Gibbs energy approach for aqueous processes with HF, HNO3, and CO2 ? CaCO3
Chemical thermodynamic calculations were used to represent vapor–liquid equilibria and chemical equilibria for aqueous systems with HF, HNO3, and CO2H2OCaCO3 solutions. The entropy production related to the dissolution reaction of calcite was calculated using multiphase thermodynamics and experiments carried out in this work. Modern simulation methods combined with experiments provide a useful tool for the research and design of new processes as well as evaluating changes in the operational conditions of chemical processes. These methods are used to study metallurgical, pulp, and paper industrial processes that involve the presented aqueous solutions. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1942–1947, 2004
Simulation of Industrial Processes Involving Concentrated Aqueous Solutions
AbstractThe Pitzer model is applied to simulate various single- and multistage modifications of the industrial conversion process 
$${\text{NaSO}}_{\text{4}}+2\;{\text{KCl}} \to {\text{K}}_{\text{2}} {\text{SO}}_{\text{4}}+ 2{\text{NaCl}}$$
 by repetitive thermochemical equilibrium calculations. In this work, good agreement between simulated values and operating data was found because the Pitzer model accurately predicts the solubility of the various salts involved in different stages of the process operating from 0 to 120°C.
Activities of water and HCl in Aqueous solution systems of HClMCln including CuCl2, NiCl2 and FeCl3
Abstract Activities of HCl in the HClCuCl2, HClNiCl2 and HClFeCl3 aqueous solution systems, which cannot be determined by the e.m.f. method, were calculated at 298 K by applying the McKay-Perring method based on the measured water activities. The water activities of these solutions and those of HClNaCl solutions were determined by a transpiration method, and the b values involved in the corrected Zdanovskii equation were evaluated as a function of water activity. The calculated values of a(HCl) of the aqueous solution system of HClNaCl agreed well with those determined by the e.m.f. method at both dilute and concentrated HCl levels. The activities of HCl in the solution systems being studied were then calculated. The change in a(HCl) with an increase in the chloride concentration is attributable to the change in ionic strength of the solution, and thus the concentration of the chemical species present in the solution.