Ian Power* and Greg Dipple

Department of Earth, Ocean and Atmospheric Sciences The University of British Columbia, *ipower@eos.ubc.ca

Assessing the carbon sequestration potential of magnesium oxychloride cement boards

This study 1) documented the fate of fixed

CO2 within magnesium oxychloride (MOC) boards, 2) fingerprinted the source of CO2 to confirm its value as a greenhouse gas offset, 3) determined the passive rate of CO2 sequestration within boards under ambient factory conditions, and 4) determined the potential for accelerating carbonation of MOC board using elevated concentrations of CO2.

2Th Degrees75706560555045403530252015105

Cou

nts

15,000

10,000

5,000

0

Quantifying carbon sequestration

Mineral abundance data and carbon analyses of MgO powders and magnesium oxychloride boards were used to

quantify the amount of sequestered carbon dioxide

X-ray diffraction pattern of MOC board with quantitative analysis

Plates of magnesium carbonate (CO2 sink) associated with needles of magnesium oxychloride phase 5

Changes in microstructure

2 µm

Fingerprinting carbon sources

Stable carbon and oxygen isotopic data were used to confirm the sequestration of atmospheric CO2 within magnesium

oxychloride boards

0

5

10

15

20

-15 -10 -5 0 5

δ18 O

(per

mil)

δ13C (per mil)

Boards MgO

Atmospheric CO2

Bedrock CO2

Rate of carbon sequestration

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 5 10 15

Seco

ndar

y C

O2 m

ass

/ boa

rd a

rea

(kg/

m2 )

Age (years)

An estimated rate of carbon sequestration within magnesium oxychloride board is 1 kg CO2/m2 of board over 15 years

Carbonation experiment

300 µm

100% CO2

Storage of boards under 100% relative humidity and 100% CO2 accelerated rates of carbon sequestration by nearly 1000x