The effect of sulphate and phosphate ions on calcium carbonate precipitation on copper substrate

Algeria following the example of other countries, grapples with water-related issues. It has very limited resources of water, in addition to facing challenging conditions that are characteristic of the region. The waters in southern Algeria are highly mineralized, and their hardness levels exceeding 100°F, leading to the rapid and harmful deposition of scale, which adheres to industrial and domestic equipment [1]. The literature’s data are contradictory concerning the activity of sulphate anions. The present work investigates the action of this ion to provide a significant approach to understanding the kinetic precipitation of scale. All experiments were carried electrochemically in pure calco-carbonic water at a hardness level of 30°F charged with potassium sulphate. A delayed effect of this ion on the formation kinetics of scale is investigated, employing chronoamperometry and electrochemical impedance spectroscopy. Furthermore, the efficacy of two chemical scale inhibitors based on phosphates (Sodium Hexametaphosphate and Medphos) on sulphate charged water is explored. It was, in this fact, might shown a synergy between the effect of sulphate and the composition of inhibitors used, which is traduced by pronounced inhibition of scaling phenomenon. Moreover, the inhibitor Medphos remains stable at high temperatures (60 °C) favouring its use in cooler circuits.