The effect of microwave on the primary nucleation of CaSO 4  from aqueous solutions

Li, Liye; Guo, Zhihua; Han, Wenxiang; Wang, Qingzhao

doi:10.1016/j.powtec.2017.03.051

Cited by 6 publications

(6 citation statements)

References 18 publications

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“…Meanwhile, the V leaching efficiency was improved by only 10% under the optimized condition, for which it was not so significant in high-cost terms. Another problem was the explanation about how this consequence was realized was not convincing enough, and the interrelation in it was also not figured out [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

et al. 2018

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Abstract:The microwave assisted leaching of the vanadium bearing-high carbonaceous shale process was investigated using surface response methodology (RSM) based on Box-Behnken design (BBD). The effect of important factors such as CaF 2 usage, H 2 SO 4 concentration, leaching time and microwave power, as well as the interactive coefficients, the signification of the model and factors were analyzed. With the condition of 9.8 wt % CaF 2 , 23.0 vol % H 2 SO 4 , 170.6 min and 350 W, the actual values of vanadium (V) leaching efficiency in microwave heating (MH) and conventional heating (CH) were 85.43% and 79.64%, which agreed well with the predicted values. Meanwhile, the influence order of the factors in MH and CH was CaF 2 dosage > H 2 SO 4 concentration > leaching time. Microwave was an efficacious impetus for V extraction, but the microwave power itself was not a significant factor when the temperature of leaching system was high enough. The further characterization of mineral components before and after leaching confirmed that the prior dissolving of muscovite and pyrite in MH was intensified, while both minerals were in fine grains and filled with black carbon. The selective heating of carbon and pyrite sequenced the large temperature gradient between solids and liquids, which accelerated the dissolving reaction of muscovite with CaF 2 present in MH condition.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

et al. 2018

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“…In respect of microwave, the concentration of Mg 2+ in steady-state solution decreases with an increasing microwave energy input at a given inflow concentration. According to previous studies, 20,21,22 the diffusion coefficient of system is enhanced significantly by the microwave electromagnetic effect. Thus, the mass transfer rate of MgCO3 units from solution to crystal surface should be increased accordingly.…”

Section: Resultsmentioning

confidence: 88%

“…This is to be expected as the diffusion coefficient (DAB) rises with the energy input in line with an Arrhenius term. 22 However, the trend line of the nucleation rate constant (kn) plotted against microwave energy inputs (E) partially deviates from Arrhenius form, which means the microwave effect on kn is interfered in crystallization system. According to the study of Zou et al, 28 the existence of inorganic salt results in the enhancement of dielectric and magnetic losses in the solution.…”

Section: Resultsmentioning

confidence: 99%

“…4,17,18,19 Meanwhile, Janney et al and Wilson et al found that the diffusion coefficients increase in the presence of the microwave electromagnetic effect as well. 20,21 Li et al found that diffusion acceleration is the main reason for the increase of nucleation rate, 22 and the diffusivity enhancement (DAB-DAB0) with energy input (E) follows the Arrhenius law.…”

Section: Introductionmentioning

confidence: 99%

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The effect of microwave on the crystallization process of magnesium carbonate from aqueous solutions

et al. 2018

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The effect of microwave on reactive crystallization is investigated with magnesium carbonate as the working substance. In the experiments, magnesium carbonate is precipitated by mixing aqueous magnesium sulfate and sodium carbonate solutions in a MSMPR crystallizer located in a microwave reactor. A population balance model along with crystallization kinetics is formulated to assess the influence of microwave energy input on nucleation, growth, agglomeration and breakage during crystallization process. A general high order moment method of classes (HMMC) framework is applied to solve the model numerically. The results show that crystallization kinetics parameters, including the nucleation rate constant (kn), the growth rate constant (kg), the exponent of growth rate (g) and the collision efficiency (Ψag) change significantly due to mass transfer enhancement in microwave field. Meanwhile, the exponent of nucleation (n) and the breakage rate constant (kbr) remain constant or only change slightly. It is further discovered that the crystal suspension attenuates the microwave effect during crystallization process.

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“…This electromagnetic effect increases as the microwave energy input increases. 101 During the initial stage of microwave heating, since the distribution of microwave energy in solution is not always completely uniform, microwave heating can create local temperature gradients in solution, which may lead to an increase in supersaturation in local areas, thereby promoting nucleation in these areas. This effect is especially pronounced at the microscale and is an important mechanism for microwave heating in promoting primary nucleation.…”

Section: Assisted Nucleation Controlmentioning

confidence: 99%

Advances and Opportunities Concerning Nucleation Measurement and Control Technology in Crystallization

Zhang,

Meng,

Long

et al. 2024

Org. Process Res. Dev.

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Nucleation as a unique phenomenon in the crystallization process has always been a hot topic. With the development of nucleation theory and process analysis technology (PAT), nucleation control technology (NCT) has been widely applied in industrial crystallization processes. This paper provides a comprehensive review of advancements in nucleation measurement and control technologies within crystallization processes, systematically analyzing the principles, advantages, disadvantages, and application scopes of various NCTs, and particularly the factors affecting nucleation and nucleation-assisted technologies, including ultrasound, gassing, and membranes, are elaborated. These technologies are crucial for managing the unpredictable nature of nucleation to improve the consistency and quality of crystalline products. These advanced or novel control technologies are very attractive in providing continuous and stable high-purity seeds without externally adding additional seeds and have proven to be effective alternative methods for generating internal seeds. In addition, the challenges and opportunities were pointed out from the stability, controllability, and consistency of nucleation to promoting the efficient development of crystallization technology. NCTs play a vital role in industrial applications by ensuring control over the size, purity, and morphology of crystals. This review also explains the application of NCTs in industrial scenarios, positioning these technologies as essential for the advancement of various industrial applications.

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The effect of microwave on the primary nucleation of CaSO 4 from aqueous solutions

Cited by 6 publications

References 18 publications

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

The effect of microwave on the crystallization process of magnesium carbonate from aqueous solutions

Advances and Opportunities Concerning Nucleation Measurement and Control Technology in Crystallization

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