Revegetation strategies for seawater neutralized bauxite residue at Rio Tinto Alcan using various amendments

Li, Yaying

doi:10.14264/uql.2017.798

Cited by 6 publications

(4 citation statements)

References 43 publications

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“…The EC of the mud fraction can be significantly higher than that of residue sand (Jones et al , 2012aLi 2017). The addition of residue sand to the mud fraction can, therefore, decrease salinity and greatly improve the permeability and hence leachability of the salinity, thus further decreasing salinity (Courtney et al 2009a).…”

Section: Soil Salinity (Ec)mentioning

confidence: 97%

“…The incorporation of gypsum plus organic matter into the surface horizon may have a greater effect on acidifying the subsurface layers compared with gypsum alone. For example, in an 8-month study, Li (2017) showed that addition of gypsum plus biosolids or cattle manure into the surface 10 cm of residue had a significant interaction in decreasing pH, exchangeable Na, and extractable Al, and increasing exchangeable Ca and grass root growth in the subsoil (10-30 cm) layer compared with surface incorporation of gypsum alone. Such an effect is attributable to downward movement of acidity (e.g.…”

Section: Gypsum Plus Organic Mattermentioning

confidence: 99%

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Soil quality and vegetation performance indicators for sustainable rehabilitation of bauxite residue disposal areas: a review

et al. 2019

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The generation of bauxite residue, the by-product of alumina manufacture from bauxite ore, has increased to a global stockpile of some 3 billion tonnes. In the absence of significant reuse options, the bulk of this residue is contained within bauxite residue disposal areas (BRDAs), which can occupy a significant footprint and pose potential environmental risk. Rehabilitation (amendment and vegetation establishment) is viewed as a significant strategy for eventual closure of the BRDAs. Major limitations to plant growth in residue include high pH, salinity, and sodicity, as well as deficiencies of macro- and micronutrients and potentially elevated levels of trace elements. The physical properties are also problematic as residue mud consolidates to form a solid mass that waterlogs easily or dries to form a massive structure, whereas sand has a very low water- and nutrient-holding capacity. A variety of techniques have been trialled at the pot level and at the field scale to bring about reductions in residue alkalinity and sodicity to promote plant establishment, with gypsum amendment viewed as the most promising. Other amendment strategies include use of organic additions or fertiliser applications, and a combined approach can lead to improved residue properties and successful plant establishment. Few reports have focused on longer term plant growth, self-propagation, and residue interactions under field conditions. There is some evidence that rehabilitated residue can support vegetation growth and soil development in the short to medium term (~15 years), but key issues such as nutrient availability and plant uptake require further study. Although rehabilitated residue can support diverse microbial communities and demonstrate trajectory analogous to soil, the ability of rehabilitated residue to support soil biota and key ecosystem processes warrants further study. The bioavailability of trace elements within rehabilitated sites and potential food chain transfer are relatively unexplored. These areas need careful study before definitive statements can be made regarding the sustainability of residue rehabilitation strategies.

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Section: Soil Salinity (Ec)mentioning

confidence: 97%

Section: Gypsum Plus Organic Mattermentioning

confidence: 99%

Soil quality and vegetation performance indicators for sustainable rehabilitation of bauxite residue disposal areas: a review

et al. 2019

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“…In 2010, the cost to transport bauxite along the outdated railway network became so high that the Canadian company Rio Tinto (until 2007 Alcan) decided to sell its stake in Ghana Bauxite Company Limited to the Chinese Bosai Minerals Group (Bertolli, 2010; Knierzinger, 2016). When the Bosai Group took over, continued difficulties with low efficiency and high costs of transportation led to a further decrease in production.…”

Section: Ghana's Bauxite-aluminium Industry and The Atewa Forest Reservementioning

confidence: 99%

The Politicisation of the Atewa Forest Reserve in Ghana

Purwins

2024

Journal of Tropical Futures: Sustainable Business, Governance &

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In 2018, the Ghanaian government signed the Sinohydro deal, a resource-backed loan using bauxite as collateral, with Ghana's president highlighting the opportunity to develop an integrated bauxite-aluminium industry and boost industrialisation across the country. The deal has led to a number of protests against bauxite mining in Ghana, particularly at one potential site: The Atewa Forest Reserve. This paper analyses the politicisation of the Atewa Forest Reserve through the lens of political ecology. Political ecology recognises that forests are not neutral entities, but are shaped by political processes and dynamics. The Atewa Forest is seen as a political forest, as a particular constellation of power constituted by ideas, practices and institutions. The paper contends that the narrative constructed around the Sinohydro Deal strategically legitimizes mining in the Atewa Forest, positioning the project as a symbol of progress and national development. It also argues that the Sinohydro deal was designed to circumvent national environmental laws, leading to quick (political) success while being embedded in a powerful narrative. Therefore, the contestation over development is increasingly shaped by a discursive closure that limits dissent, influencing public opinion and decision-making. Despite presenting the developments as visions for the future, the narrative ultimately reinforces old development tropes of resource extraction, convincing even counter-movements to focus on the location rather than opposing bauxite mining as a whole. The findings are based on interviews conducted during fieldwork in 2018, 2019 and 2020, as well as analysis of secondary data such as political documents, press statements and speeches.

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“…Compared to gypsum used solely, combining gypsum and organic amendments into the surface layer has a greater impact on subsurface remediation. For example, Li et al (2017) found that the addition of gypsum and biosolids or cattle manure in the surface layer signi cantly contributed to lower pH and exchangeable sodium content as well as increased exchangeable calcium content and plant growth in bauxite residue compared to adding gypsum only. A recent study, with pH modulating the humic-mineral interactions in bauxite residue, revealed that the organic molecules derived from decomposition of the nitrohumic acid results in the formation of organo-mineral complexes and microagglomerates by binding to cations (Ren et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Effect of calcium ions on the interaction of alkaline minerals with dissolved organic matter: Implications for organic carbon sequestration in bauxite residue

et al. 2023

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The interaction of minerals and organic matter signi cantly affects the stability of organic carbon, which is key to the rehabilitation of bauxite residue. However, due to the microscopic structure of minerals and the chemical composition of dissolved organic matter (DOM), the interaction mechanism between alkaline minerals and DOM in the presence of calcium ions that are widely used as amendments is still poorly understood. MethodsIn this work, the adsorption mechanism of organic matter by sodalite and cancrinite in the presence of calcium ions was investigated by fourier transform infrared spectroscopy (FTIR), excitation-emission matrix uorescence (EEMs), thermogravimetric analysis (TG-DSC) and atomic force microscope (AFM). ResultsThe calcium ions can act as bridges to connect the negative sites on the mineral surface with the polysaccharide functional groups of organic matter, thus allowing the DOM to enter the pore channels of mineral structure to sequester organic carbon via ligand-exchange and/or electrostatic interactions. Furthermore, DOM located in the pore structure within cancrinite may be better protected due to physical isolation. The 3D view of the interacted minerals-organic matter assemblages provided visual evidence that the adsorption sites distributed on the surface of cancrinite increased by the action of calcium ions, with different adsorption capacity of individual sites for DOM. ConclusionsThe calcium ions enhance the ability of alkaline minerals to trap dissolved organic carbon, and the work highlighted the signi cance of organo-mineral associations in the microscopic mineral structure for the organic carbon sequestration in the revegetation process of bauxite residue disposal areas.

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Revegetation strategies for seawater neutralized bauxite residue at Rio Tinto Alcan using various amendments

Cited by 6 publications

References 43 publications

Soil quality and vegetation performance indicators for sustainable rehabilitation of bauxite residue disposal areas: a review

Soil quality and vegetation performance indicators for sustainable rehabilitation of bauxite residue disposal areas: a review

The Politicisation of the Atewa Forest Reserve in Ghana

Effect of calcium ions on the interaction of alkaline minerals with dissolved organic matter: Implications for organic carbon sequestration in bauxite residue

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