The Use of Dolomite to Produce a Magnesium Potassium Phosphate Matrix for Radioactive Waste Conditioning

Abstract

Magnesium potassium phosphate (MPP) matrix MgKPO4 × 6H2O is a known material for radioactive waste (RW) conditioning; magnesium oxide MgO is used in the classical method of matrix synthesis. The aim of the work was to investigate the possibility of using the widely available natural mineral raw material dolomite, incorporating mixed magnesium and calcium carbonate, for the production of this matrix. To control the quality of the samples obtained, their phase and elemental compositions, microstructure, density, volumetric and apparent porosity, compressive strength, and hydrolytic stability were studied. As a result, it was found that using dolomite powder pre-calcined at 720 °C for 1.5 h, samples of matrix whose properties meet the regulatory requirements for solidified RW were obtained. Thus, a new, cost-effective method of synthesis of the MPP matrix has been demonstrated to solve the RW solidification problem.

Keywords

• magnesium potassium phosphate matrix
• radioactive waste
• dolomite
• compressive strength
• hydrolytic stability
• particle size distribution