Title: Thermodynamic Analysis of Heavy Metal Removal from Technogenic Waters of the "Ko'ksuv" Basin Using Calcium Hydroxide
Authors: Khojiev Sh.T., Djabbarova B.I.
Volume: 9
Issue: 9
Pages: 245-250
Publication Date: 2025/09/28
Abstract:
This study investigates the treatment of technogenic waters accumulated in the "Ko'ksuv" reservoir, formed as a result of mining and metallurgical activities, with calcium hydroxide (Ca(OH)?) to remove heavy metal ions and improve water quality for potential industrial reuse. Thermodynamic and kinetic analyses of precipitation reactions involving sulfate, nitrate, chloride, and other metal salts were performed using Gibbs free energy (?G) and equilibrium constant (Ke) relationships over a wide temperature range (5-100 °C). The results revealed that the precipitation reactions are thermodynamically favorable, with high K? values at low to moderate temperatures (20-40 °C), confirming their exothermic nature. The study established that lime treatment is highly effective in removing heavy metals such as Fe²?, Cu²?, Zn²?, Pb²?, and Al³?, while additional purification steps (sorption or ion-exchange) are required for sodium, potassium, chloride, and nitrate ions. The scientific novelty lies in the identification of reaction-specific equilibrium parameters and the optimization of process conditions, while the practical significance is the potential to implement closed-loop water circulation systems in metallurgical plants, thereby reducing ecological risks and improving water resource efficiency.