Variation of green liquor dregs from different pulp and paper mills for use in mine waste remediation

Document identifier: oai:DiVA.org:ltu-75826
Access full text here:10.1007/s11356-019-06180-0
Keyword: Engineering and Technology, Geokemi, Tillämpad geokemi, Applied Geochemistry, Beneficiation, Plasticity, Water retention, Heavy metals, Buffering capacity, Acid neutralization, Geovetenskap och miljövetenskap, Civil Engineering, Naturvetenskap, Geochemistry, Earth and Related Environmental Sciences, Natural Sciences, Geoteknik, Samhällsbyggnadsteknik, Teknik och teknologier, Geotechnical Engineering, Soil Mechanics
Publication year: 2019
Relevant Sustainable Development Goals (SDGs):
SDG 12 Responsible consumption and productionSDG 6 Clean water and sanitationSDG 2 Zero hunger
The SDG label(s) above have been assigned by OSDG.ai

Abstract:

The geotechnical, chemical, and mineralogical properties of green liquor dregs (GLDs) generated as byproducts from five paper mills were investigated to assess their buffering and heavy metal immobilization capacities and their roles as water and oxygen barriers. One type of GLD was further studied to test the effects of the retrieval process and the storage, drying, and hydration of GLD. The high water retention capacity of the GLDs is valuable for limiting O2diffusion. Laboratory results showed that the GLDs had hydraulic conductivities of 3.7 × 10−9–4.6 × 10−8 m/s and varied regularly in plasticity. The chemical and mineralogical compositions of the GLDs varied greatly, reflecting the raw material used to produce paper and the process used to retrieve GLDs. Although they had high total heavy metal contents, none of the leached elements from the GLDs (L/S 10 cm3/kg) exceeded the European Union’s limits for landfills of non-hazardous waste. The GLDs exhibited high buffering capacities. In a supplementary test, the buffering capacities varied (0.0041–0.0114 M H+/g GLD) over 72 d after acid was added to the GLD. Changing the filtration process did not greatly affect the GLDs’ properties but mainly affected the hydraulic conductivity, total heavy metal contents and sulfur content. Analyzing the storage of GLDs is necessary in the mining industry because remediation measures require large amounts of material over short periods. The buffering capacity of the dried GLD decreased slightly. The effect of dewatering caused by the mixing of 2% Na-lignosulfate with GLD (w/w) was low.

Authors

Yu Jia

Luleå tekniska universitet; Geovetenskap och miljöteknik; Department of Environment and Minerals Resources, Greenland Institute of Nature Resources, Nuuk, Greenland
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Roger Hamberg

Luleå tekniska universitet; Geovetenskap och miljöteknik; Swedish Geological Survey AB, Luleå, Sweden
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Asif Qureshi

Luleå tekniska universitet; Geovetenskap och miljöteknik; Department of Energy and Environment Engineering, Quaid-e-Awam University of Engineering, Science & Technology, Nawabshah, Pakistan
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Maria Mäkitalo

Luleå tekniska universitet; Geovetenskap och miljöteknik
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Christian Maurice

Luleå tekniska universitet; Geovetenskap och miljöteknik; Ramböll Sverige AB, Luleå, Sweden
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