Effect of MgF2 addition on sinterability and mechanical properties of fluorapatite ceramic composites fabricated by wollastonite and phosphate glass

Chen, Hui; Sun, Qing; Zhang, Jian; Sheng, Jing

doi:10.1016/j.ceramint.2022.03.325

Cited by 13 publications

(4 citation statements)

References 59 publications

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“…In Fap, the (PO 4 ) 3− was no longer isolated, but under the influence of the surrounding structural environment, the tetrahedron was distorted and the symmetry decreased from Td to Cs, which resulted in the disappearance of the triple degeneracy of the ν3 and the ν4. The ν3 split into two strong bands at 1045 cm −1 and 1,095 cm −1 and an indistinguishable shoulder at 1075 cm −1 , while the ν4 split into two sharp strong bands at 603 cm −1 and 574 cm −1 and a weak shoulder at 566 cm −1 , and caused the sharp absorption of the ν1 (symmetric stretching vibration) at 960 cm −1 to become infrared activity 44–46 . In Dolo, ν3, ν4, and ν2 (out‐of‐plane bending vibration) appeared at 1450 cm −1 , 729 cm −1 , and 880 cm −1 , respectively 47 …”

Section: Resultsmentioning

confidence: 99%

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Xie

2023

Surface & Interface Analysis

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The rare earth elements (REEs)‐bearing phosphorite was a potential REE resource, which contained all REEs except polonium, among them lanthanide, cerium, neodymium, and yttrium were especially enriched. REEs mainly occurred in fluorapatite (Fap) and had a high positive correlation with phosphorus content. By adopting a new green environmental fatty acid collector GJBW and through one roughing and one refining reverse flotation process, all REEs were pre‐enriched. The flotation concentrate was further leached with citric acid (CA), and all REEs were further enriched. The results of X‐ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray photoelectron spectroscopy (XPS) showed that dolomite (Dolo) was removed and Fap was enriched in phosphorite, the selective enrichment of phosphorus and REEs was realized. Density functional theory (DFT) calculation revealed the mechanism of deep purification of REEs and phosphorus in phosphorite by CA at the micro‐scale. The results showed that the number and strength of bonding between CA and Dolo (104) surface were greater than that between CA and Fap (001) surface, and CA was more easily adsorbed on Dolo (104) surface. Under the same conditions, Dolo in phosphorite was more easily leached by CA, while Fap was further enriched. This process provided a theoretical basis for the comprehensive recovery of REEs and phosphorus from phosphorite.

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Section: Resultsmentioning

confidence: 99%

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Xie

2023

Surface & Interface Analysis

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“…The formulation of samples in this work is shown in Table 1. It should be noted that the weight proportion of SP, WS and GF had been discussed in previous work, [ 21 ] The PC sample is set as a blank group. All the raw files were dried in a blast drying oven at 60°C for 20 h. Then, LLDPE with different weight ratios of fillers were adequately mixed through a high‐speed mixer for 40 min.…”

Section: Methodsmentioning

confidence: 99%

Improved flame retardancy and ceramifiable properties of PE composites by the combination of aluminum hypophosphite and zinc borate

Qian

Sun

Zhang

et al. 2023

Vinyl Additive Technology

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Ceramifiable polyolefin materials protect circuits by forming compact ceramic layers under fire conditions, and can have an excellent application prospect in the refractory cable field. In this paper, Aluminum hypophosphite (AHP) and zinc borate (ZB) were added to further improve flame retardancy and ceramifiable properties of polyethylene (PE)/silicon powder (SP)/wollastonite (WS)/ glass frits (GF) composites. The LOI values of composites with AHP/ZB can reach 23.5%, significantly higher than that of PE/SP/WS/GF composites (19.6%). The thermal stability behavior and char yield behaviors of composites could also be characterized by the TG test. The incorporation of AHP/ZB enhances the flexural strength of residue formed at 1000 C from 0.1 to 20.5 MPa. In addition, a new crystal is formed at high temperatures and is identified as the calcium aluminum phosphate phase [CAP, Ca 9 Al (PO 4 ) 7 ] by XRD analysis. The flow of molten ZB accelerates the reaction of AHP and WS, and this eutectic reaction promotes the formation and stability of ceramics. Furthermore, the SEM analysis reveals the fluxing effect of ZB at low temperatures and AHP at high temperatures. The incorporation of AHP/ZB with a ratio of 1:1 could effectively avoid the vitrification of ceramics and improve their dimensional stability.

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Section: Introductionmentioning

confidence: 99%

“…In this regard, this study can be viewed as proactive research into using these mixtures. Furthermore, pure MgF 2 is considered to be a suitable and effective sintering additive for the preparation of certain types of ceramics, 28,29 in manufacturing transparent IR windows, 30 in solar thermal technology, 31 MgF 2−x (OH) x during aldol condensation of furfural and acetone. 32 On the occasion of the 27th UN Climate Change Conference of the Parties (COP27), which will be held in Sharm el-Sheikh, Egypt, in November 2022, two research teams from South Valley University (Egypt) and Queen's University Belfast (UK) collaborated in a vital effort to combat global warming.…”

Section: Introductionmentioning

confidence: 99%

Mg–O–F Nanocomposite Catalysts Defend against Global Warming via the Efficient, Dynamic, and Rapid Capture of CO₂ at Different Temperatures under Ambient Pressure

et al. 2022

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The utilization of Mg−O−F prepared from Mg(OH) 2 mixed with different wt % of F in the form of (NH 4 F•HF), calcined at 400 and 500 °C, for efficient capture of CO 2 is studied herein in a dynamic mode. Two different temperatures were applied using a slow rate of 20 mL•min −1 (100%) of CO 2 passing through each sample for only 1 h. Using the thermogravimetry (TG)-temperature-programed desorption (TPD) technique, the captured amounts of CO 2 at 5 °C were determined to be in the range of (39.6−103.9) and (28.9−82.1) mg COd 2 •g −1 for samples of Mg(OH) 2 mixed with 20−50% F and calcined at 400 and 500 °C, respectively, whereas, at 30 °C, the capacity of CO 2 captured is slightly decreased to be in the range of (32.2−89.4) and (20.9− 55.5) mg COd 2 •g −1 , respectively. The thermal decomposition of all prepared mixtures herein was examined by TG analysis. The obtained samples calcined at 400 and 500 °C were characterized by X-ray diffraction and surface area and porosity measurements. The total number of surface basic sites and their distribution over all samples was demonstrated using TG-and differential scanning calorimetry-TPD techniques using pyrrole as a probe molecule. Values of (ΔH) enthalpy changes corresponding to the desorption steps of CO 2 were calculated for the most active adsorbent in this study, that is, Mg(OH) 2 + 20% F, at 400 and 500 °C. This study's findings will inspire the simple preparation and economical design of nanocomposite CO 2 sorbents for climate change mitigation under ambient conditions.

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Effect of MgF2 addition on sinterability and mechanical properties of fluorapatite ceramic composites fabricated by wollastonite and phosphate glass

Cited by 13 publications

References 59 publications

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Improved flame retardancy and ceramifiable properties of PE composites by the combination of aluminum hypophosphite and zinc borate

Mg–O–F Nanocomposite Catalysts Defend against Global Warming via the Efficient, Dynamic, and Rapid Capture of CO₂ at Different Temperatures under Ambient Pressure

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Effect of MgF2 addition on sinterability and mechanical properties of fluorapatite ceramic composites fabricated by wollastonite and phosphate glass

Cited by 13 publications

References 59 publications

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Improved flame retardancy and ceramifiable properties of PE composites by the combination of aluminum hypophosphite and zinc borate

Mg–O–F Nanocomposite Catalysts Defend against Global Warming via the Efficient, Dynamic, and Rapid Capture of CO2 at Different Temperatures under Ambient Pressure

Contact Info

Product

Resources

About

Mg–O–F Nanocomposite Catalysts Defend against Global Warming via the Efficient, Dynamic, and Rapid Capture of CO₂ at Different Temperatures under Ambient Pressure