Synthesis of Fluorite (CaF2) Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel

Khunur, Mohammad Misbah; Risdianto, Andri; Mutrofin, Siti; Prananto, Yuniar Ponco

doi:10.9767/bcrec.7.1.3171.71-77

Cited by 17 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peaks corresponding to CaF2 that are present in this sample were at 2θ = 28º, 46.6º, 55.7º, 68.7º, 75.8º and 87.4º (JCPDS no. 87-0971) [15,16]. Formation of CaF2 with the FBR was confirmed with this XRD analysis.…”

Section: Characterization Of Calcium Fluoride Crystalssupporting

confidence: 73%

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Sinharoy,

Lee,

Chung

2024

Preprint

View full text Add to dashboard Cite

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium to fluoride ratio of 0.6 within first 40 days of continuous operation. The resulting particle size increased by more than double during this time along with a 36% increase in the seed bed height indicating deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed along with high amount of Ca-F ions presence. The purity of the CaF2 crystals were determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies are explored. The addition of excess amount of calcium resulted in an additional 6% fluoride removal, however, compared to this single stage process, a two-stage approach was found to be better strategy to achieve a low effluent fluoride concentration. The fluoride removal reached 94% with this two-stage approach under optimum condition of 4 + 1 h HRT combinations and a [Ca2+]/[F-] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of inlet diameter, bottom-angle shape and width and height ratio of the reactor on mixing inside reactor and possibility of further improvement in reactor performance by optimizing the FBR configuration.

show abstract

Section: Characterization Of Calcium Fluoride Crystalssupporting

confidence: 73%

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Sinharoy,

Lee,

Chung

2024

Preprint

View full text Add to dashboard Cite

show abstract

“…The characteristic peaks corresponding to the CaF 2 were observed in the crystal samples obtained after 70 days of reactor operation. The peaks corresponding to CaF 2 that are present in this sample were at 2θ of 28 [21,22]. Formation of CaF 2 with the FBR was confirmed by this XRD analysis.…”

Section: Characterization Of Calcium Fluoride Crystalssupporting

confidence: 68%

“…The peaks corresponding to CaF2 that are present in this sample were at 2θ of 28°, 46.6°, 55.7°, 68.7°, 75.8° and 87.4° (JCPDS no. 87-0971) [21,22]. Formation of CaF2 with the FBR was confirmed by this XRD analysis.…”

Section: Characterization Of Calcium Fluoride Crystalssupporting

confidence: 64%

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor

Sinharoy,

Lee,

Chung

2024

IJMS

View full text Add to dashboard Cite

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF2 crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca2+]/[F−] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration.

show abstract

“…Focusing on the −0.5 V plating potential, the presence of calcium and calcium fluoride in the hybrid SEI surface is outlined from the Ca−F bond observed at 770 cm −1 . 23 Following the same behavior as the ex-situ XRD study, the P 2 O 5 phase is also observed at the −0.5 V plating potential and is identified by the P−O−P bond at 970 cm −1 . 24 The P�O bond at 1210 cm −1 forms from the decomposition of the KPF 6 electrolyte during the SEI formation.…”

Section: ■ Results and Discussionmentioning

confidence: 53%

“…FTIR ex-situ studies were performed to complement the findings from XRD analysis. Focusing on the −0.5 V plating potential, the presence of calcium and calcium fluoride in the hybrid SEI surface is outlined from the Ca–F bond observed at 770 cm –1 . Following the same behavior as the ex-situ XRD study, the P 2 O 5 phase is also observed at the −0.5 V plating potential and is identified by the P–O–P bond at 970 cm –1 .…”

Section: Resultsmentioning

confidence: 78%

Plating and Stripping Calcium Metal in Potassium Hexafluorophosphate Electrolyte toward a Stable Hybrid Solid Electrolyte Interphase

Chando

Shellhamer

Wall

et al. 2023

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

The use of calcium (Ca) metal anodes in batteries is currently challenged by the development of a suitable solid electrolyte interface (SEI) that enables effective Ca2+ ion transport. Native calcium electrolytes produce a passivation layer on the surface of the calcium electrodes during cycling, causing a decrease in capacity during cycling and the need for large overpotentials. The use of a hybrid SEI is a strategy to mitigate the uncontrolled production of a passivation layer and reduce the overpotentials needed for the plating and stripping of calcium. Here, we report the development of a hybrid potassium (K)/Ca SEI layer investigated in symmetric Ca//Ca cell configurations. Using KPF6 salt in a ternary mixture of carbonate solvent (EC/EMC/DMC), Ca//Ca cells can be cycled up to 200 h at a capacity of 0.15 mAh/cm2 with a current density of 0.025 mA/cm2. The symmetrical cells consistently cycle at overpotentials of 1.8 V. Ex-situ X-ray diffraction (XRD) of cycled electrodes reveals plating and stripping of both calcium and potassium. Energy dispersive X-ray (EDX) maps confirm the plating of calcium and potassium during galvanostatic cycling. Scanning electron microscopy (SEM) cross-sectional views of the calcium electrodes reveal a continuous SEI layer formed over the calcium metal. XRD analysis reveals the SEI layer consists of K-based inorganics along with the identification of permanent and transient phases. FTIR outlines the parallel plating of both calcium and potassium at both regions of redox activity. Raman spectroscopy of the electrolyte reveals compositional changes over the course of cycling that promote increased plating and stripping. The results indicate that potassium electrolytes are a possible route for tuning the SEI to enable reversible calcium electrochemical cycling.

show abstract

Synthesis of Fluorite (CaF2) Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel

Cited by 17 publications

References 3 publications

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor

Plating and Stripping Calcium Metal in Potassium Hexafluorophosphate Electrolyte toward a Stable Hybrid Solid Electrolyte Interphase

Contact Info

Product

Resources

About