Flotation Results Research Articles

Flotation separation of scheelite from calcite using mixed cationic/anionic collectors

In this study, flotation behavior of scheelite and calcite was investigated using mixed cationic/anionic collectors of dodecylamine (DDA) and sodium oleate (NaOL). Individual NaOL or DDA was also tested for comparison.The flotation results of single mineral and mixed binary minerals demonstrated a high selectivity and recovery for the flotation of scheelite from calcite at pH 7 using mixed DDA/NaOL collectors. The adsorption mechanism of the selective separation was analyzed through zeta potential measurement.

Understanding the effect of mineralogy on muscovite flotation using QEMSCAN

Muscovite mica is an industrial mineral used in many different applications including coatings, construction materials and polymers. This mineral is commonly beneficiated using froth flotation, especially when treating finer particle sizes. A common flotation scheme employs a cationic amine collector for mica, at alkaline pH, with a depressant added to depress some of the common gangue minerals in muscovite deposits such as quartz and feldspars. This work examines the effects of Custamine 8113 (collector) and Norlig-H (depressant) on the flotation of a muscovite ore from a mineralogical perspective using QEMSCAN. In addition to traditional grade-recovery curves for the various mineral components of the ore, the QEMSCAN data are used to look at: size-by-size flotation recoveries, particle size differences between flotation concentrates and tailings, and mineral liberation and association. The lab-scale flotation results are then compared to idealized size-by-size grade-recovery curves calculated from the measured QEMSCAN data.

Optimization of ilmenite flotation process in the presence of microwave irradiation

In the present study, the effect of parameters, including microwave irradiation power, pH, dosage of chemical reagents (collector, depressant and activator) were studied by microflotation (in Hallimond tube) process. The mechanical flotation tests were carried out on optimum parameters obtained from microflotation tests. The software based on experimental design method (DX7) with the two-level full factorial design was applied to determine the parameter effects and to optimize the microflotation recovery. The optimum conditions were determined by analysis of variance (ANOVA), indicating that the irradiation power was the most effective parameter. The optimum values of parameters in the microflotation process are as follows: power of microwave (1000 W), pH (6.3), dosage of chemical reagents (sodium oleate 3.65 × 10-4 M as a collector, acidified sodium silicate 2 g L–1 as a depressant, and lead(II) nitrate 2.1 × 10–5 M as an activator). By applying these optimized parameters, a product with ilmenite recovery of 83.26% was predicted by the software. The results of microflotation tests indicated that an ilmenite recovery of 82.35% was achieved being very close to the predicted value. The results of mechanical flotation based on optimized condition showed that the recovery and separation efficiency of irradiated ilmenite were improved up to 86.03% and 48.61%, respectively, indicating the positive effect of irradiation on ilmenite floatability.

Results of fibre and toner flotation depending on oleic acid dosage.

The literature was reviewed with respect to deinking flotation methods with toner samples, specifically emphasizing the speciation of copy machine and laser printing, which produce an increasing quantity of paper that is difficult to recycle. Speciation here refers to the physical-chemical characteristics of the toner, which change because of the polymerization (fusion) and oxidation process, due to exposure to heat, light and oxygen (air) during the printing process. To simulate the deinking flotation, after the ideal disintegration process, samples of toner were prepared in order to provide free toner particles. Synthetic toner has iron content and the same physical-chemical features as free disintegrated printed toner particles.We report the toner (I) and fibre (Y) recovery and the brightness (B) of laboratory filter pads formed of deinked product as deinking efficiencies. The application of oleic acid as the collector in the flotation stage gives a better flotation recovery in alkaline than in acidic conditions. The highest brightness (BF = 93.66%) and flotation recoveries (I = 90, Y = 92.82%) were achieved during testing at an oleic acid concentration of 3.38·10(-6) mol l(-1), which is the lowest dose used. This makes the use of oleic acid economical and environmentally friendly.

Dependence of morphology on anionic flotation of alumina

Morphological features of particles upon size reduction affect flotation recoveries in terms of kinetics, bubble-particle interactions and even suspension properties. The significance of surface roughness and shape factor of particles on flotation recovery and their underlying mechanism has been shown to be of importance. Towards this aim, a series of micro-flotation tests have been performed with original, ground and ground-abraded alumina particles in the presence of sodium dodecyl sulfate collector in order to demonstrate the influence of morphological features on flotation recoveries. The flotation results are discussed with the help of literature data on shape and roughness of various types of particles.

Flotation behavior and adsorption mechanism of fine wolframite with octyl hydroxamic acid

Flotation behavior and adsorption mechanism of octyl hydroxamic acid (OHA) on wolframite were investigated through flotation experiments, adsorption tests, zeta-potential measurements, infrared spectroscopy and solution chemistry calculations. Results of flotation and adsorption experiments show that the maximum values of flotation recovery and adsorption capacity occur around pH 9. In term of the solution chemistry calculations, the concentration of metal hydroxamate is greater than that of metal tungstate and metal hydroxyl, and metal hydroxamate compounds are identified to be the main species on wolframite surface at pH region of 8-10, contributing to the increase of OHA adsorption and flotation performance. Results of zeta-potential and IR spectra demonstrate that OHA adsorbs onto wolframite surface by chemisorptions. Hydroxamate ions can bond with Mn2+/Fe2+ cations of wolframite surface, forming metal hydroxamate compounds, which is a key factor in inducing the hydrophobicity of wolframite under the conditions of maximum flotation.

Separation of plastics: The importance of kinetics knowledge in the evaluation of froth flotation

Froth flotation is a promising technique to separate polymers of similar density. The present paper shows the need for performing kinetic tests to evaluate and optimize the process. In the experimental study, batch flotation tests were performed on samples of ABS and PS. The floated product was collected at increasing flotation time. Two variables were selected for modification: the concentration of the depressor (tannic acid) and airflow rate. The former is associated with the chemistry of the process and the latter with the transport of particles. It was shown that, like mineral flotation, plastics flotation can be adequately assumed as a first order rate process. The results of the kinetic tests showed that the kinetic parameters change with the operating conditions. When the depressing action is weak and the airflow rate is low, the kinetic is fast. Otherwise, the kinetic is slow and a variable percentage of the plastics never floats. Concomitantly, the time at which the maximum difference in the recovery of the plastics in the floated product is attained changes with the operating conditions. The prediction of flotation results, process evaluation and comparisons should be done considering the process kinetics.

Flotation of copper-bearing carbonaceous shale in the presence of amine type frothers

<p>Hexylamine, chloro-derivative of propylamine, and ammonium chloride were used for flotation of Permian carbonaceous copper bearing shale from the Legnica-Glogow Copper Basin region in SW Poland. It was confirmed that naturally hydrophobic shale, known as Kupferschiefer, can be made floatable by application of short chain amines as frothers. It was also established that the short chain amine chloro-derivatives as well as salmiac, the first member of the amine family, can be used as a frother for flotation of the investigated shale sample. It results from the paper that the investigated amine frothers work similarly if the comparison of the flotation results is made using their concentration expressed in relative form taking into account the critical coalescence concentration of the frother.</p>

Cationic flotation of nonsulfide minerals

From the analysis of information on flotation of quartz, barite, hematite and diamond spar using cationic reagents (amines), the authors show deficiency of thermodynamic approach to explain flotation results by one type of adsorption due to ion–electrostatic mechanism. The discussion offers hypothesis that says that at low pH collecting ability of a reagent is connected with hydrophobic attachment of the reagent ions in adsorption layer. In alkaline range of pH, the collecting ability is conditioned by formation and precipitation of ionomolecular associates in the adsorption layer of a mineral. These types of adsorption attach particle surface which is preliminarily made hydrophobic by ion–electrostatic mechanism. These adsorption types are active at bubble–liquid interface and can go to this interface upon rupture of water film between a particle and a bubble. According to the suggested hypothesis, liquid tension in the film becomes nonuniform and a surface force arises and expels kinematic constraint for particle–bubble attachment. The analytical review of the collected test data on cationic reagents proves the suggested hypothesis. The causes of breakdown of correlation between surface pressure and collecting ability for initial conditions of flotation are explained.

The concentrate ash content analysis of coal flotation based on froth images

Ash content is a vital indicator for coal flotation performance. Froth plays an important role in determining flotation concentrate grade and there are strong correlations between the concentrate froth and the ash content. Therefore, the research in the correlations is of great importance for further flotation prediction and control. In this paper, flotation experiments were conducted at different frother dosages and froth depths using a flotation column. It was found that there were relations between the ash content, yield and water recovery of the concentrates. Variables of froth property such as the average gray value, the homogeneity, the burst bubble parameters and the height over weir were extracted from video images and were analyzed to explain the flotation results. The connections between the variables and the concentrate ash content were analyzed.

Effect and mechanism of siderite on reverse anionic flotation of quartz from hematite

Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry (UV) and Fourier transform infrared spectroscopy (FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO3 2- from siderite dissolution and Ca2+ from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.

Flotation of zinc and lead oxide minerals from Olkusz region calamine ores

The paper presents chemical and mineralogical characteristics of calamine ore from the Pomorzany mine. A flowsheet for recovery of sulphide minerals of zinc and lead in the form of the Zn-Pb bulk concentrate was presented. In the following part, preparation of the feed for flotation of Zn-Pb oxide minerals and optimal conditions for separation from it iron sulphide minerals, represented by marcasite, were determined. In the final section the results of flotation of Zn-Pb oxide minerals with anionic collector AM2 belonging to the hydroxyamide group of collectors and a cationic collector in the form of a coconut amine, being a mixture of primary aliphatic amines, were presented. Basing on the obtained results, a technological flowsheet for the recovery of Zn-Pb sulphide and oxide minerals from the calamine ore of the Pomorzany mine was presented.

PROPERTIES OF FATTY ACID/DODECYLAMINE MIXTURES AND THEIR APPLICATION IN STEAM COAL REVERSE FLOTATION

A series of surfactant mixtures which consist of DAH (dodecylamine hydrochloride) and fatty acids (FAD) were made in this study. The characteristics of these fatty acids/DAH mixtures, including surface tension, critical micelle concentration (CMC) and adsorption onto coal were investigated. The reverse flotation results with these fatty acids/DAH mixtures (FAD) and DAH were compared with each other. Experimental results showed that the fatty acids/ DAH mixtures have lower CMC and γcmc than DAH. The adsorption test indicated that more amine molecules would adsorb preferentially onto the bubbles surface in FAD solutions than that in DAH solutions. Reverse flotation results showed that about 50% surfactant dosage was saved under the same froth product yield. Only 28% froth product yield was obtained in the presence of 1.66 kg/Mg DAH. However, when 0.83 kg/Mg hexadecanoic acid/DAH mixture (C16D) surfactant was used, the froth product yield reached 29%. Dodecanoic acid/DAH mixture (C12D) surfactant a showed better performance with a high mineral matter recovery similar to that with tetradecanoic acid/DAH mixture (C14D) and higher combustible recovery than with C14D and C16D.

Effect of foamability index of short chain alkyl amines on flotation of quartz

Amines can be used for flotation of various minerals, especially quartz. The flotation efficiency of quartz depends on the amine type and dose. It was proved that the shorter alkyl amine, higher amine concentration has to be used to recover quartz at the same level. In flotation amines play a role of both collectors and frothers. The ability of a amine to collect particles can be expressed in the form of contact angle, while the foaming properties by different parameters including dynamic foamability index (DFI) and critical coalescence concentration (CCC). Determination of DFI and CCC requires advanced techniques and methods. Therefore, in this paper a rapid and facile method for determination of foaming properties of amines and also other surfactants was used. It was based on measuring the initial foam and froth heights in a conventional flotation machine at different concentrations of surfactants. The foam height-concentration curve was described by utilizing an empirical equation which was based on one-adjustable parameter called the foamability index (FI ). In this work the foamability index was determined for butylamine (ButNH2 ), hexylamine (HexNH2 ) and octylamine (OctNH2 ) as examples of short chain alkyl amines. The determined foamability indices were 92, 12 and 4 mg/dm3 for ButNH2 , HexNH2 and OctNH2 , respectively. It was shown that when the flotation results of quartz were presented in the form of recovery versus normalized amine concentration in relation to the foamability index (c/FI ), all the experimental data points converged to one curve. It indicates that amines act similarly but at different concentrations expressed as FI . The foamability index seems to be a useful parameter for characterizing any flotation frother.

The critical importance of pulp concentration on the flotation of galena from a low grade lead–zinc ore

The Qixia orebody is a complex lead–zinc sulfide system with pyrite gangue and minor amounts of copper. In order to improve the flotation results, laboratory scale flotation testing of ore samples taken from this operation was performed. Flotation tests used a sequential recovery protocol for selective flotation of first the lead and thereafter the zinc. The key parameters that influence flotation performance of lead mineral were tested in this paper. The test data show that, for comparable collector, grinding time, flotation pH and solid-in-pulp concentration, the increase of solid-in-pulp concentration has the most significant effect on the recovery and selective separation of lead mineral. The increase of solid-in-pulp concentration from 27% to 55% makes the recovery of lead mineral increased from 60% to 80% and the lead grade increased from 27.5% to 29.1%.

Synergistic effect of mixed cationic/anionic collectors on flotation and adsorption of muscovite

Abstract The synergistic effect of the mixed cationic dodecyl amine-hydrochloride (DDA) and anionic collector sodium oleate (NaOL) at the air/water interface was investigated by the surface tension measurements. Various physicochemical properties such as surface activity parameters (CMC, γCMC, Γmax, Amin), the micellar and interfacial compositions ( X 1 m , X 1 σ ) and interaction parameters (βm, βσ) were evaluated according to the theory of regular solutions. It is observed that the mixed DDA/NaOL at αDDA = 0.5 exhibit a maximum synergistic interactions at the air/water interface. The flotation and adsorption of DDA/NaOL at the solid–liquid interface was investigated by flotation tests with muscovite, contact angle measurements and adsorption measurements. The flotation results indicate that the recovery of muscovite could be achieved a maximum value (98.45%) by the mixed DDA/NaOL at αDDA = 0.25 at pH 7.0. Contact angle measurements further confirm that the DDA/NaOL exhibit more superior hydrophobicity and collecting property than the individual DDA and NaOL. And a more pronounced synergistic effect of DDA/NaOL on muscovite surface at αDDA = 0.25 is observed, which could be attributed to a favourable arrangement of adsorbing species. The adsorption results show that the individual cationic DDA can be adsorbed strongly onto the muscovite, but no significant adsorption of anionic NaOL can be detected. However, in the mixed systems, the adsorption amounts of both DDA and NaOL are enhanced due to co-adsorption. It is proved that there is also a remarkable synergistic effect of mixed DDA/NaOL collectors at the solid–liquid interface.

Increasing the Useful Heating Value of Coal Using a Physico-Chemical Process

ABSTRACTCoal is of paramount importance when it comes to producing energy in the industries. In this research, an optimum condition in which coal energy reached its highest level was investigated using a flotation process. A representative coal sample was from the Kerman province mine in Iran. Crushing and screening products were homogenized and prepared to conduct flotation experiments. Based on the statistical design of experiments, solid percent, collector dosage, and frother type were the effective variables that remarkably controlled the flotation results. In this study, efficiency index and the useful heating value (UHV) were two indicators that were considered to determine the coal’s quality. Various kinds of reagents with different amounts were used to find the optimum conditions for experiments. According to the obtained results, the UHV and efficiency index were 6485 (kcal/kg) and 43%, respectively, when the collector amount, frother amount, and solid percent were 5.3 Kg/t, 78 g/t, and 10%, respectively. Three-dimensional graphs were used to visually simplify the interactions between flotation parameters in different values and their effects on the responses. Data showed that in order to increasing the amount of energy that comes from coal, it is necessary to reduce the ash quantity of the coal in a reverse relationship.

The mafic component of the lunar crust: Constraints on the crustal abundance of mantle and intrusive rock, and the mineralogy of lunar anorthosites

Most models of early lunar evolution predict that the anorthositic highlands crust is the result of plagioclase flotation on a magma ocean. However, the lunar highlands crust typically contains 4 wt% FeO and so is more mafic than the strict definition of the anorthosites thought to comprise it. We used new Clementine-based mineral maps of the Moon as inputs to a series of mixing models that calculate the abundance and distribution of major highland rock types and shed light on three possible sources of excess mafic material in the lunar highlands: mafic (15 vol% mafic minerals) anorthosites, post-magma ocean igneous activity, and mafic basin ejecta. Mixing models that feature pure anorthosites like the purest anorthosite (PAN) described by Ohtake et al. (2009) and Pieters et al. (2009) are most compatible with the data. They allow us to place an upper limit of 10–20 vol% mantle material that could be mixed with the primary highlands crust. The upper limit on mantle material indicated by the mixing models is significantly lower than the 30–40 vol% mantle material expected from simple geometric calculations of the major lunar basins’ excavation cavities based on an excavation cavity depth/diameter ratio of 1/10; this discrepancy allows us to conclude that the excavation cavities of the three largest lunar basins may have been significantly shallower than those of the smaller basins. Our results are consistent with excavation cavity depth/diameter ratios for these largest basins in the range of 0.035 to 0.06, which agrees with previous gravity measurements by Wieczorek and Phillips (1999).

The Application of Fatty Acids Emulsions in Thermal Coal Reverse Flotation

ABSTRACTReverse flotation of Pingsuo thermal coal was investigated and it turned out that a large amount of DDA-HCL (dodecylamine hydrochloride) was needed in this process. Two fatty acids (dodecanoic acid and oleic acid) of different carbon chain lengths emulsified by DDA-HCL were used to compare with DDA-HCL in the experiments. Experimental results showed that the two emulsions had stronger collectivity than DDA-HCL. Dodecanoic emulsions had higher selectivity than OA (oleic acid) emulsions. The application of dodecanoic emulsions can obtain a lower ash content of the concentrate than DDA-HCL at the same collector dosage. And it can reduce DDA-HCL consumption greatly under the same concentrate ash content. Reverse flotation results of the two emulsions were also compared. The results indicated that the selectivity of dodecanoic emulsions dropped sharply when the amount of substance ratio of DDA-HCL and dodecanoic acid was less than 1:1.

Processing ores and anthropogenic Cu-Ni feedstock with the application of technology of jet air-steam flotation

A method of flotation is investigated in which a mixture of air with saturated water steam is used as a gas phase. When steam contacts liquid, the boundary layer of the bubble is heated due to the heat of condensation, which is further spent for steam evaporation—the bubble is broadened and forces out the “hot” layer from the surface into the bulk, while its place is occupied by underheated liquid and condensation repeats. The wavelike repetition of condensation ↔ evaporation processes determines the damping pulsations of the bubble surface, which varies the result of flotation. The flotation method by the air-steam mixture is used when concentrating the copper-nickel feedstock by the scheme “in two jets”: the crude concentrate of the first flotation jet is isolated from 1/2 part of the initial feedstock, it is mixed with another 1/2 part of the ore, and the ready crude concentrate of the second flotation jet is isolated using aerosol column flotation. When concentrating the ores of the Pechenga region (Russia) by the flow chart with the jet motion of the initial feeding and crude concentrate with the application of the air-steam mixture as the gas phase during the flotation, the increment in recovery of nickel was 2.93% and that of copper was 3.22%. The passage to the technology of jet air-steam flotation when concentrating dump slags of OAO MMC Norilsk Nickel led to an increase in recovery of nickel from 45.94 to 47.34% and of copper from 78.27 to 82.77%.