Flotation Solution Research Articles

Surface tension of flotation solution and its influence on the selectivity of the separation between apatite and gangue minerals

This work presents and discusses the infl uence of the surface tension (γ LV ) of methanol/water mixtures on the fl otation response of apatite versus gangue minerals conditioned with fl otation reagents (75 g/t cornstarch and 100 g/t Berol 867) at pH 10.6. Berol 867 is a collector composed of sodium alkyl sarcosinate plus nonionic surfactant. The highest Schulz effi ciency of separation (recovery of apatite minus recovery of gangue) was achieved at ≈51.0 mN/m. The critical surface tension of wettability (γ C ) of apatite was found to occur at 34.7 mN/m when determined by means of gamma fl otation experiments, and it was 33.9 mN/m when determined by Zisman’s approach.

Infection by Eucoleus aerophilus in dogs and cats: Is another extra-intestinal parasitic nematode of pets emerging in Italy?

The occurrence of the infection by the lungworm Eucoleus aerophilus (syn. Capillaria aerophila) in dogs and cats from Italy has been evaluated with conventional diagnostic procedures. Individual faecal samples from 569 dogs and 200 cats were undertaken to faecal flotation with sugar and zinc sulphate solution. Sixteen dogs (2.8%) and 11 cats (5.5%) scored positive for eggs of E. aerophilus when samples were processed with either of the two flotation solutions. Overall 14 of 16 dogs and eight of 11 cats infected by E. aerophilus showed respiratory symptoms and the most common were general respiratory distress, dry cough, wheezing and sneezing. These results indicate that E. aerophilus is not uncommon and that canine and feline capillariosis is of clinical importance. Given the impact that E. aerophilus infections may have upon animal health and its zoonotic potential, it is strongly advisable to routinely include this disease in the differential diagnosis of (cardio)-respiratory diseases of dogs and cats.

Prueba de una técnica para recuperar huevos de Toxocara canis de muestras de tierra

contained in0.1 ml of a water suspension. In the adaptation process of the technique, it was prove three variablesmaking 20 repetitions of the following combinations: a) detergent added: acid anionic (pH 4.6), orbasic anionic (pH 11.5). b) Flotation solution used: sugar solution (density: 1.25), or saturated zincsulphate (density: 1.38). c) with or without mechanical mixing of the samples previous to theflotation process. The best result, of an average of 50.9% (p < 0.05) of the recovered added

Combination of three-stage sink–float method and selective flotation technique for separation of mixed post-consumer plastic waste

The aim of this research was to separate the different plastics of a mixed post-consumer plastic waste by the combination of a three-stage sink-float method and selective flotation. By using the three-stage sink-float method, six mixed-plastic wastes, belonging to the 0.3-0.5 cm size class and including high density polyethylene (HDPE), polypropylene (PP), polyvinylchloride (PVC), polystyrene (PS), polyethylene terephthalate (PET) and acrylonitrile-butadiene-styrene copolymers (ABS) were separated into two groups, i.e., a low density plastic group (HDPE and PP) and a high density plastic group (PET, PVC, PS and ABS) by tap water. Plastic whose density is less than that of the medium solution floats to the surface, while the one whose density is greater than that of the medium solution sinks to the bottom. The experimental results elucidated that complete separation of HDPE from PP was achieved by the three-stage sink-float method with 50% v/v ethyl alcohol. To succeed in the separation of a PS/ABS mixture from a PET/PVC mixture by the three-stage sink-float method, a 30% w/v calcium chloride solution was employed. To further separate post-consumer PET/PVC and PS/ABS based on plastic type, selective flotation was carried out. In order to succeed in selective flotation separation, it is necessary to render hydrophilic the surface of one or more species while the others are kept in a hydrophobic state. In flotation studies, the effects of wetting agent, frother, pH of solution and electrolyte on separation were determined. The selective flotation results showed that when using 500 mg l(-1) calcium lignosulfonate, 0.01 ppm MIBC, and 0.1 mg l(-1) CaCl2 at pH 11, PET could be separated from PVC. To separate ABS from PS, 200 mg l(-1) calcium lignosulfonate and 0.1 mg l(-1) CaCl2 at pH 7 were used as a flotation solution. Wettability of plastic increases when adding CaCl2 and corresponds to a decrease in its contact angles and to a reduction in the recovery of plastic in the floated product.

Nematofauna fitopatogênica de sementes comerciais de forrageiras tropicais

O objetivo deste trabalho foi identificar e quantificar a nematofauna fitopatogênica de sementes de forrageiras, destinadas aos mercados interno e externo. Examinaram-se sementes de Brachiaria brizantha (cvs. Marandu e Xaraés), B. decumbens cv. Basilisk, Panicum maximum (cvs. Massai, Mombaça e Tanzânia) e Stylosanthes capitata e S. macrocephala, componentes da cultivar Estilosantes Campo Grande. As extrações foram realizadas por flotação centrífuga, em solução de sacarose com caulim. Nas gramíneas, encontraram-se os gêneros Aphelenchoides e Ditylenchus. O maior número de espécimes de Aphelenchoides spp. foi observado nas sementes de 'Marandu', e, em seguida, nas sementes de 'Xaraés', 'Basilisk' e 'Tanzânia'. Quanto à densidade populacional de Ditylenchus spp., os maiores valores foram observados nas sementes de 'Marandu', 'Xaraés' e 'Basilisk'. Os resultados sugerem que pelo menos duas espécies de Aphelenchoides e Ditylenchus estão associadas às sementes de gramíneas forrageiras, destinadas ao mercado interno. Fitonematóides não são detectados em sementes de 'Estilosantes Campo Grande', tampouco nas cultivares Marandu, Mombaça e Tanzânia, destinadas à exportação.

A simple, robust and semi-automated parasite egg isolation protocol

Large-scale parasite quantification is required for improving our understanding of the epidemiology and genetics of host-parasite interactions. We describe a protocol that uses a low-density salt solution for flotation and centrifugation of nematode eggs. Subsequently, sucrose flotation and precipitation are used to obtain clear egg preparations. Most traditional quantification protocols such as the McMaster technique are unsuited for the standardized processing of large numbers of samples and the analysis of large amounts of feces per sample. Consequently, they are suited only for small-scale surveys. Our protocol, which can be used to analyze up to 6 g of feces, results in clear egg preparations that are concentrated in wells of a microtiter plate and that are suited for digital recording and automated counting. Starting from a fecal suspension in the first flotation solution to a digital recording requires approximately 40 min per 24 samples.

Separation of mixed post-consumer PET–POM–PVC plastic waste using selective flotation

The main objective of this research is to separate a mixed post-consumer engineering plastic waste (PET, POM, and PVC) based on type of plastic using selective flotation separation. Depressing effect of wetting agent and aluminium sulfate on plastic is attributed mainly to the separation. POM is separated from the mixture waste when using 500 mg/l calcium lignosulfonate as a wetting agent at pH 7 and air flow rate of 220 ml/min. It renders POM more hydrophilic and causes higher wettability. This corresponds to its smaller contact angle. It is found from the results that POM has smaller contact angle than PET and PVC, respectively. Therefore, POM remains in the flotation solution while air bubbles are attaching to PET and PVC. To succeed in separation of PET from PVC by selective flotation, 500 mg/l calcium lignosulfonate and 0.01% (w/v) Al 2(SO 4) 3 is added to a flotation solution at pH 5.8 and air flow rate of 180 ml/min. Negative charge ions on plastic surface are neutralized by aluminium ions. Additional, pH of solution is changed from 7 to 5.8 when 0.01% (w/v) adding Al 2(SO 4) 3. Magnitude of zeta-potential of PET and PVC changes from negative to positive value when changing basic condition to acidic one. In this current work, point of zero charge of PET and PVC are investigated. At point of zero charge, surface of plastic has a complete hydrophobic property. pH of solution plays an important role in flotation separation.

Effects of flotation solutions on sodium o-phenyl phenate injury to pears and on incidence of postharvest decay

‘Comice’ pears ( Pyrus communis) were immersed in dump tank solutions for pear flotation containing calcium lignosulfonate, sodium carbonate, potassium carbonate, potassium phosphate + potassium pyrophosphate, calcium chloride or sodium sulfate as flotation agents, alone or with 0.15 or 0.30% sodium o-phenyl phenate (SOPP). Phytotoxicity associated with SOPP was dependent on the flotation agent, the concentration of SOPP, duration of exposure and the solution temperature. Combinations of flotation agents in varying proportions, with SOPP, generally increased the incidence of phytotoxicity, although specific combinations of flotation agents did not result in fruit injury. Most flotation agents provided some control of decay in ‘Bosc’ pears inoculated with Penicillium expansum or Botrytis cinerea. Decay control generally improved with increasing concentrations of SOPP, but superior flotation agent/SOPP combinations were not identified.

The influence of flotation solution, sample dilution and the choice of McMaster slide area (volume) on the reliability of the McMaster technique in estimating the faecal egg counts of gastrointestinal strongyles and Dicrocoelium dendriticum in sheep

The present study was aimed to evaluate the influence of flotation solution, sample dilution, and the choice of McMaster slide area (volume) on the reliability of the McMaster technique in estimating the faecal egg counts of gastrointestinal (GI) strongyles and Dicrocoelium dendriticum in a composite sample of faeces from naturally infected sheep. Fourteen flotation solutions having densities between 1.200 and 1.450, and six sample dilutions, 1:10, 1:15, 1:20, 1:30, 1:40 and 1:50 were used. Each of the six dilutions was divided into 70 aliquots in order to have five replicates of each of the 14 flotation solutions at each of the six dilutions. For each McMaster slide, the GI strongyle and D. dendriticum egg counts were performed under one grid (McM 0.15 ml), two grids (McM 0.3 ml), one chamber (McM 0.5 ml), and both chambers (McM 1.0 ml). Mean eggs per gram (EPG) of faeces of GI strongyles and D. dendriticum were calculated and statistical analyses were performed on the resulting data. The type of flotation solution used significantly influenced the EPG in the GI strongyles and in the D. dendriticum egg counts. All the sucrose-based solutions at density between 1.200 and 1.350 floated more GI strongyle eggs than the others. With respect to D. dendriticum, only six solutions were capable of floating eggs and the potassium iodomercurate solution (density 1.440) floated more eggs than the others. The reliability of the McMaster technique regarding sample dilution was high for both GI strongyle and D. dendriticum EPG at 1:10 and 1:15, and then progressively decreased with increasing dilution. The reliability of the McMaster technique regarding the choice of the McMaster slide area (volume) was high for both GI strongyle and D. dendriticum EPG at the McMaster slide area (volume) of 1.0 ml, i.e. the total area of the McMaster slide. The EPG counts resulting from choosing any of the other three McMaster slide areas (volumes), i.e. McM 0.15 ml, McM 0.3 ml, or McM 0.5 ml, produced unreliable over-estimates. The findings of the present study show that the highest reliability of the McMaster technique for estimating GI strongyle and D. dendriticum egg counts in faeces from pastured sheep is obtained when using flotation solutions based on sucrose for GI strongyles, and potassium iodomercurate for D. dendriticum, dilutions which do not exceed 1:15, and the McMaster slide area (volume) of 1.0 ml.

Development of a Froth Flotation Process for Recovery of Used Emulsifiable Oil

The separation behavior of the lubricating oil from wastewater was studied using the technique; electroflotation. The optimum conditions for oil flotation were determined and the results were discussed according to a kinetic model. Further, the surface properties of the cationic collector were investigated. Cement kiln dust was used as an adsorbent applied to the flotation solution to investigate the kinetic and the adsorption equilibrium involved. According to the adsorption isotherm of the oil on the kiln dust, the optimum conditions for oil separation was suggested.

Solution and flotation chemistry of enargite

The flotation characteristics of enargite have been investigated in a micro-flotation cell in which the solution potential was controlled using hydrogen peroxide (H2O2) and sodium sulfide (Na2S). It was established that the oxidation–reduction potential of the flotation solution can have a pronounced influence on the flotation of enargite. Enargite displayed natural floatability under oxidizing conditions, and non-floatability under reducing conditions. In acidic solutions of pH<5.5, the hydrophobicty of enargite increased with increasing solution potential due to the formation of elemental sulfur on the mineral surface. However, in alkaline solutions, the hydrophobicity decreased with increasing solution potential due to the formation of CuO. The flotation of enargite was also studied in the presence of ethyl xanthate at pH 10.5. These results showed that enargite floated over a range of 0.2 V in the presence of xanthate. The floatability of the mineral increased with increasing solution potential due to the formation of cuprous xanthate and dixanthogen, then decreased with the decomposition of CuX to CuO under the influence of excess oxygen.

Fecundity and egg output by Toxocara canis in the red fox, Vulpes vulpes.

The role of the red fox Vulpes vulpes in the dissemination of eggs of Toxocara canis into the environment is considered with reference to female worm fecundity and egg output in the faeces of infected foxes collected from four localities in southern England. A significant positive correlation was found between female worm size and the number of eggs in the uterus but there was no significant relationship between T. canis worm numbers and egg output in fox faeces. Reliable estimates of worm burdens in foxes could not, therefore, be determined from faecal egg counts alone. The highest mean egg output of 2145.0 epg recorded from adult foxes indicated that fox cubs are not necessarily the main sources of environmental contamination with T. canis eggs. Saturated magnesium sulphate was found to be a more effective flotation solution than zinc sulphate and sodium chloride for recovering eggs from fox faecal samples.

Separation of Emulsifiable Oil from a Flotation Solution by Surface Tension Control

The oil flotation behaviour of emulsifiable oil was studied using N-octyl-N-benzyl-N-methylglycine (OBM) as the collector and heavy alkylate naphthalene sulphonates (HNS) as the de-emulsifier. The study showed that the surface tension has an effect on oil recovery. The interfacial tension at the air/water interface was controlled by the use of an alcohol such as ethanol, n-propanol and n-butanol and compared with the collector when used alone in froth flotation. The adsorption of the collector from the aqueous solution was investigated by measuring the surface tension as a function of concentration at different temperatures. Surface properties, in particular the critical micelle concentration (CMC), the effectiveness of surface tension reduction (ΠCMC), efficiency (PC20), the maximum surface excess (Γmax ) and the minimum surface area (Amin), were measured at temperatures of 25, 35 and 45oC, respectively. The results wermein discussed in terms of the adsorption isotherm and surface properties of the colle...

Method for detection and enumeration of Cryptosporidium parvum oocysts in feces, manures, and soils.

Eight concentration and purification methods were evaluated to determine percentages of recovery of Cryptosporidium parvum oocysts from calf feces. The NaCl flotation method generally resulted in the highest percentages of recovery. Based on the percentages of recovery, the amounts of fecal debris in the final oocyst preparations, the relatively short processing time (<3 h), and the low expense, the NaCl flotation method was chosen for further evaluation. Extraction efficiency was evaluated by using oocyst concentrations of 25, 50, 10(2), 10(3), 10(4), and 10(5) oocysts g of bovine feces-1. The percentages of recovery ranged from 10.8% (25 oocysts g-1) to 17.0% (10(4) oocysts g-1) (r2 = 0.996). A conservative estimate of the detection limit for bovine feces is ca. 30 oocysts g of feces-1. Percentages of recovery were determined for six different types of animal feces (cow, horse, pig, sheep, deer, and chicken feces) at a single oocyst concentration (10(4) oocysts g-1). The percentages of recovery were highest for bovine feces (17. 0%) and lowest for chicken feces (3.2%). Percentages of recovery were determined for bovine manure after 3 to 7 days of storage. The percentages of recovery ranged from 1.9 to 3.5% depending on the oocyst concentration, the time of storage, and the dispersing solution. The percentages of oocyst recovery from soils were evaluated by using different flotation solutions (NaCl, cold sucrose, ZnSO4), different dispersing solutions (Triton X-100, Tween 80, Tris plus Tween 80), different dispersion techniques (magnetic stirring, sonication, blending), and different dispersion times (5, 15, and 30 min). Twenty-five-gram soil samples were used to reduce the spatial variability. The highest percentages of recovery were obtained when we used 50 mM Tris-0.5% Tween 80 as the dispersing solution, dispersion for 15 min by stirring, and saturated NaCl as the flotation solution. The percentages of oocyst recovery from freshly spiked sandy loam, silty clay loam, and clay loam soils were ca. 12 to 18, 8, and 6%, respectively. The theoretical detection limits were ca. 1 to 2 oocysts g of soil-1 depending on the soil type. The percentages of recovery without dispersant (distilled H2O or phosphate-buffered saline) were less than 0.1%, which indicated that oocysts adhere to soil particles. The percentages of recovery decreased with storage time, although the addition of dispersant (Tris-Tween 80) before storage appeared to partially prevent adhesion. These data indicate that the NaCl flotation method is suitable for routine detection and enumeration of oocysts from feces, manures, soils, or soil-manure mixtures.

A useful UV spectroscopic method for the determination of the concentration of diethylenetriamine (DETA) in aqueous mineral flotation solutions

An alternative method for the determination of the concentration of diethylenetriamine (DETA) in aqueous mineral flotation solutions is described. This method is based on the formation of a DETA-Ni(II)-sulphite complex, which shows a UV absorption maximum at 285 nm that varies linearly with the concentration of DETA throughout the 0–50 mg l −1 DETA range. A high concentration of Ni(II) is used to offset the effect of any Cu(II) or Ni(II) ions that may already be present in the industrial plant solutions under analysis. The intensity of the absorbance maximum is dependent on the sulphite ion concentration, but this problem is overcome by measuring the absorbances when the test solutions are spiked with different concentrations of DETA and then extrapolating the absorbance versus DETA concentration plot to zero absorbance to obtain the original concentration of DETA in the test solutions.

Tests on the centrifugal flotation technique and its use in estimating the prevalence of Toxocara in soil samples from urban and suburban areas of Malaysia.

The influence of soil texture (silt, sand and laterite) and flotation solutions (saturated NaCl, sucrose, NaNO3, and ZnSO4) upon the recovery of Toxocara ova from seeded soil samples with the centrifugal flotation technique was investigated. Soil samples of different texture were artificially seeded with Toxocara spp. ova and subjected to a centrifugal flotation technique which used various flotation solutions. The results showed significant (P < 0.001) interactions between the soil types and the flotation solutions. The highest percentage of ova recovery was obtained with silty soil (34.9-100.8%) with saturated NaCl as the flotation solution (45.3-100.8%). A combination of washing of soil samples with 0.1% Tween 80, and flotation using saturated NaCl and a 30 min coverslip recovery period was used to study the prevalence of contamination of soil samples. Forty-six soil samples were collected from up to 24 public parks/playgrounds in urban areas of Petaling Jaya and suburban areas of Serdang. The prevalence of Toxocara species in the urban and suburban areas was 54.5% and 45.8% respectively.

The activation of sphalerite by lead — a flotation perspective

The activation of sphalerite by some metal salts has been briefly reviewed and the influence of lead nitrate on sphalerite in the presence of potassium ethyl xanthate has been investigated by a combination of batch flotation tests and solution analyses on pulps containing a mixture of sphalerite and quartz. The effect of lead addition, of pH and of complexant on the flotation behaviour has led to the conclusion that in mildly acidic conditions the activating entity is lead ion whereas in mildly alkaline conditions the activating entity is lead hydroxide. Some comparisons between lead activated sphalerite and galena have been made. The consequences of these findings in the separation of galena from sphalerite in practical flotation have been briefly discussed.

Influence of soil texture in the recovery of Toxocara canis eggs by a flotation method.

In epidemiological surveys, the evaluation of soil contamination by Toxocara canis eggs requires a quick and easy method for the isolation of parasite eggs from soil samples. The efficiency of flotation methods is influenced by sample size, soil texture, degree of soil contamination, pretreatment, flotation solutions and time of flotation. This investigation was designed to evaluate the influence of soil texture in the recovery of T. canis eggs with the centrifugal flotation technique of Dada (Dada, B.J.O., 1979. A new technique for the recovery of Toxocara eggs from soil. J. Helminthol., 53: 141-144). Four types of soil (clay silt, sandy, silty clay and sand) were artificially contaminated with T. canis eggs (200 eggs per gram). Zinc sulphate (specific gravity 1.20) and sodium dichromate (specific gravity 1.35) were used as flotation solutions. Twenty replicated examinations were performed for each type of soil and flotation solution. There was a statistically significant difference in the results depending on soil type. The highest recovery percentages were observed in soils rich in sand (62.5% for sand and 38.0% for sandy soil). Differences were also observed with different flotation solutions. Sodium dichromate solution was more efficient for recovering T. canis eggs, regardless of the soil texture.

Seed Populations ofStrigaSpecies in Nigeria

Seeds of Striga asiatica, S. gesnerioides, and S. hermonthica were separated from soil with a 2.5 M sucrose flotation solution and 250- and 150-μm mesh screens. In 34 fields, the average and range of seeds.100 g -1 of soil were 8.2 and 0−75, respectively. Seeds were recovered from 28 of the 34 fields sampled. Eighteen, six, and four fields had 1−5, 6−20, and > 21 seeds.100 g -1 of soil, respectively. The maximum number of seeds.100 g -1 of soil was 202, collected from one sample site in a field. Emerged S. asiatica, S. gesnerioides, and S. hermonthica were counted from 28 fields, and neither seeds nor plants of Striga were counted in two fields (.)

Diagnostic Parasitology

Diagnosis of parasitic infections in small animals is challenging, interesting, and fun, and involves the recognition of parasite stages based on size, morphology, color, and movement. Size and morphology are the major diagnostic parameters, and a calibrated microscope is the essential tool in the diagnostic laboratory. The fecal flotation technique is used routinely for the diagnosis of most parasites that reside within the gastrointestinal tract. The specific gravity and type of solution used often will influence the results obtained. A sugar flotation solution with a specific gravity of 1.27 is one that will float a majority of parasite stages with minimal distortion. Other techniques for diagnosis of specific gastrointestinal parasites include the direct smear and the merthiolate-iodine-formalin preservative method for diagnosis of Giardia sp, the Baermann technique for diagnosis of lungworm and other live larvae, the direct sedimentation technique for diagnosis of trematode eggs, the ether-formalin-sedimentation technique for diagnosis of trematode eggs and concentrating protozoan cysts from feces with high fat content, and the McMaster technique, a dilution modification of the fecal flotation technique. Techniques for evaluation of parasites in blood include the Knott's test, hematocrit method, and direct blood smear for diagnosis of microfilariae and thick and thin stained blood smears for diagnosis of Babesia sp, Haemobartonella sp, Cytauxzoon felis, Hepatozoon canis, and Trypanosoma cruzi. Tissue impression smears are used commonly for the diagnosis of Leishmania sp in dogs and biopsy specimens or aspirates are used for the diagnosis of Pneumocystis carinii. Diagnosis of acute toxoplasmosis can be accomplished with peritoneal and thoracic fluids, and organisms occasionally are detected in blood or spinal fluid. Serological tests for many parasitic diseases have been developed and often are used as supportive diagnostic tests.