Combination Of Flotation Research Articles

Agitation Leaching Behavior of Copper–Cobalt Oxide Ores from the Democratic Republic of the Congo

Agitation leaching is a promising technology in hydrometallurgy for treating copper–cobalt oxide ores. In this work, the behavior of oxide ores containing around 2.3% Cu and 0.3% Co received from Congo was investigated for varying particle size, acidity, pulp density, temperature, leaching time, and reduction potential. XRD, optical microscopy (OM), and ICP-OES methods were used to examine the chemical composition, morphology, and metal content of the samples. The copper and cobalt recovery reached 88.2% and 82.5%, respectively, at room temperature, with a leaching time of 4 h, a pulp density of 33%, an acidity of 178 g/L, and no reductant. The Cu and Co remaining in the leaching residue were found to be in their sulfide forms and coated with dense and fine calcium sulfate. To improve the metal recovery, a combination of flotation and agitation leaching of the flotation tailings method was adopted, after which the Cu and Co recovery reached 96.6% and 86.0%, respectively.

Treatment of Oily Effluents Through the Combination of Flotation and Wetland in Thermal Plants Under the Focus of Patent Documents: A Prospective Study

This study aimed to present a technological search for technologies in the processing of oily effluents through the physical-chemical flotation and biological wetland process generated in thermoelectric plants in the patent database of the Derwent World Patents Index (DWPI) using keywords. We found few studies for thermal power plant-effluent processing technologies and combined technologies for flotation and wetland effluent treatment. Patents indicated high efficiency in the combination of the processes. We did not find studies in Brazil for treatment technologies of effluents in thermoelectric plants. However, due to the country's energy scenario, investments in research in this area are recommended.

Morphological characterization and elastic response of a granular material

The granular structures of energetic materials made of hexogene particles embedded in a matrix are characterized using a combination of flotation, light-scattering measurements and micro-computed tomography images. The complementary nature of the three characterization techniques, when employed with this type of material, allows one to derive accurate estimates for the grain size distribution and the particle bulk density distribution. Three types of granular formulations, with the same weight fraction of particles but markedly different grains morphology and shock-sensitivity properties, are addressed. The particles granulometry and intra-granular porosities differ from one material to another. The grains spatial dispersion in the three formulations, characterized by the scale-dependent local density, also varies from one formulation to another. Specifically, we show that samples containing elongated grains display “abnormal” variance scalings for the grains local density, as a result of long-range correlations in the granular packing structure. The use of virtual microstructures to predict the materials mechanical properties is addressed and discussed.

Process Design and Economic Evaluation for the Recovery of Halite and Co-products from Lake Katwe Brine

Salt in Uganda is mainly imported from neighboring countries despite the existence of a 22.5 million t of mineral deposit at Lake Katwe, Western Uganda. Earlier attempts to extract salt from the deposit did not yield the required results. To reduce on the salt import bill and improve the livelihoods of the local miners, a modified solar concentration process was designed to extract sodium chloride and other evaporites. The process flow sheets describing the constituent unit operations were modeled using SuperPro Designer. A bench-scale experiment guided by thermodynamic calculations from the PHREEQC software was conducted to validate the process flow sheets. XRD results show that halite of > 99% purity was produced after the flotation of burkeite and trona. Furthermore, soda ash and sodium sulfate were produced after the second evaporation process by a combination of flotation, carbonation, and calcination techniques. Sodium chloride is the most abundant and feasible product. The unit production cost of sodium chloride was 0.2629 and 0.4724$/kg with a net present value of $2,447,853 and − 12,085,796 of the solar salt and mechanical evaporation processes respectively. As a result, the solar salt extraction process proved highly feasible from both engineering and economic standpoints and thus can be scaled up to a pilot scale using conventional industrial equipment.

A highly efficient multi-step methodology for the quantification of micro-(bio)plastics in sludge.

The present study develops a multi-step methodology for identification and quantification of microplastics and micro-bioplastics (together called in the current work micro-(bio)plastics) in sludge. In previous studies, different methods for the extraction of microplastics were devised for traditional plastics, while the current research tested the methodology on starch-based micro-bioplastics of 0.1-2 mm size. Compostable bioplastics are expected to enter the anaerobic or aerobic biological treatments that lead to end-products applicable in agriculture; some critical conditions of treatments (e.g. low temperature and moisture) can slow down the degradation process and be responsible for the presence of microplastics in the end-product. The methodology consists of an initial oxidation step, with hydrogen peroxide 35% concentrated to clear the sludge and remove the organic fraction, followed by a combination of flotation with sodium chloride and observation of the residues under a fluorescence microscope using a green filter. The workflow revealed an efficacy of removal from 94% to 100% and from 92% to 96% for plastic fragments, 0.5-2 mm and 0.1-0.5 mm size, respectively. The methodology was then applied to samples of food waste pulp harvested after a shredding pre-treatment in an anaerobic digestion (AD) plant in Italy, where polyethylene, starch-based Mater-Bi® and cellophane microplastics were recovered in amounts of 9 ± 1.3/10 g <2 mm and 4.8 ± 1.2/10 g ⩾2 mm. The study highlights the need to lower the threshold size for the quantification of plastics in organic fertilizers, which is currently set by legislations at 2 mm, by improving the background knowledge about the fate of the micro-(bio)plastics in biological treatments for the organic waste.

Effect of pre-desulfurization process on the sulfur forms and their transformations during pyrolysis of Yanzhou high sulfur coal

To achieve the utilization of high sulfur coals efficiently and economically, the effects of different pre-desulfurization processes including flotation, acid washing, ultrasonication and stepwise treatment on sulfur removal and changes of sulfur forms in a high sulfur coal, sulfur transformation behavior during pyrolysis and sulfur distribution in char were investigated. Flotation removed almost all the sulfate and partial pyrite from the raw coal, while ultrasonication was more effective in removing some low molecular-weight organic sulfur together with weakening the C-S bond in some sulfur species. The process of HCl-HF-HNO3 and stepwise treatment reduced the ash content and sulfur content to a larger extent, with ultrasonication after flotation and acid treatment having the highest sulfur removal from raw coal. The sulfur forms on coal surface were more modified after different pre-desulfurization processes, together with different sulfur transformations during pyrolysis. The accumulated amount of sulfur-containing gases during pyrolysis of coals after stepwise treatment, in particular of coals treated by the combination of flotation, acid washing and ultrasonication, generated the highest amount of sulfur-containing gases. For the utilization of high sulfur coals, in particular, of high organic-sulfur coals, the above-mentioned treatment of combination of traditional flotation technique and organic sulfur removal process should be considered, which could remove the inorganic sulfur and organic sulfur simultaneously, and release the most sulfur-containing gases during pyrolysis. Besides, it would be helpful to choose the utilization methods based on the sulfur species in raw coal, and the effect of pre-desulfurization process on sulfur transformation behavior.

Selective Separation and Recovery of Valuable Metals by Vacuum Distillation of Copper Anode Slime Flotation Tailings

The combination of flotation and metallurgical processing to treat copper anode slime produces approximately 1400 tons of flotation tailings every year in Yunnan Province. These tailings contain a large amount of valuable metals. In this article, a vacuum distillation three-stage condensation process is proposed to efficiently and selectively separate valuable metals. A laboratory-scale experiment was carried out under the conditions of 1273 K, 120 min and 0.1–5 Pa. The precious metals silver (95.4%) and gold (96.9%) were recovered in the residue; the base metals lead (99.7%), antimony (95.8%) and bismuth (99.8%) were removed and mainly concentrated in the first volatile phases; the rare metals selenium (90.9%) and tellurium (92.2%) were enriched in the second volatile phase. No waste was produced. This method represents a new technology for the treatment of flotation tailings and provides guidance for industrialization by vacuum distillation.

Intestinal parasitism and nutritional status among indigenous children from the Argentinian Atlantic Forest: Determinants of enteroparasites infections in minority populations

ObjectiveIntestinal parasitoses, especially in the less favored populations of tropical and subtropical areas, are a scourge of high impact in public health. We conducted a cross-sectional survey to investigate the prevalence of helminths and protozoa pathogens, malnutrition, and their determinants in children from indigenous Mbyá Guaraní villages of Iguazú, in the subtropical Atlantic Forest of Argentina. MethodsParasitological assessment was performed using a combination of flotation, sedimentation, and centrifugation techniques, as well as temporal and permanent stains. Nutritional assessment was based on nutritional indicators derived from anthropometric measurements. Statistical analysis of socio-demographic determinants was assessed by Generalized Linear Mixed Models at individual, household, and village levels. ResultsA total of 303 children from 140 families from Fortin Mbororé and Yriapú Jungle villages participated, and 87.8% of them resulted positive to at least one parasite. Multiparasitism reached 70% and children with up to six different parasites were detected. Thirteen genera were identified, of which eight were pathogenic. The most frequent soil-transmitted helminths were hookworms and Strongyloides stercoralis with 60.7 and 41.9%, respectively. Enterobius vermicularis was detected in 28.4% of children. Giardia duodenalis was the main protozoan and reached the 33.3%. The prevalence of stunting and underweight were 38.9% and 6.9%, whereas for overweight and obesity were 28.1% and 12.9%, respectively. An association was observed between stunting in older children and the presence of parasites, multiparasitism, and giardiasis. Individual conditions and habits were important determinants for most of the parasitoses. ConclusionsWe evidenced that the community is affected by the double burden of malnutrition and parasitoses. To face this alarming situation, public policies are needed to improve sanitation, hygiene education access, community deworming programs, and quality nutrition on a regular basis of intercultural approaches.

Evaluation of digital image processing (DIP) in analysis of magnetic separation fractions from Na-feldspar ore

Combination of flotation and magnetic separation methods is widely used for enrichment of feldspar ores by purifying from dark-colored gangue minerals such as iron and titanium. In this study, the removal of dark-colored minerals from feldspar ore (Aydin Cine region of Turkey) was studied using a dry magnetic separator. The effect of several parameters such as feed particle size, blade angle, and roll speed on the removal efficiency was investigated in detail. In addition, the gangue contents of the magnetic and non-magnetic products were determined by a digital image processing (DIP) method in terms of using color differences between the feldspar sample and gangue minerals. The results obtained from this study clearly indicated that the dry magnetic separation method can be successfully applied in enrichment of feldspar. Meanwhile, the particle size of the sample showed no significant influence on the separation recovery. According to the results obtained from the digital image processing process, the sample with 0.04% cross sectional area of dark-colored minerals can be obtained at roll speed of 100 rpm and 130° of blade angle using the original particle size of 500×106 μm. Additionally, most importantly, these results showed that digital image processing method can be used to determine gangue content (dark-colored minerals) of the magnetic separation products compared to conventional methods as a simple, a reliable, and a repeatable method.

Removal of iron ore slimes from a highly turbid water by DAF

ABSTRACTThis paper addresses Dissolved Air Flotation (DAF) process variables, such as the flocculation parameters and the recycle water addition, as well as the pretreatment chemical variables (coagulation conditions), to determine the optimal values for the flotation of iron ore slimes found in a highly turbid water sample from the Gualaxo do Norte River, a tributary of the Doce River Basin in Minas Gerais, Brazil. This work was conducted using a flotatest batch laboratory-scale device to evaluate the effectiveness of DAF for cleaning the water polluted by the Samarco tailings dam leakage and determine the ability of DAF to reduce the water turbidity from 358 NTU to values below 100 NTU, aiming to comply with current legislation. The results showed that the four types of tested coagulants (PAC, ferric chloride, Tanfloc SG and Tanfloc SL) provided adequate conditions for coagulation, flocculation and flotation (in the range of 90–99.6% turbidity reduction). Although the process variables were optimized and low residual turbidity vales were achieved, results revealed that a portion of the flocs settled at the bottom of the flotatest columns, which indicated that the turbidity results represented removal caused by a combination of flotation and sedimentation processes simultaneously.

The solvent sublation of bromocresol green from waters solutions

The object of research is wastewaters contaminated with dyes. The available methods for treating wastewater from dyes are often imperfect, ineffective or absent. This calls for the development and implementation of efficient and inexpensive to use and operate dye removal technologies. When treating wastewater, the biggest problem is removing the dyes from dilute low-concentration solutions. For the purification of such effluents, solvent sublation is suggested. This method is based on a combination of flotation and extraction techniques, and on the transmission of gas bubbles through the aqueous phase and removal of the pollutant (sublate) into the organic phase. During the study, imitates of contaminated wastewater with an anionic dye bromocresol green are used in the concentration range of 2–20 mg/dm 3 . The influence of some parameters on the dye removal degree is studied: the pH of the initial solution, the molar ratio surfactant: dye, the size of the air bubbles, the initial concentration of the dye, and the solvent sublation duration. The rational conditions for removing the dye are established: pH 3–3.5, molar ratio bromocresol green-hexadecylpyridinium chloride=1:1. Effective removal of the dye is ensured by using a Schott filter with a pore diameter of 100 μm, an air flow rate of 110–120 cm 3 /min, duration –10 min. Under these conditions, the dye removal degree is 88–99 %. The obtained results confirm the prospects of the proposed method for the effective removal of dyes from low-concentration aqueous solutions. The method has several advantages: possibility to work with large volumes of water bodies; active substance is carried out by gas bubbles and enters the hydrophobic liquid layer without mixing the phases; process is not equilibrium and is not limited by the distribution constant; impossibility of formation of emulsions; multiple concentration of ions in small volumes of organic solvent; requires a small amount of extractant compared to liquid extraction.

Promising Mining Technologies for Gold Placers in Transbaikalia

The discussed basic features of geology of gold placers in Transbaikalia include: long extent, occurrence of a gold pay streak nearby gutter, small thickness of a gold pay streak and deep occurrence sometimes, majority of fine flattened gold particles. It is suggested to enhance development of such placers using new engineering solutions. It is recommended to carry out flushing by means of technologies based on the combination of flotation and gravity concentration followed by activation leaching of gold from concentrates and bullion minerals–gold concentrators. A new leaching technology offered for deep-seated placers involves pre-drainage of a pay streak, saturation of the pay streak with photoelectron-activated concentrated solutions and, finally, electrodiffusion leaching of gold.

Insight on the larval habitat of Afrotropical Culicoides Latreille (Diptera: Ceratopogonidae) in the Niayes area of Senegal, West Africa.

BackgroundCertain biting midges species of the genus Culicoides (Diptera: Ceratopogonidae) are vectors of virus to livestock worldwide. Culicoides larval ecology has remained overlooked because of difficulties to identify breeding sites, methodological constraints to collect samples and lack of morphological tools to identify field-collected individuals to the species level. After the 2007 unforeseen outbreaks of African horse sickness virus (AHSV) in Senegal (West Africa), there is a need to identify suitable and productive larval habitats in horse farms for the main Culicoides species to evaluate the implementation of vector control measures or preventive actions.MethodsWe investigate twelve putative larval habitats (habitat types) of Culicoides inside and outside of three horse farms in the Niayes area of Senegal using a combination of flotation and emergence methods during four collection sessions.ResultsAmong the three studied horse farms, three habitat types were found positive for Culicoides larvae: pond edge, lake edge and puddle edge. A total of 1420 Culicoides individuals (519♂/901♀) belonging to ten species emerged from the substrate samples. Culicoides oxystoma (40 %), C. similis (25 %) and C. nivosus (24 %) were the most abundant species and emerged from the three habitat types while C. kingi (5 %) was only retrieved from lake edges and one male emerged from puddle edge. Culicoides imicola (1.7 %) was found in low numbers and retrieved only from pond and puddle edges.ConclusionsLarval habitats identified were not species-specific. All positive larval habitats were found outside the horse farms. This study provides original baseline information on larval habitats of Culicoides species in Senegal in an area endemic for AHSV, in particular for species of interest in animal health. These data will serve as a point of reference for future investigations on larval ecology and larval control measures.

Occurrence and seasonality of internal parasite infection in elephants, Loxodonta africana, in the Okavango Delta, Botswana.

It is known from studies in a wide range of wild and domestic animals, including elephants, that parasites can affect growth, reproduction and health. A total of 458 faecal samples from wild elephants were analysed using a combination of flotation and sedimentation methods. Coccidian oocysts (prevalence 51%), and nematode (77%) and trematode (24%) eggs were found. Species were not identified, though trematode egg morphology was consistent with that of the intestinal fluke Protofasciola robusta. The following factors were found to have a significant effect on parasite infection: month, year, sex, age, and group size and composition. There was some evidence of peak transmission of coccidia and nematodes during the rainy season, confirmed for coccidia in a parallel study of seven sympatric domesticated elephants over a three month period. Nematode eggs were more common in larger groups and nematode egg counts were significantly higher in elephants living in maternal groups (mean 1116 eggs per gram, standard deviation, sd 685) than in all-male groups (529, sd 468). Fluke egg prevalence increased with increasing elephant age. Preservation of samples in formalin progressively decreased the probability of detecting all types of parasite over a storage time of 1-15 months. Possible reasons for associations between other factors and infection levels are discussed.

Recovery Cu from a Copper Oxide Ore by Flotation and Leaching

The copper oxide ore is high oxidation ratio and the high combination ratio with a low grade of Cu 0.71%. Copper concentrate of Cu 15.02% with a recovery of 38.55% was obtained by flotation. The optimum acid leaching conditions were investigated. Effects of lixiviant concentration, solid-to-liquid ratio, leaching time were investigated. The acid leaching efficiency was 78.75% relative to flotation tailings. By the combination of flotation and acid leaching flotation tailings, most of the Cu in the minerals can be enriched, the total recovery of copper reached 86.85%.

Development of a bio-based collector by isolating a bacterial strain using flotation and culturing techniques

A microbial bio-based collector was isolated from iron mine soil using a combination of flotation and culturing techniques. Four microbial strains with greater than 75% recovery of pure hematite were separated using the technique. Classification and identification of the 4 strains by 16S rDNA sequences were conducted. Among them only 1 strain, termed F3, can act as a collector for hematite, as it is not pathogenic to humans. The morphology and hematite adsorption (by scanning electron microscopy; SEM), composition, zeta potential and hydrophobicity of strain F3 were further evaluated. Based on the changes in the zeta potential and hydrophobicity of a hematite surface before and after adsorption with F3, its adsorption mechanism was also analysed. The results revealed that the combination technique of flotation and bacterial culturing is a highly effective technique for isolating bio-collectors from iron mine soil. Two flotation stages were required to isolate strain F3, which belongs to the genus Stenotrophomonas. This rod-shaped bacterium had CH2, CH3 and phosphate groups on its cell wall that imparted strong hydrophobicity and negative charge. Adsorption of strain F3 reduced the zeta potential of a hematite surface and enhanced its hydrophobicity. The adsorption of F3 to hematite is presumed to be through chemical adsorption. Therefore, strain F3 can be used as a bio-collector for hematite flotation.

Combination of flotation and flame atomic absorption spectrometry for determination, preconcentration and separation of trace amounts of metal ions in biological samples

An efficient enrichment procedure based on the combination of flame atomic absorption spectrometry (FAAS) and flotation for determination of Cd(2+), Ag(+) and Zn(2+) ions in various biological samples using new collector is studied. The influence of pH, amount of 2-(((1H-benzo[d]imidazol-2-yl)methoxy)methyl)-1H-benzo[d]imidazole (HBIMMHBI) as collector, sample matrix, type and amount of eluting agent, type and amount of surfactant as floating agent, ionic strength and air flow rates on the extraction efficiency were evaluated and optimized. It is ascertained that under study metal ions is preconcentrated simultaneously from matrix in the presence of 0.005 M HBIMMHBI, 0.085% (w/v) of SDS form 750 mL at pH 6.5. The floated complexes metal ions eluted quantitatively with 6 mL of 1.0 M HNO3 in methanol lead to achieve preconcentration factor of 125. The detection limits for analyte ions were in the range of 1.3-2.4 ng mL(-1), with recoveries more than 95% and relative SD lower than 4%.

A study on the recovery of Pt−Pd and MgO from Yunnan Cu–Ni ore in China

The combination of flotation and hydrometallurgy had been introduced to dressing the ore in Yunnan, which involves Pt and Pd metallic minerals and serpentines containing high MgO, for recovering both simultaneously, which may be a new try in China. Based on experiments of leaching of Mg2+ and Fen+ and flotation of copper minerals and nickel minerals, two processing flowsheets are reported. One flowsheet is flotation leaching with sulphuric, and the other is leaching flotation of the residue. Generally, the first flowsheet is better in which recoveries of Cu, Ni, Pt and Pd are all over 80%, and MgO ratio of leaching is 98·81%, while the second is better in commercial and practical consideration.

Development of dissolved air flotation technology from the first generation to the newest (third) one (DAF in turbulent flow conditions)

This paper gives a brief description of the development of dissolved air flotation DAF (or so-called high pressure flotation) as an unit operation for removal of solids in water and wastewater treatment during the last 80 years up to this time. The first DAF-systems used in the water industry were the ADKA and Sveen-Pedersen ones from the 1920s. Some of these are still in use. The tanks in which the flotation phenomenon takes place in these systems are very shallow and narrow as well as rather long. The flow rate of water is some 2-3 m/h (at most less than 5 m/h only) and there is a very thin micro-bubble blanket below the water surface between the dry sludge blanket on that and the clarified water which flows almost horizontally below the bubble blanket toward the end of the tanks to be taken out there from near the bottom. The second generation of DAF was introduced in the 1960s and these units are widely in use today. Their tanks are almost square ones having usually a little bit more length than breadth. They are rather deep, too. There is an under-flow wall in front of the back wall of the units having a narrow horizontal gap on the bottom of the tanks for letting out the clarified water from the flotation space. The flow rate of water is usually 5-7 m/h or at most less than 10 m/h. The direction of flow is 30-45 degrees below the horizontal. There is a rather thick micro-bubble bed at the beginning of the tank below the dry sludge blanket. This bubble-bed becomes clearly thinner, when going toward the end of the tank. There are also round DAF tanks which are based on the same hydraulic principles as the rectangular ones presented above. A special application of DAF called the flotation filter was invented at the very end of the 1960s. It is a combination of flotation and rapid sand filtration, both of those being placed in the same tank. Flotation takes place in the upper part of the tank and the filter has been placed in the lower part of it. The direction of water flow is now vertically down from the free surface of water in the tank toward the deep-bed filter. This controls the direction of flow in the flotation space of the tank above the filter bed. The flow rate of water in flotation filters may be 10-15 m/h, but the flow conditions are still laminar. It is the threat that the head-loss of filters would grow too rapidly which in practice is limiting the hydraulic flow rate of flotation filters in this area. The third generation of DAF has been developed at the end of the 1990s. The operational idea is based on that of the flotation filter. The filter bed on the bottom of the tank has been replaced by a thin stiff plate with plenty of round orifices throughout the plate. This plate, having a very much lower flowing resistance than a sand filter can have, controls the vertical flow of water in the flotation space above the plate and distributes it evenly throughout the horizontal cross-section of the tank. The flotation tank is almost square seen from above and its depth is clearly more than the length and breadth of it. This kind of flotation unit can be operated with flow rates of water in the range 25-40 m/l. Even a flow rate of more than 60 m/h has been reported from this kind of DAF-units. There is no risk of clogging of the plate by suspended solids which could limit the flow rate. This is to say that it is possible to operate DAF also in turbulent flow conditions. The depth of the micro-bubble bed below the surface of water can be 1.5-2.5 m. There actually is a continuously regenerated micro-bubble bed in the tank filtering water which is going through this bed. The lower surface of the micro-bubble bed is really a horizontal one a little bit above the plate controlling the flow in the flotation space. The clarified water below the micro-bubble bed is totally clear. It can be said that in this case the removal of suspended solids takes place much more by filtering water by a deep-bed micro-bubble filter than by attaching micro-bubbles onto solids, when both of these are mixed with each other in the inlet shaft of the flotation unit, because the retention time of water in the inlet shaft is very short indeed.

Non-ionic polyethylene oxide frothers in graphite flotation

The Kringel Mine (Woxna Graphite AB) in Hälsingland, Sweden, is one of the largest graphite flake deposits in the world with over 10 million tonnes of ore suitable for open cast mining. Concentration of crystalline graphite is carried out through a combination of flotation, gravimetric and magnetic separation. In the present study, several polyethylene oxide type frothers were evaluated as flotation frothers for the graphic ore. From (a) laboratory dynamic and equilibrium surface tension experiments, (b) froth equilibrium height measurements, (c) bench scale flotation tests and (d) plant trials, it was shown that a polyoxypropylene glycol butyl ether (MW 300 and HLB 6.5) was the most effective frother for the graphic particles. The frother was found to produce closed packed, molecular cohesive films at the air/solution interface showing high elasticity at low concentrations, which appeared to prevent bubble coalescence. The plant has been successfully using this frother as a replacement for MIBC since July 1997.