Effects of Galvanic Interaction between Chalcopyrite and Monoclinic Pyrrhotite on Their Flotation Separation

The galvanic interaction between chalcopyrite and monoclinic pyrrhotite and its effect on flotation separation were studied using monomineral flotation tests, adsorption capacity tests, X-ray photoelectron spectroscopy (XPS) characterization, and scanning electron microscopy (SEM) test. These results showed that the interaction promoted the reduction of O2 on the cathodic chalcopyrite surface and accelerated the generation of Fe(OH)3, which was not conducive to collector adsorption; hence, the flotation recovery decreased by 10–16%. On the other hand, galvanic interaction accelerated the oxidation of S on the anodic monoclinic pyrrhotite surface to S0 or SO42− and produced a large amount of H+, thus preventing the formation of Fe(OH)3. Meanwhile, the Cu2+ eluted from chalcopyrite surface activated monoclinic pyrrhotite; hence, the flotation recovery increased by 3–10%. Galvanic interaction reduced the floatability difference between the two minerals, and the separation difficulty was significantly increased. Even with an increase in the amount of lime, the separation could not be improved.

Influence Mechanism of Magnetized Modified Kerosene on Flotation Behavior of Molybdenite

The effects and mechanism of magnetized kerosene on the flotation behaviors of molybdenite were studied by micro-flotation, ultraviolet spectrum, infrared spectrum, surface tension, and liquid viscosity. According to the results of micro-flotation, magnetized kerosene improved the flotation recovery of molybdenite, and the improvements were more obvious with smaller molybdenite particles. Spectral analysis showed that the magnetization did not change the chemical composition of kerosene, but transformed the linear aliphatic hydrocarbons in kerosene into linear isomers and reduced the lengths of the carbon chains. Moreover, the magnetization reduced the viscosity of kerosene and oil/water interfacial tension, and improved the dispersion of kerosene in the pulp. The external magnetic field transformed the disorder of the additional magnetic moment in the kerosene molecules into order, and reduced the compactness of the kerosene molecules. The experimental results provided a theoretical explanation for the role of magnetization in mineral flotation.

Enhanced Flotation Recovery of Fine Molybdenite Particles Using a Coal Tar-Based Collector

Low flotation efficiency has always been a problem in the separation of low-grade molybdenum ores because of the finely disseminated nature and crystal anisotropy of molybdenite. In this study, a novel kerosene–coal tar collector (KCTC) was prepared and used to explore the feasibility of improving the recovery of fine molybdenite particles. The results showed that KCTC achieved better attaching performance than that shown by kerosene, and the surface coverage and attaching rate constant were improved significantly, especially for finer particles of −38 + 20 μm. Compared with kerosene, KCTC showed more affinity for molybdenite particles and greater adsorbed amounts of KCTC on molybdenite particles were achieved. Moreover, the composite collector was shown to float single molybdenite particles of different sizes, and it was found that the recovery of molybdenite particles of different sizes, particularly in the case of those at −20 μm, was improved dramatically by KCTC. The flotation results of actual molybdenum ores further confirmed that KCTC was beneficial to flotation recovery and the selectivity of molybdenite. This indicated that KCTC is a potential collector for the effective flotation of low-grade deposits of molybdenum ores, and more studies should be conducted on further use in industrial practice.

Selection of an Appropriate Depressant in Flotation Separation of Molybdenum Oxide from Fluorapatite

The depressive efficiency of sodium silicate, sodium hexametaphosphate, and tartaric acid on the flotation separation of molybdenum oxide from fluorapatite were examined using cetylpyridinium chloride (CPC) as the collector. The corresponding depression mechanisms of all three depressants were studied with the use of laboratory measurements. Individual mineral flotation tests and adsorption studies showed that all these depressants have a higher depression effect on fluorapatite than molybdenum oxide. Sodium hexametaphosphate has the strongest depression effect on fluorapatite and can reduce the flotation recovery as low as less than 20%. Infrared spectroscopy and zeta potential tests proved the rationality of the flotation results, indicating that when CPC was used as a collector, the effect of sodium hexametaphosphate on the surface of molybdenum oxide was smaller than that on fluorapatite. The adsorption of hexametaphosphate on the surface of fluorapatite was determined to be physical adsorption.

Reduction in Technogenic Burden on the Environment by Flotation Recovery of Rare Earth Elements from Diluted Industrial Solutions

Unconventional raw materials are widely used in construction sectors; for example, phosphate sludge with the addition of rare earth elements (REE) when producing brick. The second example is nanostructured composite systems of REE when forming covers of construction materials. This article studies flotation recovery of REE, the impact of chlorides on distribution coefficient, and pH recovery. The study proves the possibility of effective REE recovery from diluted industrial solutions and, consequently, the significant decrease in their content in wastewaters, which allows the improvement of the ecological situation in the industrial plant areas. In this article, optimum flotation conditions of REE by flotation are given by the example of yttrium (III) and lanthanum (III) salts. The processes of rare earth elements recovery by sodium dodecyl sulphate as salts of various compositions were studied. Distribution coefficients for target components as a function of aqueous phase pH and the presence of foreign anions were determined. The analysis of dependences obtained by the comparison of rare earth elements’ chloro and hydroxo complexes stability constants was made. The products of REE obtained by the authors will be used when manufacturing various kinds of building materials: carbon cement, baked brick, light construction materials, and high-tensile steel.

Role of Sparger Configuration in Determining Flotation Performance under Oscillatory Air Supply

Bubble size is crucial for determining flotation efficiency. Fine bubbles can be cost-effectively generated using a multi-orifice sparger with oscillatory air supply. Sparger configuration is defined by the orifice size, the plate thickness and the chamber volume. To date, the effect of sparger configuration on bubble size with oscillatory air supply is not clear yet. To facilitate the control of bubble size formed with oscillatory air supply, the present work investigated the dependence of bubble size on sparger configuration. It was found that bubble size was positively correlated with the chamber volume and the orifice size, while a nonlinear relationship was observed with the plate thickness. Besides, it was found that flotation recovery decreased over increasing bubble size when changing the sparger configuration. The results indicated that sparger configuration exhibited a significant effect on flotation performance via influencing bubble size when oscillatory air supply was applied.