Conventional Flotation Research Articles

A Study on the Effect of Ultrasound Irradiation as Pretreatment Method on Flotation of Sedimentary Phosphate Rock with Carbonate–Silicate Gangue

This research aims to explore the effect of ultrasound irradiation as a pretreatment method on the reverse flotation of phosphates. Ultrasonic treatment was used prior to flotation at various ultrasound intensities. The feed sample containing 10.34% P2O5 and 48.01% CaO was obtained from Lar mountain located in southwest of Iran. Flotation experiments were performed using two approaches: (1) a 2-level fractional factorial design with six variables and (2) try and error method. The results of experimental design showed that depressant type and pH were the effective parameters. The collected data from try and error experiments indicated that the conditioning time was the most effective parameter on the recovery. (By reducing the conditioning time from 11 to 6 min, the recovery was increased from 65.93 to 87.88%.) Furthermore, surface cleaning of phosphate minerals treated by ultrasound waves was proved by kinetic analysis, semiquantitative analysis by XRD and SEM–EDX. It was concluded that efficiency of phosphate flotation using ultrasound irradiation due to the cavitation bubbles that led to clean surface of particles is higher compared to the conventional flotation. After a cleaner step, the final grade and recovery of P2O5 reached 21.31% and 77.18%, respectively.

Effects of simultaneous ultrasonic treatment on the separation selectivity and flotation kinetics of high-ash lignite

The purpose of this study was to investigate the effects of conventional flotation and simultaneous ultrasonic flotation in the pulp/froth zones on the separation selectivity and kinetics of high-ash lignite flotation. Particularly, the mechanism of ultrasonic flotation in the froth zone, which improved the flotation performance of lignite, was elucidated. Flotation tests, wet screening, SEM, and froth layer observation tests were employed to reveal the mechanism by which simultaneous ultrasonic flotation improved lignite flotation. The flotation results indicated that the lowest concentrate ash content was obtained using ultrasonic flotation in the pulp zone, while the highest concentrate yield and water recovery were achieved using ultrasonic flotation in the froth zone. The wet screening and SEM results indicated that ultrasonic flotation in the pulp zone afforded the best surface cleaning on the coal surface, which significantly improved the flotation selectivity of lignite. Ultrasonic treatment in the froth zone produced large bubbles and a thin froth layer due to ultrasonic cavitation and oscillation, thereby improving the recovery of fine particles by water entrainment. However, simultaneous ultrasonic treatment in the froth zone did not improve the separation selectivity of lignite flotation. In addition, the second-order model with rectangular distribution of floatability provided the best fit with the experimental data of all the flotation types, based on the analysis of the model fit and stability. Notably, the flotation rate constants of ultrasonic flotation in the froth and pulp zones were 1.8981 min−1 larger and 1.476 min−1 smaller, respectively, than those of conventional flotation.

Effects of Conventional Flotation Frothers on the Population of Mesophilic Microorganisms in Different Cultures

Bioleaching is an environment-friendly and low-investment process for the extraction of metals from flotation concentrate. Surfactants such as collectors and frothers are widely used in the flotation process. These chemical reagents may have inhibitory effects on the activity of microorganisms through a bioleaching process; however, there is no report indicating influences of reagents on the activity of microorganisms in the mixed culture which is mostly used in the industry. In this investigation, influences of typical flotation frothers (methyl isobutyl carbinol and pine oil) in different concentrations (0.01, 0.10, and 1.00 g/L) were examined on activates of bacteria in the mesophilic mixed culture (Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, and Acidithiobacillus thiooxidans). For comparison purposes, experiments were repeated by pure cultures of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans in the same conditions. Results indicated that increasing the dosage of frothers has a negative correlation with bacteria activities while the mixed culture showed a lower sensitivity to the toxicity of these frothers in comparison with examined pure cultures. Outcomes showed the toxicity of Pine oil is lower than methyl isobutyl carbinol (MIBC). These results can be used for designing flotation separation procedures and to produce cleaner products for bio extraction of metals.

Recovering unburned carbon from gasification fly ash using saline water

Gasification fly ash is one of the wastes generated by coal gasifiers, and the unburned carbon therein seriously restricts the resource utilization of gasification fly ash. Flotation is one of the best ways to recover unburned carbon from it; however, surface pores of gasification fly ash are developed and contain several hollow hydrophilic glass beads, which makes it difficult for conventional flotation to recover unburned carbon effectively and the dosage of the flotation reagent is too high. In this study, different concentrations of saline water (NaCl, MgCl2, and AlCl3) are configured to the flotation solution, and their effect on the recovery of unburned carbon of gasification fly ash is investigated. Furthermore, the gasification fly ash treated with saline water is chosen to study the basic properties by the measurement of Zeta potential, surface tension, and flotation foam behavior. The experimental results show that with an increase in the valence state of the inorganic salt cation, the unburned carbon recovery efficiency of the gasification fly ash is significantly improved. When the concentration of Al3+ reaches 0.4 mol/L and the dosage of frother is 7.5 kg/t, the unburned carbon removal rate of the tailings reaches 95% or more. Saline water reduces the surface tension of the flotation system and weakening bubble decay; in the solution of Al3+, the flotation foam size is the smallest, followed by the solution of Mg2+, Na+. Furthermore, the saline water effectively reduces the Zeta potential of the particle surface and improves the floatability of the solid particles.

Improving Coal Flotation by Gaseous Collector Pretreatment Method and its Potential Application in Preparing Coal Water Slurry

Low-rank coal is difficult to upgrade using conventional flotation methods due to its high hydrophilic properties. Thus, it is necessary to explore new methods for upgrading and utilizing low-rank coal. In this investigation, a gaseous dodecane pretreatment method was used to enhance the flotation performance of low-rank coal. Pore distribution analysis, FTIR (Fourier Transform Infrared Spectroscopy), and contact angle measurements were used to study the surface properties of the coal sample. Size distribution and float-sink test results indicated that the coal sample contained a lot of clean coal with low ash content, which could be used as a high quality raw material for making coal water slurry. FTIR, pore distribution analysis, and contact angle results showed that the coal was very hydrophilic due to the high concentration of -OH group and the large number of pores and cracks on the coal surface. The hydrophobicity of the coal sample was significantly improved by the gaseous dodecane pretreatment method. Clean coal with 67.2% combustible matter recovery and 10.5% ash content was obtained by gaseous dodecane pretreatment flotation method. Coal water slurry with 60% concentration was prepared using the flotation clean coal.

Separation performance of flotation column with dilution water in pulp zone

ABSTRACT Flotation columns show a good separation performance for fine coal slime and have been widely used in coal preparation plants. In this study, to reduce the ash content of the concentrate, dilution water was added to the pulp zone of the flotation column. Tailings discharge was also correspondingly increased to ensure the balance of coal pulp in the flotation column. The results indicate that ash content and yield of concentrate decrease with the increasing dilution water. The flotation efficiency index increases initially and then decreases as the rate of dilution water increases, and the highest flotation efficiency index is obtained at a dilution water rate of 0.18 cm/s, this indicates that appropriate addition of dilution water in the pulp zone improves the separation performance of the flotation column. In addition, the closer the dilution water is to the bottom of the flotation column, the better the separation performance of the flotation column becomes. Moreover, compared with a conventional flotation column with a feed pulp concentration of 40 g/L, the flotation column with dilution water has a similar pulp concentration in the pulp zone and shows a better separation performance.

Bubble Size Distribution Characteristics of a Jet-Stirring Coupling Flotation Device

In this study, a new jet-stirring coupling flotation device that incorporates the advantages of three conventional flotation machines (specifically, Jameson cell, mechanical flotation cell, flotation column) was designed based on jet suction. The suction capacity of a double cosine self-aspirated nozzle utilized by the device was analyzed under different feeding pressures, and the effects of frother concentration, feeding pressure, suction capacity, and height of sampling location on the bubble size distribution (BSD) were investigated using a high-speed video system. It was found that a large amount of air was sucked into the flotation cell by the self-aspirated nozzle arranged in a non-submerged manner, which met the requirements of flotation in terms of the suction amount of air. The suction capacity showed a positive linear correlation with negative pressure inside the nozzle. When the Methyl isobutyl carbinol (MIBC) concentration reached the critical coalescence concentration (CCC), the bubble size stabilized at approximately 0.31 mm, which was smaller than the bubble size produced by the conventional flotation machine. This indicated that bubbles suitable for flotation were generated. D32 linearly decreased with increasing of feeding pressures and conversely increased with increasing suction capacities and sampling location heights, independent of the frother concentration.

Selective separation of chalcopyrite from pyrite with a novel non-hazardous biodegradable depressant

Pyrite depression in copper ore flotation often requires large doses of inorganic depressants that lead to high toxicity, high costs, and low selectivity. Thus, this study offers a novel pyrite depressant, polyglutamic acid (PGA), in the selective flotation of chalcopyrite with xanthate as a collector. The flotation and adsorption mechanism on chalcopyrite and pyrite were systematically studied using a series of flotation tests, zeta potential measurements, adsorption analysis, infrared spectral (IR) analysis, and X-ray photoelectron spectroscopy (XPS) analysis. The addition of PGA depressed the flotation of pyrite more strongly than chalcopyrite in the wide pH range of 8–12. In the presence of PGA, selective separation between the two minerals was achieved at pH 9, and the recovery of chalcopyrite was over 85% and that of pyrite was less than 20%. All of the surface analysis techniques indicated that PGA interacted differently with the two minerals and the surface of pyrite adsorbed a much greater amount of PGA than that of chalcopyrite. Prior addition of PGA significantly reduced the adsorption of the collector on the pyrite surface and thus depressed its flotation. However, the significant adsorption of the collector and its oxidation to dixanthogen on the chalcopyrite surface caused its improved flotation even in the presence of PGA. Therefore, PGA, which is a non-hazardous, biodegradable, and renewable reagent, could be used as an alternative pyrite depressant in Cu–Fe conventional flotation circuits.

Study effects of conventional flotation reagents on bioleaching of zinc sulfide

Although flotation and bio-extraction of metals from its products are extensively investigated, there are few studied which evaluated the effects of reagents on bioleaching process. Both structure and concentration of flotation reagents are effective factors on microorganism activities. In this study, Kendall’s tau (τ) as a statistical method was used to statistically access the effect of typical sulfide flotation surfactants (collectors: potassium amyl-xanthate, potassium isobutyl-xanthate, sodium ethyl-xanthate, potassium isopropyl-xanthate, and Dithiophosphate), and frothers: pine oil and methyl isobutyl carbinol) on the bioleaching of Zn sulfides in a mixed culture (Leptospirillum ferrooxidans, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans). To consider both structure and concentration of these reagents, their molarities were used for the statistical evaluations. The Kendall assessments indicated that by increasing in the molarity of reagents, the pH value (the most effective factors of bioleaching) was increased (τ: 0.56) while the ORP value (τ: −0.54), Fe3+Fe2+ ratio (τ: −0.51) and numbers of oxidizing bacteria (τ: −0.38) in the solution were decreased. Therefore, as a result of these multi-interactions, by increasing the molarity of reagents, Zn recovery was decreased (τ: −0.45). These results potentially can be used for selection of flotation reagents when bioleaching would be the metallurgical metal extraction method.

Recovery of unburned carbonaceous matter (UCM) from sugar mill bottom ash

ABSTRACT Millions of tons of coal fly and bottom ash are produced each year in many countries including Turkey. Coal combustion which is the main source of energy in sugar mill and many other industries produce massive quantities of waste. The present study aims to separate the unburned carbonaceous matter (UCM) from the bottom ash of Bor, Nigde-Turkey sugar plant has been studied using the mechanical flotation technique. For this purpose, the performances of three classical oils were investigated and then chemical parameters such as sodium silicate (Na2SiO3), collector (fuel-oil) and frother (pine-oil) were systematically examined by using Yates’ statistical technique. A product with 41.58% combustible grade at 87.44% recovery was obtained at 0 g/t sodium silicate, 7464 g/t fuel-oil, 888 g/t pine-oil, 15% pulp density, 1200 rpm impeller speed and natural pH. The results obtained from the experiments indicated that it was possible to enrich the bottom ash by using conventional flotation.

Application of the Oily-Bubble flotation of Shengli lignite and its optimization

ABSTRACT The upgrading of low-rank coal is important for its utilization. The lignite used in this study had extremely low surface hydrophobicity and responded poorly to the conventional flotation process. Therefore, to enhance its flotation, a laboratory device known as oily-bubble flotation was used. With this device, the combustible matter recovery at a collector dosage of 6.4 kg/t reached 32.94% which was comparable to that of the conventional flotation at the collector dosage of 50 kg/t. For improving recovery, utilization of electrochemical conditions for pulp, i.e., pH, and NaCl and CaCl2 solutions, was used to further enhance the oily-bubble flotation performance. Based on the response-surface methodology, a functional model for combustible matter recovery was established, and the regulator scheme in oily-bubble flotation was optimized to achieve a combustible recovery of 59.19% with pH and NaCl and CaCl2 concentrations of 6.03, 61.26 mmol/L, and 80 mmol/L, respectively. Results showed that an increased combustible matter recovery of 78.69% could be obtained using this optimization scheme.

Ultrasonic-assisted flotation for enhancing the recovery of flaky graphite from low-grade graphite ore

The feasibility of low-frequency ultrasound in enhancing the flotability of flaky graphite from low-grade graphite ore was investigated in this present study. This study involves a fundamental understanding of ultrasonic-assisted graphite flotation process and its relative comparison with the conventional flotation process. The flotation experiments were conducted in three stages viz., rougher, cleaner, re-cleaner stage during both convention and ultrasonic-assisted flotation. It was found that the efficiency of ultrasonic-assisted flotation was significantly higher than conventional flotation. The yield, fixed carbon content and percentage recovery of the flotation concentrate products increased significantly under ultrasonic-assisted flotation. Furthermore, the ultrasonic mechanism and its effect responsible for the breakage of graphite-impurities locked particles and particle size reduction were also discussed comprehensively. The raw graphite (RG) and final flotation concentrate products of conventional and ultrasonic-assisted flotation process were characterized by Stereomicroscope, X-Ray Diffraction, Field Emission Scanning Electron Microscope and Raman Spectroscopy to understand the graphite liberation properties, mineralogical properties, surface properties and microcrystalline properties, respectively.

An investigation of the effect of clay type on coal flotation along with DLVO theoretical analyses

ABSTRACTCoals generally exist with clay minerals, which are very fine-sized minerals, and adversely affect the flotation of coal. For instance, they make the coal surface hydrophilic by coating coal surfaces and therefore, they inhibit bubble-particle attachment. Clay minerals can also cause over-consumption of reagents due to their high surface area. Additionally, clay minerals can transfer into the concentrate during the flotation process by entrainment because of their low weight and small particle size, and thus, increase pulp viscosity and changing froth stability. In this study, the influence of various clay minerals (kaolinite, illite, and bentonite) on the flotation behavior of coal sample was studied in detail by conventional flotation tests. In addition, the values obtained from flotation tests were correlated with theoretical energy barrier values established with classical DLVO theory based on zeta potential values of coal and clay samples measured at different pH values. According to the results of this study, no significant effect of clay minerals was observed on coal flotation. This was probably because of the high floatability of the coal used for this study. Both the results obtained from the experiments and theoretical analysis, DLVO calculations, showed that the type of clay mineral is the main indicator parameter for coal flotation.

Importance of Parasitological Screening in Extensive Poultry Farming Based on Organic Production.

Timely and valid diagnostic of parasitic diseases are prerequisites for profitable traditional poultry breeding, which enables adequate prophylaxis and effective therapy. This research is retrospective of the prevalence of endoparasites in 880 hens, 291 ducks, 171 geese and 302 turkeys in extensive poultry breeding in the Republic of Serbia. Qualitative parasitological examination was done by conventional gravitational flotation method and sedimentation method. In rare cases of animal death, an autopsy was performed. In the period from 2012 to 2017, in 12 examined localities in the Republic of Serbia, single or mixed infections with endoparasites Eimeria spp., Ascaridia galli, Heterakis gallinarum, Capillaria contorta, Amidostomum anseris and Syngamus trachea were diagnosed. The highest prevalence of ascaridiosis was detected in hens (15.69-24.05%), trichostrongylidosis in ducks (20.53-30.19%), heterakiosis (20.89- 25.86%) and capillariosis (20.68-26.08%) in geese, and syngamosis (23.39%) and capillariosis (14.28- 24.17%) in turkeys. Endoparasites were the most prevalent in hens in south Serbia (63.21%), in ducks in central Serbia (54.71%) and in geese (46.55%) and turkeys (58.24%) in north Serbia. Among mixed infections predominant was polyparasitism of Heterakis spp. and Capillaria spp. An epizootiological and clinical diagnostic approach based on the results of parasitological screening is very important from the aspect of organic poultry farming.

Preparation and characterization of silicon nanomaterials with different morphologies

Coal combustion produces a large number of pollutants, leading to serious air pollution. The development of efficient ash removal technology from coal is imminent. Coal is a mixture of carbonaceous organic matter and inorganic mineral ash. Usually, the clean coal and inorganic mineral ash are separated by flotation according to the Hydrophobicity of carbonaceous organic matter and the hydrophilicity of inorganic mineral ash. Hydrophilic silica nanorods we prepared have high surface energy and chemical activity, which is easy to adsorb inorganic mineral ash, and then be floatated by flocculation. In this paper, a series of silicon nanomaterials with different morphologies were prepared by microemulsion method. On the basis of hydrophobic difference between coal and mineral ash, The inorganic ash minerals are adsorbed on the nanomaterials, and then separated by conventional flotation. At the same time, we used XRD and SEM to characterize the silicon nanomaterials.

Direct Leaching of Low-Grade Zinc Oxide Ore Containing High Amounts of Iron and Manganese

Consumption of zinc metal has been rapidly increased in the world. Zinc metal exists as oxide, sulfide, carbonate and silicate ores, among which zinc oxide ores have not been mined because it is very difficult to separate zinc from gangue or to concentrate using the conventional flotation processes. In the current study, a low-grade zinc oxide ore containing 5.9% Zn, 33.4% Fe and 13.7% Mn was selected to investigate direct leaching. Results of the direct leaching at conventional conditions showed that the Zn leaching efficiency was improved at high acidity, high temperature and grinding conditions and reached about 60% at temperature of 50 °C, d80 of 110 microns, leaching time of 120 min and sulfuric acid consumption of 3.3 kg/kg Zn. Results showed that between 20 and 30% of zinc is associated with other species containing manganese IV. In the reductive leaching experiments by using Na2SO3 as reductant, the maximum Zn and Mn leaching efficiencies are about 82.7% and 96.2%. Dissolving high manganese as impurity in the pregnant solution is a potential concern with the reductive leaching process that needs further investigation.

New Approach to Quartz Coarse Particles Flotation Using Nanobubbles, with Emphasis on the Bubble Size Distribution

This study investigates the influence of bubble size distribution and operational parameters on the flotation behavior of quartz coarse particles. The parameters evaluated during this study include the different bubble size distribution, air flow rate and impeller speed. Experiments were conducted at three different bubble sizes: 110, 171 and 293[Formula: see text]nm as db(32). Then, the results were compared with common air bubbles of the conventional flotation process. The bubble size distribution was measured using a laser particle size analyzer (LPSA). Results showed that the recovery of [Formula: see text]m particles increased in presence of nano bubbles (NBs) up to 25% compared to the conventional flotation. The maximum recovery of 95.59% was obtained using NBs size of 171[Formula: see text]nm at the impeller speed of 900[Formula: see text]rpm and air flow rate of 30[Formula: see text]l/h. It was also indicated that NBs caused an increasing in flotation recovery for all the samples in any size ranges in comparison with the conventional method.

The role of sodium oleate (NaOL) in the magnetic separation of pentlandite from serpentine using magnetic coating

The efficient separation of pentlandite from serpentine remains a challenging issue in the processing of nickel sulfide ores. In this study, selective magnetic coating-magnetic separation was employed to separate the pentlandite from serpentine with adding NaOL as a coagulant, which is different from the conventional flotation. The results indicate that it was very effective for their separation. Furthermore, the role of NaOL in the separation was evaluated in detail by means of adsorption tests, zeta potential measurements, Fourier transform infrared (FTIR) spectra analyses, solution chemistry calculations X-ray photoelectron (XPS) spectra analyses, and scanning electron microscopy-energy dispersive spectra (SEM-EDS) analyses. It turns out that NaOL can adsorb selectively onto the surfaces of pentlandite and magnetite through the Ni and Fe sites (serpentine was pre-depressed by sodium hexametaphosphate (NaHMP)) and form the hydrophobic surfaces between the two minerals. As a result, the pentlandite surface was selectively coated by the magnetite fines and then was separated from serpentine using magnetic separation. Therefore, our results provide an alternative technology for their separation and exhibit great potential for further study and applications.

Determination of surface chemistry and flotation properties of rare earth mineral allanite

In this study, flotation properties of allanite, a sorosilicate rare earth mineral that commonly found in some new complex ore reserves, was studied with EDA (CH3–(CH2)9–O–(CH2)3–NH2/ethylenediamine), a commercial cationic collector in the etheramine acetate group, and R845N (tetrasodium N-(1,2-dicarboxyethyl-N-octadecyl/octadecenyl sulfosuccinamate), a commercial anionic collector in the alkyl succinamate group. In this context, firstly micro-flotation studies were carried out using a pure crystalline allanite specimen. In accordance with micro-flotation studies; zeta potential, contact angle, and bubble-particle attachment time measurements were also carried out to investigate the surface properties of allanite mineral. Conventional flotation experiments were also carried out under the conditions determined in the surface chemistry studies. The micro-flotation experiments showed that the flotation recovery increased up to approximately 93.00% and 48.50% at 100 ppm for EDA and R845N, respectively. A strong relationship between flotation recovery and bubble-particle attachment time were observed. The zeta potential and contact angle values of the allanite sample increased with the increasing concentrations for both collectors which indicated a successful collector adsorption onto allanite surface. Moreover, a correlation between the results of flotation recovery, contact angle and zeta potential measurements was also determined. Thus, a significant contribution was achieved in terms of understanding the micro-flotation results. The results of conventional flotation were consistent with the micro-flotation results as the ΣREE grade of the floated fractions were 0.59% and 0.99%, and the recovery rate of floating fractions were 81.39% and 64.24% for EDA and R845N, respectively. The obtained results clearly demonstrated that R845N, a collector of the alkyl succinamate class, can be used for selective separation of allanite from the other silicate gangue minerals.

Leaching of a Tailings from Oxy-sulfur Copper Ore with Sulfuric Acid

In this paper, mineralogy and leaching comprehensive utilization of tailings from an oxy-sulfide copper ore were studied. Tailings grade was 0.526%, of which copper was primary free copper oxide. Malachite was not completely dissolved although it flake aggregate size was much larger than other minerals. When the tailings were ground again to a fineness of -0.074 mm 93.5%, the copper grade in the tailings could only be reduced to 0.489% after one roughing and two scavenging. It was difficult to effectively recover copper with conventional flotation methods. Under the pulp concentration of 33%, the pulp temperature of 45 °C and 55 °C, sulfuric acid dosage of 160 kg/t, leaching time of 0.5 h, immersion liquid contained copper 2.37 g/L, the leaching rate of 91.34% was obtained with acid leaching, which the copper tailings got effectively recycled.