TY  - GEN
CY  - London, UK
A1  - Yue, Y
A1  - Zhou, Q
A1  - Bai, Y
A1  - Li, L
A1  - Song, J
A1  - You, C
A1  - Qian, J
A1  - McCague, C
A1  - Jin, F
A1  - Al-Tabbaa, A
A1  - Mo, L
A1  - Deng, M
T3  - Cement and Concrete Science Conference
N2  - Disposal of Caesium (Cs) by incorporating it into host matrices has been proved as a promising concept.
Even though Portland cement (PC) based systems can be used to encapsulate low (LLW) or intermediate
level waste (ILW), they are not efficient for immobilising Cs due to the very high water-solubility of Cs.
Magnesium phosphate cement (MPC), a chemically bonded ceramic consists of struvite families produced by
the acid based reactions between dead-burnt magnesium oxide (MgO) and phosphates (e.g., KH2PO4), can
be a potential candidate for hosting Cs, since it has been reported that Cs can be incorporated in the Kstruvite
structures by substituting potassium (K) to form (K,Cs)-struvite. However, the acid-based reaction to
form MPC under ambient temperature between magnesium oxide (MgO) and phosphates (e.g., KH2PO4) is
violent and exothermic, which raises concerns about industrial application of MPC in real world. In this work,
ground-granulated blast-furnace slag (GGBS) and pulverised fuel ash were used to replace MPC in order to
reduce the heat released. The feasibility of MPC, as well as MPC-based blends, i.e. GGBS-MPC or PFAMPC
matrices, for immobilising Cs was assessed by their leaching behaviour at the ages of 3d, 7d and 28d.
In addition, two typical PC based systems currently used in nuclear waste immobilisation, i.e., pure PC and
PC-GGBS (1:9) mixes, were also produced and tested as controls. The results indicated that all the MPC
mixes, including pure MPC, GGBS-MPC and PFA-MPC, demonstrated superb capability for immobilising Cs,
with the immobilisation rates achieved more than 99.5% at all curing age investigated. Compared to the
traditional PC and PC/GGBS mixes, the MPC mixes nearly doubled the Cs immobilisation rate, which is
rather encouraging.
ID  - discovery1523325
UR  - http://www.iom3.org/cementitious-materials-group/
PB  - The Institute of Materials, Minerals and Mining
N1  - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions.
TI  - Immobilisation of caesium in magnesium phosphate-based blends
Y1  - 2016/09/05/
AV  - public
ER  -