The fluorine-based chemical method shows great potential in leaching lithium(Li) from lepidolite. Leaching kinetics of Li in a mixture of sulfuric acid and hydrofluoric acid, which is a typical lixivant for the fluori...The fluorine-based chemical method shows great potential in leaching lithium(Li) from lepidolite. Leaching kinetics of Li in a mixture of sulfuric acid and hydrofluoric acid, which is a typical lixivant for the fluorine-based chemical method, was carried out under crucial factors such as different HF/ore ratios(1:1-3:1 g/mL) and leaching temperatures(50-85℃). The kinetics data fit well with the developed shrinking-core model, indicating that the leaching rate of Li was controlled by the chemical reaction and inner diffusion at the beginning of leaching(0-30 min) as a calculated apparent activation energy(Ea) of 20.62 kJ/mol. The inner diffusion became the rate-limiting step as the leaching continues(60-180 min). Moreover, effects of HF/ore ratio and leaching temperature on selective leaching behavior of Li, Al and Si were discussed. 90% of fluorine mainly existed as HF/F-in leaching solution, which can provide theoretical guidance for further removal or recovery of F.展开更多
An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investiga...An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method.展开更多
AIM: To review the current evidence of the treatment of hydrofluoric acid(HF) exposure to the human cornea.METHODS: A comprehensive manual search of the literature was conducted through the Ovid interface to assess th...AIM: To review the current evidence of the treatment of hydrofluoric acid(HF) exposure to the human cornea.METHODS: A comprehensive manual search of the literature was conducted through the Ovid interface to assess the mechanism and efficacy of each irrigator through a variety of clinical cases and experimental studies.· RESULTS: Ocular exposure to HF is extremely damaging to the eye and swift recognition and decontamination with an appropriate agent forms the basis of treatment. Although there are various decontamination solutions that have efficacy against the corrosive action of HF, irrigation with Hexafluorine proved to be the most safe and effective treatment for the eye.CONCLUSION: In conclusion emergency departments could benefit from the availability of Hexafluorine for the treatment of HF ocular burns in patients.展开更多
BACKGROUND Hydrofluoric acid(HF)is one of the most common causes of chemical burns.HF burns can cause wounds that deepen and progress aggressively.As a result,HF burns are often severe even if they involve a small are...BACKGROUND Hydrofluoric acid(HF)is one of the most common causes of chemical burns.HF burns can cause wounds that deepen and progress aggressively.As a result,HF burns are often severe even if they involve a small area of the skin.Published cases of HF burns have mostly reported small HF burn areas.Few cases of HF inhalation injury have been reported to date.CASE SUMMARY A 24-year-old man suffered from extensive hydrofluoric acid burns covering 60%of the total body surface area(TBSA),including deep second degree burns on 47%and third degree burns on 13%of the TBSA,after he fell into a pickling pool containing 15%HF.Comprehensive treatments were carried out after the patient was admitted.Ventricular fibrillation occurred 9 times within the first 2 h,and the lowest serum Ca2+concentration was 0.192 mmol/L.A dose of calcium gluconate(37 g)was intravenously supplied during the first 24 h,and the total amount of calcium gluconate supplementation was 343 g.Extracorporeal membrane oxygenation(ECMO)was applied for 8 d to handle the acute respiratory distress syndrome(ARDS)induced by the HF inhalation injury.The patient was discharged after 99 d of comprehensive treatment,including skin grafting.CONCLUSION Extensive HF burns combined with an inhalation injury led to a potentially fatal electrolyte imbalance and ARDS.Adequate and timely calcium supplementation and ECMO application were the keys to successful treatment of the patient.展开更多
Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial was...Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial waste water containing HF. The results show that HF can effectively destabilize the Cr（VI）-bearing minerals, resulting in the mobilization of Cr（VI） from COPR into the leachate. Particle size significantly influences the leaching of acid-soluble Cr（VI） from COPR, followed by leaching time, whereas the effects of HF concentration and leaching temperature are slight and the influence of stirring rate is negligible. The leaching process of acid-soluble Cr（VI） from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and -2.013 3, respectively.展开更多
Objective The Yangtze craton collisional orogeny at ca. extensional events at ca. 1 experienced Paleoproterozoic 1.95-2.0 Ga and post-orogenic 85 Ga related to amalgamation of the Columbia （Nuna） supercontinent （Zh...Objective The Yangtze craton collisional orogeny at ca. extensional events at ca. 1 experienced Paleoproterozoic 1.95-2.0 Ga and post-orogenic 85 Ga related to amalgamation of the Columbia （Nuna） supercontinent （Zhao and Cawood, 2012）. A ca. 2.15 Ga suprasubduction zone ophiolitic melange was recongized in the Archean- Paleoproterozoic Kongling Complex of the northern Yangtze craton （Han et al., 2017）. However, the tectonic evolution in early Paleoproterozoic from 2.4 Ga to 2.2 Ga remains unclear. We report here the presence of a suite of Paleoproterozoic （2.2 Ga） granites in the Huangling dome, northern Yangtze craton, which may provide important insights into crustal growth processes in the craton prior to the assembly of Columbia.展开更多
The results of XPS measurements of commercially pure titanium cp-Ti) before and after chemical treatment are presented. We have measured XPS spectra of core levels (Ti 2p, O 1s, C 1s, F 1s) and valence bands of coarse...The results of XPS measurements of commercially pure titanium cp-Ti) before and after chemical treatment are presented. We have measured XPS spectra of core levels (Ti 2p, O 1s, C 1s, F 1s) and valence bands of coarse-grained cp-Ti before and after standard acid treatment accepted in dentistry (in 1% HF and 40% HF for 1 min). It is found, that acid treatment of cp-Ti reduces the content of hydrocarbons increasing the surface energy and bio-compatibility of Ti-implants. On the other hand, it is fixed that oxygen concentration on the surface of the acid treated cp-Ti is much higher than for the untreated sample, because the acid treatment removes the contaminated surface layers, increases their reactivity, provides a better passivation and formation of thick protecting TiO2 layer.展开更多
基金Project(51474237)supported by the National Natural Science Foundation of China
文摘The fluorine-based chemical method shows great potential in leaching lithium(Li) from lepidolite. Leaching kinetics of Li in a mixture of sulfuric acid and hydrofluoric acid, which is a typical lixivant for the fluorine-based chemical method, was carried out under crucial factors such as different HF/ore ratios(1:1-3:1 g/mL) and leaching temperatures(50-85℃). The kinetics data fit well with the developed shrinking-core model, indicating that the leaching rate of Li was controlled by the chemical reaction and inner diffusion at the beginning of leaching(0-30 min) as a calculated apparent activation energy(Ea) of 20.62 kJ/mol. The inner diffusion became the rate-limiting step as the leaching continues(60-180 min). Moreover, effects of HF/ore ratio and leaching temperature on selective leaching behavior of Li, Al and Si were discussed. 90% of fluorine mainly existed as HF/F-in leaching solution, which can provide theoretical guidance for further removal or recovery of F.
基金Project(51474237) supported by the National Natural Science Foundation of China
文摘An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method.
文摘AIM: To review the current evidence of the treatment of hydrofluoric acid(HF) exposure to the human cornea.METHODS: A comprehensive manual search of the literature was conducted through the Ovid interface to assess the mechanism and efficacy of each irrigator through a variety of clinical cases and experimental studies.· RESULTS: Ocular exposure to HF is extremely damaging to the eye and swift recognition and decontamination with an appropriate agent forms the basis of treatment. Although there are various decontamination solutions that have efficacy against the corrosive action of HF, irrigation with Hexafluorine proved to be the most safe and effective treatment for the eye.CONCLUSION: In conclusion emergency departments could benefit from the availability of Hexafluorine for the treatment of HF ocular burns in patients.
基金Supported by the National Nature Science Foundation of China,No.81701899 and No.81671911Youth Incubation Plan of the Military Medical Science and Technology,No.16QNP091+3 种基金Naval Medical University Youth Start-up Fund,No.2016QN10the Logistics Scientific Research Program,No.AWS14C001-4Jiangsu Provincial Health Commission Project,No.H2017071Suzhou Clinical Medical Center Construction Program,No.SZZXJ201506
文摘BACKGROUND Hydrofluoric acid(HF)is one of the most common causes of chemical burns.HF burns can cause wounds that deepen and progress aggressively.As a result,HF burns are often severe even if they involve a small area of the skin.Published cases of HF burns have mostly reported small HF burn areas.Few cases of HF inhalation injury have been reported to date.CASE SUMMARY A 24-year-old man suffered from extensive hydrofluoric acid burns covering 60%of the total body surface area(TBSA),including deep second degree burns on 47%and third degree burns on 13%of the TBSA,after he fell into a pickling pool containing 15%HF.Comprehensive treatments were carried out after the patient was admitted.Ventricular fibrillation occurred 9 times within the first 2 h,and the lowest serum Ca2+concentration was 0.192 mmol/L.A dose of calcium gluconate(37 g)was intravenously supplied during the first 24 h,and the total amount of calcium gluconate supplementation was 343 g.Extracorporeal membrane oxygenation(ECMO)was applied for 8 d to handle the acute respiratory distress syndrome(ARDS)induced by the HF inhalation injury.The patient was discharged after 99 d of comprehensive treatment,including skin grafting.CONCLUSION Extensive HF burns combined with an inhalation injury led to a potentially fatal electrolyte imbalance and ARDS.Adequate and timely calcium supplementation and ECMO application were the keys to successful treatment of the patient.
基金Project(2009FJ1009) supported by Major Program of Hunan Provincial Science and Technology, ChinaProject(2005CB6237) supported by the National Basic Research Program of China
文摘Leaching kinetics of acid-soluble Cr（VI） in chromite ore processing residue （COPR） using hydrofluoric （HF） acid solution as a leaching agent was investigated for potential remediation of COPR with industrial waste water containing HF. The results show that HF can effectively destabilize the Cr（VI）-bearing minerals, resulting in the mobilization of Cr（VI） from COPR into the leachate. Particle size significantly influences the leaching of acid-soluble Cr（VI） from COPR, followed by leaching time, whereas the effects of HF concentration and leaching temperature are slight and the influence of stirring rate is negligible. The leaching process of acid-soluble Cr（VI） from COPR is controlled by the diffusion through the product layer. The apparent activation energy is 8.696 kJ/mol and the reaction orders with respect to HF concentration and particle size is 0.493 8 and -2.013 3, respectively.
基金supported by the funded project of the China Geological Survey(grants No.12120113061700,121201009000150013 and DD20160029)
文摘Objective The Yangtze craton collisional orogeny at ca. extensional events at ca. 1 experienced Paleoproterozoic 1.95-2.0 Ga and post-orogenic 85 Ga related to amalgamation of the Columbia （Nuna） supercontinent （Zhao and Cawood, 2012）. A ca. 2.15 Ga suprasubduction zone ophiolitic melange was recongized in the Archean- Paleoproterozoic Kongling Complex of the northern Yangtze craton （Han et al., 2017）. However, the tectonic evolution in early Paleoproterozoic from 2.4 Ga to 2.2 Ga remains unclear. We report here the presence of a suite of Paleoproterozoic （2.2 Ga） granites in the Huangling dome, northern Yangtze craton, which may provide important insights into crustal growth processes in the craton prior to the assembly of Columbia.
文摘The results of XPS measurements of commercially pure titanium cp-Ti) before and after chemical treatment are presented. We have measured XPS spectra of core levels (Ti 2p, O 1s, C 1s, F 1s) and valence bands of coarse-grained cp-Ti before and after standard acid treatment accepted in dentistry (in 1% HF and 40% HF for 1 min). It is found, that acid treatment of cp-Ti reduces the content of hydrocarbons increasing the surface energy and bio-compatibility of Ti-implants. On the other hand, it is fixed that oxygen concentration on the surface of the acid treated cp-Ti is much higher than for the untreated sample, because the acid treatment removes the contaminated surface layers, increases their reactivity, provides a better passivation and formation of thick protecting TiO2 layer.
