Geochemical evolution of Sb migration species in carbonate and thermal waters in relation to Sb hydrogenic mineralization

Based on the synthesis of hydrogeochemical materials on Sb occurrence in carbonate and thermal waters and thermodynamic simulations, genetic analysis was conducted of the transformations of probable Sb migration species (particularly oxygen-bearing and sulfide ones), and their transformations were calculated depending on the main parameters of hydrogeochemical systems ( , T , R/W, Eh, and pH). The oxygen 2HSbO 2 0 + 3H 2 S = Sb 2 S 3 + 4H 2 O (2SbO 2 − + 3HS − + 5H + = Sb 2 S 3 + 4H 2 O) and sulfide HSb 2 S 4 − + H + = Sb 2 S 3 cr + H 2 S (Sb 2 S 4 2− + 2H + = Sb 2 S 3 cr + H 2 S) models for the genesis of hydrogenic Sb 2 S 3 (cr) were simulated. Information on occurrences of carbonate and thermal waters in various regions worldwide was generalized, and the reasons were identified for the geochemical separation of As and Sb in carbonate and thermal waters. The causes and conditions of an increase in Sb concentrations in thermal waters were revealed, and Sb migration species in carbonate and thermal waters were identified for various parameters of hydrogeochemical systems. Variations in Sb speciation were demonstrated for hydrogeochemical systems depending on their boundary conditions ( , T , and R/W). Models were outlined responsible for the precipitation of Sb 2 S 3 (cr) from carbonate and thermal waters.