Conductivity Measurements of Dilute Aqueous LiOH, NaOH, and KOH Solutions to High Temperatures and Pressures Using a Flow-Through Cell

Abstract

The limiting molar conductance (Λ0) and molal ion association constant (K A(m)) of dilute (10-5 to 10-3 mol kg-1) aqueous LiOH, NaOH, and KOH solutions were determined by a flow-through conductance cell from 50 to 410 °C and pressures up to 33 MPa. The flow-through cell is designed to measure molar conductances of dilute aqueous electrolytes with a high degree of accuracy at high temperatures and pressures. The results are complementary to our previously reported results measured with a static high-pressure cell, which was incapable of yielding reliable measurements at concentrations < 0.001 mol·kg-1 and densities < 0.4 g·cm-3. The new Λ0 values of all three hydroxides at densities (ρ) ≥ 0.5 g·cm-3 are in good agreement with those measured using the static cell. However, at densities below 0.5 g·cm-3 the new results are slightly higher and less scattered than the previous results at comparable conditions. On the other hand, the K A(m) values of all three hydroxides are in excellent agreement with the static cell results under analogous conditions.

Experimental study of the stability of aluminate-borate complexes in hydrothermal solutions 1 1Associate editor: L. G. Benning

“…Speciation calculations were performed with the help of GIBBS computer code within the framework of the HCh software package Shvarov and Bastrakov, 1999). The pH values computed using dissociation constants listed in Table 1 always agree within Ϯ0.01 unit with those calculated using H 2 O dissociation constant determined potentiometrically by Sweeton et al (1974), and NaCl and NaOH dissociation constants determined via electrical conductivity measurements by Ho et al (1994) and Ho et al (2000), respectively. Dissociation constant of NH 3 used in calculations (Table 1) lies between values determined by Hitch and Mesmer (1976) and Read (1982) via potentiometric and conductivity measurements, respectively.…”

Experimental determination of the stabilities of Au2S(cr) at 25°C and at 25–250°C

“…Speciation calculations were performed with the help of GIBBS computer code within the framework of the HCh software package (Shvarov, 1999;Shvarov and Bastrakov, 1999). H 2 O and NaOH dissociation constants were taken from Marshall and Frank (1981) and Ho et al (2000), respectively. For NaHS the dissociation constant of NaCl determined by Ho et al (1994) was used.…”

A New Pitzer Parameterization for the Binary NaOH–H2O and Ternary NaOH–NaCl–H2O and NaOH–LiOH–H2O Systems up to NaOH Solid Salt Saturation, from 273.15 to 523.15 K and at Saturated Vapor Pressure

“…Na þ =OH À (a 1 = 2) and C / Na þ =OH À Several other studies [43][44][45][46][47][48][49][50] consider the neutral species NaOH 0 (aq). In particular, Sharma and Kashyap [50] have experimentally identified this ion pair in concentrated aqueous solutions of sodium hydroxide, using a Raman spectrometer.…”