rehydroxylation [rhx]: some scientific comments and issues christopher hall
DESCRIPTION
Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall University of Edinburgh School of Engineering Centre for Materials Science & Engineering UoE/National Museums Scotland Research Laboratory for Conservation Science. Moisture dynamics in buildings and - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/1.jpg)
Rehydroxylation [RHX]:
Some scientific comments and issues
Christopher Hall
University of EdinburghSchool of Engineering
Centre for Materials Science & Engineering
UoE/National Museums Scotland Research Laboratory for Conservation Science
![Page 2: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/2.jpg)
Moisture dynamics in buildings andmasonry structures
Hall, Hamilton, Viles et al 2010
![Page 3: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/3.jpg)
Delta-Min Marie Curie Network
Mechanisms of Mineral Replacement Reactions 2009-2012
![Page 4: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/4.jpg)
![Page 5: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/5.jpg)
Penn floor tileSt Bride’s ChurchFleet StreetLondon UK
Museum of London WFG62
Assigned date AD 1350-1390
![Page 6: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/6.jpg)
Penn floor tileSt Bride’s ChurchFleet StreetLondon UK
Museum of London WFG62
Assigned date AD 1350-1390
![Page 7: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/7.jpg)
![Page 8: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/8.jpg)
![Page 9: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/9.jpg)
![Page 10: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/10.jpg)
![Page 11: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/11.jpg)
![Page 12: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/12.jpg)
![Page 13: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/13.jpg)
![Page 14: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/14.jpg)
![Page 15: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/15.jpg)
![Page 16: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/16.jpg)
![Page 17: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/17.jpg)
![Page 18: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/18.jpg)
Normalised stage 2 slope ln(α/α25) plotted against 103 /T K-1, where α25 is theinterpolated slope at 25 °C, for three fired clay brick and tile samples. Red: Romanopus spicatum clay paving brick, London; blue: ‘Westminster’ clay tile, MertonPriory; green: clay brick, King Charles II Court, Greenwich
Arrhenius plot: effect of temperature on rehydroxylation mass gain rate.
![Page 19: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/19.jpg)
![Page 20: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/20.jpg)
![Page 21: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/21.jpg)
Samian ware:X-ray diffraction
![Page 22: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/22.jpg)
![Page 23: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/23.jpg)
![Page 24: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/24.jpg)
Stackhouse, Coveney et al.
![Page 25: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/25.jpg)
Stage I
Stage II
Variation of the fractional mass gain (Δm/mo) with the fourth root of time (time)1/4 of kaolin samples fired at different temperatures [Hesham Mesbah]
![Page 26: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/26.jpg)
Open questions
Why (time)1/4?
![Page 27: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/27.jpg)
![Page 28: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/28.jpg)
A Putnis Rev Mineralogy Geochem 2009
Pseudomorphic replacement of calcite and aragonite byHydroxyapatite
Normal diffusion
(time)1/2
![Page 29: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/29.jpg)
![Page 30: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/30.jpg)
Lizana and Ambjörnsson Phys Rev Lett 2008 v100 20601
![Page 31: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/31.jpg)
Lizana and Ambjörnsson Phys Rev Lett 2008 v100 20601
![Page 32: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/32.jpg)
Open questions
Why (time)1/4?
… and, if single-file diffusion, on what structure?
![Page 33: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/33.jpg)
![Page 34: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/34.jpg)
Open questions
Why (time)1/4?
… and, if single-file diffusion, on what structure?
Why rehydroxylation when firing has proceeded to 1050 °C?
Does accurately describe the entire process on 1000 year time scales?
![Page 35: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/35.jpg)
Some conclusions
Incontrovertible evidence that the RHX process occurs more or less universally in all fired clay ceramics
Strong evidence that the (time)1/4 clock is valid
Data acquisition for a single sample is still laborious
Major validation studies needed
Mechanistic and materials fundamentals not fullyunderstood
![Page 36: Rehydroxylation [RHX]: Some scientific comments and issues Christopher Hall](https://reader034.vdocuments.mx/reader034/viewer/2022051623/56815854550346895dc5aee1/html5/thumbnails/36.jpg)
AcknowledgementsMoira Wilson, Margaret Carter, Ceren Ince, Bill Hoff, Hesham Mesbah (Manchester)
Andrea Hamilton (Edinburgh)