Use of NaHPO and (NaPO) as a phosphate source for development of magnesium phosphate cements

Garca-Lodeiro, I.*; Kai Wuen, O.*; 入澤 啓太; 中澤 修; 木下 肇*

no journal, , 

Magnesium phosphate cements (MPCs) is an important engineering material that have been extensively used as fast setting repair cements in civil engineering. MPCs are formed through an exothermic acid-base reaction between MgO and a soluble phosphate source (commonly NHHPO or KHPO) forming a crystalline magnesium phosphate salt (struvite or K-struvite respectively). The present study investigates the effect of using different sodium phosphate sources (NaHPO and/or (NaPO)) and reduction of water content can be highly beneficial for encapsulation of radioactive wastes, since it would minimise the risk of hydrogen gas generation from the radiolysis of water by the radioactive waste components. Our preliminary investigation revealed that the use of these phosphates all resulted in the generation of amorphous products, and curing at 80C also led to a scueessful reduction of the water contents by 50% in all systems investigated. However, the type of phosphates used appears to have a significant impact on the stability of the products in water, and the mixed use of NaHPO and (NaPO) indicated the best outcome.