Evaluation of Main Factors for Improvement of the Scandium Leaching Process from Russian Bauxite Residue (Red Mud) in Carbonate Media

Bauxite residue, known as “red mud,” is a potential raw material for extracting rare-earth elements (REEs). The main REEs (Sc, Y, La, Ce, Nd, Nb, and Sm) from the raw bauxite are concentrated in RM after the Bayer leaching process. The earlier worldwide studies were focused on the scandium (Sc) extraction from RM by concentrated acids to enhance the extraction degree. This leads to the dissolution of major oxides (Fe2O3 and Al2O3) from RM. This article studies the possibility of selective Sc extraction from alkali fusion red mud (RMF) by diluted nitric acid (HNO3) leaching at pH ≥ 2 to prevent co-dissolution of Fe2O3. RMF samples were analyzed by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and inductively coupled plasma mass spectrometry (ICP-MS). It was revealed that Sc concentration in RMF can reach up to 140–150 mg kg−1. Sc extraction was 71.2% at RMF leaching by HNO3 at pH 2 and 80 °C during 90 min. The leaching solution contained 8 mg L−1 Sc and a high amount of other REEs in the presence of relatively low concentrations of impurity elements such as Fe, Al, Ti, Ca, etc. The kinetic analysis of experimental data by the shrinking core model showed that Sc leaching process is limited by the interfacial diffusion and the diffusion through the product layer. The apparent activation energy (Ea) was 19.5 kJ/mol. The linear dependence of Sc extraction on magnesium (Mg) extraction was revealed. According to EPMA of RMF, Sc is associated with iron minerals rather than Mg. This allows us to conclude that Mg acts as a leaching agent for the extraction of Sc presented in the RMF in an ion-exchangeable phase.

Download Full-text

Selective Scandium (Sc) Extraction from Bauxite Residue (Red Mud) Obtained by Alkali Fusion-Leaching Method

10.20944/preprints202111.0413.v1 ◽

2021 ◽

Author(s):

Andrei Shoppert ◽

Irina Loginova ◽

Julia Napol’skikh ◽

Aleksey Kyrchikov ◽

Leonid Chaikin ◽

...

Keyword(s):

Red Mud ◽

Inductively Coupled Plasma ◽

Bauxite Residue ◽

Product Layer ◽

X Ray ◽

Inductively Coupled ◽

Leaching Process ◽

Alkali Fusion ◽

Shrinking Core ◽

Alumina Industry

One of the potential sources of rare-earth elements (REEs) is the solid waste from alumina industry - bauxite residue, known as “red mud” (RM). The main REEs from the raw bauxite are concentrated in RM after the Bayer leaching process. The earlier worldwide studies were focused on the scandium (Sc) extraction from RM by concentrated acids to enhance the extraction degree. This leads to the dissolution of major oxides (Fe2O3 and Al2O3) from RM. This article studies the possibility of selective Sc extraction from alkali fusion red mud (RMF) by diluted nitric acid (HNO3) leaching at pH ≥ 2 to prevent co-dissolution of Fe2O3. RMF samples have been analyzed by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and inductively coupled plasma mass spectrometry (ICP-MS). Sc extraction has been found to be 71.2 % at RMF leaching by HNO3 at pH=2 and at 80 °C during 90 min. The kinetic analysis of experimental data by the shrinking core model has shown that Sc leaching process is limited by the interfacial diffusion and the diffusion through the product layer. The apparent activation energy (Ea) was 19.5 kJ/mol. We have established that according to EPMA of RMF, Sc is associated with iron minerals; it could act as the product layer. The linear dependence of Sc extraction of magnesium (Mg) extraction has been revealed. This fact indicates that Mg can act as a leaching agent of Sc presented in RMF by ion-exchangeable phase.

Download Full-text

Red mud pressure filtration for the alumina refinery’s bauxite residue tailings disposal

Proceedings of the 16th International Seminar on Paste and Thickened Tailings ◽

10.36487/acg_rep/1363_17_avery ◽

2013 ◽

Cited By ~ 1

Author(s):

Quentin Avery ◽

K Wilson

Keyword(s):

Red Mud ◽

Bauxite Residue ◽

Pressure Filtration ◽

Tailings Disposal ◽

Mud Pressure

Download Full-text

Biotechnological trends and market impact on the recovery of rare earth elements from bauxite residue (red mud) – A review

Resources Conservation and Recycling ◽

10.1016/j.resconrec.2021.105645 ◽

2021 ◽

Vol 171 ◽

pp. 105645

Author(s):

Sandeep Panda ◽

Rachel Biancalana Costa ◽

Syed Sikandar Shah ◽

Srabani Mishra ◽

Denise Bevilaqua ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Red Mud ◽

Bauxite Residue ◽

Market Impact

Download Full-text

An Alternative to Clay in Building Materials: Red Mud Sintering Using Fly Ash via Taguchi’s Methodology

Advances in Materials Science and Engineering ◽

10.1155/2013/757923 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

Suchita Rai ◽

Dilip H. Lataye ◽

M. J. Chaddha ◽

R. S. Mishra ◽

P. Mahendiran ◽

...

Keyword(s):

Fly Ash ◽

Construction Industry ◽

Red Mud ◽

Morphological Analysis ◽

Building Materials ◽

Sintering Temperature ◽

Bauxite Residue ◽

Significant Parameter ◽

Alkaline Waste ◽

Free Caustic Soda

“Red mud” or “bauxite residue” is a highly alkaline waste generated from alumina refinery with a pH of 10.5–12.5 which poses serious environmental problems. Neutralization or its treatment by sintering in presence of additives is one of the methods for overcoming the caustic problem as it fixes nearly all the leachable free caustic soda present in red mud. In the present study, feasibility of reducing the alkaline nature of red mud by sintering using fly ash as an additive via Taguchi methodology and its use for brick production, as an alternative to clay, is investigated. The analysis of variance (ANOVA) shows that sintering temperature is the most significant parameter in the process. A pH of 8.9 was obtained at 25–50% of red mud and 50–75% fly ash with water and temperature of . Alternatively 50% of red mud can be mixed with 50% of fly ash with water at temperature of to get a pH of about 8.4. The mechanism of this process has been explained with also emphasis on chemical, mineralogical, and morphological analysis of the sintered red mud. The results would be extremely useful in utilization of red mud in building and construction industry.

Download Full-text

MATHEMATICAL MODELING OF LEACHING PROCESS OF RED MUD IN ORDER TO OBTAIN THE KINETICS PARAMETERS

Revista de Engenharia Térmica ◽

10.5380/reterm.v14i2.62140 ◽

2015 ◽

Vol 14 (2) ◽

pp. 90 ◽

Cited By ~ 2

Author(s):

K. L. M. Dos Passos ◽

B. M. Viegas ◽

E. N. Macêdo ◽

J. A. S. Souza ◽

E. M. Magalhães

Keyword(s):

Experimental Data ◽

Mathematical Model ◽

Red Mud ◽

Mineralogical Composition ◽

Raw Material ◽

Data Conversion ◽

Kinetics Parameters ◽

Leaching Process ◽

Iron Leaching ◽

The Mathematical Model

The use of the waste of the Bayer process, red mud, is due to its chemical and mineralogical composition that shows a material rich in oxides of iron, titanium and aluminum. Some studies conducted show that this waste can be applied as a source of alternative raw material for concentration and subsequent recovery of titanium compounds from an iron leaching process, which is present in higher amounts, about 30% by weight. To obtain a greater understanding about the leaching kinetics, the information of the kinetic data of this process is very important. In this context, the main objective of this work is the development of a mathematical model that is able to fit the experimental data (conversion / extraction iron, titanium and aluminum) of the leaching process by which is possible to obtain the main kinetic parameters such as the activation energy and the velocity of chemical reactions as well as the controlling step of the process. The development of the mathematical model was based on the model of core decreasing. The obtained model system of ordinary differential equations was able to fit the experimental data obtained from the leaching process, enabling the determination of the controlling step, the rate constants and the activation energies of the leaching process.

Download Full-text

Red Mud-Blast Furnace Slag-Based Alkali-Activated Materials

Sustainability ◽

10.3390/su132011298 ◽

2021 ◽

Vol 13 (20) ◽

pp. 11298

Author(s):

Alessio Occhicone ◽

Mira Vukčević ◽

Ivana Bosković ◽

Claudio Ferone

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Red Mud ◽

Blast Furnace Slag ◽

Bauxite Residue ◽

Sodium Silicate Solution ◽

Silicate Solution ◽

Waste Products ◽

Furnace Slag ◽

Alkali Activated

The aluminum Bayer production process is widespread all over the world. One of the waste products of the Bayer process is a basic aluminosilicate bauxite residue called red mud. The aluminosilicate nature of red mud makes it suitable as a precursor for alkali-activated materials. In this work, red mud was mixed with different percentages of blast furnace slag and then activated by sodium silicate solution at different SiO2/Na2O ratios. Obtained samples were characterized by chemical–physical analyses and compressive strength determination. Very high values of compressive strength, up to 50 MPa, even for high percentage of red mud in the raw mixture (70 wt.% of RM in powder mixture), were obtained. In particular, the higher compressive strength was measured for cubic samples containing 50 wt.% of RM, which showed a value above 70 MPa. The obtained mixtures were characterized by no or scarce environmental impact and could be used in the construction industry as an alternative to cementitious and ceramic materials.

Download Full-text

Integrated carbothermic smelting – Acid baking – Water leaching process for extraction of scandium, aluminum, and iron from bauxite residue

Journal of Cleaner Production ◽

10.1016/j.jclepro.2021.129905 ◽

2021 ◽

pp. 129905

Author(s):

John Anawati ◽

Gisele Azimi

Keyword(s):

Bauxite Residue ◽

Water Leaching ◽

Leaching Process

Download Full-text

Red Mud (RM) and Soil Amelioration

Advances in Environmental Engineering and Green Technologies - Amelioration Technology for Soil Sustainability ◽

10.4018/978-1-5225-7940-3.ch009 ◽

2019 ◽

pp. 151-167 ◽

Cited By ~ 1

Author(s):

Amit Kumar

Keyword(s):

Red Mud ◽

Sodium Hydroxide Solution ◽

Bauxite Residue ◽

Acid Soils ◽

Large Area ◽

Vegetation Growth ◽

Ground Water Pollution ◽

Trace Metal Content ◽

Rich Material ◽

Ph Range

Rapid growth in industrialization, which is necessary and inevitable for society progress, has also created negative encroachment. Red mud produced during alumina production has strong alkanity in a pH range of 10-13% because of the sodium hydroxide solution used in the refining process. The base is strong enough to kill plant and animal life, and due to finer particle and trace metal content, it creates soil contamination, ground water pollution, and suspension in ocean; hence, we need precautions while we use this waste to add with soil. Red mud occupies a large area or its deposition in it. Red mud has properties similar to sandy clay. Red mud has property similar to clay and sand, even if it does not contain quartz or clay mineral. Bauxite residue/red mud can be mixed with variant type of saline soils, acid soils organic rich material, and silicate soil suitable pH conditions were achieved to promote vegetation growth.

Download Full-text