Title: INHIBITION OF APATITE DISSOLUTION DUE TO FORMATION OF CALCIUM OXALATE COATING
Abstract: The amount of apatite dissolution increased with decreasing final pH when two apatite samples (0.2-0.04mm) were treated with 10mmol L-1 of citric acid or 4-0mmol L-1 HCl. However, when they were treated with 10mmol L-1 of oxalic acid, the amount of dissolution was much smaller than the treatment with the same concentration of citric acid at around pH 4. According to the X-ray diffraction (XRD), scanning electron microscope (SEM) observation and energy dispersive X-ray analysis (EDX) of the oxalic acid-treated apatite, a coating of calcium oxalate was formed on the surface of the apatite particles which inhibited the dissolution of apatite under the experimental conditions.