Brine

About: Brine is a research topic. Over the lifetime, 6542 publications have been published within this topic receiving 76741 citations.

Hydrothermal alteration of graywacke by brine and seawater; roles of alteration and chloride complexing on metal solubilization at 200 degrees and 350 degrees C

Abstract: Graywacke was reacted with seawater and with a saturated NaCl brine containing Ca, Mg, and K, using a solid/liquid ratio of 1/10. The degree of reaction was minimal at 200 degrees C but significant at 350 degrees C. In both fluids anorthite, dolomite, and some illite and quartz, amounting to about 25 percent of the graywacke, were converted to smectite-chlorite and albite. Both fluids lost all their Mg and gained K, Ca, and CO 2 . Only the brine gained and maintained significant concentrations of heavy metals, indicating the importance of chloride complexing. Chloride concentration in seawater is apparently insufficient for extensive complexing under the experimental conditions.Chloride complexing, however, serves only to maintain metals in solution and prevents their reprecipitation as alteration products. Alteration involving production and consumption of hydrogen ions is required for the release of metals from the source matrix. In the experiments Mg metasomatism and dedolomitization provided the H (super +) for the process. Metal solubilization by the brine followed the order of abundance in the graywacke: Zn > Ni > Cu > Pb > Sb > Cd, suggesting a common matrix and no selective leaching effect. In other words, as a given increment of rock was altered, all of its component metals were released. Metal concentration in solution therefore was not limited by sulfide solubility and represents minimum values.Changes in the bulk composition of the graywacke were minimal, except for increases in Mg content, and the final rock would probably not be recognized as an altered source rock in the field.The fluids generated during the experiments would likely subject wall rock at the site of ore deposition to hydrolytic alteration, including potassium metasomatism.

Phase diagrams and thermochemical modeling of salt lake brine systems. II. NaCl+H2O, KCl+H2O, MgCl2+H2O and CaCl2+H2O systems

Abstract: This study is part of a series of studies on the development of a multi-temperature thermodynamically consistent model for salt lake brine systems. Under the comprehensive thermodynamic framework proposed in our previous study, the thermodynamic properties of the binary systems (i.e., NaCl+H2O, KCl+H2O, MgCl2+H2O and CaCl2+H2O) are simulated by the Pitzer–Simonson–Clegg (PSC) model. Various thermodynamic properties (i.e., water activity, osmotic coefficient, mean ionic activity coefficient, enthalpy of dilution and solution, relative apparent molar enthalpy, heat capacity of aqueous phase and solid phases) are collected and fitted to the model equations. The thermodynamic properties of these systems are reproduced or predicted by the obtained model parameters. Comparison to the experimental or model values in the literature suggests that the model parameters determined in this study can describe all of the thermodynamic and phase equilibria properties over wide temperature and concentration ranges. This modeling study of binary systems provides a solid basis for property predictions of salt lake brines under complicated conditions.