• Title, Summary, Keyword: hydrofluoric acid

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A Study on Occupational Hydrofluoric Acid Burns in a Hydrofluoric Acid Manufacturing Factory (불산제조업체에서 발생한 불산화상에 관한 조사연구)

  • Lim, Hyun-Sul;Cheong, Hae-Kwan;Kim, Ji-Young
    • Journal of Preventive Medicine and Public Health
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    • v.26 no.4
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    • pp.587-598
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    • 1993
  • Hydrofluoric acid is one of the strongest irritating, corrosive and poisonous inorganic chemicals. Hydrofluoric acid burns are occurring with ever-increasing frequency due to the wide use of this acid in industries. Hydrofluoric acid burns are characterized by severe progressive tissue destruction and excruciating pain due to the unique properties of the freely dissolvable fluoride ion. The authors reviewed medical records of 32 cases (36 spells) of hydrofluoric acid burns which occurred in a hydrofluoric acid manufacturing factory from Sep. 1, 1990 to June 30, 1993. The results are as follows; 1. Eleven measurements of air concentrations of hydrofluoric acid by detection tube method from 1990 to 1992 were all below TLV (Department of Labor, R.O. K). 2. There were 19 cases (22 spells) of hydrofluoric acid burns which occurred during the study period among regular employees. The overall incidence density of hydrofluoric acid was 17.8 cases (20.6 spells) per 100 person-year. Incidence density was 19.0 cases (22.0 spells) per 100 person-year among male workers and there were no female cases. Incidence density was 32.9 cases (38.3 spells) per 100 person-year among production workers and 1.9 cases (1.9 spells) per 100 person-years among management workers with the difference being statistically significant (P<0.01). 3. Of 32 cases (36 spells) of hydrofluoric acid burns among workers who were regularly employed or temporarily employed, 26 spells (81.2%) were between age 20 to 39. In 15 spells(41.7%) burns occurred between 12:00 and 17:59 with 16 spells(44.3%) having arrived at hospital within 2 hours after the accident. 4. Of 36 spells, the main cause of hydrofluoric acid burns were by splashes (8 spells, 22.2 %). The most frequent site of burns were fingers and pain was the most frequent symptom. Thirty spells (83.3%) of the hydrofluoric acid burns were treated with local injection of antidote (calcium gluconate). Complete recovery without scarring were observed in most of the cases (34 out of 36 cases, 94.4%). The study results suggest that to prevent hydrofluoric acid burns, environmental control and the wearing of hydrofluoric acid resistant protective clothes and gloves are important. It is also stressed that establishment of an emergency management and a transfer system for hydrofluoric acid burn victims is necessary.

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Two Cases of Chemical Burns by Hydrofluoric Acid (불화수소산에 의한 화학화상 2례)

  • Jang, Sung-Won;Sohn, You-Dong;Choi, Woo-Ik
    • Journal of Trauma and Injury
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    • v.19 no.2
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    • pp.173-177
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    • 2006
  • Hydrofluoric acid is a colorless gas or fuming liquid with a strong, irritating odor. Hydrofluoric acid burns are uncommon; however, if severe burn occur, they caused death from systemic effects, such as fatal cardiac arrthmia. We experienced two cases of hydrofluoric acid chemical burns on digits. These patients had typical clinical features of hydrofluoric acid chemical burns, such as pulsating pain at the burn site, as well as ischemic and necrotic skin changes. The hydrofluoric acid chemical burn was confirmed by a history of exposure. Subsequently, we made a calcium gluconate gel by mixing 20% calcium gluconate, an antagonist against hydrofluoric acid, with lubricant, and we injected 10% calcium gluconate subcutaneously when they complained of pain rated at higher than 5 on the pain scale. Simultaneously, we monitored the patients' electrocardiographs and checked their serum total calcium, ionized calcium, and magnesium levels serially. Clinical presentations and the emergency management of hydrofluoric acid chemical burns were reviewed along with the current literature. These patients were discharged without any significant complications.

Effect of Hydrofluoric Acid Etching on Shear Bond Strength between Resin Cement and Zirconia cores (표면 불산처리가 레진시멘트와 지르코니아 하부구조물의 전단결합강도에 미치는 영향)

  • Kim, Sa-Hak;Kim, Sun-Moon;Kim, Chong-Kyen
    • The Journal of the Korea Contents Association
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    • v.18 no.10
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    • pp.361-367
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    • 2018
  • The purpose of this study was to evaluate the influence of hydrofluoric acid etching treatment on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal(Y-TZP). Four groups of zirconia-resin cement specimens were prepared; 1) ZGS group (zirconia, no treatment), 2) ZGSH group (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS group (Hybrid zirconia, no treatment) 4) H-ZGSH group (Hybrid zirconia, hydrofluoric acid etching treatment). The shear bond strength between zirconia and porcelain was measured using a Instron Universal Testing Machine(Model DBBP-500, Instron Corporation, Kyonggi, Korea). Data were statistically analyzed using independent t-test and two-way ANOVA(${\alpha}=0.05$). The ceramic-resin cement bonding strength was affected by hydrofluoric acid etching treatment(p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in hydrofluoric acid etching treatment with treated zirconia and hybrid zirconia groups.

EFFECTS OF HYDROFLUORIC ACID CONCENTRATION & ETCHING TIME ON THE SHEAR BOND STRENGTH BETWEEN LITHIUM DISILICATE CERAMIC AND RESIN CEMENT (불산 식각 농도 및 시간이 lithium disilicate 도재와 레진시멘트의 전단결합강도에 미치는 영향)

  • Seo, Jae-Min;Park, Charn-Woon;Ahn, Seung-Geun
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.4
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    • pp.407-418
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    • 2007
  • Purpose: The objective of this study was to evaluate the effects of hydrofluoric acid concentration & etching time on the shear bond strength between IPS Empress 2 ceramic and resin cement. Material and methods: Thirty three rectangular shape ceramic specimens($20{\times}12{\times}5mm$ size, IPS Empress 2 core materials) were used for this study. The ceramic specimens divided into ten experimental groups with three specimens in each group and were etched with hydrofluoric acid(4%, 9%) according to different etching times(30s, 60s, 90s, 120s, 180s). Etched surfaces of ceramic specimens were bonded with resin cement(Rely X Unicorn) using acrylic glass tube. All cemented specimens were tested under shear loading until fracture on universal testing machine at a crosshead speed of 0.5mm/min and the maximum load at fracture(kg) was recorded. Collected shear bond strength data were analyzed with one way ANOVA and Duncan tests. All etched ceramic surfaces were examined morphologically using SEM(scanning electron microscopy). Results: Shear bond strength of etching group$(35.89{\sim}68.01MPa)$ had four to seven times greater than no-etching group$(9.53{\pm}2.29MPa)$. The ceramic specimen etched with 4% hydrofluoric acid for 60s showed the maximum shear bond strength$(68.01{\pm}11.78MPa)$. Ceramic surface etched with 4% hydrofluoric acid for 60s showed most retentive surface texture. Conclusion: It is considered that 60s etching with 4% hydrofluoric acid is optimal etching methods for IPS Empress 2 ceramic bonding.

Novel Method for Stripping of Molybdenum(VI) after Its Extraction with Cyanex 301

  • Saberyan, Kamal;Maragheh, Mohammad Ghannadi;Ganjali, Mohammad Reza
    • Bulletin of the Korean Chemical Society
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    • v.25 no.4
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    • pp.460-465
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    • 2004
  • Hydrofluoric acid has been used as a novel stripping agent for molybdenum(VI) after its extraction with Cyanex 301. In the extraction step, the effects of parameters such as type and initial concentration of acid, type of diluent, extractant concentration, metal concentration and temperature have been studied. In the stripping step, the effects of various stripping agents on stripping efficiency have been investigated. Hydrofluoric acid has been chosen as an effective stripping agent, and the effects of concentration of hydrofluoric acid, stripping time, volume of hydrofluoric acid and the number of stages of stripping have been studied. Molybdenum(VI) has been effectively separated from a large number of elements in binary mixtures, with a very high tolerance limit. Finally, the optimized method has been extended for the analysis of Mo(VI) in spent molybdenum catalysts.

Ingestion of Hydrofluoric acid: A rapid and fetal poisoning (불화수소산 음독에 의한 심정지 1례)

  • Lee, Jae-Hee;Jung, Jin-Hee;Eo, Eun-Kyung
    • Journal of The Korean Society of Clinical Toxicology
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    • v.5 no.2
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    • pp.135-137
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    • 2007
  • Hydrofluoric acid is a weak inorganic acid used for etching and as rust removals. Systemic toxicity after oral ingestion induces rapid development of hypocalcemia and hyperkalemia, leading to ventricular fibrillation and finally asystole. We report a case of intentional ingestion of hydrofluoric acid producing an altered mental state at the time of the patient's arrival in the emergency department. The patient died approximately 80 minutes after the exposure with asystol.

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Acid Pickling Characteristics of Stainless Steel by the Mixed Solution of Hydrochloric acid, Hydrofluoric acid and Hydrogen Peroxide (염산-불산-과산화수소 혼합용액에 의한 스테인레스강의 산세 특성)

  • Chun, Heedong;Choi, SangGyo
    • Clean Technology
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    • v.11 no.1
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    • pp.21-28
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    • 2005
  • Nitric acid free pickling solution was applied to solve the severe environmental problems attributed to nitric acid during pickling process of stainless steel product. In points of pickling capability and erosion of stainless steel base metal, a solution contains I% of hydrochloric acid and 2% of hydrofluoric acid and hydrogen peroxide was revealed as the best alternative to conventional mixed acid of nitric acid and hydrofluoric acid. To keep the pickling capability, it was necessary to maintain the concentration ratio of hydrogen peroxide to hydrochloric acid above 0.5.

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Myopericarditis by an Ingestion of Hydrofluoric acid - A case report (불화수소 음독 후 발생한 심금염 1례)

  • Kim Sun Hyu;Kim Hyun;Ji Ho Jin;Jang Yong Soo;Oh Sung Bum;Lee Kang Hyun;Hwang Sung Oh
    • Journal of The Korean Society of Clinical Toxicology
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    • v.2 no.1
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    • pp.63-66
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    • 2004
  • Hydrofluoric acid (HF), one of the strongest inorganic acids, is used mainly for industrial purpose. Hydrofluoric acid injuries has a potential for both systemic as well as severe local tissue destruction. One of the most serious consequences of severe exposure to HF by any route is marked lowering of serum calcium (hypocalcemia) and other metabolic changes, such as hypomagnesemia and which may result in a fatal outcome if not recognized and treated. promptly cardiotoxicity is not well known except arrhythmias, which are a primary cause of death. We report a case of myopericarditis by ingestion of hydrofluoric acid.

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TEM Sample Preparation for Cultured Neurons on a Glass Coverslip (Hydrofluoric acid 용액을 이용한 유리 커버글라스에 배양된 신경세포의 전자현미경 시료제작법)

  • Oh, Hyun-Woo;Park, Ho-Yong
    • Applied Microscopy
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    • v.35 no.4
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    • pp.10-15
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    • 2005
  • Cultured neurons from Drosophila brain on a glass coverslip to understand the structural basis of synapse were prepared for TEM observations. Neurons on a coverslip were fixed, dehydrated and embedded in Epon without separating from coverslip. After polymerization, the block was placed in 49% hydrofluoric acid to remove the coverslip. The block was examined under a light microscope to select exact neurons, then trimmed and sectioned for TEM observation.