Semiconducting Characteristics of Galena Electrodes Relationship to Mineral Flotation

TLDR: In this article, the effect of variable space-charge layer on oxygen reduction and xanthate chemisorption was discussed, and it was shown that highly n-type electrodes have a cleavage potential (V /sub FBp/) of approx. =-0.2V (SCE).

Abstract: Electrochemical, interfacial capacitance, and surface photovoltage (SPV) measurements have been used in a study of oxygen reduction and xanthate chemisorption on in situ cleaved natural and synthetic lead sulfide crystals. Electrodes cleaved in nitrogen-sparged 0.1M sodium tetraborate assume the flatband potential, V /sub FBp/ at the instant of cleavage, and thus the cleavage potential decreases with increasing bulk electron concentration. Highly n-type electrodes have a cleavage potential (V /sub FBp/) of approx. =-0.6V (SCE), and highly p-type electrodes have a value of approx. =-0.2V (SCE). The space charge is readily varied by applied potentials in the range -0.2 to -0.6V. This Bureau of Mines, U.S. Department of the Interior, report discusses the effect of the variable space-charge layer on oxygen reduction and xanthate chemisorption.