Effect of Ultrasonics on Agglomeration

Nývlt, Jaroslav; Žáček, Stanislav

doi:10.1002/crat.2170300805

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…This is attributed to the fact that the reaction between Ca 2+ and CO 3 2– is significantly enhanced by ultrasonic irradiation, leading to the formation of loose scale floccules suspending in the solution, which can be easily washed away by the flowing liquid. This finding of accelerating reaction is consistent with Nishida et al, − but different from what is reported in some literatures, , i.e., a retardation effect on the crystallization of calcium carbonate is introduced with ultrasonic irradiation, the induction time is prolonged and the ionic reaction is retarded to obstruct the formation of scale…”

Section: Resultssupporting

confidence: 86%

“…In addition, ultrasonic irradiation shows superior characteristics, including cost-effectiveness, longevity, and environmental friendliness, as compared to chemical treatment methods. , It is difficult to determine the antiscaling efficiency and dissolution capacity for a specific scale in an oilfield, because there usually exists more than one type of scale. ,, No attempts have been made to systematically and quantitatively examine effects of frequency and acoustic intensity on the antiscaling efficiency. So far, contradictory statements on how ultrasonic irradiation affects crystallization have been found in the literature: accelerating reaction − and retarding reaction. , Ultrasonic irradiation is found to significantly accelerate the reaction of Ca 2+ and CO 3 2– ions together with a shortened crystallization initiation time. − On the contrary, it is deemed to be difficult for these two ions to react and form scale under ultrasonic irradiation due to the retarded crystal growth rate through dehydration and surface diffusion, imposing no effect on either the morphology or size of the formed calcium carbonate. , Such contradictory findings might be explained by considering different experimental conditions. As for the accelerating reaction, the ultrasonic frequencies used in the experiments are 24 kHz, whereas retarding reaction is found in a highly supersaturated solution with the ultrasonic irradiation of 17.7 Hz …”

Section: Introductionmentioning

confidence: 99%

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Determination of Antiscaling Efficiency and Dissolution Capacity for Calcium Carbonate with Ultrasonic Irradiation

Jian-guo

Yang

2012

Ind. Eng. Chem. Res.

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A systematic technique has been developed to determine antiscaling efficiency and dissolution capacity for calcium carbonate in oilfield brines under various ultrasonic treating conditions. During the static experiments, effects of ultrasonic frequency, acoustic intensity, treating time, and water level on the antiscaling efficiency have been evaluated, while the underlying antiscaling mechanism is identified and determined. Physically, the formation of calcium carbonate is promoted as a result of the decreased molecular force and accelerated movement of salty ions under ultrasonic irradiation. Most of the formed scale is found to loosely suspend in the liquid, rather than tightly adhere to the solid surface. During the dynamic experiments, orthogonal tests have been designed to examine effects of interval time, treating time, and flow velocity on antiscaling efficiency. As for the dissolution experiment, dissolution capacity is measured to evaluate the effect of ultrasonic frequency on dissolution of the formed calcium carbonate. The antiscaling efficiency is found to achieve its maximum value of 81.1%, using the ultrasonic treatment with a frequency of 28 kHz, an acoustic intensity of 0.61 W/cm2, an interval time of 2 h, a treatment time of 15 min, and a flow velocity of 1.8 m/s. It is also found that dissolution capacity does not impose a dominant effect on scale prevention and that the highest dissolution capacity of 19.3% is obtained with an ultrasonic frequency of 28 kHz.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Determination of Antiscaling Efficiency and Dissolution Capacity for Calcium Carbonate with Ultrasonic Irradiation

Jian-guo

Yang

2012

Ind. Eng. Chem. Res.

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“…Ultrasound has been widely reported to influence the primary nucleation process accelerating nucleation kinetics, this is typically expressed in terms of reducing the induction time and MSZW [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Ultrasound can also increase the rate of secondary nucleation, this is manifested as a reduction on the product crystal size distribution [20,22,24,31,32,[34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

et al. 2017

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Sono-crystallisation has been used to enhance crystalline product quality particularly in terms of purity, particle size and size distribution. In this work, the effect of impurities and ultrasound on crystallisation processes (nucleation temperature, yield) and crystal properties (crystal size distribution determined by Focused Beam Reflectance Measurement (FBRM), crystal habit, filtration rate and impurity content in the crystal product by Liquid Chromatography-Mass Spectroscopy (LC-MS)) were investigated in bulk suspension crystallisation experiments with and without the use of ultrasound. The results demonstrate that ultrasonic intervention has a significant effect on both crystallisation and product crystal properties. It increases the nucleation rate resulting in smaller particles and a narrower Particle Size Distribution (PSD), the yield has been shown to be increase as has the product purity. The effect of ultrasound is to reduce the level acetanilide impurity incorporated during growth from a 2 mol% solution of the selected impurity from 0.85 mol% to 0.35 mol% and likewise ultrasound reduces the uptake of metacetamol from 1.88 mol% to 1.52 mol%.

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“…In recent years, the technique of ultrasound irradiation has been used in the preparation of different functional materials during their precipitation from solution. Thus, it has been reported that ultrasonic irradiation can accelerate or retard precipitation , change the crystal size distribution and shape of crystals , or cause agglomeration of particles of different materials. Several authors have been investigating the effect of ultrasound application on the precipitation of calcium carbonate , particularly on its crystal growth , particle size , aggregation , and scaling .…”

Section: Introductionmentioning

confidence: 99%

Polymorphic composition and morphology of calcium carbonate as a function of ultrasonic irradiation

Džakula

Kontrec

Ukrainczyk

et al. 2014

Crystal Research and Technology

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This paper reports on the precipitation of CaCO 3 polymorphs, having various crystal morphologies under different conditions. In particular, systems that were subject to ultrasonic irradiation were compared to the corresponding reference systems in the absence of such a treatment. The application of ultrasonic irradiation predominantly resulted in a change of particle size distribution and polymorphic composition of the precipitate, in comparison to the reference systems. Thus, it was found that the supersaturation and temperature influenced the size distribution, in both the reference and sonicated systems. A mixture of calcite, vaterite and aragonite was obtained in all reference systems, at 25°C. At this temperature, the sonication caused the vaterite content to increase, while aragonite was not detected. In reference and sonicated systems at 80°C, only aragonite precipitated. The results also indicate that the principle parameter responsible for the morphology of vaterite was the initial supersaturation: at higher supersaturation spherical vaterite particles precipitated, while at lower supersaturation hexagonal platelets were obtained. The morphological investigations also indicated different mechanisms of vaterite formation in the systems in which precipitation was initiated at higher supersaturation: spherulitic growth of vaterite was observed in sonicated systems, while the aggregation of primary particles was predominant in the reference systems. At lower supersaturation, the effect of c(Ca 2+ )/c(CO 3 2− ) on the morphology of hexagonal platelets of vaterite was observed as well. By varying the c(Ca 2+ )/c(CO 3 2− ), significant changes of the polymorphic composition were observed only in the sonicated systems, at 25°C.

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Effect of Ultrasonics on Agglomeration

Cited by 6 publications

References 8 publications

Determination of Antiscaling Efficiency and Dissolution Capacity for Calcium Carbonate with Ultrasonic Irradiation

Determination of Antiscaling Efficiency and Dissolution Capacity for Calcium Carbonate with Ultrasonic Irradiation

The Effect of Ultrasound on the Crystallisation of Paracetamol in the Presence of Structurally Similar Impurities

Polymorphic composition and morphology of calcium carbonate as a function of ultrasonic irradiation

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