Characterization of red mud derived from a combined Bayer Process and bauxite calcination method

Liu, Yong; Lin, Cheng‐Fang; Wu, Yali

doi:10.1016/j.jhazmat.2006.12.015

Cited by 275 publications

(103 citation statements)

References 20 publications

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“…Soluble K and Mg results ( However, the concentration of exchangeable Ca increased and dominated the exchangeable basic cations in transformed bauxite residue, indicating that a large concentration of exchangeable Na was replaced with exchangeable Ca during transformation processes, also, gypsum addition promoted its replacement. This should be attributed to a reduction in pH (changes shown in Table 2) over transformation process, resulting in the initially negatively-charged alkaline compounds becoming zero-charged [59], which leads to reducing alkalinity of the residue by means of cation exchange (i.e. Ca source contributing to alkalinity relief).…”

Section: Solution Chemistrymentioning

confidence: 99%

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Kong

Xue

et al. 2017

Journal of Hazardous Materials

141

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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.

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Section: Solution Chemistrymentioning

confidence: 99%

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Kong

Xue

et al. 2017

Journal of Hazardous Materials

141

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“…It is somewhat spreaded along the temperature axis and can also be attributed to magnesium carbonate decarbonation [27]. It was reported that calcium carbonate decomposition takes place between 680 and 776°C [28], and, in the case of some red muds, between 560 and 720°C [29]. In this work, calcium carbonate decarbonation is represented by a well shaped LC at 685.4 ºC, which is accompanied by a simultaneous endotherm.…”

Section: Resultsmentioning

confidence: 54%

Lodos procedentes de la industria de tratamiento de superficies metálicas como aditivos a matrices cerámicas

Corpas-Iglesias¹,

Pérez‐Villarejo²,

Guerrero³

et al. 2011

Bol. Soc. Esp. Ceram. Vidr.

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Ceramic processing is one of the most efficient and environmentally friendly solutions to the enormous amounts of industrial mud produced in metal surface treatments. Moreover, ceramized products may represent an important secondary source to replace clay materials and cut down manufacturing costs. After characterization, in order to prepare specimens by uniaxial die pressing, mud was incorporated into a clay matrix at rates between 1 and 5 wt %. Compression strength, linear contraction, suction capacity and water absorption of the moulded materials were evaluated. Finally, metal leakage was characterized through chemical analysis of lixiviates. The results showed an improvement in mechanical properties following the incorporation of mud into the ceramic materials. The resulting materials meet health and safety regulations regarding dangerous waste recycling.Keywords: Valorization, Mud, Ceramic, Waste. Lodos procedentes de la industria de tratamiento de superficies metálicas como aditivos a matrices cerámicasLa ceramización es una de las soluciones más eficientes y medioambientalmente más ecológicas para las enormes cantidades de lodos industriales que se producen en el tratamiento de superficies metálicas. Además estos lodos convenientemente ceramizados pueden representar una fuente de materia prima que sustituya en parte el consumo de arcilla, lo que se traduce en una disminución de los costes de fabricación. Tras caracterizarse, los lodos fueron incorporados en la matriz cerámica en proporciones desde el 1% hasta el 5%, fabricándose así piezas cerámicas por compresión uniaxial en seco. A las piezas conformadas se les midieron una serie de características tecnológicas tales como la resistencia a la compresión, la contracción lineal, capacidad de succión y la absorción de agua. Finalmente se realizaron análisis químicos de lixiviados para evaluar la liberación al medio de metales. Los resultados conseguidos muestran una mejora de las propiedades mecánicas tras la inclusión de los lodos en matrices cerámicas. Los materiales así fabricados satisfacen la normativa referente al reciclaje de residuos peligrosos.

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“…The process yields a residue which is known as red mud. According to Liu, Lin, & Wu (2007) . Some of these chemical properties render red mud too harsh and unsuitable as a plant growing medium, so it just accumulates in deposition ponds and landfills.…”

Section: Introductionmentioning

confidence: 99%

The Utilization of Red Mud as a Plant Growing Medium with The Addition of Ultisol Soil Material and Compost

Aini

Iskandar

Darmawan

2017

Sains Tanah J. Soil Sci. Agroclimatology

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The utilization of red mud, which is a residue from the extraction of aluminum from mined bauxite ore, as a plant growing medium, needs to be studied further. There are some chemical aspects that may hinder the growth of, or even cause mortality in, plants such as very high pH, electrical conductivity (EC) and exchangeable Na (Na exch ), and very low nutrient elements content. The objective of this study was to investigate the effects of adding Ultisol soil material, mixed with compost, both soil ameliorating agents, to red mud for use as a growing medium for Sengon (Paraserianthes falcataria) seedlings. This study was conducted in two stages, namely: washing of the red mud, and trial planting in the greenhouse using different combinations of the soil ameliorants. Washing of the red mud with tap water was intended to reduce the levels of Na, EC, and pH. Trial planting in the greenhouse was carried out in 2-factorial Completely Randomized Design (CRD). , respectively. The treatment of using a mixture of 750 g red mud + 750 g sm-Ultisol, and adding compost at 117.18 g/polybag gave the best result in improving the chemical property of the red mud growing medium, and producing the best plant growth among all treatment combinations.

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Characterization of red mud derived from a combined Bayer Process and bauxite calcination method

Cited by 275 publications

References 20 publications

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Acid transformation of bauxite residue: Conversion of its alkaline characteristics

Lodos procedentes de la industria de tratamiento de superficies metálicas como aditivos a matrices cerámicas

The Utilization of Red Mud as a Plant Growing Medium with The Addition of Ultisol Soil Material and Compost

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