Exploratory study high purity colbalt using an anion exchange resin

Author

Charles Edward Hoffman, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

6-30-1959

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering

First Advisor

C. L. Mantell

Second Advisor

Joseph Joffe

Third Advisor

Saul I. Kreps

Abstract

This investigation accounts for the exploratory phase of a program to develop a commercial or semi-commercial process for producing high purity cobalt; in effect, a separation of cobalt and nickel.

An extensive review of all published literature, patents, etc. from 1900 to 1958 of all known commercial, semi-commercial and analytical methods of separating cobalt and nickel was completed. Qualitative evaluation of these methods to determine the possibility of one being practically extended and/or developed to produce high purity cobalt yielded one potential commercial method. Developed for analytical purposes by Moore and Kraus (1), use is made of the fact that cobalt forms an anionic chloride complex in 9N H Cl which can be adsorbed with a strong anion exchange resin, while nickel does not form the requisite complex but passes through as though a cation. One other commercially valuable fact is that removal of the cobalt is accomplished by eluting simply with water or weak hydrochloric acid.

The experimental phase of the investigation was designed to demonstrate whether chemical reaction/complex formation was the controlling mechanism for the system of cobalt chloride in 9N hydrochloric acid with a strong anion exchange resin; this mechanism is suggested by Herber and Irvine (2) from their equilibrium studies. If disproven, the kinetics of the exchange was to be extended to establish the boundaries for film diffusion, particle diffusion, and/or both. This type of information would then be available for planning the future phase of the program, column characteristics of the system.

The results of the kinetic study show that the system-cobalt chloride in 9N H Cl with a strong anion exchange resin (Amberlites used in this study) - is not chemical reaction/complex formation controlling, but is particle diffusion controlling over the entire range of the variables studied. Initial cobalt chloride concentrations of 0.00091N to 0.0716N, mesh sizes of -16 20, -20 30, -30, 40, -100 200, and -200 325, and mixing speeds of 200 to 1350 RPM were used in the study.

The particle diffusional equation of Boyd et al (3),

F=1-6/π² Σ∞ n-1 -eⁿ²Bt/n²

where F=Fractional exchanged

B : Variable constant = π²Dⁱ/r²

has been shown to define the kinetics of the system. Experimental results satisfy the criteria that the fractional exchange rate (T, and therefore B) is independent of initial cobalt chloride concentration and inversely proportional to the square of the particle radius. Furthermore, knowledge that B is equal to 0.02 for a radius Cr) of x..,51 mm, permits the prediction of the fractional exchange rate for the entire concentration,-particle size range.

Recommended Citation

Hoffman, Charles Edward, "Exploratory study high purity colbalt using an anion exchange resin" (1959). Theses. 3253.
https://digitalcommons.njit.edu/theses/3253