The effect of electromagnetic waves on the physical properties of water during floration of minerals

Abstract

In previous reports ['1] we e~abl/shed that high-frequency electromagnetic waves have a beneficial effect on the flotation of sulfide minerals. When a mineral slurry/s activated with currents of frequency 40 Mc for 5 min, extraction of galena and chalcopyrite is increased by 60% and 20%,respectively. This favorable effect was largely attributed ro influence of the electromagnetic waves on the surface of the minerals subjected to flotation. In connection with an extensive study of the structural properties of water as a strongly associated liquid, we investigated the effect of electromagnetic fields on the physical properties of water itself before it is fed to the flotation plant.It is known that water molecules display markedly directed association at the hydrogen bonds, so movement of these molecules will be impeded by continuous combination and rupture at these bonds. The energy of the hydrogen bond of a water molecule can be taken as 5000 cal/mole [2]. In intermolecular and van tier Waals interaction of water molecules, oriented interaction greatly predominams over other types of intermolecular interaction. According to London [3], oriented interaction of hydrogen bonds in the case of water is 190 erg/cm s, while induced and dispersed interaction are 10 and 47 erg/cm s respectively. Continuous hydrogen bonding between water molecules leads to a short-range order of the molecules, which leads in turn to the appearanc e of structural properties within the liquid water as a whole.Bernal and Fowler [4] have made detailed and extensive studies of the structure of water. According to these authors, water has a rather loose quartz-type structme with tetrahedral ordering. It may be assumed that water has an open quasi-crystalline structure, thermal movement of the water molecttles tending to increase the degree of disordering~ while the orientation effect at the hydrogen bonds increases the degree of ordering.In each temporary equilibrium position, a water molecule executes vibrations owing to fluctuation of the medium's thermal energy. Frenkel' has shown the particular role of translational movement of water molecules: it has a stepwise character and consists of activated jumps of the molecules from one temparary equilibrium position to the next. From a study of the Raman spectrum of water, Hibben [fi] established that the wave number of vibrations of water molecules in a temporary equilibrium position is 150 cm "1. The frequency of the nalxtral vibrations of water molecules is, therefore, v~----C 150 cm'*, where v 0 is the natural frequency of the vibrations of water molecules, and C is the velocity of light, 3 9 101~ ern/sec; Vo=3. I0 '~ 150---4.5. I0 'z sec-*, According to Frenkel', the mean residence rime of water molecule.s with an energy E in a temporary equilibrium position can be written as r exp (E/RT), where r is the mean residence time of the water molecules in the equilibrium position, r 0 is the Period of natural vibrations of the water molecules, E is the energy, R is the gas constant,, and T is the t...

A Quantitative Examination of the Mixed Potential Mechanism in Mineral Flotation

“…For the mixed potential theory to be applicable to a system, in which the above two are the partial reactions which determine the open-circuit mixed potential Em and the corresponding current i~, the following conditions should be satisfied = +a = +"* [6] and E = Em [7] The applicability of the mixed potential model can be tested by two methods. Method I: Calculation of E"* and /.,.--Combining Eq.…”

“…For SOS and SOs, potassium sulfate is used for example, whereas for CO and CO2 the electrolyte will consist basically of K~COs. In the case of the sulfur oxide sensors, the electrode reaction may be written as follows (6) SOs(g) + V~O~(g) +2e-~SO~-(s) [1] In the sulfur oxide sensor, the metal electrodes are comprised of platinum or gold, according to whether the total sulfur content is to be measured or just the SOs without modifying the gas phase equilibrium (7,8). The development of the new sensor involved studying different types of reference electrodes, of which the most important so far as sulfur oxides axe concerned are (i) gas reference electrodes based on circulation of a known mixture of SO2 and air (6), (ii) gas reference electrodes obtained by the thermal decomposition of a sulfate (7), (iii) Ag/Ag + type of reference electrode [1% Ag2SO4 added to the K2SO4 of the electrode (6)], and (iv) zirconia reference electrodes where two solid electrolytes are brought into contact, one containing the oxyanion of the oxide to be measured, e.g., K2SO4, the other being stabilized zirconia (7).…”

Impedance Spectra of a Mineral Galena Electrode: Relationship to Xanthate Flotation

“…The penetration into the crystal of defects either from the etching solution or during the experiments could give rise to inhomogeneous doping and thus to dispersion according to the model reported in Ref. 4. The variations of b ~ and 1/C 2 with V being linear, C~ is not frequency dependent.…”

“…The correction was only made for some spectra to determine R, the sum of the electrolyte and semiconductor resistance which was found to be slightly lower than R~. Plotting gin t in the Cole-Cole plane (Z~.t = Z -R~) 1 ---=C'-jC"=C* [4] diagrams like the one given in Fig. 3 were found.…”

“…The use of this technique thus seems particularly relevant to basic studies connected with mineral processings and especially flotation. The possible influence of the semiconducting nature of minerals on their flotation behavior was put forward 25 years ago (4), and it was suggested that the chemisorption of oxygen converted the surface from nto p-type semiconductor. Further, it was claimed (5) that natural galena is so doped by impurities that it behaves like a "degenerate semiconductor" i.e., like a metal (6).…”