QUARTZ-CRYSTAL MICROBALANCE INVESTIGATION OF ELECTROCHEMICAL CALCIUM-CARBONATE SCALING

Electrochemical calcareous scaling was investigated by using a quartz microbalance in order to devise an accelerated scaling test. The chron oamperometric and the chronoelectrogravimetric curves were simultaneou sly recorded during scaling in carbonically pure waters. The basic pro cesses involved in scale gravimetric evaluation were surveyed: influen ce of mass transport on O-2 reduction, influence of electrode vibratio n, and calibration of the mass measurement; Then the validation of the quartz crystal microbalance (QCM) technique was carried out by changi ng some experimental conditions: flow rate, calcium concentration, and polarization potential. At the end foreign ions, commonly encountered in natural waters, were added to the synthetic waters. The scaling ra te was determined by deriving the chronoelectrogravimetric curve. It w as demonstrated that the QCM technique gives much more information on the scaling process than chronoamperometry and can be used as a practi cal scaling test.