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EN
Preconditioning of coal tailings with flocculants is a useful technology to improve filtration performance. In this study, anionic and cationic polyacrylamides were used for the pretreatment coal tailings before filtration. Nondestructive and rapid measurement of the filter cakes of coal tailings at different filtration stages was conducted using a nuclear magnetic resonance (NMR). The transverse relaxation time (T2) results of NMR provided the information concerned the state of water in filter cake, showing that free water entrapped in larger pores was removed mainly during coal tailings filtration, and the pressure in this study cannot remove the inherent moisture of filter cake of coal tailings. The significant increase in the amplitude of T2 value between 0.1 and 1.0 ms revealed that the flocs collapsed into smaller ones with water entrapped in them during filtration. Comparing the NMR results with different flocculants shows that anionic polyacrylamide of 800 g/Mg produced a larger structure in the initial stage of filter cake formation. The final filter cake entrapped more water. The NMR results well validated the filtration experiments.
EN
Phosphoric acid sludge is one of the prominent problems in the phosphate industry. Its formation is co-occurred by considerable losses of P2O5 that affect the process performance. Management and valorization of this waste is a key issue. This work aimed to deal with this industrial concern by studying the influence of the flocculation on the sludge sedimentation and thus the P2O5 recovery rate. The flocculation tests were conducted in the presence of various types of anionic polymers. The effect of dosage, molecular weight, and type of flocculant were examined. The results indicated that all polymers showed settling performance improvement. And, the flocculant with the highest molecular weight (F1), showed the best settling performance with a pace of 3.3 cm/min and the lowest turbidity value of 40.4 NTU using a dosage of 5 ppm. Due to its high molecular weight, this polymer carries a polyelectrolyte bridging mechanism, which allows the absorbed polymer to move further away from the surface of the particle and then increases the particle radius, the number of collisions, and thus the particle size. However, for the P2O5 recovery rate, the sulfonic polymer (F5) was the best performer allowing recovery of 78.8% of the total mass of the sludge. F5 is weakly amphoteric. Polymers containing sulfonic acid groups are known to be inherently powerful than the carboxylic acid groups as they are stable due to their high energy barrier. According to the results, the flocculation increases the recovery of P2O5, which represents a profit of more than 30 kg of clarified phosphoric acid per 1 tone of sludge.
EN
Low-rank coals are generally processed with wet methods including washing, flotation, etc. Fine-sized tailings of these processes are discharged to tailing ponds with a significant amount of associated water which contains a high amount of dissolved ions. These tailings should be dewatered employing coagulation/flocculation in terms of technological and environmental aspects. In this study, the coagulation/flocculation behavior of coal processing plant tailings obtained from Manisa, Turkey was investigated in the presence of monovalent (Na+, K+) and divalent (Mg2+, Ca2+) ions and an anionic flocculant (SPP-600). First, the coagulation properties of coal tailings were determined. Then, the flocculation experiments were carried out, and the turbidity values of the suspensions were measured. Moreover, the sizes of the flocs were determined using a laser diffraction particle size analyzer to analyze the strength of the flocs. The results of the coagulation experiments showed that while divalent ions were more effective at 10-1 mol/dm3, higher settling rate and lower turbidity values were obtained in the presence of monovalent ions at 1 mol/dm3 concentration. The optimum flocculant dosage was obtained as 150 g/Mg from the flocculation experiments. The floc size and strength measurements indicated that the larger flocs were obtained with Na+ than Ca2+ in the presence of the flocculant. The strongest flocs were obtained at 10-1 mol/dm3 Ca2+ + 150 g/Mg flocculant. It can be concluded from this study that the coagulation followed by the flocculation method can be employed to obtain fast flocculation behavior and low turbidity for the dewatering of coal tailings.
EN
Using more efficient collector to improve the recovery efficiency of fine copper oxide has become imperative as the shortage of copper mineral resources. In this study, the new collector 3-hydroxy butyrate-carboxy methyl cellulose xanthate (HCMCX) was synthesized by carboxy methyl cellulose, 3-hydroxy butyrate and carbon disulfide, all of which as raw materials . The structural characteristics of HCMCX was detected by both infrared spectrum and ultraviolet spectrum. Besides, the interacting behavior between HCMCX and fine malachite was investigated through particle size analysis, contact angle measurements, and flotation tests. Particle size analysis indicated that the mean size of malachite was increased by 8 μm while the HCMCX concentration at 200 mg/dm3. The contact angle measurements demonstrated that, comparing with the collector AX at a same dosage, the mineral surface of malachite showed a stronger hydrophobicity after interacting with HCMCX. Microflotation tests results exhibited that the recovery of malachite was about 94% when the pulp pH 8 and collector concentration at 200 mg/dm3. The results of practical ore flotation tests showed that HCMCX could as an excellent collector for flotation of fine malachite, finally to achieve the concentrates containing 20% Cu and 88% Cu recovery.
EN
The main aim of the article is to analyse physical and chemical factors affecting the structure and strength of aggregates generated during coagulation and flocculation of water admixtures in the aspect of computer process simulation. The proposed mathematical relationships were used for computer modelling of the process and visualization of the obtained results. The results of the operation and visualization of the algorithms are presented in graphical form. Laboratory tests were carried out in order to check the correctness of the proposed algorithm.
PL
Głównym celem artykułu jest analiza czynników fizycznych i chemicznych wpływających na strukturę i wytrzymałość agregatów powstających podczas koagulacji i flokulacji domieszek wody w aspekcie komputerowej symulacji procesu. Zaproponowane zależności matematyczne wykorzystano do komputerowego modelowania procesu oraz wizualizacji uzyskanych wyników. Wyniki działania i wizualizacji algorytmów przedstawiono w formie graficznej. W celu sprawdzenia poprawności proponowanego algorytmu przeprowadzono badania laboratoryjne.
EN
The launch of new pressure flotation installations (DAF) and the optimization of existing installations of this type requires a number of laboratory and pilot plant tests. Such studies are expensive and labor-intensive. Using the principles of computer modelling it would be possible to minimize both costs and time of conducting research. This paper presents a proposal to use the developed mathematical model of the DAF process based on the law of conservation of momentum (impulse) and the Navier-Stokes equation. The model allows to describe the kinetic relations between the water stream, air bubbles and aggregates arising as a result of coagulation of surface water pollution. The model takes into account the exchange of impulses between different phases as a result of laminar and turbulent flow. The developed model was used to prepare a simulation computer program. In order to check the applicability of the model, laboratory tests were carried out under static conditions, the results of which demonstrated the suitability of the model for analyzing the effectiveness of solid phase removal from water in the coagulation/dissolved air flotation process used in surface water treatment.
PL
Uruchomienie nowych instalacji flotacji ciśnieniowej (DAF) i optymalizacja już istniejących instalacji tego rodzaju wymaga przeprowadzenia szeregu badań laboratoryjnych i pilotowych. Takie badania są kosztowne i pracochłonne. Wykorzystując zasady modelowania matematycznego, można zminimalizować zarówno koszty, jak i czas prowadzenia badań. W niniejszej pracy przedstawiono propozycję wykorzystania opracowanego modelu matematycznego procesu DAF w oparciu o prawo zachowania pędu (impulsu) i równania Naviera-Stokesa. Model pozwala opisać relacje kinetyczne pomiędzy strumieniem wody, pęcherzykami powietrza i agregatami powstającymi w wyniku koagulacji zanieczyszczeń wód powierzchniowych. Model uwzględnia wymianę impulsów między różnymi fazami w wyniku przepływu laminarnego i turbulentnego. Opracowany model posłużył do przygotowania symulacyjnego programu komputerowego. W celu sprawdzenia aplikacyjności modelu przeprowadzono testy laboratoryjne w warunkach statycznych, których wyniki wykazały przydatność modelu do analizy skuteczności usuwania fazy stałej z wody w procesie koagulacja//flotacja ciśnieniowa wykorzystywanym w uzdatnianiu wód powierzchniowych.
EN
The recycling of water treatment residues (WTR) inside drinking water treatment plants (DWTP) to be a good option for reusing this type of waste, as well as for reducing the costs with its disposal off and with the acquisition of treatment chemicals. Therefore, a WTR was reused for auxiliary of the coagulation-flocculation processes for reducing the use of aluminium sulfate (coagulant) in a DWTP. Three series of experiments have been conducted involving three water samples with different turbidity and colour, different WTR samples with different total suspended solids (TSS) concentrations and different aluminium sulfate concentrations. The results showed that WTR can efficiently be used for the removal of turbidity between 21 NTU and 218 NTU and colour between 194 HU and 1509 HU for TSS concentration between 1635 mg/dm3 and 5420 mg/dm3, with better results in the range between 1635 mg/dm3 and 2678 mg/dm3. For higher TSS concentrations, the removal of both parameters decrease because there are excess of organics released to water, which demands the use of more coagulant.
PL
Celem pracy było wykorzystanie granulometru laserowego do pomiaru wielkości cząstek powstających w procesie koagulacji z zastosowaniem koagulantów żelazowych w wodzie niezawierającej znacznych ilości substancji organicznych. Badania przeprowadzono z wykorzystaniem wody wodociągowej pochodzącej z ujęć podziemnych. Do wody dozowano koagulant żelazowy PIX112 (siarczan żelaza(III) – Fe2(SO4)3) w dawkach o 2,0 do 10 mg Fe/dm3. Już w kilka sekund po dozowaniu koagulantu w wodzie pojawiały się drobne cząstki o wymiarach od 0,03 µm do ok 0,5 µm. Następnie następował stały wzrost wielkości kłaczków, do rozmiarów około 130÷500 µm, przy którym proces osiągał stan ustalony. Prędkość zwiększania się wymiarów kłaczków oraz czas, po którym kłaczki osiągały maksymalne rozmiary, był zależny od dawki siarczanu żelaza. Wraz ze zwiększaniem dawki koagulantu kłaczki szybciej powiększały swoje wymiary i szybciej osiągały maksymalne rozmiary. Pomimo systematycznego wzrostu kłaczków w początkowym okresie, w roztworze nadal utrzymywały się najdrobniejsze cząstki, które stopniowo wbudowywane były w większe aglomeraty. Proces ten trwał od kilku sekund do kilku minut i był zależny od dawki koagulantu. Im mniejsza była dawka, tym dłuższy był czas utrzymywania się najmniejszych cząstek.
EN
The aim of the work was to use a laser granulometer to measure the size of particles produced by coagulation using ferric coagulants in water containing no significant amounts of organic substances. The research was carried out using tap water, coming from underground water intakes. PIX112 coagulant was dosed into the water at doses of 2.0 to 10 mg Fe/dm3. Already a few seconds after dosing the coagulant, small particles of size from 0.03 μm to about 0.5 μm appeared in the water. Then there was a constant increase in the size of flocks, to the size of about 130÷500 μm, at which the process reached steady state. The rate of increase in the size of the flocs and the time after which the flocs reached the maximum size was dependent on the dose of iron sulphate. With increasing the dose of coagulant, the floccules increased their size faster and reached their maximum sizes faster. Despite the systematic growth of flocs in the initial period, the smallest particles, which were gradually incorporated into larger agglomerates, still remained in the solution. The process lasted from a few seconds to several minutes and was dependent on the dose of the coagulant. The smaller the dose, the longer the time of maintaining the smallest particles.
9
Content available remote Laboratoryjne badania sedymentacji wielostrumieniowej zawiesin nieziarnistych
PL
Przedstawiono wyniki badań procesu sedymentacji zawiesin nieziarnistych z koagulacji drobnouziarnionych zawiesin reprezentatywnych dla wód ujmowanych do stacji uzdatniania wody. Zaprezentowano wpływ zmiany obciążenia powierzchniowego zawiesin skoagulowanych różnymi dawkami flokulantów i wykazano skuteczność techniki sedymentacji wielostrumieniowej dla klarowania takich właśnie zawiesin. Wykazano przydatność techniki sedymentacji wielostrumieniowej również dla zawiesin nieziarnistych.
EN
Two non-granular slurries were prepd. by mixing silty and clay soils with water and then sepd. by sedimentation after addn. of an Al flocculant (15-65 ppm). The removal of solids from the suspensions was higher than 75%. The turbidity of the purified water was below 20 NTU.
EN
A low-grade copper ore from Mpanda Mineral Field (MMF), Tanzania containing 0.90% Cu, 10.40% Fe and 58.3% SiO2 was subjected to beneficiation adopting selective dispersion, flocculation and flotation techniques. Based on the mineralogical characterization of the sample chalcopyrite, pyrite and quartz were identified as the major minerals. The isoelectric point of MMF ore was observed to be at pH 2.7, signifying that the ore was highly siliceous. The addition of sodium trisilicate and xanthan gum shifted the zeta potential of ore to more electronegative values. Adsorption of xanthan gum on chalcopyrite and silica indicated that the maximum adsorption was at pH 2.3 for chalcopyrite and the adsorption isotherm exhibited L2 type of the Giles classification. On the contrary, no adsorption of xanthan gum on silica was observed. The ground ore was selectively dispersed and flocculated at pH 9.7 using 30 ppm of sodium trisilicate and 30 ppm of xanthan gum. The grade of CuFeS2 was improved to 19.8% after 3 desliming stages. Flotation of the flocculated portion was carried out at pH 10.30 using 30 g/t of potassium amyl xanthate and potassium ethyl xanthate (1:1) , 40 g/t of Na2S as a sulphidising agent and methyl iso-butyl carbinol (MIBC) as a frother yielding a rougher concentrate with silica and chalcopyrite grades of 8.4% and 23.5% respectively with corresponding recoveries of 4.8% and 92.8% respectively. Additionally, rougher concentrate was subjected to cleaner flotation yielding silica and chalcopyrite grades of 1.8% and 29.2 % respectively and with recoveries of 1.2% and 89.1% respectively.
EN
Talc usually exists as a gangue mineral in copper-nickel sulfide, molybdenite etc. In order to separate precious metals, naturally hydrophobic talc should be depressed effectively in flotation process. The effect of fenugreek-gum (FG) on the flotation performance of talc with different particle sizes was studied. The depression mechanism was investigated extensively through tests of flotation, adsorption and zeta potential, as well as infrared spectroscopy and laser particle size analysis. Flotation results indicated that the FG had a strong depression ability for talc with the particle size of -0.074 + 0.037 mm, -0.037 mm and -0.010 mm when proper dosage of FG was added. The coarse talc was completely depressed by 2.5 mg/ dm3 FG. When the particle size decreased, more FG was required to obtain the maximum depressing effect, which was verified by adsorption tests. FG reduced the electronegativity on the talc surface by chemical adsorption, and flocculation of talc powders caused a high efficient depressing effect.
EN
There is a need to create a low-cost and effective resource-saving technology for wastewater treatment contaminated with paintwork materials, which would allow reusing water in the production cycle of the enterprise. Studies have been carried out to prove the possibility of using spent technological solutions in the joint purification of sewage from galvanic and paint and varnish industries. The developed technology enables to reduce the costs of the enterprises for its cleaning and negative impact on the environment, reduce the load on urban treatment facilities, and reduce the equipment costs.
EN
The objective of this work was to test the impact of coagulant and flocculant at the stage of mechanical wastewater treatment on the wastewater treatment plant operation, performed in the A2O process. In this paper, the principles of correct conduct of coagulation in wastewater treatment have been discussed. It appears from the research performed that significant elimination of BOD5 such as 20÷30%, total suspended matter up to 90%, COD up to 50% and total nitrogen at 30% level was achieved supported by the coagulation process in the pre-settling tanks. Approximately 50% of phosphorus was eliminated after the mechanical part. Additionally, a significant impact of Superfloc flocculant on the effectiveness of the solid phase separation (activated sludge) in the secondary settling tank was noted under diversified flow conditions.
PL
Przedstawiono wyniki pomiarów spadków ciśnienia podczas przepływu emulsji stabilizowanych solą sodową karboksymetylocelulozy (Na-CMC, M = 250 000, stopień podstawienia DS = 1,2) przez złoże szklanych cząstek kulistych. Silnie sflokulowane emulsje z dodatkiem Na-CMC posiadały granicę płynięcia, a krzywe płynięcia opisano modelem Herschela-Bulkley’a. Z analizy danych doświadczalnych wynika, że zaproponowana metoda obliczania strat ciśnienia daje zadowalające rezultaty (błąd względny poniżej 10%) jedynie dla bardzo małych wartości promienia bezwymiarowego.
EN
The study presents the measurements results of pressure drop during the flow of emulsions stabilized by carboxymethylcellulose sodium salt (Na-CMC, M = 250 000, degree of substitution DS = 1.2) through a packed bed of glass spheres. Highly flocculated emulsions with the addition of Na-CMC appeared to be yield-stress fluids whose flow curve can be described by the Herschel-Bulkley equation. The analysis of experimental data shows that the proposed method of pressure drop calculation gives satisfactory results (relative error below 10%) only for very smali values of dimensionless radius.
15
Content available remote Charakterystyka procesu sedymentacji mikroglonów Chlorella vulgaris
PL
Dokonano oceny możliwości wykorzystania różnych metod separacji alg z medium hodowlanego. Szczegółowo omówiono wyniki badań własnych nad wykorzystaniem w tym celu procesu sedymentacji. Określono wpływ początkowego stężenia zawiesiny na szybkość procesu sedymentacji oraz wskazano na możliwość wykorzystania zjawiska autoflokulacji w celu poprawy procesu rozdziału.
EN
The paper evaluates the possibility of using different algae harvesting methods for their separation from cultivation medium. The research results dealing with the application of sedimentation process for this purpose are discussed in details. The influence of initial suspension concentration on the sedimentation rate was determined and possibility of using the autoflocculation to improve separation process was indicated.
EN
Transport of fine sediments depends mainly on the efficiency of flocculation. Flocculation, understood as the result of simultaneous processes of aggregation of particles and floc break-up, is a common phenomenon in marine environments. It is typical of fine sediments. This study presents a mathematical model of fine sediment transport. A model of flocculation is an important part of this model. Its main assumption is that flocculation is governed by turbulence. The model was qualitatively tested in a simplified theoretical waterbody. Such factors as the wind direction, wind speed, river discharge and concentration of suspension in the river were investigated. The results show that the proposed model describes reasonably well the lithodynamic processes characteristic of fine flocculating sediments. Thus it seems possible to apply it for description of fine sediment transport under real wave–current conditions that occur in many marine waterbodies near river mouths.
EN
The article presents the possibilities of employing an integrated flocculation/ultrafiltration system in the treatment of washings generated upon the rinsing of filter beds in pool water installations. Single ultrafiltration process was used as a comparator. Flocculation was carried out using commercial dialuminium pentahydroxychloride solution widely used at pool facilities for the removal of contaminants in flocculation processes. The studies consisted in determination of correlations between the conditions of the flocculation process (variable doses of Al3+ ions: from 4 to 280 mg/L) and the transport/separation characteristics of ultrafiltration membranes. Flocculation was performed at different temperatures of washings i.e. 8, 21, and 30°C for each of the pre-defined doses. Ultrafiltration was highly capable of reducing the turbidity of washings and removing a large group of contaminants as determined by turbidimetry and UV254 absorbance measurements. The studies revealed that the best transport/ separation characteristics of ultrafiltration membranes were obtained in a system in which ultrafiltration was performed following flocculation of washings carried out at 21°C using a 40 mgAl3+/L solution. The turbidity was reduced by ca. 99% and UV absorption was reduced by ca. 94% while the relative volumetric stream of the permeate increased by more than 35% (as compared to the filtration of washings in a single-process system). Membrane ultrafiltration significantly increased the quality of the waste stream consisting of washings from the pool water installation. Pre-processing of washings is required before ultrafiltration in order to limit the blocking of membrane pores. Flocculation may be one of such pre-processing methods.
PL
W pracy zaprezentowano wyniki badań nad zastosowaniem membran kompozytowych z poliakrylonitrylu (PAN) domieszkowanego tlenkiem grafenu (GO) do usuwania zanieczyszczeń ze ścieków pogalwanicznych. Membrany otrzymywano metodą inwersji faz z roztworu PAN i GO w N,N-dimetyloformamidzie (DMF). Pozyskane ścieki wstępnie podczyszczano za pomocą flokulanta Magnafloc®336. Następnie w celi ultrafiltracyjnej AMICON prowadzono ultrafiltrację podczyszczonych ścieków, na wytworzonych wcześniej membranach kompozytowych PAN/GO. Badania właściwości fizykochemicznych oraz składu roztworów przed i po procesach zintegrowanego oczyszczania prowdzono za pomocą spektrofotometru UV-Vis oraz atomowej spektrometrii absorpcyjnej (ASA). W wyniku prowadzonej flokulacji ze ścieków zostały usunięte fosforany (97%), chlorki (5,2%), siarczany (5,9%) oraz żelazo (82%). Natomiast w trakcie ultrafiltracji całkowicie usunięto aniony fosforanowe (100%) oraz żelazo (91÷92%), cynk (68÷84%), ołów (65–98%) i kadm (~67%).
EN
The paper presents the results of research on the use of composite membranes of polyacrylonitrile (PAN) doped with graphene oxide (GO) to remove the contaminations of galvanic wastewater. Membranes were obtained using phase inversion method from PAN and GO solution in N,N-dimethylformamide (DMF). Wastewater was pre-treated with the flocculant Magnafloc®336. Next, ultrafiltration of the treated wastewater was carried out in the ultrafiltration cell AMICON on the PAN/GO composite membranes prepared beforehand. The physicochemical properties and composition of solutions before and after the integrated purification process were analyzed by means of a UV-Vs spectrophotometer and atomic absorption spectrometry (AAS). As a result of flocculation from wastewater, phosphates (97%), chlorides (5,2%), sulfates (5,9%) and iron (82%) have been removed. In addition, as a result of ultrafiltration, a complete removal of phosphate anions (100%) and iron (~91–92%), zinc (68÷84%), lead (65–98%) and cadmium (~67%) was achieved.
EN
The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide) copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland) were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD). It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST). Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.
EN
Although the flocculation process was invented a half century ago, the novel methods of suspension destabilization are still of great interest of both scientific community and industry. The goal of this work is to review the current state of application of stimuli-responsive polymers as stabilization agents in solid-liquid dispersion systems.
PL
Proces flokulacji opracowano pół wieku temu, ale metody destabilizacji zawiesin nadal cieszą się dużym zainteresowaniem zarówno środowiska naukowego, jak i przemysłu. Artykuł stanowi przegląd aktualnego stanu wiedzy na temat zastosowania polimerów reagujących na bodźce zewnętrzne jako czynników stabilizujących układy dyspersyjne typu ciało stałe-ciecz.
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