. Bauxite residue was utilised in construction and structure industries to make geopolymers. It was also used in the making of glass-ceramics and a coating material. Recently bauxite residue has been utilised to extract rare earth elements like scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd) and dysprosium (Dy). In this review article, the mineralogical characteristics of bauxite residue are summarised and current progresses on utilisation of bauxite residue in different fields of science and engineering are presented in detail.

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