Study by DTA/TG of the formation of calcium aluminate obtained from an aluminium hazardous waste

López‐Delgado, Aurora; López, Félix A.; Gonzalo-Delgado, L.; López-Andrés, Sol; Alguacil, Francisco José

doi:10.1007/s10973-009-0597-z

Cited by 16 publications

(4 citation statements)

References 9 publications

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“…Processes developed for the treatment of HAWrelated wastes have generally sought to render them inert, for example by very high temperature thermal treatment (Lindsay 1995) or by stabilization/solidification with cement or gypsum (Lo´pez-Go´mez & Lo´pez-Delgado 2004, Shinzato & Hypolito 2005. Other procedures were developed to obtain valuable products, using synthesis and crystallization methods (Lin & Lo 1998, Lo´pez-Delgado et al, 2010. Vitrification has also been studied as a way of obtaining valuable glasses from waste similar to HAW, as an aluminium oxide source (Lo´pez-Delgado et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Recycling of hazardous waste from tertiary aluminium industry in a value-added material

Gonzalo-Delgado¹,

López‐Delgado²,

López³

et al. 2010

Waste Manag Res

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The recent European Directive on waste, 2008/98/EC seeks to reduce the exploitation of natural resources through the use of secondary resource management. Thus the main objective of this study was to explore how a waste could cease to be considered as waste and could be utilized for a specific purpose. In this way, a hazardous waste from the tertiary aluminium industry was studied for its use as a raw material in the synthesis of an added-value product, boehmite. This waste is classified as a hazardous residue, principally because in the presence of water or humidity, it releases toxic gases such as hydrogen, ammonia, methane and hydrogen sulfide. The low temperature hydrothermal method developed permits the recovery of 90% of the aluminium content in the residue in the form of a high purity (96%) AlOOH (boehmite). The method of synthesis consists of an initial HCl digestion followed by a gel precipitation. In the first stage a 10% HCl solution is used to yield a 12.63 g L(-1) Al( 3+) solution. In the second stage boehmite is precipitated in the form of a gel by increasing the pH of the acid Al(3+) solution by adding 1 mol L(-1) NaOH solution. Several pH values were tested and boehmite was obtained as the only crystalline phase at pH 8. Boehmite was completely characterized by X-ray diffraction, Fourier transform infrared and scanning electron microscopy. A study of its thermal behaviour was also carried out by thermogravimetric/differential thermal analysis.

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Section: Introductionmentioning

confidence: 99%

Recycling of hazardous waste from tertiary aluminium industry in a value-added material

Gonzalo-Delgado¹,

López‐Delgado²,

López³

et al. 2010

Waste Manag Res

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“…Dross is melted with salt flux to recover the metallic aluminium occluded in the oxides and the non-metallic fraction is subjected to digestion and blended with CaO to form calcium aluminate with high magnesium and calcium contents. The use of HAW as the raw material for the synthesis of several calcium aluminates has been studied (Gonzalo-Delgado et al, 2010; López-Delgado et al, 2010). A precursor of the aluminate phase was obtained as amorphous material by a hydrothermal method at different values of pH.…”

Section: The Case Studymentioning

confidence: 99%

Can hazardous waste become a raw material? The case study of an aluminium residue: a review

López‐Delgado¹,

Tayibi²

2011

Waste Manag Res

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The huge number of research studies carried out during recent decades focused on finding an effective solution for the waste treatment, have allowed some of these residues to become new raw materials for many industries. Achieving this ensures a reduction in energy and natural resources consumption, diminishing of the negative environmental impacts and creating secondary and tertiary industries. A good example is provided by the metallurgical industry, in general, and the aluminium industry in this particular case. The aluminium recycling industry is a beneficial activity for the environment, since it recovers resources from primary industry, manufacturing and post-consumer waste. Slag and scrap which were previously considered as waste, are nowadays the raw material for some highly profitable secondary and tertiary industries. The most recent European Directive on waste establishes that if waste is used as a common product and fulfils the existing legislation for this product, then this waste can be defined as ‘end-of-waste’. The review presented here, attempts to show several proposals for making added-value materials using an aluminium residue which is still considered as a hazardous waste, and accordingly, disposed of in secure storage. The present proposal includes the use of this waste to manufacture glass, glass-ceramic, boehmite and calcium aluminate. Thus the waste might effectively be recovered as a secondary source material for various industries

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“…Lopez-Delgado et al 21 , have achieved the synthesis of calcium aluminate (CA) from a Spanish hazardous waste, that has been used as a source of Al 2 O 3 . An amorphous precursor was obtained through the hydrothermal method, where the precipitation of calcium aluminate (CA) was occurring starting from 700 °C.…”

Section: Introductionmentioning

confidence: 99%

Maximize the use of municipal waste generated by the hydrogen peroxide industry in the production of high-quality refractory CAC

Amer

El-Maddah

Abuelela

et al. 2022

Sci Rep

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High-grade calcium aluminate cement (CAC) has been successfully synthesized from municipal alumina waste and limestone under mild reaction conditions. Mineralogical composition and microstructure of the sintered mixes were investigated using X-ray diffraction and FESEM; valuable cementing phases such as CA, CA2, and C12A7 were observed in addition to the C3A phase that was detected in the mixes with high CaCO3 content. Mix CA60 containing 60 wt% alumina waste has achieved the best sinterability (less than 1 vol% porosity) and the highest densification (~ 2.65 g/cm3 bulk density) at 1450 °C. Densification, cold-crushing strength (CCS), and microstructure of the hydrated cement samples (From Mix CA60) were investigated. The cast cement specimens revealed better density and CCS characteristics (63.1 and 74 MPa at 7 and 28 days, respectively) in comparison with the commercial cement. Conventional castables (5 × 5 × 5 cm3) were prepared from mixtures composed of 15 wt% cement and 85 wt% aggregates (40% Al2O3), where CA60 and commercial cement were used to compare the effect of the manufactured CA60 cement with the commercial one. The castables prepared with CA60 cement have shown a higher strength at 110 °C with 4.5 MPa when compared to the commercial CAC at the same temperature (1.8 MPa). Accordingly, this study contributes not only to preserving the environment from the accumulation of industrial wastes but also to valorizing and adding value to these wastes.

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Study by DTA/TG of the formation of calcium aluminate obtained from an aluminium hazardous waste

Cited by 16 publications

References 9 publications

Recycling of hazardous waste from tertiary aluminium industry in a value-added material

Recycling of hazardous waste from tertiary aluminium industry in a value-added material

Can hazardous waste become a raw material? The case study of an aluminium residue: a review

Maximize the use of municipal waste generated by the hydrogen peroxide industry in the production of high-quality refractory CAC

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