Synthesis of magnetic zeolite at low temperature using a waste material mixture: Fly ash and red mud

To maximize the utilization of red mud in geopolymers, a red mud–metakaolin (RM-MK) geopolymer and red mud–fly ash (RM-FA) geopolymer were prepared, respectively. The effects of red mud content on the compressive strength and microstructure of the geopolymers were investigated under three different curing conditions. The results showed that the strength of the geopolymer decreased linearly with an increase in the red mud content, whether curing at room temperature or 80 °C. Surprisingly, curing in an autoclave, the appropriate amount of red mud had a favorable impact on the mechanical properties of the geopolymers. When the amount of red mud was 50%, the strength of the RM-MK geopolymer reached its highest compressive strength, 36.3 MPa, and the strength of the RM-FA geopolymer reached its highest at 31.7 MPa. Compared with curing at low temperature, curing the red mud-based geopolymers under a higher temperature and higher pressure can maximize the use of red mud. XRD analysis indicated that zeolite minerals formed. The SEM results showed that the geopolymers cured in an autoclave had a dense structure.

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Environmental potentials of asphalt mixtures fabricated with red mud and fly ash

Road Materials and Pavement Design ◽

10.1080/14680629.2021.1900899 ◽

2021 ◽

pp. 1-12

Author(s):

Mayara S. Siverio Lima ◽

M. Hajibabaei ◽

L. P. Thives ◽

V. Haritonovs ◽

A. Buttgereit ◽

...

Keyword(s):

Fly Ash ◽

Red Mud ◽

Asphalt Mixtures

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Influence of red mud on performance enhancement of fly ash-based geopolymer concrete

Innovative Infrastructure Solutions ◽

10.1007/s41062-021-00578-x ◽

2021 ◽

Vol 6 (4) ◽

Author(s):

Ramamohana Reddy Bellum ◽

Chava Venkatesh ◽

Sri Rama Chand Madduru

Keyword(s):

Fly Ash ◽

Red Mud ◽

Performance Enhancement ◽

Geopolymer Concrete

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Hemp Fiber Reinforced Red Mud/Fly Ash Geopolymer Composite Materials: Effect of Fiber Content on Mechanical Strength

Materials ◽

10.3390/ma14030511 ◽

2021 ◽

Vol 14 (3) ◽

pp. 511 ◽

Cited By ~ 1

Author(s):

Eyerusalem A. Taye ◽

Judith A. Roether ◽

Dirk W. Schubert ◽

Daniel T. Redda ◽

Aldo R. Boccaccini

Keyword(s):

Fly Ash ◽

Mechanical Strength ◽

Red Mud ◽

Fiber Reinforced ◽

Brazilian Tensile Strength ◽

Hemp Fiber ◽

Hemp Fibers ◽

The Matrix ◽

Geopolymer Composites ◽

Scanning Electron

Novel hemp fiber reinforced geopolymer composites were fabricated. The matrix was a new geopolymer based on a mixture of red mud and fly ash. Chopped, randomly oriented hemp fibers were used as reinforcement. The mechanical properties of the geopolymer composite, such as diametral tensile (DTS) (or Brazilian tensile) strength and compressive strength (CS), were measured. The geopolymer composites reinforced with 9 vol.% and 3 vol.% hemp fiber yielded average DTS values of 5.5 MPa and average CS values of 40 MPa. Scanning electron microscopy (SEM) studies were carried out to evaluate the microstructure and fracture surfaces of the composites. The results indicated that the addition of hemp fiber is a promising approach to improve the mechanical strength as well as to modify the failure mechanism of the geopolymer, which changed from brittle to “pseudo-ductile”.

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Durability of Red Mud Based Geopolymer Paste in Acid Solutions

Materials Science Forum ◽

10.4028/www.scientific.net/msf.866.99 ◽

2016 ◽

Vol 866 ◽

pp. 99-105 ◽

Cited By ~ 3

Author(s):

Smita Singh ◽

M.U. Aswath ◽

R.V. Ranganath

Keyword(s):

Mechanical Properties ◽

Acetic Acid ◽

Fly Ash ◽

Red Mud ◽

Acetic Acid Solution ◽

Strength Loss ◽

Acid Solutions ◽

Test Results ◽

Acid Attack ◽

Geopolymer Paste

The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.

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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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