MINERALS ENGINEERING
·
2022
·
IF 5.479
Lijia Zhu,Jie Liu,Yimin Zhu,Guichen Gong,Yuexin Han
As an essential raw material for the tin industry, cassiterite ore needs to be effectively separated and purified, and the removal of impurities such as fluorite becomes the key to cassiterite flotation. In this study, the flotation separation of cassiterite (SnO 2 ) and fluorite (CaF 2 ) was enhanced by using hydroxylcitric acid (HCA) as fluorite inhibitor and 2-carboxyphenyl phosphonic acid (CEPPA) as collector. With a reagent scheme of 120 mg/L CEPPA and 4.5 mg/L HCA at pH 10.0, the flotation recovery of cassiterite and fluorite was 92.80% and 13.57%, respectively. Under the same experimental conditions of artificially mixed mineral flotation, the flotation index of cassiterite concentrate grade 78.19% and recovery 90.29% was obtained. The selective adsorption mechanism of CEPPA and HCA on minerals was investigated by Zeta potential, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The results showed that CEPPA anions had chemically adsorbed on cassiterite and fluorite, and the adsorption of HCA on fluorite surface was stronger than that on cassiterite surface. XPS analyses further confirmed that Ca sites exposed on fluorite had a stronger affinity for HCA than cassiterite. Furthermore, the addition of HCA had little effect on the adsorption of CEPPA on cassiterite, while the strong chemisorption of HCA on fluorite surface prevented the adsorption of CEPPA on fluorite. These results provide a theoretical basis and promising new strategy for the flotation separation of cassiterite and fluorite.
研究领域:
矿物加工工程
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表面化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Feng Liu,Linsheng Wang,Simeng Xiang,Xiang Lin,Jiao Feng,Hongyu Yang,Xiaming Feng,Chaojun Wan
Epoxy vitrimers combine the advantages of thermosetting and thermoplastic materials, making them an ideal alternative to traditional thermosetting resins. However, the fabrication of high-performance flame-retardant epoxy vitrimers remains a challenge. In this study, utilizing (2-carboxyethyl)phenylphosphinic acid (CEPPA) as a curing agent, we facilely fabricated a dual-dynamic epoxy vitrimer incorporating carboxylate esters and phosphonate esters (CEEP). Compared to traditional epoxy resin (DDEP), the epoxy vitrimer exhibited tensile strength comparable to traditional epoxy resins and significantly outperformed in terms of Young’s modulus. In comparison to carboxylate ester epoxy vitrimer (PAEP), CEEP demonstrated improved solvent resistance and the ability for recycling without the need for a catalyst. Additionally, CEEP exhibited outstanding flame retardancy, achieving a V-0 rating in UL-94 testing, with a remarkable 66.9% reduction in peak heat release rate (PHRR) and a significant 34.5% decrease in total heat release (THR) in cone calorimetry test compared to DDEP. The work offers a promising way for the facile fabrication of high-performance flame-retardant epoxy vitrimers.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 137
·期 20
·48687
·
IF 2.188
Xiangyang Chen,Dongfeng Xu,Hua Zhang,Xinxing Feng,Jianping Deng,Kai Pan
A novel halogen-free flame retardant copolyamide 6,6 (FR-PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2-carboxy ethyl (phenyl) phosphinic acid (CEPPA). The elemental composition and chemical structure of FR-PA66 were characterized by energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and 13 C Nuclear magnetic resonance spectrometer. The flame retardancy, thermal stability, and morphology of char residues were also investigated by the limiting oxygen index (LOI), UL 94 test, thermogravimetric analysis, and scanning electron microscopy. The results showed that FR-PA66 samples had much better flame retardancy and char formation ability than pure PA66 after the flame retardant modification. The LOI values were increased from 24.0 to 28.0% by adding 6 wt % of CEPPA and all FR-PA66 samples were rated as V-0 rating in UL-94 test. Furthermore, the thermal stability analysis indicated that in situ polymerization with CEPPA effectively decreased the initial decomposition temperature and increased the amount of char residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137 , 48687.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2021
·
IF 2.475
Guichen Gong,Jie Liu,Yuexin Han
The structure–property relationship and adsorption mechanism of a novel collector for cassiterite, 2-carboxyethylphenylphosphinic acid (CEPPA), were comprehensively investigated and compared with those of styrene phosphonic acid (SPA) by density functional theory (DFT) calculations and flotation tests. The net Mulliken charge and frontier molecular orbital (FMO) theory study results indicated that CEPPA exhibited stronger electron-donating ability and higher chemical reactivity than SPA. The flotation test results demonstrated that CEPPA had stronger collecting ability for cassiterite in a much wider effective pH range than SPA. The adsorption simulation results confirmed that the CEPPA molecule was adsorbed on cassiterite (110) surface by two hydrogen bonds. CEPPA monoanion and dianion were adsorbed on cassiterite (110) surface by a series of O-Sn bonds, and the interactions between the O atoms in CEPPA phosphinic group with the Sn atoms on cassiterite (110) surface were stronger than those between the O atoms in CEPPA carboxyl group with the Sn atoms on cassiterite (110) surface. The formation of the O-Sn bonds was mainly contributed from the 2p orbital of O atoms and 5s and 5p orbitals of Sn atoms. The various adsorption configurations of CEPPA on cassiterite accounted for the better collecting ability of CEPPA for cassiterite than that of SPA. The quantitative analysis results were in good agreement with the qualitative experimental test results in a previous paper.
研究领域:
化学工程
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材料科学
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表面化学
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矿物加工
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产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2022
·
IF 5.546
Weiwen Gu,Lifei Wei,Tianyi Ma,Yuhang Wu,Anying Zhang,Jianfei Wei,Rui Wang
2-Carboxyethyl(phenyl) phosphinic acid (CEPPA) is an effective phosphorus-containing flame retardant for PET. However, the release of poisonous and harmful smoke increases when CEPPA is added to PET matrix (CEPPA-PET) during the combustion process. To address this, biomass gelatin-based Carbon Dots (gCDs) was adopted as nontoxic green smoke suppression agent. When the gCDs was copolymerized into CEPPA-PET matrix by in situ polymerization (CEPPA-gCDs-PET), the peak smoke production rate was reduced by 59.38% and the CO yield was decreased by 13.83%. It was found the limited oxygen index of CEPPA-gCDs-PET rose to 31% from 21% and could achieve a V-0 rating in the UL-94 test when the content of gCDs and CEPPA were only 1.0 wt% and 5.0 wt%, respectively. What is more, in comparison with neat PET, the peak heat release rate significantly decreased by 42.66% and the total heat release was reduced by 48.10%, the peak smoke production rate is also reduced by 59.38%. Besides, the tensile strength of CEPPA-gCDs-PET increased by 11.93% for CEPPA-PET. At the same time, the addition of gCDs was beneficial for the improvement of UV resistance for CEPPA-PET, and the transmittance of sleeves prepared from the fiber of CEPPA-gCDs-PET is less than 5% from 240 nm to 400 nm. Thus, a higher efficiency flame retardant, mechanical enhancement and UV resistance system was constructed with only 5 wt% CEPPA and 1 wt% gCDs toward CEPPA-PET copolymer.
研究领域:
材料科学
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高分子化学
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阻燃性
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
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