Formation and Occurrence of Magnesite and Brucite

Shand, Mark A.

doi:10.1002/0471980579.ch2

Cited by 4 publications

(12 citation statements)

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“…These include hydromagnesite [4MgCO3.Mg(OH)2.4H2O] and artinite [MgCO3. Mg(OH)2.3H2O] (Shand, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Deposits of massive cryptocrystalline magnesite occur in serpentized ultrabasic rock that has undergone a hydrothermal leaching of magnesium from the serpentine, H4Mg3Si2O9, in Eq (1). The hydrothermal solution contains dissolved carbon dioxide necessary for the dissolution process (Shand, 2006). The magnesium carbonate is deposited in veins and the silica carried away in solution.…”

Section: Introductionmentioning

confidence: 99%

“…The magnesium carbonate is deposited in veins and the silica carried away in solution. Magnesite may also form through the serpentization of ultrabasic rock, under low-temperature and lowpressure conditions, which favor the exosolution of hydrothermal cryptocrystalline magnesite (Shand, 2006 The magnesite occurs as massive bodies, lenticular (lens-shaped) masses, and veins of varying thickness (Shand, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The calcination of magnesium carbonate has not been as extensively studied as limestone (CaCO3). However, much of the theory of limestone The decomposition of magnesite occurs between 402 and 750C (Shand, 2006). The reaction proceeds rapidly above 550°C (Seeger, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The reaction proceeds rapidly above 550°C (Seeger, 2005). The differences are probably due to the different sources of magnesite with its impurity level, crystallographic structure, and microstructure that effect to its calcination properties (Shand, 2006).…”

Section: Introductionmentioning

confidence: 99%

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The Characteristics of Padamarang Magnesite under Calcination and Hydrothermal Treatment

Yuniati

Wawuru²,

Mursito³

et al. 2019

Ris.Geo.Tam

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Magnesite (MgCO3) is the main source for production of magnesium and its compound. In Indonesia, magnesite is quite rare and can be only found in limited amount in Padamarang Island, Southeast Sulawesi Provence. Thus the properties of magnesite and the reactivity degree of the obtained product are of technological importance. The aim of this work was to analyze the characteristics of Padamarang magnesite under calcination and hydrothermal treatment processes. The processes were carried out at various temperatures with range of 150-900°C for 30 minutes. The solids were characterized with respect to their chemical and physical properties by using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). SEM image indicates that magnesite was formed from thin and flat hexagon sheets. The FTIR and XRD analysis disclose that MgO formed at temperature above 300°C, where as the magnesite sample also lost its mass around 50%. These results demonstrate that Padamarang magnesite decomposes to magnesium oxide and carbon dioxide at high temperature.Magnesit (MgCO3) merupakan sumber utama untuk produksi magnesium dan senyawa-senyawanya. Di Indonesia, magnesit cukup jarang dan hanya dapat ditemukan dalam jumlah yang terbatas di Pulau Padamarang, Propinsi Sulawesi Tenggara. Oleh karena itu sifat magnesit dan derajat reaktivitas dari produk-produk magnesit penting untuk diketahui. Penelitian ini bertujuan untuk menganalisis karakteristik magnesit Padamarang dengan perlakuan kalsinasi dan hidrothermal. Proses dilakukan pada temperatur yang bervariasi dari 150-900°C selama 30 menit. Sifat kimia dan fisika dari magnesit dikarakterisasi dengan menggunakan scanning electron microscopy dengan energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), dan X-ray diffraction (XRD). Gambar dari analisis SEM menunjukkan bahwa magnesit terbentuk dari lembaran-lembaran heksagonal yang tipis dan datar. Hasil analisis dengan FTIR dan XRD menunjukkan bahwa MgO terbentuk pada temperatur diatas 300°C, dimana sampel magnesit juga kehilangan massanya sekitar 50% pada suhu tersebut. Hal ini menunjukkan bahwa Magnesit Padamarang terdekomposisi menjadi magnesium oksida dan karbon dioksida pada temperatur tinggi.

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“…These include hydromagnesite [4MgCO3.Mg(OH)2.4H2O] and artinite [MgCO3. Mg(OH)2.3H2O] (Shand, 2006).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Characteristics of Padamarang Magnesite under Calcination and Hydrothermal Treatment

Yuniati

Wawuru²,

Mursito³

et al. 2019

Ris.Geo.Tam

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A diagenetic study of the Woodford Shale in the southeastern Anadarko Basin, Oklahoma, USA: Evidence for hydrothermal alteration in mineralized fractures

Roberts¹,

Elmore

2018

Interpretation

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The objective of this study is to test if external fluids (e.g., hydrothermal) altered the Woodford Shale in the southeast Anadarko Basin and how the diagenesis caused by such fluids, particularly in mineralized fractures, has affected the reservoir quality and mechanical behavior of the Woodford Shale. Two Woodford Shale cores from the Anadarko Basin were sampled to identify diagenetic events, interpret their origin, and determine the diagenetic history of the shale. Thin sections for both cores were analyzed using reflected and transmitted light, cathodoluminescence (CL), and scanning electron microscopy to identify minerals and cross-cutting and textural relationships. X-ray computed tomography was conducted to further characterize fracture networks seen on the petrographic scale. Early diagenesis is dominated by events in the matrix and allochems, with later diagenesis dominated by events associated within fracturing and brecciation. The mineralized fractures and brecciated intervals contain complex mineralogies. Multiple minerals, interpreted to be hydrothermal in origin, are present, including magnesite, norsethite, witherite, gorceixite, potassium feldspar, sphalerite, chalcopyrite, and saddle dolomite. CL in minerals within fractures reveals evidence of evolving fluids and multiple fluid-flow events. Although porosity is present within pyrite framboids, between clay sheets, and as dissolution vugs within fractures and allochems, fracture porosity was destroyed by mineralization that filled the fractures and permeated into the matrix. Vitrinite reflectance data from both cores indicate a correlation between thermal maturity and level of hydrothermal alteration, with core A (0.80% [Formula: see text] [approximately 125°C]) displaying a lower amount of alteration and core C (approximately 1.5% [Formula: see text] [approximately 210°C]) displaying a higher amount of alteration. The extensive faulting present in the southeastern Anadarko Basin likely facilitated the movement of the hydrothermal fluids through the unit. The presence of hydrothermal minerals not only has implications for the thermal maturity and reservoir quality of the Woodford Shale, but it also contributes to the discussion of whether or not shales behave as open or closed systems.

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Recent Advances in Magnesia Blended Cement Studies for Geotechnical Well Construction—A Review

et al. 2021

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The current paper presents a literature review on the studies of incorporation of magnesia (magnesium oxide) into Portland cement material from the geotechnical well construction perspective. Starting with a comparison of application conditions between civil construction and geotechnical well cementing, this work reviewed the Portland cement categorizations, magnesia manufacturing routes at first. Then, the physical-chemical-mechanical properties were investigated which includes the reactivity of magnesia, expansion influence from its hydration, and carbonation/dehydroxylation of magnesia blended Portland cement. The development of cement material hydration modeling methods is also summarized. Moreover, the experimental characterization methods have also been elucidated including composition determination, particle size analysis, volumetric variation measurement, compressive strength testing, shear-bond strength testing, transition state analysis, etc. Meanwhile, the results and conclusions were extracted from the literature. Through this route, a comprehensive understanding of the scientific research progress on magnesia blended Portland cement development for geotechnical well construction is derived. Additionally, it is concluded that incorporating magnesia into Portland cement can provide benefits for this material utilization in geotechnical well constructions provided the reasonable tuning among the characteristics of magnesia, the downhole surrounding conditions, and the formulation of the cement slurry. Satisfying these pre-conditions, the effective expansion not only mitigates the micro-annulus issues but also increases the shear bonding strength at the cementing interfaces. Moreover, the caustic magnesia introduction into Portland cement has the potential advantage on carbon dioxide geological sequestration well integrity compared with the Portland cement sheath without it because of the denser in-situ porous matrix evolvement and more stable carbon fixation features of magnesium carbonate. However, since the impact of magnesia on Portland cement strongly depended on its properties (calcination conditions, particle size, reactivity) and the aging conditions (downhole temperature, pressure, contacting medium), it should be noted that some extended research is worth conducting in the future such as the synchronized hydration between magnesia and Portland cement, the dosage limit of caustic magnesia in Portland cement in terms of CO2 sequestration and the corresponding mechanical properties analysis, and the hybrid method (caustic magnesia, Portland cement, and other supplementary cementitious materials) targeting the co-existence of the geothermal environment and the corrosive medium scenario.

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Formation and Occurrence of Magnesite and Brucite

Cited by 4 publications

References 0 publications

The Characteristics of Padamarang Magnesite under Calcination and Hydrothermal Treatment

The Characteristics of Padamarang Magnesite under Calcination and Hydrothermal Treatment

A diagenetic study of the Woodford Shale in the southeastern Anadarko Basin, Oklahoma, USA: Evidence for hydrothermal alteration in mineralized fractures

Recent Advances in Magnesia Blended Cement Studies for Geotechnical Well Construction—A Review

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