Correlating the amorphous phase structure of vitrified bauxite residue (red mud) to the initial reactivity in binder systems

2022 ◽  
pp. 104410
Author(s):  
Tobias Hertel ◽  
Amy Van den Bulck ◽  
Bart Blanpain ◽  
Yiannis Pontikes
Keyword(s):  
Amorphous Phase ◽  
Red Mud ◽  
Phase Structure ◽  
Bauxite Residue ◽  
Initial Reactivity

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

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

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

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
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.

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

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.

Red Mud (RM) and Soil Amelioration

2019 ◽  
pp. 151-167 ◽  
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.

Cost Analysis as a Tool for the Development of Sc Recovery Processes from Bauxite Residue (Red Mud)

2018 ◽  
Vol 6 (4) ◽  
pp. 5333-5341 ◽  
Author(s):  
Remya P. Narayanan ◽  
Liang-Chih Ma ◽  
Nikolaos K. Kazantzis ◽  
Marion H. Emmert
Keyword(s):  
Cost Analysis ◽  
Red Mud ◽  
Bauxite Residue ◽  
Recovery Processes

scholarly journals pH-Dependent Leaching Characteristics of Major and Toxic Elements from Red Mud

2019 ◽  
Vol 16 (11) ◽  
pp. 2046 ◽  
Author(s):  
Yulong Cui ◽  
Jiannan Chen ◽  
Yibo Zhang ◽  
Daoping Peng ◽  
Tao Huang ◽  
...  
Keyword(s):  
Environmental Protection Agency ◽  
Red Mud ◽  
Geochemical Modeling ◽  
Bauxite Residue ◽  
Combined Processes ◽  
Geochemical Model ◽  
Modeling Analysis ◽  
Leaching Characteristics ◽  
Ph Level ◽  
Leaching Pattern

This study analyzes the leaching behavior of elements from red mud (bauxite residue) at pH values ranging from 2 to 13. The leaching characteristics of metals and contaminated anions in five red mud samples produced by Bayer and combined processes were analyzed using the batch leaching technique following the US Environmental Protection Agency (USEPA) Method 1313. In addition, the geochemical model of MINTEQ 3.1 was used to identify the leaching mechanisms of metals. The results showed that Ca, Mg, and Ba follow the cationic leaching pattern. Al, As, and Cr show an amphoteric leaching pattern. The leaching of Cl− is unaffected by the pH. The maximum leaching concentration of the proprietary elements occurs under extremely acidic conditions (pH = 2), except for As. The leaching concentration of F− reaches 1.4–27.0 mg/L in natural pH conditions (i.e., no acid or base addition). At the same pH level, the leaching concentrations of Pb, As, Cr, and Cu are generally higher from red mud produced by the combined process than that those of red mud from the Bayer process. The leaching concentration of these elements is not strongly related to the total elemental concentration in the red mud. Geochemical modeling analysis indicates that the leaching of metal elements, including Al, Ca, Fe, Cr, Cu, Pb, Mg, Ba, and Mn, in red mud are controlled by solubility. The leaching of these elements depended on the dissolution/precipitation of their (hydr)oxides, carbonate, or sulfate solids.

Extraction of rare earths from bauxite residue (red mud) by dry digestion followed by water leaching

2018 ◽  
Vol 119 ◽  
pp. 82-92 ◽  
Author(s):  
Rodolfo Marin Rivera ◽  
Brecht Ulenaers ◽  
Ghania Ounoughene ◽  
Koen Binnemans ◽  
Tom Van Gerven
Keyword(s):  
Rare Earths ◽  
Red Mud ◽  
Bauxite Residue ◽  
Water Leaching ◽  
Dry Digestion

Bacillus alkalicellulosilyticus sp. nov., isolated from extremely alkaline bauxite residue (red mud) site

2020 ◽  
Author(s):  
Guo-Hong Liu ◽  
Manik Prabhu Narsing Rao ◽  
Xiao-Ying Wang ◽  
Tong-Wei Chu ◽  
Bo Liu ◽  
...  
Keyword(s):  
Red Mud ◽  
Bauxite Residue

scholarly journals Concentration of Rare Earth Elements (Sc, Y, La, Ce, Nd, Sm) in Bauxite Residue (Red Mud) Obtained by Water and Alkali Leaching of Bauxite Sintering Dust

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 500 ◽  
Author(s):  
Leonid Chaikin ◽  
Andrei Shoppert ◽  
Dmitry Valeev ◽  
Irina Loginova ◽  
Julia Napol’skikh
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Red Mud ◽  
Electrostatic Precipitator ◽  
Bauxite Residue ◽  
X Ray ◽  
Before And After ◽  
Shrinking Core ◽  
Alkali Leaching ◽  
Rotary Kilns

One of the potential sources of rare-earth elements (REE) is the industrial waste known as red mud (bauxite residue), in which the majority of REE from the initial bauxite are concentrated via the Bayer process. Therefore, the studies of the subject, both in Russia and outside, focus almost exclusively on red mud processing. This article looks into the possibility of REE concentration into red mud by leaching an intermediate product of the bauxite sintering process at Russian alumina refineries, namely electrostatic precipitator (ESP) dust. The experimental works were performed by X-ray diffraction (XRD)and electron probe microanalysis (EPMA) of the sinter and sinter dust. The determination of major and rare-earth elements in the sinter from the rotary kilns and in the ESP dust before and after leaching was carried out by X-ray fluorescence (XRF) and plasma mass spectrometry (ICP-MS). The study showed that it is possible to obtain red mud that contains three times more REE than traditional waste red mud after two-stage leaching ESP dust in the water at 95 °C followed by leaching in an alkaline-aluminate liquor at 240 °C. The shrinking core model was used to study the kinetics of leaching of the original ESP dust and water-treated dust in alkaline-aluminate liquor. The study showed the change in the limiting stage of the alkaline leaching process after water treatment, with the activation energy growing from 24.98 to 33.19 kJ/mol.

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