Solubility of Barium Sulfate in Water at Elevated Temperatures and Pressures

[Image: see text] There are few measurements of barium sulfate (BaSO(4)) solubility in water above 373 K available in the literature. BaSO(4) solubility data at water saturation pressure are scare. The pressure dependence on BaSO(4) solubility has not previously been comprehensively reported for the pressure range 100–350 bar. In this work, an experimental apparatus was designed and built to measure BaSO(4) solubility in aqueous solutions under high-pressure (HP), high-temperature (HT) conditions. The solubility of BaSO(4) was experimentally determined in pure water over the temperature range from T = (323.1 to 440.1) K and pressures ranging from p = (1 to 350) bar. Most of the measurements were done at water saturation pressure: six data points were done above the saturation pressure (323.1–373.1 K) and 10 experiments were conducted at water saturation (373.1–440.1 K). The reliability of the extended UNIQUAC model and results generated in this work was demonstrated by comparing with the scrutinized experimental data reported in the literature. The model gives a very good agreement with BaSO(4) equilibrium solubility data, demonstrating the reliability of the extended UNIQUAC model. The accuracy of the model at high temperature and saturated pressure due to data insufficiencies is discussed.