Application of Air Floatation in Water Quality Maintenance of Ecolandscape Pool in Zhongxing Mangrove Bay

The invasion of various pollutant sources and lack of water circulation may easily lead to the eutrophication and deteriorated water quality of the landscape water system.This study focuses on the application of air floatation method in water quality maintenance with the eco-landscape pool of Zhongxing Mangrove Bay as the study object,so as to provide a scheme for maintaining the water quality of artificial lakes.

Research on Performance of a Rectangular Floatation Cushion with High Stiffness for a Pneumato-static Slideway

In this paper, a high stiffness rectangular floatation cushion with a variable-section pressure equalizing groove of an elastic membrane for a pneumato-static slideway is presented and designed in order to increase stiffness of the floatation cushion. Gas film pressure distribution and carrying capacity of the floatation cushion are studied through theoretical analysis and by using the overlapping stitching technique. The carrying capacity and stiffness were obtained by using the coupling procedure of the gas lubrication governing equation and elastic deformation of the membrane governing equation. The results of theoretical calculations can obtain a conclusion that the effect of the gas pressure makes the annular elastic membrane elastically deform that brings about changes of throttling area and pressure groove depth of the floatation cushion. It makes carrying capacity and stiffness of the new style floata- tion cushion markedly improve over the conventional flotation cushion. The new floatation cushion has a wider ap- plication and popularization of space. Key words： floatation cushion; variable-section pressure equalizing groove;stiffness

Indirect Determination of CTMAB with Sodium Chloride and Ammonium Thiocyanate by Floatation and Separation of Zinc

A new method for indirect determination of cetyl-trimethyl ammonium bromide (CTMAB) with NaCl and NH4SCN by floatation and separation of zinc has been studied. The study shows that Zn(II) can associate with NH4SCN and CTMAB to form insoluble ternary ion-association complex, and the precipitate can float on the surface of the liquid phase. A good linear relationship is observed between the floatation yield (E%) of Zn(II) and the amount of CTMAB. On the ground, CTMAB can be indirectly determined by determining E% of Zn(II). The results were satisfactory.

AQUEOUS TWO-PHASE GAS FLOATATION SPECTROPHOTOMETRIC DETERMINATION OF TRACE TETRACYCLINE IN ENVIRONMENTAL WATER SAMPLE

A green method for separating and enriching trace tetracycline （TC） in environment water by Aqueous Two-phase Gas Floatation Spectrophotometry has been proposed, the principium was discussed. In this paper, the hydrophobic complex composed of Mg（II） and TC was floated into organic phase under the optimal conditions： pH=10, the floatation equipment is home-made, n-propyl alcohol as the organic solvent, sodium chloride as the separating phase reagent. The data were obtained by spectrophotometry after floatation; The linear regression equation is A=2.33×10^5C（mol/L）＋0.2179, linear range is from 3.77×10^-7mol/L to 6.32×10^-5 mol/L, respectively, with thecorrelation coefficient （r） better than 0.9997, relative recoveries is 99.7% to 100.3%, limit of detection was 4.29×10^-5mol/L, The method can be applied to analyse the trace TC in water sample, the result is better.

ENRICHMENT OF TRACE OF GOLD BY MEANS OF ION FLOATATION

Froth floatation possesses the advantages of simplicity, rapidity, and high efficiency. It may be divided into two classes: ion and precipitate floatations. At present, the enrichment factor for ion floatation of gold is 30, or the sample is enriched to a concentration of 5×10-4 mol. Our procedure attains an enrichment factor not less than 102, while the time does not exceed half an hour.

Microthermokinetic study of xanthate adsorption on impurity-doped galena

Six kinds of galena with different impurities were synthesized and the effects of impurities on the floatability of galena were investigated. The thermodynamic and kinetic parameters on the galena surface were measured using microcalorimetry, and the adsorption configuration and energy of butyl xanthate on the surfaces of galena with different impurities were simulated by density functional theory. Flotation experiments showed that Ag and Bi significantly promoted the recovery of galena, while Zn, Sb, Mn, and Cu reduced the recovery of the flotation. Microthermokinetic results indicated that the absolute value of xanthate adsorption heat was directly proportional to the flotation recovery of galena. Adsorption heat and reaction rate coefficients of xanthate on galena containing Ag or Bi were larger than those on pure galena, but smaller on galena containing Cu or Sb. Additionally, the relationship between the heat of unsaturated adsorption of xanthate and the adsorption energy of impurity atom on galena surface was investigated.

Growth of covellite crystal onto azurite surface during sulfurization and its response to flotation behavior

In this work,the growth of copper sulfide crystal onto azurite surfaces during sulfurization and its response to flotation are investigated.Filed emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM) and X-ray diffraction(XRD) studies confirmed that the sulfurization of azurite is not limited to the mineral surface,but rather penetrates into the bulk to form covellite crystal(synCuS),creating favorable conditions for the stable adsorption of xanthate and greatly promoting the azurite flotation.Additionally,as demonstrated by X-ray photoelectron spectroscopy(XPS) and time of flight secondary ion mass spectrometry(TOF-SIMS) analyses,a redox reaction occurred during this process,and Cu(Ⅱ) onto the mineral surface was reduced to Cu(Ⅰ).Correspondingly,reduced S^(2-) was oxidized to(S_(2))^(2-),(S_n)^(-2),and even to deeper oxidation state S~0,(S_(x)O_(y))^(n-) and SO_(4)^(2-).Excess sodium sulfide strengthens copper sulfide to form onto the azurite surface,and provides enough raw material for crystal copper sulfide to grow,resulting in the formation of "flake-like" covellite with a better crystallinity.However,the floatability of azurite decreased dramatically under this condition,because the generated massive colloidal copper sulfide in flotation pulp deteriorates the flotation environment,resulting in a decreased effective adsorption of collector onto azurite surfaces.

Experimental investigation and modeling of flotation column for treatment of oily wastewater

A unique cyclonic static microbubble flotation column was developed for oily wastewater separation.The separation effciency was found to be highly dependent on gas holdup and bubble size distribution.By changing the circulation pressure,gas flow rate,frother concentration,the effect of operation parameters on gas holdup and oil removal effciency were attained.A mathematical modeling between the kinetic constant and the gas holdup was established for oily water separation process.The results show that higher gas holdup and smaller microbubble sizes are benefcial to improve oil removal effciency.

Synthesis of γ-alkoxy-propylamines and their collecting properties on aluminosilicate minerals

alkoxy-propylamines, C12H25O（CH2）3NH2, C14H29O（CH2）3NH2, C16H33O（CH2）3NH2, C18H37O-（CH2）3NH2 were synthesized from aliphatic alcohol and acrylonitrile. The flotation tests of kaolinite, pyrophyllite and illite were conducted. The flotation mechanisms were explained in view of the structures of reagents and aluminium silicate minerals, zeta potential and Fourier transform infrared spectrum measurements. The results show that the synthesized r-alkoxy-propylamines are more effective than dodecyl amine for flotation of kaolinite, pyrophyllite and illite. For flotation kaolinite and illite, the collecting ability is in the order of C18H37O（CH2）3NH2>C16H33O-（CH2）3NH2>C14H29O（CH2）3NH2>C12H25O（CH2）3NH2, but the r-alkoxy-propylamines types of collectors have almost the same collecting ability on pyrophyllite, which demonstrating that γ-alkoxy-propylamines are new selective collectors for reverse floatation to remove aluminium silicate minerals from bauxite.

Flotation of Xinhua molybdenite using sodium sulfide as modifier

The feasibility of using sodium sulfide as the sole modifier for the flotation of Xinhua molybdenite ore was examined.The potential mechanisms involved in the different flotation systems were discussed.The comparative flotation results reveal that in the kerosene-sodium silicate flotation system,better recovery and grade of the molybdenum are obtained using sodium sulfide as the slurry pH adjustment agent than using CaO.Under the optimal conditions(64 g/t kerosene and 6 kg/t Na2S),satisfied recovery and grade of molybdenite concentrate can be achieved(84%and 8.2%,respectively),indicating that sodium sulfide is a potential substitute modifier of sodium silicate.The open-circuit flotation test results further confirm the effectiveness of sodium sulfide which may render recycling the tailing water possible and make the flotation process more environmental acceptable and more economical due to the less use of kerosene and scavengers.

Flotation of kaolinite and diaspore with hexadecyl dimethyl benzyl ammonium chloride

Tertiary amine was synthesized from fatty amine and formaldehyde. And then the synthesized tertiary amine was used to react with benzyl chloride to synthesize hexadecyl dimethyl benzyl ammonium chloride (1627) at ambient pressure. Using the synthesized 1627 as collector,the flotation properties of diaspore and kaolinite were investigated by single mineral and mixed mineral test. The flotation mechanism of diaspore,kaolinite and 1627 was discussed based on FTIR spectra. The results show that the mass ratio of aluminum to silicate achieves 15.02 and the recovery of alumina in concentrate is 43.07% using 1627 as a collector. The 1627 is found to be a more effective and a promising collector for reverse flotation to remove aluminum-silicate minerals from bauxite.

Effect of 2-aminothiophenol on the separation of jamesonite and marmatite

The minerals jamesonite and marmatite have similar surface properties.Separating them using a flotation method is inefficient.For separation of lead and zinc the lead mineral is generally floated preferentially to the zinc mineral,which appears in the sinks.In this study a new of collector,2-aminothiophenol,is introduced that can float a zinc mineral,as a product entrapped in foam,preferentially.Single mineral flotation tests revealed that 2-aminothiophenol has good selectivity for flotation of marmatite. An artificial mixture of minerals used in a flotation test showed that 2-aminothiophenol can effectively separate marmatite from jamesonite.A product assaying at 45.06%Zn and 4.06%Pb was produced.FTIR spectra were employed to probe the adsorption mechanism of 2-aminothiophenol onto marmatite.The results indicate that adsorption of 2-aminothiophenol onto jamesonite and marmatite were,respectively,physical adsorption and chemical adsorption.This agrees with the flotation results.

Effect of copper slag recovery on hydrometallurgical cut-off grades considering environmental aspects

Determining the hydrometallurgical cut-off grades specifies the destination of low grade materials and this is subjected to more benefits in mining. Copper production rate is considered as one of the fundamental issues in hydrometallurgical cut-off grades determination. Slags are remarked as one of the main sources of copper. It is not only regarded as a waste but also identified as another resource extracting base metals. Slags are characterized by copper high grade. Thus, slag copper recovery can be led to different cut-off grades and net present value(NPV). The current research scrutinizes the effect of slag recovery by both flotation and hydrometallurgical methods on the hydrometallurgical cut-off grades. For this purpose, the optimum cut-off grade algorithms of hydrometallurgical methods are developed by considering associated environmental parameters, incomes and also the costs. Then, their optimum amounts are calculated with NPV maximization as an objective function. The results indicate that considering slag copper recovery in the hydrometallurgical cut-off grade algorithms reduces the environmental costs caused by slag dumping and leads to more NPV by 9%.

EXPERIMENTAL STUDY ON UPGRADING OF A FINE-SCALED GRAPHITE ORE BY FLOTATION

Based on the quality and analysis of the medium carbon product whose grade was 81%-82%, the emphasis of the study was placed on the orthogonal experiments of roughing flotation reagent and single factors, such as abrasive grain, pulp concentration and the rotating speed of flotation machine. The result with improvement in the grade of concentrate to 95% through the routine floatation method was achieved.

Study on the Mechanism of Ultrasonically Enhanced Flotation Desulphurization

The mechanism of ultrasonic action and the influence of ultrasonic treatment on the changfs or particle size, dissolved oxygen, pH and the feasibility of flotation desul phurization with ultrasonic enhancement are studied. A new means of ultrasonic treatment for slurry is put forward. The test results indicate that by employing this means and an approprlate floatation technology and pyrite-depressed method, the optimum effect of rlotation desul phurization can be achieved.

SURFACE CHEMICAL CHARACTERISTICS AND FLOATION SEPARATION OF WOLLASTONITE AND GARNET

In order to nealize the efficient floatation separation of garnet and uiollastonite , the authors studied the surface chemical charac-teristics and various floatation behaviour of the two minerals?developed acidic combination depressant FDi and introduced sodium oleate j FeCls and FDi as the flotation agent, they achieved success. In the experimental re-search on the artificiallymixed ores separation, the recovery and concentra-tion grade of the two minerals ivere both over 92% and 95% respectively. At the same time , it was found that the chemical absorption form of iron oleate presented bridge and chelating patterns on the surfaces of garnet and wollastonite activated by Fe3+.

Removal of Silica and Alumina as Impurities from Low-Grade Iron Ore Using Wet High-Intensity Magnetic Separation and Reverse Flotation

This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.

Utilization of Bubbles and Oil for Microplastic Capture from Water

The removal of microplastics(MPs)from water using oil has shown early promise;however,incorporation of this technique into a feasible in situ method has yet to be developed.Here,a simple yet effective method of MP capture from water using vegetable oil with bubbles is demonstrated to achieve high removal efficiencies of>98%.Comparisons are made with other methods of agitation,and higher removal efficiencies are observed when bubbles are used.Due to the low agitation provided by the bubbles,the oil layer remains unbroken,meaning that no oil is released into the bulk water phase.In this way,secondary contamination is avoided—unlike membrane filtration,another effective removal method,in which polymer-based membranes can break down due to chemical backwashing and ageing.It is demonstrated that variation in MP size within the micrometer range(50–170 lm)has minor impact on the removal efficiency;however,100%removal is achieved for larger,millimeter-sized MPs(500–5000 lm).Similarly,a high removal efficiency of greater than 99%is achieved in the capture of microfibers.Other factors such as oil volume and water salinity are also investigated and discussed.Based on these results,the proposed method can be introduced into multiple setting types as a passive and continuous method of MP capture.

The treatment of black-odorous water using tower bipolar electro-flocculation including the removal of phosphorus,turbidity,sulfion,and oxygen enrichment

The large amount of municipal wastewater discharged into urban rivers sometimes exceeds the rivers’self-purification capacity leading to black-odorous polluted water.Electro-flocculation has emerged as a powerful remediation technology.Electro-flocculation in a bubble column tower with a bipolar electrode(BPE)was tested in an attempt to overcome the high resistance and weak gas-floatation observed with a monopolar electrode(MPE)in treating such water.The BPE reactor tested had a Ti/Ta2O_(5)-IrO_(2)anode and a graphite cathode with an iron or aluminum bipolar electrode suspended between them.It was tested for its ability to reduce turbidity,phosphate and sulphion and to increase the concentration of dissolved oxygen.The inclusion of the bipolar electrode was found to distinctly improved the system’s conductivity.The system’s electro-flocculation and electrical floatation removed turbidity,phosphate and sulphion completely,and the dissolved oxygen level improved from 0.29 to 6.28 mg/L.An aluminum bipolar electrode performed better than an iron one.Changes in the structure of the microbial community confirmed a significant improvement in water quality.

Analysis of plant remains at the Neolithic Yangjia Site, Wuxi City, Jiangsu Province (East China)

According to archaeological investigation and preliminary excavation, the Yangjia Site, located in the northern Taihu Lake region, at Wuxi City, Jiangsu Province, is a Neolithic archaeological site dominated by cultural remains attributed to the late Majiabang Culture(6270–5920 cal. a BP). Here a systematic archaeobotanical study was conducted to investigate vegetation landscape, environmental characteristics and rice agriculture in the prehistoric northern Taihu Lake area. The abundance, frequency and standard density of charred rice were the highest of all of the remains of the seed plants unearthed. In addition, a variety of wetland weeds, such as Haloragaceae, Cyperaceae, Carex sp., and Oxalis corniculata, were found. Pollen and phytoliths recorded that the evergreen-deciduous broadleaf mixed forest(represented by Quercus and Castanopsis) tends to decrease, while Poaceae was the most significant of the terrestrial herbs, water area expanded and water activities strengthened, indicating generally warm and humid conditions at the Yangjia Site during the late Majiabang Culture. All indicators of pollen, phytolith and macro-plant remains suggest that wild rice should be once distributed at or around the site before human occupation, after which rice agriculture progressed rapidly during the late Majiabang Culture.