Thermal decomposition of hydromagnesite 4MgCO3 - Mg(OH)2 - 4H2O under different partial pressures of carbon dioxide

Sawada, Yutaka; Uematsu, Keizo; Mizutani, Nobuyasu; Kato, Masanori

doi:10.1016/0040-6031(78)85020-5

Cited by 53 publications

(46 citation statements)

References 11 publications

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“…Decomposition of hydromagnesite begins to occur at about 220°C and progresses through two major mass losses ( Figure 3). These mass losses have been reported [24,33,[35][36][37][38][39]44] The decomposition of the resultant magnesium carbonate to magnesium oxide has been shown to follow different mechanisms depending on the partial pressure of carbon dioxide in the atmosphere [33,36,37]. The presence of carbon dioxide causes the magnesium carbonate to crystallise [39] exothermically instead of directly decomposing.…”

Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 98%

“…Crystalline magnesium carbonate decomposes at a higher temperature than the form of magnesium carbonate left directly after liberation of water from the crystal. The crystallisation of magnesium carbonate has also been linked to the rate of heating [31,36]. Rates of heating of greater than 18.5°C min -1 were reported by Khan [31] to cause exothermic crystallisation of the magnesium carbonate.…”

Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 99%

“…It is stated that "since hydromagnesite has a release temperature of 320 -350°C, we used Mg(OH) 2 as the hydroxide control sample". It has been shown by many authors [24,25,29,33,[35][36][37][38][39]62] that hydromagnesite decomposes over a range of about 220 -550°C. Morgan also states that in his electron micrographs the hydromagnesite particles "can be clearly seen amongst the larger huntite particles".…”

Section: Heat Release Studies By Cone Calorimetrymentioning

confidence: 99%

“…It has been shown [30,31,33,[35][36][37][38][39]] that a high partial pressure of carbon dioxide or a high heating rate can cause some of the magnesium carbonate formed during the decomposition of hydromagnesite to crystallise rather than immediately decompose giving off carbon dioxide. Crystalline magnesium carbonate decomposes at a higher temperature than the non-crystalline form, causing the complete decomposition of hydromagnesite to be delayed to a higher temperature.…”

Section: Decomposition Of Hydromagnesite and Huntite When Incorporatementioning

confidence: 99%

“…There has been much work published regarding the structure [18][19][20][21][22][23] and thermal decomposition [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] of hydromagnesite and huntite. A recent article [40], by the current authors, reviews this body of work in detail.…”

Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 99%

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The fire retardant behaviour of huntite and hydromagnesite – A review

Hollingbery

Hull

2010

Polymer Degradation and Stability

137

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Naturally occurring mixtures of hydromagnesite and huntite have found important industrial use. Their endothermic decomposition over a temperature range similar to that of commonly used polymers and their release of water and carbon dioxide, has led to such mixtures being successfully used as fire retardants. They have replaced aluminium hydroxide and magnesium hydroxide in many applications. The current understanding of the thermal decomposition mechanism of both minerals and their combination in natural mixtures has been reviewed and related to their fire retardant action. Both minerals contribute to the reduction in flammability of polymers although the extent of these interactions has not been fully investigated. However, the fire retardant mechanism of these minerals appears more complicated than either aluminium hydroxide or magnesium hydroxide. This paper critically examines the literature on the fire retardant behaviour of mixtures of hydromagnesite and huntite, providing information of particular use to formulators of fire retardant polymers using these minerals. It also highlights the gaps in understanding of the fire retardant mechanisms of mixtures of hydromagnesite and huntite and areas that require further research.

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Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 98%

Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 99%

Section: Heat Release Studies By Cone Calorimetrymentioning

confidence: 99%

Section: Decomposition Of Hydromagnesite and Huntite When Incorporatementioning

confidence: 99%

Section: Hydromagnesite and Huntite As Fire Retardant Additivesmentioning

confidence: 99%

See 3 more Smart Citations

The fire retardant behaviour of huntite and hydromagnesite – A review

Hollingbery

Hull

2010

Polymer Degradation and Stability

137

View full text Add to dashboard Cite

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ChemInform Abstract: THERMAL DECOMPOSITION OF HYDROMAGNESITE 4MGCO3 . MG(OH)2 . 4H2O UNDER DIFFERENT PARTIAL PRESSURES OF CARBON DIOXIDE

Sawada¹,

Uematsu²,

Mizutani³

et al. 1979

Chemischer Informationsdienst

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Induced morphological changes on vicinal MgO (100) subjected to high-temperature annealing: step formation and surface stability

Syrlybekov

Arca

Verre

et al. 2015

Surf. Interface Anal.

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a Highly regular step and terrace structures have been produced on surfaces of single crystalline MgO, miscut from the low-index (001) plane, upon annealing in air. Here, the evolution of the surface morphology of such surfaces is investigated. We demonstrate that the periodicity of these structures can be widely tuned in the submicron range by controlling the annealing conditions. Surface faceting resulted from annealing in the temperature range 1100-1580°C. The surfaces were characterized by atomic force microscope, X-ray diffraction, transmission electron microscope, and X-ray photoelectron spectroscopy to assess the role of contamination, temperature, and miscut angle in the final morphology. The presence of Al contamination in the post-annealed samples was found to be essential for the formation of the step and terrace structure. The stability of the resultant structures when exposed to ambient conditions is discussed. The cause of the apparent destruction of the surface morphology upon long-term atmospheric exposure has been identified, and a method to recover the faceted morphology is proposed. Overall, the study further facilitates the growth of nanostructures on such faceted surfaces.

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Thermal decomposition of hydromagnesite 4MgCO3 - Mg(OH)2 - 4H2O under different partial pressures of carbon dioxide

Cited by 53 publications

References 11 publications

The fire retardant behaviour of huntite and hydromagnesite – A review

The fire retardant behaviour of huntite and hydromagnesite – A review

ChemInform Abstract: THERMAL DECOMPOSITION OF HYDROMAGNESITE 4MGCO3 . MG(OH)2 . 4H2O UNDER DIFFERENT PARTIAL PRESSURES OF CARBON DIOXIDE

Induced morphological changes on vicinal MgO (100) subjected to high-temperature annealing: step formation and surface stability

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