Flotation Research by the measurement of Electrode Potential

Abstract

Flotation reactions at mercury surfaces were studied by the measurements of electrode potential and contact angle in mercury-electrolyte solution and mercury-xanthate solution systems. The results are summarized as follows:-
1) In a solution of NaCN, KCN, or Na₂S, the value of the mercury electrode potential and themagnitude of the contact angle on mercury are much affected decreasingly with increasing of the electrolyteconcentration. Conversely, in a solution of NaCI, or KCI, the increase in electrolyte concentration makes a, slight change of the electrode potential and gives no effect on the contact angle.
2) In the solution of xanthate, the value of the mercury electrode potential varies its sign from positive to negative and at concentrations less than 100mg/l, the potential-concentration curve is similar to the-Freundl ich's adsortion isotherm and at concentrations more than about 100mg/l, it is like to the line according; to the Nernst equation, the expression as to the potential of an electrode. From the above results the relation between the adsorption and the potential is obtained.
3) In the mercury-xanthate solution system the electrode potential and the contact angle are affected by, pH value at xanthate concentrations less than about 30mg/l, while at the concentrations more than about 30mg/l being scarecely affected by pH value. Above these results show the relation between xanthate concentration and pH value on the reaction of xanthate for the mercury. Perhaps, these results may be recognized, as a rule, for various sulphide minerals. Accordingly, it may be said that the depressant action by the pH value, in sulpide flotation using xanthate depends upon the xanthate concentration and is effective only in the much. dilute xanthate concentration.
4) From the critical points where the mercury electrode potential in the xanthate solution starts, being governed by the pH value, the magnitude of contact angle on mercury for xanthate solution decreases with increasing the pH value. Along this critical curve, the following relation between xanthate ion concent ration and pH value is derived;
d [X-] n/4 [pH] =d [X^-] n/d [pH-] =d [x^-] n/dlog [OH^-] =constant.