论文信息 - Solubility of Litharge (a-PbO) in Alkaline Media at Elevated Temperatures

Solubility of Litharge (a-PbO) in Alkaline Media at Elevated Temperatures

An inert, flowing autoclave facility is used to investigate the solubility behavior of {alpha}-PbO (litharge, tetragonal) in aqueous solutions of morpholine, ammonia and sodium hydroxide between 38 and 260 C. Lead solubilities increased from about 0.4 mmol kg{sup -1} at 38 C to about 4.5 mmol kg{sup -1} at 260 C and were relatively insensitive to the concentration and identity of the pH-reagent. The measured lead solubilities were interpreted using a Pb(II) ion hydroxocomplexing model and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. A consistent set of thermodynamic properties for the species Pb(OH){sup +}, Pb(OH){sub 2}(aq) and Pb(OH){sub 3}{sup -} is provided to permit accurate lead oxide solubility calculations over broad ranges of temperature and alkalinity.

D. A. Palmer | L. Anovitz | P. Bénézeth | S. Ziemniak | D. Palmer

[1] R. Smith,et al. Solubility of Lead(II) Oxide and Copper(II) Oxide in Subcritical and Supercritical Water , 1999 .

[2] Yizhak Marcus,et al. A simple empirical model describing the thermodynamics of hydration of ions of widely varying charges, sizes, and shapes , 1994 .

[3] B. B. Benson,et al. The solubility and isotopic fractionation of gases in dilute aqueous solution. IIa. solubilities of the noble gases , 1989 .

[4] R. Mesmer,et al. Base strength of amines at high temperatures. Ionization of cyclohexylamine and morpholine , 1977 .

[5] R. Mesmer,et al. The ionization of aqueous ammonia to 300°C in KCl media , 1976 .

[6] C. Baes,et al. Acidity measurements at elevated temperatures. VII. Dissociation of water , 1974 .

[7] I. Barin. Thermochemical data of pure substances , 1989 .