Synthesis and Characterization of Geopolymer from Bayer Red Mud with Thermal Pretreatment

Ye, Nan; Yang, Jiakuan; Ke, Xinyuan; Zhu, Jing; Li, Yalin; Xiang, Cheng; Wang, Huabin; Li, Lei; Xiao, Bo

doi:10.1111/jace.12840

Cited by 198 publications

(69 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Globally, the accumulative storage of bauxite residue has arrived at over 4 billion tons, and is still rapidly increasing [6][7][8], and as yet there is no economic alternative to landfill [9][10][11][12][13]. Therefore, almost all bauxite residue continues to be stored indefinitely in bauxite residue disposal areas (BRDAs) [14,15], which require on-going efforts to manage the waste and lower its potential to contaminate water, occupy land and disturb the surrounding ecology [16][17][18][19][20][21][22]. Furthermore, leaching of alkaline waste from BRDAs is an added problem [23,24].…”

Section: Introductionmentioning

confidence: 99%

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Kong

Xue

et al. 2017

Journal of Hazardous Materials

149

View full text Add to dashboard Cite

Graphical abstractHighlights  Speciation and transformation of solid and soluble alkalinities were investigated. SEM, NEXAFS, and STXM were used to observe particle morphology and alkaline Na speciation and distribution. Gypsum combination promoted leaching of Na-bearing solids and the replacement of exchangeable Na. The use of organic citric acid to transform bauxite residue alkalinity.ABSTRACT: Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR.Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging.

show abstract

Section: Introductionmentioning

confidence: 99%

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Kong

Xue

et al. 2017

Journal of Hazardous Materials

149

View full text Add to dashboard Cite

show abstract

“…Crystalline phases like spinel solid solutions are identified in all samples. The preexisting cancrinite (i.e., in the raw BR) transforms during heat treatment to nepheline, while the gehlenite formation can be explained possibly by hydrogrossular degradation and recrystallization [19,31,32]. These silicates are examples of mineral phases which were not predicted in the thermodynamic calculation for the given compositions, except for Pr_BR.…”

Section: Characterization Of Precursormentioning

confidence: 91%

“…In view of the highly amorphous character and hence the high reactivity of the silica source, rice husk ash, the addition of sodium silicate was not necessary. Ye et al [19] mixed ground-granulated blast furnace slag (GGBFS) in varying proportions with calcined BR (800°C), reaching, for instance, 50 MPa after 28 days in a 50-50 wt% mix. Foamed BR-based geopolymers were synthesized by Badanoiu et al [20] using up to 25 wt% bauxite residue in combination with waste glass in the solid mix and the filtrate of red mud slurry and NaOH solution, respectively, as liquid component.…”

Section: Introductionmentioning

confidence: 99%

A Proposal for a 100 % Use of Bauxite Residue Towards Inorganic Polymer Mortar

Hertel

Blanpain

Pontikes

2016

J. Sustain. Metall.

View full text Add to dashboard Cite

A new process is suggested in the present work turning bauxite residue (BR) into a ready-made mortar for the synthesis of inorganic polymers, effectively transforming the Bayer process into a zero-waste process. This was achieved by firing BR at 1100°C which supports the formation of liquid phase and results after subsequent fast cooling in a semivitreous material. Based on thermodynamic calculations, the process was subsequently improved by adding minor quantities of C and silica to BR before firing which leads to the carbothermic reduction of ferric iron into ferrous iron; the new blends demonstrated an increase in the melt formation and eventually in the content of amorphous phase after solidification. The resulting material was activated using a K-silicate solution and was cured at 60°C for 72 h. The synthesized materials were water insoluble and dense, demonstrating compressive strength exceeding 40 MPa for the silica-rich blend. These inorganic polymers can find applications in construction, such as pavement tiles or floor/roofing tiles. A possible implementation of the process to transform BR within the alumina refinery is also represented.

show abstract

“…There are many characteristics of geopolymers, such as the ability to incorporate waste materials or by-products as raw materials, low emission of greenhouse gases due to their low synthesis temperature, low energy consumption, low cost by the use of waste materials as a raw material, good compressive strength, low fluid permeability, good chemical resistance [20], excellent fire resistance, stability at high temperatures [21], and durability. For these properties, geopolymers are an excellent alternative to OPC for construction materials, being already used in the formulation of structural elements and civil engineering with excellent results in some countries [22].…”

Section: Introductionmentioning

confidence: 99%

Geopolymers based on the valorization of Municipal Solid Waste Incineration residues

Giró-Paloma

Maldonado-Alameda

Formosa

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

View full text Add to dashboard Cite

Use of municipal solid waste incineration bottom ash and crop by-product for producing lightweight aggregate J Giro-Paloma, V Ribas-Manero, A Maldonado-Alameda et al.-APC fly ashes stabilized with Portland cement for further development of road sub-base aggregates J Formosa, J Giro-Paloma, A MaldonadoAlameda et al. Abstract. The proper management of Municipal Solid Waste (MSW) has become one of the main environmental commitments for developed countries due to the uncontrolled growth of waste caused by the consumption patterns of modern societies. Nowadays, municipal solid waste incineration (MSWI) is one of the most feasible solutions and it is estimated to increase in Europe where the accessibility of landfill is restricted. Bottom ash (BA) is the most significant by-product from MSWI as it accounts for 85 -95 % of the solid product resulting from combustion, which is classified as a non-hazardous residue that can be revalorized as a secondary aggregate in road sub-base, bulk lightweight filler in construction. In this way, revalorization of weathered BA (WBA) for the production of geopolymers may be a good alternative to common reuse as secondary aggregate material; however, the chemical process to obtain these materials involves several challenges that could disturb the stability of the material, mainly from the environmental point of view. Accordingly, it is necessary that geopolymers are able to stabilize heavy metals contained in the WBA in order to be classified as non-hazardous materials. In this regard, the SiO 2 /Al 2 O 3 ratio plays an important role for the encapsulation of heavy metals and other toxic elements. The aim of this research is to formulate geopolymers starting from the 0 -2 mm particle size fraction of WBA, as a unique raw material used as aluminumsilicate precursor. Likewise, leaching tests of the geopolymers formulated were performed to assess their environmental impact. The findings show that it is possible to formulate geopolymers using 100 % WBA as precursor, although more investigations are needed to sustain that geopolymer obtained can be considered as nonhazardous materials. IntroductionNowadays, within a circular economy, waste is a pressing environmental, social, and economic subject, which is gradually accepted and revalorized as a secondary resource. From the last 20 years, waste incineration (waste-to-energy plants, WtE) has grown progressively; hence, the incineration of municipal solid waste (MSWI) residues has become an appreciated alternative in waste management. Thermal energy recovery is a key in the management model of MSW in Europe. This allows the energy recovery contained in the MSW, decreasing the managed fraction in landfills, according to the management hierarchy and guidelines of Directive 2008/98 / EC [1]. The MSWI has increased by 60 % since the last 20 years [2], allowing reducing the waste mass and volume, and it generates energy over combustion. Although a substantial waste reduction can be obtained, during the MSWI process, about 20 % of the non-combustib...

show abstract

Synthesis and Characterization of Geopolymer from Bayer Red Mud with Thermal Pretreatment

Cited by 198 publications

References 37 publications

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

A Proposal for a 100 % Use of Bauxite Residue Towards Inorganic Polymer Mortar

Geopolymers based on the valorization of Municipal Solid Waste Incineration residues

Contact Info

Product

Resources

About