Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments

Mõtlep, Riho; Sild, Terje; Puura, Erik; Kirsimäe, Kalle

doi:10.1016/j.jhazmat.2010.08.073

Cited by 35 publications

(36 citation statements)

References 21 publications

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“…Similarly, the diagenesis of other secondary Ca-silicate phases is significantly subdued during a longterm deposition. However, the mineralogical data presented by Mõtlep et al [40] suggests the dissolution of amorphous glass phases and precipitation of secondary smectite-type clay phases. The high activity of dissolved Si and the specifically high K (>500 mg/l) [55] in the water in contact with ash would suggest the precipitation of secondary mixed-layer clays, zeolites and/or authigenic K-feldspar phases, similar to the hydration of volcanic glasses in evaporitic alkaline hypersaline or diagenetic environments.…”

Section: Diagenesis Of Ash In Depositsmentioning

confidence: 96%

“…However, on a large scale, in waste deposits, where the contact with atmospheric CO 2 is hindered by the added layers of ash, a significant, yet not complete, carbonation of portlandite is only achieved in the uppermost 0.5-1 m layer of the deposit, and the content of calcite decreases over about a 5-m depth interval, whereas portlandite is well preserved in the deeper parts of the ash deposit [40].…”

Section: Diagenesis Of Ash In Depositsmentioning

confidence: 99%

See 1 more Smart Citation

Open-Air Deposition of Estonian Oil Shale Ash: Formation, State of Art, Problems and Prospects for the Abatement of Environmental Impact

Kuusik¹,

Uibu²,

Kirsimäe³

et al. 2012

Oil Shale

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Section: Diagenesis Of Ash In Depositsmentioning

confidence: 96%

Section: Diagenesis Of Ash In Depositsmentioning

confidence: 99%

Open-Air Deposition of Estonian Oil Shale Ash: Formation, State of Art, Problems and Prospects for the Abatement of Environmental Impact

Kuusik¹,

Uibu²,

Kirsimäe³

et al. 2012

Oil Shale

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“…It is known that when fly ash is in contact with water, dissolution of the solid phase occurs, with changes in pH and the release of potentially harmful components [12][13][14][15][16]. The principal processes affecting the leaching process are dissolution of primary solids as well as sorption and hydrolysis reactions, etc.…”

Section: Introductionmentioning

confidence: 99%

Leaching Behaviour of Estonian Oil Shale Ash-Based Construction Mortars

Irha¹,

Uibu²,

Jefimova³

et al. 2014

Oil Shale

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To estimate the environmental properties of oil shale ash-based mortars the leaching of harmful components was studied. The leachates were highly alkaline. The predominant ions were Ca 2+ , K + , Na + , SO 4 2-. The leachable content of soluble components in PF ash mortars was higher in comparison with that in CFB ash mortars. Results indicated that over curing time the fraction of readily soluble inorganic components decreased and the mobility of potentially hazardous Cd and Zn did not increase. Addition of bypass dust could affect the content of leachable ions. Results give new knowledge about the environmental properties of oil shale ash-based materials, including backfilling composites for underground mining technology.

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“…Most of the OSA is deposited in waste piles due to current lack of practical applications and becomes the source of solid, liquid and gaseous pollutants. Various studies have shown that leaching of the minerals and organics from OSA-s is a continuous and relatively long-term process, which means that the ash piles contaminate the environment for a long time [4][5][6]. CaSO 4 is the main sulfur compound present in the oil shale ashes, but also traces of sulfides are found [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Series of reactions (eqns. (1)- (6)), [5,8,9]) occur during ash contact with water and atmospheric components at open-air deposits, including release of gaseous hydrogen sulfide (H 2 S(g)) [3,9] under certain conditions. H 2 S(g) is an extremely toxic and irritating gas, which affects the nervous system, intermits breathing or impairs cardiac function.…”

Section: Introductionmentioning

confidence: 99%

Transformations of sulfur compounds in oil shale ash suspension

Tamm¹,

Kuusik²,

Uibu³

et al. 2012

WIT Transactions on Ecology and the Environment

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Oil shale (sulfur content <2%) is mainly used for the production of electricity and heat in Estonia. Calcium-rich waste formed in the process of oil shale combustion can be used as sorbents in the CO 2 mineralisation process. CaSO 4 is the main sulfur compound in the ashes of oil shale, but traces of sulfides are also found. This means that transformations of sulfur compounds in the water environment must be considered while using hydrotransport and open air deposition of oil shale ash as well as treating alkaline ash transportation waters. The transformations of sulfur compounds in model systems (ash -water and CaS -water) were studied in anaerobic and aerobic conditions as well as in the process of aqueous carbonization. The separation of poisonous H 2 S(g) was continuously monitored. The results revealed that the leachates of oil shale ash contained mainly sulfates in both aerobic and anaerobic conditions but sulfides and sulfites were also present. Small amount of H 2 S(g) was emitted already in the first minutes of carbonation process at high pH region (~12). The alkalinity decreased during carbonation of ash -water suspensions, triggering substantial H 2 S release at pH<9 (the content of H 2 S(g) in off-gas reached to 110 ppm). Taking environmental issues into consideration, the critical pH value of the aqueous carbonation system of oil shale ash must be optimized in order to minimize the separation of gaseous H 2 S emissions.

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Composition, diagenetic transformation and alkalinity potential of oil shale ash sediments

Cited by 35 publications

References 21 publications

Open-Air Deposition of Estonian Oil Shale Ash: Formation, State of Art, Problems and Prospects for the Abatement of Environmental Impact

Open-Air Deposition of Estonian Oil Shale Ash: Formation, State of Art, Problems and Prospects for the Abatement of Environmental Impact

Leaching Behaviour of Estonian Oil Shale Ash-Based Construction Mortars

Transformations of sulfur compounds in oil shale ash suspension

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