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The sulphation-flotation of artificial Pb/Zn ores involves the sulphation of the Pb/Zn bulk concentrate, followed by depression of galena during sphalerite flotation. Optimum conditions for sulphation were found to be 30 degrees C, and 7 to 10 minutes of retention, with 17 vol.% H2SO4. Under these conditions galena was sulphated only slightly leading to complete depression during flotation. Dissolution of sphalerite proceeds only slowly and showed a satisfactory flotation behaviour after activation by copper sulphate. A series of differential flotation tests using an artificial Pb/Zn ore were also carried out. Results obtained indicated that separation of Pb/Zn ores is efficiently achieved by a sulphation-flotation method., The sulphation-flotation of artificial Pb/Zn ores involves the sulphation of the Pb/Zn bulk concentrate, followed by depression of galena during sphalerite flotation. Optimum conditions for sulphation were found to be 30 degrees C, and 7 to 10 minutes of retention, with 17 vol.% H2SO4. Under these conditions galena was sulphated only slightly leading to complete depression during flotation. Dissolution of sphalerite proceeds only slowly and showed a satisfactory flotation behaviour after activation by copper sulphate. A series of differential flotation tests using an artificial Pb/Zn ore were also carried out. Results obtained indicated that separation of Pb/Zn ores is efficiently achieved by a sulphation-flotation method.

The optimum conditions for sulphatisation of galena and sphalerite independent of flotation aspects were determined. Using these conditions, a series of differential flotation tests were done using an artificial Pb/Zn mixture. The separation of Pb/Zn ores by the sulphatisation/flotation method is shown to be possible., The optimum conditions for sulphatisation of galena and sphalerite independent of flotation aspects were determined. Using these conditions, a series of differential flotation tests were done using an artificial Pb/Zn mixture. The separation of Pb/Zn ores by the sulphatisation/flotation method is shown to be possible.

A novel flotation method for the separation of galena from sphalerite without the use of cyanides is proposed. The applicability of a sulphation-flotation process for the separation of artificial Pb-Zn ore is discussed. The method consists of sulphation of a Pb-Zn bulk concentrate, followed by depression of galena during the floation of sphalerite., A novel flotation method for the separation of galena from sphalerite without the use of cyanides is proposed. The applicability of a sulphation-flotation process for the separation of artificial Pb-Zn ore is discussed. The method consists of sulphation of a Pb-Zn bulk concentrate, followed by depression of galena during the floation of sphalerite.

Interaction forces between spherical silica and iron oxide particles attached to the top of the AFM probe and air bubbles generated on a flat surface were measured and found in the case of silica to be repulsive over a wide range of conditions. These were considered to be electrostatic forces. In the case of iron oxide, the forces were attractive when the pH was lower than the isoelectric point of the iron oxide but repulsive when the pH was higher. The attractive forces were stronger and longer-range than the force predicted by heterocoagulation theory and could explain qualitatively the results of batch column flotation with nitrogen gas bubbles., Interaction forces between spherical silica and iron oxide particles attached to the top of the AFM probe and air bubbles generated on a flat surface were measured and found in the case of silica to be repulsive over a wide range of conditions. These were considered to be electrostatic forces. In the case of iron oxide, the forces were attractive when the pH was lower than the isoelectric point of the iron oxide but repulsive when the pH was higher. The attractive forces were stronger and longer-range than the force predicted by heterocoagulation theory and could explain qualitatively the results of batch column flotation with nitrogen gas bubbles.

Interaction forces between a spherical silica particle attached to the top of the AFM probe and an air bubble generated on a flat surface were measured in dodecylamine hydrochloride (DAH) surfactant solution by atomic force microscopy. When a hydrophilic silica particle was used, electrostatic force was observed at a large separation distance even when DAH concentration was low. When hydrophobised silica was used, the range of attractive force became shorter with increasing DAH concentration and the repulsive force before attraction was very strong at high DAH concentrations. The origin of the strong repulsive force was assumed to be the steric force between adsorbed dodecylammonium ions, which would cause the depression of the particle in flotation., Interaction forces between a spherical silica particle attached to the top of the AFM probe and an air bubble generated on a flat surface were measured in dodecylamine hydrochloride (DAH) surfactant solution by atomic force microscopy. When a hydrophilic silica particle was used, electrostatic force was observed at a large separation distance even when DAH concentration was low. When hydrophobised silica was used, the range of attractive force became shorter with increasing DAH concentration and the repulsive force before attraction was very strong at high DAH concentrations. The origin of the strong repulsive force was assumed to be the steric force between adsorbed dodecylammonium ions, which would cause the depression of the particle in flotation.

The new type of flocculant, with high magnetic intensity and a high positive charge, is useful for flocculating fine particles in suspension. It is prepared by adsorbing cationic polyelectrolytes on the surface of magnetite particles, resulting in the ability to capture fine particles by electrostatic force in a wide pH range and to recover the flocs quickly by magnetic force, without changing the properties of the liquid. The use of four kinds of cationic polyelectrolyte was compared to determine optimum production conditions. In all cases, higher pH (especially above 7) during polyelectrolyte adsorption gave a higher surface potential, while higher polyelectrolyte concentration gave better flocculant dispersion. Three kinds of polyelectrolyte were not detached from magnetite even by several washings, indicating that the flocculant can be used repeatedly. Polyethylene imine proved the best, giving a flocculant with a potential of around 40 mV in 0.001 mol/l NaCl solution., The new type of flocculant, with high magnetic intensity and a high positive charge, is useful for flocculating fine particles in suspension. It is prepared by adsorbing cationic polyelectrolytes on the surface of magnetite particles, resulting in the ability to capture fine particles by electrostatic force in a wide pH range and to recover the flocs quickly by magnetic force, without changing the properties of the liquid. The use of four kinds of cationic polyelectrolyte was compared to determine optimum production conditions. In all cases, higher pH (especially above 7) during polyelectrolyte adsorption gave a higher surface potential, while higher polyelectrolyte concentration gave better flocculant dispersion. Three kinds of polyelectrolyte were not detached from magnetite even by several washings, indicating that the flocculant can be used repeatedly. Polyethylene imine proved the best, giving a flocculant with a potential of around 40 mV in 0.001 mol/l NaCl solution.

The Limu Nb-Ta deposit in Guangxi was granite. It contained such minerals as cassiterite, wolframite, scheelite, pyrite, chalcopyrite, sphalerite and tetrahedrite for ore minerals and quartz, mica minerals, carbonates, silicates, fluorite and a slight amount of clay minerals for gangue. The structure was so fine and complex that the size of complete mineral liberation was micrometre order. The Zaoyang rutile deposit in Hubei was crystalline schist. The main ore-forming mineral was hornblende and it contained poikiloblastic rutile and quartz. Garnet and epidote also coexisted. The grain size was not so fine except for the poikiloblastic rutile., The Limu Nb-Ta deposit in Guangxi was granite. It contained such minerals as cassiterite, wolframite, scheelite, pyrite, chalcopyrite, sphalerite and tetrahedrite for ore minerals and quartz, mica minerals, carbonates, silicates, fluorite and a slight amount of clay minerals for gangue. The structure was so fine and complex that the size of complete mineral liberation was micrometre order. The Zaoyang rutile deposit in Hubei was crystalline schist. The main ore-forming mineral was hornblende and it contained poikiloblastic rutile and quartz. Garnet and epidote also coexisted. The grain size was not so fine except for the poikiloblastic rutile.