The performance of several barium sulfate dissolvers (polyaminoacetic acid compounds) was investigated. Macroscopic dissolution tests were performed in conjunction with surface analysis and computer theoretical studies on changes in the surface morphology. The objective of this study is to rationalize the dissolution behavior of barite dissolvers derived from the kinetics of macroscopic experiments with results of a microscopic level investigation. Dissolution of barium sulfate particles in a stirred system may be described by a surface-controlled, first-order kinetic reaction. SFM (Scanning Force Microscopy) investigations reveal that these dissolvers create similarly shaped trapezoidal pits as they remove barium from the surface of the scale by a layer-by-layer process. The dissolution behavior may be reconciled with the geometry of the active
(001) barium sulfate surface and the chemical structure of these dissolvers. Molecular modeling study results are consistent with the observed etch pit geometries.