Thermal stability of the ‘cave’ mineral brushite CaHPO4•2H2O -mechanism of formation and decomposition
Thermogravimetry combined with evolved gas mass spectrometry has been used to ascertain the stability of the ‘cave’ mineral brushite. X-ray diffraction shows that brushite from the Jenolan Caves is very pure. Thermogravimetric analysis coupled with ion current mass spectrometry shows a mass loss at 111°C due to loss of water of hydration. A further decomposition step occurs at 190°C with the conversion of hydrogen phosphate to a mixture of calcium ortho-phosphate and calcium pyrophosphate. TG-DTG shows the mineral is not stable above 111°C. A mechanism for the formation of brushite on calcite surfaces is proposed, and this mechanism has relevance to the formation of brushite in urinary tracts.
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|Item Type:||Journal Article|
|Additional Information:||This is the work of student Sara Palmer|
|Keywords:||thermogravimetry, urinary calculi, brushite, phosphate, kidney stones|
|Subjects:||Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Structural Chemistry and Spectroscopy (030606)|
|Divisions:||Past > Schools > Chemistry
Past > QUT Faculties & Divisions > Faculty of Science and Technology
|Copyright Owner:||Copyright 2011 Elsevier|
|Copyright Statement:||This is the author’s version of a work that was accepted for publication in Thermochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Thermochimica Acta, [VOL 521, ISSUE 1-2, (2011)] DOI: 10.1016/j.tca.2011.03.035|
|Deposited On:||27 Jun 2011 23:28|
|Last Modified:||06 May 2014 23:35|
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