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Determination of Ferric Ion Diffusion and Activity Coefficients from Chronopotentiometric Data.

Madsen BW
MISSING :23 pages
As part of a program to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, the Bureau of Mines conducted research to determine the diffusion coefficients for ferric ions in synthetic copper leach solutions. Determination of ferric ion diffusion coefficients in typical dump leach solutions is necessary for predicting leaching rates of copper from large-scale leaching operations and for optimizing concentrations of ferric iron in solutions to maximize leaching efficiency. Derivative chronopotentiometry, an electroanalytical technique, was used to determine ferric ion diffusion coefficients. The diffusion coefficient decreased dramatically with increasing concentration of iron in solution. An empirical model was used to relate the ferric ion diffusion coefficient to the total amount of sulfate in solution. Measuring the diffusion coefficient dependence on temperature yielded an activation energy of 5.5 Kcal/mole of ferric ion. Activity coefficients of ferric ions as a function of concentration were calculated from diffusion coefficient data.
Publication Date
Document Type
IH; Report of Investigations
Fiscal Year
Identifying No.
RI 8617
NIOSH Division
Source Name
Page last reviewed: November 19, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division