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21 pages, 2029 KiB

Open AccessArticle

The Role of Barite in the Post-Mining Stabilization of Radium-226: A Modeling Contribution for Sequential Extractions

by Clémence Besançon, Camille Chautard, Catherine Beaucaire, Sébastien Savoye, Paul Sardini, Martine Gérard and Michael Descostes

Minerals 2020, 10(6), 497; https://doi.org/10.3390/min10060497 - 29 May 2020

Cited by 15 | Viewed by 2694

Abstract

Barite is ubiquitous and known to incorporate ²²⁶Ra through the formation of a solid-solution. In U mining mill tailings, barite is one of the dominant sulfate-binding minerals. In such environments, sequential extractions are generally used to identify the U- and ²²⁶Ra-binding [...] Read more.

Barite is ubiquitous and known to incorporate ²²⁶Ra through the formation of a solid-solution. In U mining mill tailings, barite is one of the dominant sulfate-binding minerals. In such environments, sequential extractions are generally used to identify the U- and ²²⁶Ra-binding phases and their associated reactivity. To better decipher the main processes governing the behavior of ²²⁶Ra during such sequential extractions, a geochemical model was developed with PHREEQC mimicking the sequential extraction of U and ²²⁶Ra from Bois-Noirs Limouzat U mine tailings, France. The model results were compared with a dataset produced by an experimental sequential extraction from the same mine tailings and including data on the solids and selective extraction results with the major elements, U and ²²⁶Ra. The simulations reproduced the results of the experimental chemical extractions accurately, with iron oxyhydroxides being the major U binding phase. However, the modeling indicated rather that barite would be the main ²²⁶Ra binding phase, instead of the iron oxyhydroxides identified by the experimental extractions. This is consistent with the ²²⁶Ra concentration measured in pore water, but in disagreement with the direct interpretation of the sequential extractions. The direct interpretation disregarded the role of barite in the geochemical behavior of ²²⁶Ra because barite was not specifically targeted by any of the extraction steps. However, the modeling showed that the dissolution of ²²⁶Ra-binding barite by reactants would lead to a ²²⁶Ra redistribution among the clay minerals, resulting in a skew in the experimental results. Similar results were achieved by referring simply to the bulk mineralogy of the tailings. This study highlights the importance of considering the mineralogy, mineral reactivity and retention capacity for more realistic interpretation of sequential extractions. Moreover, this paper provides new perspectives on the long-term consequences of these mill tailings in which barite controls the geochemical behavior of the ²²⁶Ra. Full article

(This article belongs to the Special Issue Barite)

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11 pages, 3467 KiB

Open AccessArticle

Lauryl Phosphate Flotation Chemistry in Barite Flotation

by Ying Lu, Weiping Liu, Xuming Wang, Huaigang Cheng, Fangqin Cheng and Jan D. Miller

Minerals 2020, 10(3), 280; https://doi.org/10.3390/min10030280 - 20 Mar 2020

Cited by 9 | Viewed by 2957

Abstract

Barite has numerous applications including barium mud for oil well drilling, manufacture of elemental barium, filler for paper and rubber industries, and contrast material for X-ray radiology for the digestive system. Currently, froth flotation is the main method for the beneficiation of barite [...] Read more.

Barite has numerous applications including barium mud for oil well drilling, manufacture of elemental barium, filler for paper and rubber industries, and contrast material for X-ray radiology for the digestive system. Currently, froth flotation is the main method for the beneficiation of barite using fatty acid as a typical collector. In this research, it was found that lauryl phosphate is also a promising collector for barite flotation. Results from microflotation, contact angle, and zeta potential indicate that lauryl phosphate is adsorbed on the barite surface and thus achieves superior flotation efficiency at a wide pH range. The interfacial water structure and wetting characteristics of barite surface with/without lauryl phosphate adsorption were also evaluated by molecular dynamics simulations (MDS). The results from molecular dynamics simulations and interaction energy calculations are in accord with the experimental results, which suggest that lauryl phosphate might be a potential collector for the flotation of barite. Full article

(This article belongs to the Special Issue Barite)

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11 pages, 2725 KiB

Open AccessArticle

Optimisation of Radium Removal from Saline Produced Waters during Oil and Gas Extraction

by Joel Garner and David Read

Minerals 2020, 10(3), 278; https://doi.org/10.3390/min10030278 - 19 Mar 2020

Cited by 3 | Viewed by 2966

Abstract

Unconventional shale gas exploitation presents complex problems in terms of radioactive waste disposal. Large volumes of saline produced water resulting from hydraulic fracturing are typically enriched in radium isotopes, up to several hundred Bq/dm³, orders of magnitude above national discharge limits. [...] Read more.

Unconventional shale gas exploitation presents complex problems in terms of radioactive waste disposal. Large volumes of saline produced water resulting from hydraulic fracturing are typically enriched in radium isotopes, up to several hundred Bq/dm³, orders of magnitude above national discharge limits. There is a need, therefore, to decontaminate the fluid prior to discharge, preferably by creating a less problematic radium-containing, solid waste form. Barite (barium sulphate) co-precipitation is a cost-effective method for achieving these objectives, provided the process can be controlled. In this work, radium recovery of ~90% has been achieved for simulant produced waters containing 100 Bq/dm³, using a single, optimised co-precipitation step. However, salinity has a significant effect on the efficiency of the process; higher salinity solutions requiring substantially more reagent to achieve the same recovery. If >90% radium removal is sought, multiple co-precipitation steps provide a much faster alternative than post-precipitation recrystallization of the barite solid phase, albeit at higher cost. The resulting solid waste has a relatively high specific radium activity but a much smaller volume, which presents a less intractable disposal problem for site operators than large volumes of radium-contaminated fluid. Full article

(This article belongs to the Special Issue Barite)

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20 pages, 4302 KiB

Open AccessFeature PaperArticle

Combination of MRI and SEM to Assess Changes in the Chemical Properties and Permeability of Porous Media due to Barite Precipitation

by Jenna Poonoosamy, Sabina Haber-Pohlmeier, Hang Deng, Guido Deissmann, Martina Klinkenberg, Bulat Gizatullin, Siegfried Stapf, Felix Brandt, Dirk Bosbach and Andreas Pohlmeier

Minerals 2020, 10(3), 226; https://doi.org/10.3390/min10030226 - 29 Feb 2020

Cited by 16 | Viewed by 3861

Abstract

The understanding of the dissolution and precipitation of minerals and its impact on the transport of fluids in porous media is essential for various subsurface applications, including shale gas production using hydraulic fracturing (“fracking”), CO₂ sequestration, or geothermal energy extraction. In this [...] Read more.

The understanding of the dissolution and precipitation of minerals and its impact on the transport of fluids in porous media is essential for various subsurface applications, including shale gas production using hydraulic fracturing (“fracking”), CO₂ sequestration, or geothermal energy extraction. In this work, we conducted a flow through column experiment to investigate the effect of barite precipitation following the dissolution of celestine and consequential permeability changes. These processes were assessed by a combination of 3D non-invasive magnetic resonance imaging, scanning electron microscopy, and conventional permeability measurements. The formation of barite overgrowths on the surface of celestine manifested in a reduced transverse relaxation time due to its higher magnetic susceptibility compared to the original celestine. Two empirical nuclear magnetic resonance (NMR) porosity–permeability relations could successfully predict the observed changes in permeability by the change in the transverse relaxation times and porosity. Based on the observation that the advancement of the reaction front follows the square root of time, and micro-continuum reactive transport modelling of the solid/fluid interface, it can be inferred that the mineral overgrowth is porous and allows the diffusion of solutes, thus affecting the mineral reactivity in the system. Our current investigation indicates that the porosity of the newly formed precipitate and consequently its diffusion properties depend on the supersaturation in solution that prevails during precipitation. Full article

(This article belongs to the Special Issue Barite)

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17 pages, 5696 KiB

Open AccessEditor’s ChoiceArticle

The Formation of Barite and Celestite through the Replacement of Gypsum

by Pablo Forjanes, José Manuel Astilleros and Lurdes Fernández-Díaz

Minerals 2020, 10(2), 189; https://doi.org/10.3390/min10020189 - 19 Feb 2020

Cited by 25 | Viewed by 8412

Abstract

Barite (BaSO₄) and celestite (SrSO₄) are the end-members of a nearly ideal solid solution. Most of the exploitable deposits of celestite occur associated with evaporitic sediments which consist of gypsum (CaSO₄·2H₂O) or anhydrite (CaSO₄ [...] Read more.

Barite (BaSO₄) and celestite (SrSO₄) are the end-members of a nearly ideal solid solution. Most of the exploitable deposits of celestite occur associated with evaporitic sediments which consist of gypsum (CaSO₄·2H₂O) or anhydrite (CaSO₄). Barite, despite having a broader geological distribution is rarely present in these deposits. In this work, we present an experimental study of the interaction between gypsum crystals and aqueous solutions that bear Sr or Ba. This interaction leads to the development of dissolution-crystallization reactions that result in the pseudomorphic replacement of the gypsum crystals by aggregates of celestite or barite, respectively. The monitoring of both replacement reactions shows that they take place at very different rates. Millimeter-sized gypsum crystals in contact with a 0.5 M SrCl₂ solution are completely replaced by celestite aggregates in less than 1 day. In contrast, only a thin barite rim replaces gypsum after seven days of interaction of the latter with a 0.5 M BaCl₂ solution. We interpret that this marked difference in the kinetics of the two replacement reactions relates the different orientational relationship that exists between the crystals of the two replacing phases and the gypsum substrate. This influence is further modulated by the specific crystal habit of each secondary phase. Thus, the formation of a thin oriented layer of platy barite crystals effectively armors the gypsum surface and prevents its interaction with the Ba-bearing solution, thereby strongly hindering the progress of the replacement reaction. In contrast, the random orientation of celestite crystals with respect to gypsum guarantees that a significant volume of porosity contained in the celestite layer is interconnected, facilitating the continuous communication between the gypsum surface and the fluid phase and guaranteeing the progress of the gypsum-by-celestite replacement. Full article

(This article belongs to the Special Issue Barite)

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14 pages, 3949 KiB

Open AccessArticle

Power Generation: Feedstock for High-Value Sulfate Minerals

by Lucian C. Staicu, Tomasz Bajda, Lukasz Drewniak and Laurent Charlet

Minerals 2020, 10(2), 188; https://doi.org/10.3390/min10020188 - 19 Feb 2020

Cited by 5 | Viewed by 3595

Abstract

Coal-fired power facilities generate a polymetallic effluent (Flue Gas Desulfurization—FGD) rich in sulfate. FGD effluents may be considered an important secondary resource. This paper investigates the recovery of sulfate as barite (BaSO₄), a mineral with high commercial value and a critical [...] Read more.

Coal-fired power facilities generate a polymetallic effluent (Flue Gas Desulfurization—FGD) rich in sulfate. FGD effluents may be considered an important secondary resource. This paper investigates the recovery of sulfate as barite (BaSO₄), a mineral with high commercial value and a critical raw material. Using equimolar BaCl₂, >99% desulfurization of an FGD effluent produced by a coal-fired power plant operating in central Poland was achieved, yielding up to 16.5 kg high purity barite m⁻³. The recovered barite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TGA), scanning electron microscopy analysis (SEM), surface properties (PZC), density, and chemical stability (TCLP), and was compared with a commercial reference material. Barite recovery also led to the reduction in concentration of Al (86%), Cu (52%), K (69%), Mo (62%), Se (40%), Sr (91%), and U (75%) initially present in the FGD effluent. TCLP results indicate the entrapment and the stabilization of ~70% Se and ~90% Al in the barite structure. Based on this dataset, an in-depth characterization of the recovered barite is presented, and the removal mechanism of the elements is discussed. The study also provides a preliminary cost benefit analysis of the process. To our best knowledge, this is the first work showing barite recovery and metal removal from FGD effluents using a one-step process. Full article

(This article belongs to the Special Issue Barite)

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11 pages, 1165 KiB

Open AccessArticle

High Specific Activity of Radium Isotopes in Baryte from the Czech Part of the Upper Silesian Basin—An Example of Spontaneous Mine Water Treatment

by Jakub Jirásek, Dalibor Matýsek, Petr Alexa, Michal Osovský, Radim Uhlář and Martin Sivek

Minerals 2020, 10(2), 103; https://doi.org/10.3390/min10020103 - 25 Jan 2020

Cited by 5 | Viewed by 2784

Abstract

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium [...] Read more.

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium mill tailings, and as a by-product of phosphoric acid manufacturing. Recently, we recognized Ra-rich baryte as a precipitate in the water drainage system of a bituminous coal mine in the Czech part of the Upper Silesian Basin. The precipitate is a relatively pure baryte, with the empirical formula (Ba_0.934Sr_0.058Ca_0.051Mg_0.003)_Σ1.046S_0.985O_4.000. The mean specific activity of ²²⁶Ra was investigated by the two-sample method and it equals 39.62(22) Bq/g, a level that exceeds known natural occurrences. The values for ²²⁸Ra and ²²⁴Ra are 23.39(26) Bq/g and 11.03(25) Bq/g. The radium content in the baryte is 1.071 ng/g. It is clear that the Ra-rich baryte results from the mixing of two different mine waters—brines rich in Ba, Sr, and isotopes ²²⁶Ra and ²²⁸Ra and waters that are affected by sulfide weathering in mine works. When this mixing occurs in surface watercourses, it could present a serious problem due to the half-life of ²²⁶Ra, which is 1600 years. If such mixing spontaneously happens in a mine, then the environmental risks will be much lower and will be, to a great, extent eliminated after the closure of the mine. Full article

(This article belongs to the Special Issue Barite)

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Review

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24 pages, 3840 KiB

Open AccessReview

Toward an Improved Understanding of the Marine Barium Cycle and the Application of Marine Barite as a Paleoproductivity Proxy

by Samantha C. Carter, Adina Paytan and Elizabeth M. Griffith

Minerals 2020, 10(5), 421; https://doi.org/10.3390/min10050421 - 09 May 2020

Cited by 52 | Viewed by 5202

Abstract

Marine barite (BaSO₄) is a relatively ubiquitous, though minor, component of ocean sediments. Modern studies of the accumulation of barite in ocean sediments have demonstrated a robust correlation between barite accumulation rates and carbon export to the deep ocean. This correlation [...] Read more.

Marine barite (BaSO₄) is a relatively ubiquitous, though minor, component of ocean sediments. Modern studies of the accumulation of barite in ocean sediments have demonstrated a robust correlation between barite accumulation rates and carbon export to the deep ocean. This correlation has been used to develop quantitative relationships between barite accumulation rates and export production and is used to reconstruct export production in the geologic past, particularly during times of dynamic changes in the carbon cycle. We review the processes that affect the formation and preservation of marine barite, as well as those controlling the relationship between the barium (Ba) and carbon biogeochemical cycles. Additionally, we take a new approach to modeling the marine Ba cycle as a two-box model, specifically evaluating Ba utilization in the surface ocean and refining the equation describing the relationship between export production and barite formation. We compare these new results with past modeling efforts. The new model demonstrates that increases in export production can lead to sustained increases in barite accumulation in marine sediments without resulting in complete surface water Ba depletion, which is distinctly different from previous modeling results. Full article

(This article belongs to the Special Issue Barite)

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