Continuous synthesis of lithium iron phosphate (LiFePO4) nanoparticles in supercritical water: Effect of mixing tee

Hong, Sungryong; Kim, Su Jin; Chung, Kyung Yoon; Chun, Myung‐Suk; Lee, Byung Gwon; Kim, Jae-Hoon

doi:10.1016/j.supflu.2012.11.008

Cited by 45 publications

(32 citation statements)

References 54 publications

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“…It can be seen that the metal salt solution and supercritical water were uniformly mixed and heated. As commented in a previous study, 12 when an asymmetric mixer is used in the SWHS reaction, heterogeneous nucleation and growth at the wall of the mixer are often observed as a result of an insufficient mixing rate and asymmetric flow. Some symmetric mixers, such as swirling-tee 12 and central collision-type 11 mixers, have been studied.…”

Section: Symmetric Multiple-tee Mixermentioning

confidence: 87%

“…The kth moment can be defined as 12) where N is the specified number of moments with a value of 6. From these moments, the four parameters describing the gross properties of the particle population can be derived, namely, the total number of particles N t , length L t , area A t , and volume V t of solid particles per unit volume of mixture suspension = N m t 0…”

Section: Population Balance Equationmentioning

confidence: 99%

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Impact of Mixing for the Production of CuO Nanoparticles in Supercritical Hydrothermal Synthesis

Zhou

Wang

2013

Ind. Eng. Chem. Res.

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The mixing process of metal salt solutions and supercritical water is essential to supercritical water hydrothermal synthesis (SWHS) to produce nanoparticles. A computational fluid dynamics (CFD) model was developed for predicting mixing efficiency and crystallization kinetics in SWHS mixers. The mixing efficiency was calculated from the micromixing model, and the kinetics model of crystallization was built from the population balance equation. The effects of the fluid dynamics of mixing (Reynolds number and mixer diameter) on the mixing efficiency and crystallization kinetics (nucleation rate and growth rate) were investigated. The results showed that faster mixing can lead to a higher crystallization rate and the production of smaller particles with a narrower particle size distribution. INTRODUCTIONThe supercritical water hydrothermal synthesis (SWHS) method is widely used to produce metal oxide nanoparticles from metal salt aqueous solutions using high-temperature and -pressure water as the reaction medium. The extremely low dielectric constant of supercritical water can lead to a high hydrothermal synthesis reaction rate and a low solubility of metal oxides, which help to produce fine particles. 1 Compared with single atoms and bulk materials, nanomaterials have high application value because of their special size-related properties. For example, they can be used in transducers, batteries, and ceramics and as efficient photocatalysts. The SWHS method has the advantages of fast reaction, high product purity, and good environmental compatibility. Furthermore, the morphological structure and particle size of the synthesized particles can be controlled by the processing parameters such as reaction temperature, pressure, precursor concentration, and flow rate. 2−5 In the SWHS reaction, proper design of the mixer is a key factor in obtaining products with decreased particle sizes and narrow particle size distributions (PSDs). 2,6 The usual process of continuous SWHS is that metal salt solution mixes directly with supercritical water and is rapidly heated to the supercritical state. The process has advantages including high heating rate, short residence time, and easy industrial scaleup. 7,8 However, in the continuous SWHS reaction system, particle plugging and hard-to-control particle size are frequently encountered problems. The source of the problems is unreasonable design of the mixer, resulting in slow and nonuniform mixing of the metal salt solution and supercritical water. To date, various types of mixers have been developed in the study of the SWHS method for the preparation of nanoparticles. In addition to the traditional tee mixer, some new mixers have also been reported, such as Y-type, 9 nozzle-type, 10 central collisiontype, 11 and swirl-type 12 mixers. From an engineering perspective, to optimize the design of the mixer, it is necessary to acknowledge the fluid dynamics inside the mixer and the crystallization kinetics on the mixing time scale of tens of milliseconds. 13

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Section: Symmetric Multiple-tee Mixermentioning

confidence: 87%

Section: Population Balance Equationmentioning

confidence: 99%

Impact of Mixing for the Production of CuO Nanoparticles in Supercritical Hydrothermal Synthesis

Zhou

Wang

2013

Ind. Eng. Chem. Res.

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“…Lanthanum oxide nanoparticles [56], lithium iron phosphate (LiFePO 4 ) nanoparticles [57], NiO nanoparticles [58], zinc oxide nanoparticles [59], ZnO nanoparticles formation by reactions of bulk Zn with H 2 O and CO 2 [60], CFD simulation of ZnO nanoparticle synthesis [61], hafnium oxide nanoparticles [62], effect of cations and anions on properties of zinc oxide particles [63], metallic cobalt nanoparticles [64], Bi 2 Te 3 nanoparticles [65], g-Al 2 O 3 nanoparticles [66], Perovskite oxide Ca 0.8 Sr 0.2 Ti 1Àx Fe x O 3Àd (CTO) nanoparticles [67], anatase TiO 2 nanoparticles [68], nanoparticulate yttrium aluminum garnet [69], CoFe 2 O 4 nanoparticles [70], YVO 4 and rare earth-doped YVO 4 ultrafine particles [71], lithium iron phosphate (LiFePO 4 ) [72], YAG monodispersed particles [73], luminescent yttrium aluminum garnet (Y 3 Al 5 O 12 ) [74], copper manganese oxide nanocrystals [75], Zn 2 SiO 4 :Mn 2þ fine particles [76], iron nanoparticles [77], iron oxide (a-Fe 2 O 3 ) nanoparticles in activated carbon [78], high-temperature LiCoO 2 [78,90], KNbO 3 powders [79], MgFe 2 O 4 nanoparticles [80], Zn 2 SnO 4 anode material (synthesized in batch mode) [81], lithium iron phosphate particles [82], ZnGa 2 O 4 :Mn 2þ nanoparticles [83], magnetite particles [84], and lithium iron phosphate (LiFePO 4 ) nanoparticles [85], boehmite nanoparticles [89]. Formation of fine particles during hydrothermal and supercritical water synthesis of compounds is due to the extremely high hydrolysis reaction rate and the low solubility of produced compounds in supercritical water.…”

Section: Hydrolysismentioning

confidence: 99%

Hydrothermal and Supercritical Water Processing of Inorganic Substances

Brunner¹

2014

Hydrothermal and Supercritical Water Processes

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“…A number of possible arrangements are shown in Figure 13.15 [28]. The reasons are: Increased corrosion in the subcritical region, uncontrolled reactions at nonoptimal conditions, insufficient mixing of the reaction compounds.…”

Section: Chapter 13 Process Components and Processesmentioning

confidence: 99%

“…The geometry of a mixing tee and flow rates affect the properties of the synthesized product (LiFePO 4 [28]), such as particle size, surface area, crystalline structure, morphology, and electrochemical performance. For example, for an increasing flow rate, the particle size decreases; but amount of particles FIGURE 13.13 Experimental setup with a tubular reactor for supercritical water oxidation SCWO in a tubular reactor [24].…”

Section: Chapter 13 Process Components and Processesmentioning

confidence: 99%

Process Components and Processes

Brunner¹

2014

Hydrothermal and Supercritical Water Processes

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Continuous synthesis of lithium iron phosphate (LiFePO4) nanoparticles in supercritical water: Effect of mixing tee

Cited by 45 publications

References 54 publications

Impact of Mixing for the Production of CuO Nanoparticles in Supercritical Hydrothermal Synthesis

Impact of Mixing for the Production of CuO Nanoparticles in Supercritical Hydrothermal Synthesis

Hydrothermal and Supercritical Water Processing of Inorganic Substances

Process Components and Processes

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