Oxidative dissolution of pyritic sludge from the Aznalcóllar mine (SW Spain)

Domènech, Cristina; Pablo, Joan de; Ayora, Carlos

doi:10.1016/s0009-2541(02)00124-9

Cited by 79 publications

(50 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, since the pyrite dissolution rate (ca. 10 −10 mol m −2 s −1 at pH from 3 to 5 and O 2 concentration of 3 × 10 −4 mol L −1 ; Domènech et al, 2002) was approximately six to seven orders of magnitude slower than that of gypsum (10 −3 mol m −2 s −1 ; Palandri and Kharaka, 2004), it was assumed that most of the released S was from dissolving gypsum. As the gypsum dissolution rate was not affected by dissolved CO 2 (Jeschke et al, 2001) or by pH, the S decrease was probably caused by a decrease in the gypsum reactive surface area as gypsum dissolved (Fig.…”

Section: Resultsmentioning

confidence: 99%

Interaction between a fractured marl caprock and CO2-rich sulfate solution under supercritical CO2 conditions

Dávila

Luquot

Soler

et al. 2016

International Journal of Greenhouse Gas Control

View full text Add to dashboard Cite

Please cite this article in press as: Dávila, G., et al., Interaction between a fractured marl caprock and CO 2 -rich sulfate solution under supercritical CO 2 conditions. Int. J. Greenhouse Gas Control (2015), http://dx.doi.org/10.1016/j.ijggc.2015.11.005 Geological CO 2 sequestration at pilot-plant scale will be developed at Hontomín (Spain). CO 2 will be injected into a limestone reservoir that contains a NaCl-and sulfate-rich groundwater in equilibrium with calcite and gypsum. The caprock site is composed of marl. The present study seeks to evaluate the interaction between the Hontomín marl and CO 2 -rich sulfate solutions under supercritical CO 2 conditions (P Total = 150 bar, pCO 2 = 61 bar and T = 60 • C). Flow-through percolation experiments were performed using artificially fractured cores to elucidate (i) the role of the composition of the injected solutions (S-free and S-rich solutions) and (ii) the effect of the flow rate (0.2, 1 and 60 mL h −1 ) on fracture permeability. Major dissolution of calcite (S-free and S-rich solutions) and precipitation of gypsum (S-rich solution) together with minor dissolution of the silicate minerals contributed to the formation of an altered skeleton-like zone (mainly made up of unreacted clays) along the fracture walls. Dissolution patterns changed from face dissolution to wormhole formation and uniform dissolution with increasing Peclet numbers. ARTICLE IN PRESSIn S-free experiments, fracture permeability did not significantly change regardless of the flow rate despite the fact that a large amount of calcite dissolved. In S-rich solution experiments, fracture permeability decreased under slow flow rates (0.2 and 1 mL h −1 ) because of gypsum precipitation that sealed the fracture. At the highest flow rate (60 mL h −1 ), fracture permeability increased because calcite dissolution predominated over gypsum precipitation.

show abstract

Section: Resultsmentioning

confidence: 99%

Interaction between a fractured marl caprock and CO2-rich sulfate solution under supercritical CO2 conditions

Dávila

Luquot

Soler

et al. 2016

International Journal of Greenhouse Gas Control

View full text Add to dashboard Cite

show abstract

“…Change in mineral surface area A m (m 2 mineral m −3 rock) is calculated assuming that area is proportional to the volume fraction of the mineral to the power 2/3. The numerical model developed to reproduce the experimental conditions ("batch" simulation) considered (a) the mineralogical composition of the rock according to the measured values by XRF and (b) the rate laws for the reacting minerals showed in the literature [44][45][46][47].…”

Section: Applied Techniques and Methodsmentioning

confidence: 99%

Qualitative and Quantitative Changes of Carbonate Rocks Exposed to SC CO2 (Basque-Cantabrian Basin, Northern Spain)

Berrezueta

Kovács²,

Luquot

2017

Applied Sciences

View full text Add to dashboard Cite

Abstract:This study aims at the qualitative and quantitative determination of porosity, mineralogical and textural changes in carbonate rock samples after injection of (i) supercritical CO 2 -rich brine and (ii) dry supercritical CO 2 , under similar experimental conditions (P ≈ 75 bar, T ≈ 35 • C, 970 h exposure time and no CO 2 flow). The studied rocks were sampled in the western Basque-Cantabrian Basin, North Spain, and consist of vuggy carbonates ("Carniolas") of the Puerto de la Palombera formation (Hettangian). Mineralogical and pore space characterization is completed using optical microscopy, scanning electron microscopy and optical image analysis. In addition, X-ray fluorescence analyses are performed to refine the mineralogical information and to obtain whole rock geochemical data and the brine composition is analysed before and after the experiment. Mineralogical and chemical results indicate that the carbonate rocks exposed to supercritical CO 2 in dry conditions do not suffer significant changes. However, the injection of supercritical CO 2 -rich brine induces chemical and physical changes in the rock due to the high reactivity of calcite at the low pH conditions produced by the acidified brine. Numerical modelling validates the experimental observations. These results can be used to characterize the behaviour of carbonate rocks under conditions similar to the vicinity of a CO 2 injection well. The results should be considered only at the scale of the studied samples and not at reservoir scale.

show abstract

“…Solubilisation kinetics have been reported to differ between metal suphides: Caille et al [88] found lead and copper sulphides were released more rapidly than zinc. Whilst Domenech et al [91] noted that sphalerite (ZnS) oxidized faster than pyrite (FeS 2 ) and galena (PbS) and chalcopyrite (CuFeS 2 ) had similar oxidation rates to pyrite. Furthermore the rate of galena dissolution was enhanced at low pH, an effect not apparent for sphalerite or chalcopyrite.…”

Section: Changes In Mineral Form and The Release Of Trace Metal Contamentioning

confidence: 99%

Environmental Risk of Metal Mining Contaminated River Bank Sediment at Redox-Transitional Zones

2014

View full text Add to dashboard Cite

Diffuse metal pollution from mining impacted sediment is widely recognised as a potential source of contamination to river systems and may significantly hinder the achievement of European Union Water Framework Directive objectives. Redox-transitional zones that form along metal contaminated river banks as a result of flood and drought cycles could cause biogeochemical changes that alter the behaviour of polyvalent metals iron and manganese and anions such as sulphur. Trace metals are often partitioned with iron, manganese and sulphur minerals in mining-contaminated sediment, therefore the dissolution and precipitation of these minerals may influence the mobility of potentially toxic trace metals. Research indicates that freshly precipitated metal oxides and sulphides may be more "reactive" (more adsorbent and prone to dissolution when conditions change) than older crystalline forms. Fluctuations at the oxic-anoxic interface brought about through changes in the frequency and duration of flood and drought episodes may therefore influence the reactivity of secondary minerals that form in the sediment and the flux of dissolved trace metal release. UK climate change models predict longer dry periods for some regions, interspersed with higher magnitude flood events. If we are to fully comprehend the future environmental risk these climate change events pose to mining impacted river systems it is recommended that research efforts focus on identifying the primary controls on trace metal release at the oxic-anoxic interface for flood and drought cycles of different duration and frequency. This paper critically reviews the literature regarding biogeochemical processes that occur at different temporal scales during oxic, OPEN ACCESSMinerals 2014, 4 53 reducing and dry periods and focuses on how iron and sulphur based minerals may alter in form and reactivity and influence the mobility of trace metal contaminants. It is clear that changes in redox potential can alter the composition of secondary iron and sulphur minerals and influence the sorption of toxic trace metals and susceptibility to dissolution when further redox potential changes occur. However further work is needed to determine: (i) The extent to which different duration and frequency of wet and dry cycles influences the dissolution and precipitation of iron and sulphur minerals in mining contaminated river bank sediment; (ii) The temporal effects on mineral reactivity (sorption capacity and susceptibility to dissolution); (iii) The key biogeochemical processes that control the mobility of contaminant trace metals under these dynamic redox potential conditions.

show abstract

Oxidative dissolution of pyritic sludge from the Aznalcóllar mine (SW Spain)

Cited by 79 publications

References 26 publications

Interaction between a fractured marl caprock and CO2-rich sulfate solution under supercritical CO2 conditions

Interaction between a fractured marl caprock and CO2-rich sulfate solution under supercritical CO2 conditions

Qualitative and Quantitative Changes of Carbonate Rocks Exposed to SC CO2 (Basque-Cantabrian Basin, Northern Spain)

Environmental Risk of Metal Mining Contaminated River Bank Sediment at Redox-Transitional Zones

Contact Info

Product

Resources

About