• Biomolecules & Therapeutics
• /
• v.8 no.2
• /
• pp.179-183
• /
• 2000

To determine biosafety of fluorosilicic acid as a source of fluoride, we carried out acute toxicity and general pharmacological studies using mouse. Fluorosilicic acid had little effects on general behavior, pain response, convulsion, skeletal muscle function and intestinal mobility as compared to controls. It had either little adverse effects on alkaline phosphatase and collagen levels in osteoblast cells. This study supports the safety of fluorosilicic acid in animals.

• Environmental Analysis Health and Toxicology
• /
• v.14 no.3
• /
• pp.113-120
• /
• 1999

Fluorination of drinking water has been used world widely to reduce the incidence of caries. Recently, contradictory results on the cytotoxicity of fluoride compounds are reported. In addition, there are attempts to use fluorosilicate for fluorination of drinking water in Korea, therefore, we tried to analyze the cytotoxicity of fluoride compounds on oral epidermoid carcinoma (KB and A253) and osteosarcoma (HOS and MG-63) cells in this study. We treated cells with 0, 10, 50 and 250 ppm of fluorosilicic acid (domestic or from Fluka, F$\_$6/H$_2$Si), sodium fluorosilicate (F$\_$6/Na$_2$Si), sodium fluoroacetate (FCH$_2$CO$_2$Na), sodium fluoride (NaF) or potassium fluoride(KF) and measured the relative cell survival by MTT assay. At the concentration of < 10ppm, no significant cytotoxicity was observed. At 50 ppm, each cells revealed different response to fluoride treatment. Among cells used in this study, MG-63 was the most resistant to fluoride treatment. Comparable toxicity data from domestic and imported fluorosilicic acids were obtained. When we compared the relative cytotoxicity of fluoride compounds against their fluoride contents, the differences in relative cell survival were smaller. Most of cells showed < 20% of survival at 250 ppm. In order to analyze the pH dependence of the cytotoxicity of fluorosilicates, the pH of cell culture media containing fluorosilicate was adjusted to 7.4 or 6.5 and the relative cytotoxicity was measured. At lower pH, about 10% higher cytotoxicity was obtained. Thus, our data suggested that the toxicity of domestic fluorosilicic acid was similar to that of fluorosilicic acid from Fluka, and the cytotoxicity of fluoride compounds was dependent on the relative content of fluoride and pH.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.25-26
• /
• 2004

• Journal of Electrochemical Science and Technology
• /
• v.2 no.3
• /
• pp.168-173
• /
• 2011

The availability, low toxicity, and high degree of technological development make silicon the most likely material to be used in solar cells, the cost of solar cells depends entirely on cost of high purity silicon production. The present work was conducted to electrodeposite of silicon from $K_2SiF_6$, an inexpensive raw material prepared from fluorosilicic acid ($H_2SiF_6$) produced in Iraqi Fertilizer plants, and using inexpensive graphite material as cathode electrode. The preparation of potassium fluorosilicate was performed at ($60^{\circ}C$) in a three necks flask provided with a stirrer, while the electro deposition was performed at $750^{\circ}C$ in a three-electrodes configuration with melt containing in graphite pot. High purity potassium fluorosilicate (99.25%) was obtained at temperature ($60^{\circ}C$), molar ratio-KCl/$H_2SiF_6$(1.4) and agitation (600 rpm). Spongy compact deposits were obtained for silicon with purity not less than (99.97%) at cathode potential (-0.8 V vs. Pt), $K_2SiF_6$ concentration (14% mole percent) with grain size (130 ${\mu}m$) and level of impurities (Cu, Fe and Ni) less than (0.02%).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.926-933
• /
• 2012

Phosphoric acid used for the production of phosphate fertilizers is synthesized by the reaction of phosphate rock and sulfuric acid. As the reaction is exothermic, yield of phosphoric acid is poor at elevated temperature. Therefore, enhancement in its yield requires the process temperature be maintained by releasing the vapor ($80^{\circ}C$) containing HF and SiF4 through a vacuum cooler. However, these valuable resources; Fand Si, which can be utilized for the manufacture of refrigerant and polysilicon, respectively, are being wasted in the treatment process. We performed lab-scale experiments to estimate the amount of recoverable H2SiF6, a by-product of phosphoric acid manufacturing process. The experimental results showed a decrease of fluorine concentration by 0.12wt% in the liquid phase. Preliminary estimation showed a possible recovery of 5,509 ton/yr of fluorine considering the scale of the fertilizer manufacturing plant. Furthermore, field-scale experiment showed that H2SiF6 could be enriched in liquid phase from 0.35wt% to 7.33wt% and the vapor flow-rate from vacuum cooler was estimated at $51,000m^3/hr$. Anew, the efficiency of fluorine recovery in the pilot-scale experiment was found to be 76.74% and the production of H2SiF6 was estimated at 5,340 ton/yr.

• Journal of the Society of Disaster Information
• /
• v.9 no.3
• /
• pp.266-275
• /
• 2013

New paradigm to the advancement of disaster management is required for building resilient and safe society. In these circumstances, the importance of local government disaster management capacity has been emphasized through experiencing a series of accidents including 2012 september Gumi fluorosilicic acid diffusion accident. The increase of people's disaster awareness has emerged the public demands on disaster management information of local area. In this study, the disaster management capacity analysis program is developed for self-assessment of local government. The program is designed for disaster managers to database the categorized index of disaster management capacity and recognize the capacity level. For the public announcement of disaster management capacity, the analysis results are shown for citizens in the understandable format. It is expected that the enhancement of emergency management capacity of local society can be achieved by the efforts of local government analyzing and improving the vulnerability as well as the participation of local society.