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EN
In order to effectively eliminate the effect of fine carbonate minerals on quartz flotation, the influence of fine siderite on quartz flotation was studied as well as the mechanism or role of ultrasonic treatment in the process. The results of adsorption capacity measurement and flotation solution chemical calculation show that fine siderite and its dissolved components have a great influence on the collector consumption and the surface properties of quartz. In addition, SEM, EDS and XPS analysis were used to study the surface morphology and chemical environment changes of quartz with and without ultrasonic treatment. The results of flotation test show that the recovery of quartz increase from 38.79% to 58.38% under the condition that ultrasonic time was 0.5 min and ultrasonic power was200 W. The mechanical effect caused by ultrasonic cavitation can clean the quartz surface to a certain extent and increase its active sites, thus improving the floatability of quartz.
EN
The dissolution characteristics of minerals, dissolution of flotation agents in solutions, and equilibrium of dissociations and associations serve as the basis for determining the optimal conditions for the effective components of flotation agents and for evaluating the interaction between flotation agents and minerals. This basis provided the theoretical support for the flotation separation of minerals. Based on this, the flotation separation of magnesite and calcite was realized using sodium dihydrogen phosphate, also known as monosodium phosphate (MSP), as a regulator and dodecylamine (DDA) as a collector. When MSP was used in the DDA system, single-mineral and binary mixed-ore flotation tests revealed that the floatability of calcite was significantly greater than that of magnesite and the separation of magnesite and calcite was more effective, respectively. Zeta potential measurements showed that MSP-containing negative groups could selectively reduce the zeta potential of calcite and promote the adsorption of DDA-containing positive groups on the surface of the calcite. However, this effect was negligible on the zeta potential of magnesite. Due to the stronger affinity of MSP to Ca2+ than that to Mg2+, as demonstrated by Fourier transform infrared and X-ray photoelectron spectroscopy analyses, the MSP was adsorbed onto the surface of calcite primarily by hydrogen bonds rather than magnesite, which promoted the stronger adsorption of DDA-containing positive groups on the surface of the calcite. As a result, the differences in the floatability of magnesite and calcite were enlarged by MSP. Thus, MSP can be utilized an effective regulator for the efficient separation of magnesite from calcite via reverse flotation.
EN
The utilization of seawater in mineral flotation is the future development trend because of the shortage of fresh water resources. However, at present, the flotation behavior and mechanism of galena in seawater are not clear. Therefore, this paper comprehensively carried out the effect mechanism of seawater on the flotation of galena. Micro-flotation results illustrated that the recovery of galena was higher in deionized water than that in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater. Contact angle determination and Zeta potential distribution measurements showed that hydrophilic substances adsorbed on the surface of galena under alkaline conditions. X-ray photoelectron spectroscopy (XPS) analysis further indicated that these substances were hydroxides precipitates, carbonate precipitates and hydroxyl complexes formed by divalent magnesium and calcium ions, which prevented the adsorption of collector on mineral surface. As a result, the galena recovery declined in 5×10-2 mol/L MgCl2 solution, 1×10-2 mol/L CaCl2 solution and seawater.
EN
In this study, the effects of copper ions (Cu2+) on the sulfidization (Na2S) flotation of malachite was investigated using micro-flotation experiments, zeta-potential measurements, X-ray photoelectron spectroscopy (XPS) analysis, adsorption experiments, and Materials Studio simulation. The results indicated that the flotation recovery of malachite decreased after the pretreatment of the mineral particles with Cu2+ ions prior to the addition of Na2S. The results for zeta-potential measurements and XPS analysis revealed that less sulfide ion species in the pulp solution transferred onto the mineral surface, the sulfidization of malachite surface weakened. The adsorption amount of collector on the mineral surface decreased, and this finding was confirmed by the results of the zeta-potential and adsorption experiments. Materials Studio simulation revealed that the adsorption energy of HS- ions and C4H9OCSS- ions on malachite surface increased after the adding of Cu2+ ion. The competitive adsorption made Cu2+ ions depress sulfidization flotation of malachite, the dissolution of mineral surface affected the adsorption of reagents on it, and decreased the floatability of malachite.
EN
The influence of pulp temperature on the floatability of magnesite and dolomite were studied by flotation test. Inductive Coupled Plasma Emission Spectrometer (ICP) was used to measure the dissolved metal ion content in the pulp by minerals in solution. X-ray photoelectron spectroscopy (XPS) was used to measure the presence and relative content of metal ions on mineral surfaces and the amount of sodium oleate adsorbed on mineral surfaces was measured by UV-Visible Spectrophotometer (UV-Vis). The results show that magnesite and dolomite have a great difference in flotation performance when the pulp temperature is 15 ℃ and the effective separation of magnesite from dolomite can be achieved. The main reason is that after the pulp is stirred at a pulp temperature of 15 ℃ and the pH of the pulp is adjusted with HCl and NaOH, the amount of metal ions remaining on the surface of the magnesite is much larger than that on the surface of the dolomite. Therefore, the active targets (metal ion) adsorbing oleate ions on the surface of the magnesite are more than that on the dolomite. When magnesite and dolomite coexist, oleic acid ion mainly acts on the surface of magnesite at the optimum temperature, which makes magnesite float up and the separation of magnesite from dolomite could be achieved.
EN
Heterocoagulation can occur between fine siderite and hematite particles, which would result in the low efficiency of their separation during the flotation process. To date, there have been no mature methods to increase their separation efficiency. In this paper, citric acid was used as a regulator to enhance the slurry dispersion efficiency. Micro-flotation, scanning electron microscopy (SEM) analysis, settling tests, particle size measurements, zeta potential measurements and E-DLVO theoretical calculations were conducted in the investigations. A maximum recovery difference (53.98%) between siderite and hematite in their mixtures flotation was obtained. Settling tests confirmed that citric acid contributed to improving the dispersion degree of the slurry. SEM analysis indicated that citric acid could clean the surface of particles and weaken the coagulation between siderite and hematite, which were in line with the results of particle size measurements. The zeta potential measurements and Extended-Derjaguin-Landau-Verwey-Overbeek (E-DLVO) theoretical calculations indicated that the citric acid could adsorb on the siderite and hematite surfaces and decreased the surface charge, resulting in a visible increase of the repulsion energy between siderite and hematite particles. Therefore, citric acid can be applied to remove the easily-ground carbonate minerals first to improve the flotation performance of hematite in the separation process of carbonate-containing iron ores.
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