Study On The Structure And Property Of Barium Iron Phosphate Glass-ceramic Wasteforms

The iron glass phosphate wasteforms has been widely recognized and studied due to its low melting temperature,good thermodynamic properties and stable chemical properties.Barium iron phosphate glass has been proven to have good property for high level waste.Glass-ceramic wasteforms contain the advantages of both glass wasteforms and ceramic wasteforms,and it's a new generation of wasteforms with a promising future.In this paper,iron phosphate?40Fe₂O₃-60P₂O₅?is chosen as base glass,1.Different content of CeO₂ is added to the base glass,and preparing cerium iron phosphate glass-ceramic by slow cooling;2.5 mol%BaO is added to the base glass with different content of CeO₂,and preparing barium cerium iron phosphate glass-ceramic by slow cooling;3.Preparation of iron phosphate and barium iron phosphate glass-ceramic wasteforms by sintering different grain size glass raw materials,next the structure and morphology of the samples were characterized by modern analytical methods such as XRD,SEM-EDS,FTIR and Raman,at the same time,DSC and PCT were used to study the thermal stability and chemical stability of the samples.The main conclusions were summarized as follows:?1?Cerium iron phosphate glass-ceramic dopped CeO₂:When Ce content up to 2 mol%,CePO₄ and FePO₄ separate out.The crystalline increase with the Ce content in both glass-ceramic and contain more Q⁰ units,the glass phase has good thermal stability.When CeO₂ content up to 8 mol%,the leaching rates of samples is low,the leaching rate could reach 10^-5g·m^-2·d^-1 order of magnitude.?2?Glass-ceramic doped with 5 mol%BaO:Ba promote the separate FePO₄ out,and when Ce content up to 4 mol%,CePO₄ separate.The main unit is Q⁰,the results of DTA show the glass phase has good thermal stability,the chemical durability is high,the leaching rate of Ce and Fe ion could reach10^-5 g·m^-2·d^-1 order of magnitude,the leaching rate of Ba ion is higher,could reach 10^-4 g·m^-2·d^-1 order of magnitude.?3?Glass-ceramic wasteforms prepared by sintering with different meshes:The crystals in both samples are FePO₄ and Fe₄?P₂O₇?₃.The result of XRD shows BaO induced the separate out of FePO₄.SEM and density results indicate the structure of the samples with BaO is more compact.FTIR shows samples with Ba O contain more Q⁰ units and samples without BaO contain more Q¹ units.The chemical stability of the samples is good,and BaO has little effect of the mass loss rate and leaching rate.The mass loss rate reach 10^-8 g·cm^-2·min^-1 order of magnitude,leaching rate of Fe could reach 10^-5 g·cm^-2·min^-1 order of magnitude and leaching rate of Ba reach 10^-4 g·cm^-2·min^-1 order of magnitude.