Approaches Regarding Red Mud Valorization for a Green Future and Sustainable Environment

Today the red mud generated from alumina production is a resource, a material that can be valorized, an opportunity. The current practice in waste management in some parts of the planet has to be revised. We need to change technologies and become more aware and thoughtful on our footprint on Earth. Red mud is the main waste generated from the bauxite Bayer process. Having a complex composition with predominantly Al2O3 (14-27%), Fe2O3 (19-56%) contents, viable solutions were sought for the reuse of the red mud. A number of applications have resulted in the recovery of metallic components, chemical industry, and building materials industry. A field of red mud applicability, which has enabled the development of innovative and sustainable techniques, is that of the environment. The paper presents the results of the researches carried out in order to valorize the red mud in the treatment of two categories of wastewater: phosphates waters and mine waters. The influence of the experimental parameters on the pollutant removal efficiencies in these wastewaters is highlighted.

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Bayern`s Method of Al2O3 Production – Possibilities of Red Mud Disposal and Utilization

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.176.11 ◽

2011 ◽

Vol 176 ◽

pp. 11-20 ◽

Cited By ~ 1

Author(s):

Mariola Saternus

Keyword(s):

Chemical Composition ◽

Red Mud ◽

Building Materials ◽

Short Description ◽

Iron Recovery ◽

Alumina Production ◽

Advantages And Disadvantages ◽

Primary Aluminium

Bayern`s method is the first stage of obtaining primary aluminium. The product of this process is alumina. The paper presents how much alumina was produced in the last couple of years and who were its leading producers. As the main ore for alumina production is bauxite; it was necessary to describe its characteristics: chemical composition and types of bauxites. Short description of the method (digestion, precipitation and calcination) was presented. During this process a lot of pollution is usually emitted to the atmosphere, but mostly a lot of red mud is generated. This is the main waste of the process, which at the same time is very harmful to the environment. The ways red mud is disposed or utilized were reviewed. Two kinds of red mud disposal are known: wet and dry disposal. Both were characterized and their advantages and disadvantages were outlined. The possibilities of red mud utilization were shown. The focus was put on iron recovery or recovery of compounds such as Al2O3 or TiO2. The use of red mud in building materials was discussed. Radioactivity of such materials was also analyzed. Possibility of red mud utilization as a pigment and radiopaque material was also mentioned.

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

Minerals ◽

10.3390/min10090773 ◽

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.

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Influence of Sodium Sulfate Addition on Iron Grain Growth during Carbothermic Roasting of Red Mud Samples with Different Basicity

Metals ◽

10.3390/met10121571 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1571

Author(s):

Pavel Grudinsky ◽

Dmitry Zinoveev ◽

Denis Pankratov ◽

Artem Semenov ◽

Maria Panova ◽

...

Keyword(s):

Magnetic Separation ◽

Grain Growth ◽

Red Mud ◽

Sodium Sulfate ◽

Phase Distribution ◽

Solid Phase ◽

Alumina Production ◽

Metallic Particles ◽

Iron Phase ◽

High Alkalinity

Red mud is an iron-containing waste of alumina production with high alkalinity. A promising approach for its recycling is solid-phase carbothermic roasting in the presence of special additives followed by magnetic separation. The crucial factor of the separation of the obtained iron metallic particles from gangue is sufficiently large iron grains. This study focuses on the influence of Na2SO4 addition on iron grain growth during carbothermic roasting of two red mud samples with different (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21, respectively. Iron phase distribution in the red mud and roasted samples were investigated in detail by Mössbauer spectroscopy method. Based on thermodynamic calculations and results of multifactorial experiments, the optimal conditions for the roasting of the red mud samples with (CaO + MgO)/(SiO2 + Al2O3) ratio of 0.46 and 1.21 were duration of 180 min with the addition of 13.65% Na2SO4 at 1150 °C and 1350 °C followed by magnetic separation that led to 97% and 83.91% of iron recovery, as well as 51.6% and 83.7% of iron grade, respectively. The mechanism of sodium sulfate effect on iron grain growth was proposed. The results pointed out that Na2SO4 addition is unfavorable for the red mud carbothermic roasting compared with other alkaline sulfur-free additives.

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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.

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A Study of the Potential Use of Red Mud to Obtain Compositions Based on Portland Cement

KnE Materials Science ◽

10.18502/kms.v6i1.8128 ◽

2020 ◽

Author(s):

Ekaterina Gerasimova ◽

Elizaveta Gumirova

Keyword(s):

Portland Cement ◽

Red Mud ◽

Waste Product ◽

Cement Stone ◽

Mathematical Planning ◽

Alumina Production ◽

Mineral Additive ◽

Composition Properties ◽

Planning Of Experiments ◽

Potential Use

The paper deals with the problem of utilization of red mud which is a waste product from alumina production using the Bayer method. The principal possible use for the red mud of JSC “Bogoslovsky aluminum plant” (Sverdlovsk region) for the compositions based on Portland cement is shown. It was found that the mud introduction accelerates beginning of the cement paste setting and thickens the paste reducing its mobility. It is concluded that the introduction of red mud up to 30 % is justified in terms of strength indicators. The work is carried out using mathematical planning of experiments. Keywords: red mud, Portland cement, active mineral additive, composition, properties, bauxite, chemical composition, cement stone strength, mathematical planning of experiments

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Bamboo Utilization as a Sustainable Building Material

Advances in Civil and Industrial Engineering - Health and Well-Being Considerations in the Design of Indoor Environments ◽

10.4018/978-1-7998-7279-5.ch004 ◽

2021 ◽

pp. 79-96

Author(s):

Paul C. Okonkwo ◽

Israr Ul Hassan ◽

Wesam H. Beitelmal

Keyword(s):

Government Policy ◽

Building Material ◽

Building Materials ◽

Industrial Revolution ◽

Environmentally Friendly ◽

Building Design ◽

Global Market ◽

Building Construction ◽

Sustainable Building ◽

Sustainable Environment

The extraction of building materials from their resources through harvesting, preservation, and utilization has become a significant segment of human contribution to the global ecosystem since the industrial revolution. Bamboo is the world's fastest-growing woody plant, and bamboo grows multiple times quicker than most species. Housing is one of the focused demands for bamboo, and as a result of the current scarcity of home units, the demand for bamboo is increasing. Bamboo building construction is portrayed by a basic edge approach like that applied in traditional building design and construction. Applying bamboo as an environmentally friendly material is seen as a movement towards creating a sustainable environment and reducing greenhouse emissions. The need to employ government policy in addressing the production and application of bamboo is reported, and the challenges of bamboo in the global market are highlighted in this chapter.

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Experimental reedbed systems for the treatment of airport runoff

Water Science & Technology ◽

10.2166/wst.1997.0697 ◽

1997 ◽

Vol 36 (8-9) ◽

pp. 385-390 ◽

Cited By ~ 14

Author(s):

D. M. Revitt ◽

R. B. E. Shutes ◽

N. R. Llewellyn ◽

P. Worrall

Keyword(s):

Pilot Scale ◽

Surface Flow ◽

Pollutant Removal ◽

Biological Processes ◽

Metal Concentrations ◽

Physical Chemical ◽

Flow Systems ◽

Total Ammonia ◽

Removal Efficiencies

The relative efficiencies of pollutant removal from airport runoff by three different designs of pilot scale reedbed treatment systems located at Heathrow airport are described. The sub-surface flow and surface flow systems generally performed more effectively than the rafted systems for reduction of BOD, COD, total ammonia, nitrate, phosphate and metal concentrations. The variable removal efficiencies are explained in terms of the physical, chemical and biological processes which are relevant to each reedbed system.

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The Improvement of Pollutant Removal in the Ferric-Carbon Micro-Electrolysis Constructed Wetland by Partial Aeration

Water ◽

10.3390/w12020389 ◽

2020 ◽

Vol 12 (2) ◽

pp. 389 ◽

Cited By ~ 4

Author(s):

Cheng Dong ◽

Mengting Li ◽

Lin-Lan Zhuang ◽

Jian Zhang ◽

Youhao Shen ◽

...

Keyword(s):

Water Quality ◽

Wastewater Treatment ◽

Constructed Wetland ◽

Sewage Treatment ◽

Pollutant Removal ◽

Functional Genes ◽

Subsurface Flow Constructed Wetland ◽

Removal Efficiencies ◽

Oxidation Efficiency ◽

Denitrification Process

Subsurface flow constructed wetland (SSFCW) has been applied for wastewater treatment for several decades. In recent years, the combination of ferric-carbon micro-electrolysis (Fe/C-M/E) and SSFCW was proven to be an effective method of multifarious sewage treatment. However, Ferric substrate created a relatively reductive condition, decreased the oxidation efficiency of NH4+-N, and blocked the following denitrification process, which led to the low removal efficiencies of NH4+-N and total nitrogen (TN). In this study, partial aeration was introduced into the ferric-carbon micro-electrolysis SSFCW (Fe/C-M/E CW) system to solve the problem above. The water quality and nitrogen-related functional genes of bacteria on the surface of substrate were measured for mechanism exploration. The results showed that, the removal efficiencies of NH4+-N and total phosphorus (TP) in an aerated Fe/C-M/E CW system were 96.97% ± 6.06% and 84.62% ± 8.47%, much higher than 43.33% ± 11.27% and 60.16% ± 2.95% in the unaerated Fe/C-M/E CW systems. However, the TN removal in Fe/C-M/E CW system was not enhanced by aeration, which could be optimized by extending more anoxic section for denitrification.

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Effect of red mud addition on the corrosion parameters of reinforced concrete evaluated by electrochemical methods

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952012000400004 ◽

2012 ◽

Vol 5 (4) ◽

pp. 451-467 ◽

Cited By ~ 9

Author(s):

D.V. Ribeiro ◽

J.A. Labrincha ◽

M.R. Morelli

Keyword(s):

Electrical Resistivity ◽

Reinforced Concrete ◽

Red Mud ◽

Corrosion Potential ◽

Corrosion Process ◽

Bayer Process ◽

Alumina Production ◽

High Ph ◽

High Electrical Resistivity ◽

Bauxite Ore

Red mud, the main waste generated in aluminum and alumina production from bauxite ore by the Bayer process, is considered "hazardous" due to its high pH. The high pH also provides greater protection of rebars, which is reflected in the low corrosion potential and high electrical resistivity (filler effect) of concrete. The corrosion potential was monitored by electrochemical measurements and the electrical resistivity was evaluated using sensors embedded in concrete test specimens. The results showed that the addition of red mud is beneficial to concrete, reducing its corrosion potential and increasing its electrical resistivity. Red mud proved to be a promising additive for concrete to inhibit the corrosion process.

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