Crystallization of calcium oxalate（CaOxa） was investigated in the presence of magnesium tartrate（Mgtart） with different concentrations in gel system by a double diffusion technique.The phase composition and morphology of the crystals were determined by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.In the presence of Mgtart with a low concentration（0.02 mol/L）,calcium oxalate monohydrate（COM） is the dominant crystal phase.The mass fraction of calcium oxalate dihydrate（COD） was about 12% and no calcium oxalate trihydrate（COT） was observed.When the concentration of Mgtart increased to 0.06 mol/L,the mass fraction of COT was increased to 33%,and that of COM decreased to 55%,but the mass fraction of COD changed less in the studied concentration range.The inhibitive capacity of Mgtart was stronger than that of either MgCl2,or H2tart,or a mixture of MgCl2 and H2tart.This indicates that not only Mgtart may be used to cure and prevent CaOxa stones,but also may had a stronger capacity than MgCl2 or H2tart or a mixture of MgCl2 and H2tart.
