Behavior of sodium nitrate and caliche mineral in seawater: Solubility and physicochemical properties at different temperatures and concentrations

Nowadays, the recovery of sodium nitrate through leaching caliche minerals with seawater is an industrial alternative due to scarce water resources, especially in desert areas. With a view to industrial applications, we determined the density, refraction index, ionic conductivity and viscosity of unsaturated solutions of the sodium nitrate + seawater system (seawater: 3.5% salinity) at six temperatures (298.15 to 323.15) K for different molalities in the range of (1 to 11) m. Data from saturation concentrations of the system at the same temperatures were determined. Property data were compared to the sodium nitrate + freshwater system. The experimental data on density, viscosity, and refraction index were correlated using the Othmer rule. The conductivity data were analyzed with the Casteel–Amis equation. Solubility, density, refraction index, ionic conductivity and viscosity of caliche mineral + seawater and caliche mineral + freshwater were measured at the same temperatures. The properties of caliche measured in the seawater system are greater than those in the pure water system, with an average difference of 1.30% with respect to seawater for density values, 0.23% for refraction index values, 2.42% for ionic conductivity values and 4.25% for viscosity values.

► We study the caliche and sodium nitrate in seawater.
► We measured different properties of both systems at different temperatures.
► The solubility and density values in freshwater system are higher than in seawater.
► All properties were correlated adequately using Othmer and Casteel–Amis equation.
► Using seawater in nitrate treatment systems of mining operations is recommended.