Masters Theses


"The influence which ZnS, CdS, Cu2S, PbS, and FeS has on the thermal decomposition rate of ZnSO4 was studied by measuring the SO2 gas evolved per unit of time for various ZnSO4-MeS mixtures at 600°C, and analyzing the solid phases by means of X-ray diffraction patterns.

The SO2 gas evolved upon heating the pellets was analyzed as a function of time by absorbing the gas in a solution of distilled water, H2O2, and NaOH, and measuring the time required for the SO2 to neutralize the NaOH. The gas absorption was found to be accurate and reproducible.

The thermal decomposition of ZnSO4 occurred through the formation of several basic sulfates (xZnO·yZnSO4). The basic sulfate formed at 600°C was identified as ZnO·2ZnSO4.

The admixtures markedly increased the decomposition rate of ZnSO4. The rate of reaction for mole:mole mixtures of ZnSO4 and ZnS, CdS, and Cu2S was approximately identical. The decomposition of the sulfate was much more rapid with PbS and FeS. One step that the ZnS, CdS, and Cu2S systems had in common was the formation of the intermediate phase ZnO·2ZnSO4. The faster PbS and FeS reactions passed through no basic sulfate formation step. The decomposition of the basic sulfate was shown to be the rate determining step. The following steps were proposed for the ZnS, CdS, and Cu2S systems:

(1) The formation of oxide(s) or sulfate (fast).

(2) The formation of the basic sulfate, ZnO·2ZnSO4 (fast).

3) The decomposition of the basic sulfate (slow).

The d values and relative intensities of the experimental X-ray diffraction pattern for the ZnO·2ZnSO4 phase are reported"--Abstract, pages i-ii.


Larson, Andrew H.

Committee Member(s)

Schlechten, A. W.
Johnson, James W., 1930-2002
Lorey, G. Edwin


Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering


Missouri School of Mines and Metallurgy

Publication Date



ix, 92 pages

Note about bibliography

Includes bibliographical references (pages 62-63).


© 1962 Larry G. Twidwell, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 1409

Print OCLC #


Electronic OCLC #


Included in

Metallurgy Commons