Prediction of the long-term performance of green liquor dregs as a sealing layer to prevent the formation of acid mine drainage

Mäkitalo, Maria; Lu, Jinmei; Maurice, Christian; Öhlander, Björn

doi:10.1016/j.jece.2015.10.005

Cited by 12 publications

(7 citation statements)

References 17 publications

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“…The high buffer capacity of the dregs is well known 56 , and it has been studied as an alternative liming material in soil 25 . The maintenance of the dregs´ alkaline condition, used as remediation of acid mine drainage in a long-term project, suggests a strong potential for this application 57 . Alkaline compounds such as carbonates and hydroxides in dregs and grits 25,49,50,55 react with hydrogen ions, neutralizing or increasing the pH of the solution and removing metals through precipitation mechanisms 10,58 .…”

Section: Resultsmentioning

confidence: 99%

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Farage

Quina

Gando-Ferreira

et al. 2020

Sci Rep

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Mining is an essential human activity, but results in several environmental impacts, notably the contamination of ground and surface water through the presence of toxic substances such as metals and sulfates in mine drainage. permeable reactive barriers (pRB) have been applied to remediate this environmental impact, but the high costs associated with the maintenance of this system are still a challenge. the main objective of this study was to evaluate the use of kraft pulp mill alkaline residues, known as dregs and grits, as material for pRB, and to determine their capacity for retaining copper and sulfate. the work was carried out in laboratory adsorption kinetics assays, batch assays and column tests. tests for elemental characterization, point of zero charge, acid neutralization capacity, total porosity, bulk density and moisture of the dregs and grits were conducted. the results showed high retention of Cu due to a chemical precipitation mechanism, notably for dregs (99%) at 5 min in adsorption kinetics. The grits presented similar results after 180 min for the same assay. Sulfate retention was effective at pH below 5, with an efficiency of 79% and 89% for dregs and grits, respectively. Dregs presented the best results for acid drainage remediation, notably with a solid:liquid (S:L) ratio of 1:10.Acid mine drainage (AMD) is caused by the oxidation of sulfur-bearing materials in the presence of oxygen and water, resulting in sulfate and metals solubilization and forming acidic solutions 1-4 . Active and inactive mining activities for metals, such as copper, lead, zinc, gold, silver and uranium, provoke potential degradation of the environment by the presence of different contaminants, particularly due to metals and sulfates in acid drainage 5 . Indeed, the acid drainage formation is an important environmental aspect of mining practices. The sulfate concentrations may reach 2,400 to 20,800 mg/L 6,7 , well above the limit of 250 mg/L established by the World Health Organization 8 . It might cause damage not only to human health but also to the environment, and depreciation of structures and equipment 2,9 , resulting in high costs for control and management by the mining companies 2,10 . Copper concentration may be in the range from 77 to 615 mg/L, with higher values in the Cu mines 1,11 . Other metals such as Al, Mn, Fe, Mg, and Zn are also commonly found in AMD in these mines 10,12 .AMD remediation can be actively accomplished off-site with the pumping of the contamination plume to a treatment plant, or passively on-site with the use of permeable reactive barriers (PRB), with lower installation and maintenance costs. It can be carried out with the flow directed to the system, by the Funnel model, or the grid-type, by the installation of a perpendicular barrier to the contamination plume 13,14 . The PRB was first proposed in Canada in the 1990s 13,15 , with different materials used as adsorbent media, from single barriers with only one material to composites of different materials, or multiple sequential barrier...

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Section: Resultsmentioning

confidence: 99%

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Farage

Quina

Gando-Ferreira

et al. 2020

Sci Rep

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“…The alkalinity of the dregs showed a direct effect on the stability of certain elements, extending the benefits of using this potential waste. Mäkitalo et al [55] also evaluated the long-term efficiency of green liquor dregs sealing layers along the years. Green liquor dregs fresh and aged (3 to 13 years) were collected and analyzed to determine how aging affects its chemical and physical properties.…”

Section: Green Liquor Dregsmentioning

confidence: 99%

Wastes from pulp and paper mills - a review of generation and recycling alternatives

et al. 2018

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The production of pulp and paper is increasing worldwide, and wastes are therefore being generated in appreciable amounts. Various materials are generated in pulp and paper mills, such as ash, dregs, grits, lime mud and pulp mill sludge. Over the years, these wastes have typically been sent to landfills or incinerated. However, with increased environmental awareness new alternatives have been investigated, especially the valorization of these materials. In this review, the characteristics of the manufacturing process, generated wastes, main destinations and recycling alternatives are addressed. The state of the art indicates that dregs are useful in agriculture as soil amendments, while lime mud can be used in agriculture and in environmental technology, mainly in wastewater treatment. Grits are commonly employed in construction, and pulp mill sludge shows applications in agriculture, construction and energy processes. In conclusion, this review shows several successful cases of recycling wastes from pulp and paper mills.

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“…In recent years, studies have been focusing on the use of alternative materials such as industrial and municipal waste for mine waste remediation, which could solve two waste problems at the same time. The application of incineration ashes, waste from wood and paper industry and other industries, sewage sludge, steel slag and combinations of these materials for construction of sealing layers and for other applications in mine waste remediation have been investigated [8][9][10]. Using various types of materials as dry covers on mine waste has been successfully applied at many sites throughout the world [11,12].…”

Section: Sealing Layermentioning

confidence: 99%

“…The long term application potential of GLD is also investigated [9,17]. The results showed that the GLD's buffering capacity is high and can last for a long time [17].…”

Section: Green Liquor Dregs (Gld) From Paper Mills As Dry Covermentioning

confidence: 99%

“…The results showed that the GLD's buffering capacity is high and can last for a long time [17]. According to the calculation from leaching experiments, a 30 cm thick GLD sealing layer with a hydraulic conductivity of 1E-08 m/s would retain its buffering capabilities for more than 200,000 years [9]. Therefore, GLD is a good cover material that can be used in large scale in the field and effective in the longterm.…”

Section: Green Liquor Dregs (Gld) From Paper Mills As Dry Covermentioning

confidence: 99%

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The possibilities and challenges of using industrial rest products on mine waste management in the Arctic

Lu¹,

Yuan²,

Barabadi³

et al. 2016

WIT Transactions on Ecology and the Environment

Self Cite

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Acid Rock Drainage (ARD) generated from oxidation of sulphide-bearing mine waste is one of the main pollution problems associated with mining activities. Dry cover and water cover are normally used methods to prevent the formation of ARD. However, in the Arctic region, the harsh cold climate, the vulnerability of ecosystems and the drastic climate change make the waste management methods different from other non-Arctic regions. This paper reviewed several successful case studies of dry cover and water cover applications with industrial rest products and further discussed the possibilities and challenges of using industrial rest products to manage mine waste in the Arctic region.

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Prediction of the long-term performance of green liquor dregs as a sealing layer to prevent the formation of acid mine drainage

Cited by 12 publications

References 17 publications

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Wastes from pulp and paper mills - a review of generation and recycling alternatives

The possibilities and challenges of using industrial rest products on mine waste management in the Arctic

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