• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.343-346
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• 1983

This paper was prepared to characterize a physico-chemical and mineralogical examination on blast furnace slag as a source of silicate fertilizer, which was quenched with high pressure water stream in process of iron refinery at Pohang Iron and Steel Manufacturing Inc. Quenched slag was more coarse in particle size compared to present commercial silicate fertilizer milled from air-cooled slag and mostly generated in size of 1 to 2 mm. The total chemical composition of quenched and air-cooled slags was same but mineralogical composition was quite different. The former was composed of amorphous materials resulting in more soluble silica content, however, the latter contained dominantly crystalline minerals such as akermanite, gehlenite and wollastonite which meant less soluble ones. Latent cementing property and angular surface of gain of the slag made it difficult to apply the slag directly, however, it could be used as a source of silicate fertilizer and soil ammendment.

• Safety and Health at Work
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• v.1 no.2
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• pp.134-139
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• 2010

Objectives: The lung cancer mortality in Korea has increased remarkably during the last 20 years, and has been the first leading cause of cancer-related deaths since 2000. The aim of the current study was to examine the time trends of occupational lung cancer and carcinogens exposure during the period 2006-2009 in South Korea, by assessing the proportion of occupational burden. Methods: We defined occupational lung cancer for surveillance, and developed a reporting protocol and reporting website for the surveillance of occupational lung cancer. The study patients were chosen from 9 participating university hospitals in the following 7 areas: Seoul, Incheon, Wonju, Daejeon, Daegu, Busan, and Gwangju. Results: The combined proportion of definite and probable occupational lung cancer among all lung cancers investigated in this study was 10.0%, 8.6%, 10.7%, and 15.8% in the years 2006 to 2009, respectively, with an average of 11.7% over the four-year study period. The main carcinogens were asbestos, crystalline silica, radon, polyaromatic hydrocarbons (PAHs), diesel exhaust particles, chromium, and nickel. Conclusion: We estimated that about 11.7% of the incident lung cancer was preventable. This reveals the potential to considerably reduce lung cancer by intervention in occupational fields.

• Korean Journal of Materials Research
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• v.28 no.12
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• pp.763-768
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• 2018

In this study, glass fibers are fabricated via a continuous spinning process using manganese slag, steel slag, and silica stone. To fabricate the glass fibers, raw materials are put into an alumina crucible, melted at $1550^{\circ}C$ for 2 hrs, and then annealed at $600^{\circ}C$ for 2 hrs. We obtain a black colored glass. We identify the non-crystalline nature of the glass using an XRD(x-ray diffractometer) graph. An adaptable temperature for spinning of the bulk marble glass is characterized using a high temperature viscometer. Spinning is carried out using direct melting spinning equipment as a function of the fiberizing temperature in the range of $1109^{\circ}C$ to $1166^{\circ}C$, while the winder speed is in the range of 100rpm to 250rpm. We investigate the various properties of glass fibers. The average diameters of the glass fibers are measured by optical microscope and FE-SEM. The average diameter of the glass fibers is $73{\mu}m$ at 100rpm, $65{\mu}m$ at 150rpm, $55{\mu}m$ at 200rpm, and $45{\mu}m$ at 250rpm. The mechanical properties of the fibers are confirmed using a UTM(Universal materials testing machine). The average tensile strength of the glass fibers is 21MPa at 100rpm, 31MPa at 150rpm, 34MPa at 200rpm, and 45MPa at 250rpm.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.302-324
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• 2022

Objectives: The objective of this study is to investigate exposure to occupational carcinogens in the nationwide electronics industries and to establish a strategy for control of occupational carcinogens in South Korea. Methods: We evaluated occupational carcinogens as defined by International Agency for Research on Cancer (IARC) using a nationwide work environment measurement database on the electronics industry in South Korea measured between 2013 and 2017 in accordance with the Occupational Safety and Health Act. Results: The number of occupational carcinogens found in the electronics industry in South Korea were: 20 for IARC Group 1, 14 for Group 2A, and 30 for Group 2B. The occupational carcinogens (Group 1) most frequently exposed were strong-inorganic-acid mists containing sulfuric acid (sulfuric acid), welding fumes, mineral oils (untreated or mildly treated), nickel compounds, silica dust, crystalline substances in the form of quartz or cristobalite, formaldehyde, arsenic and inorganic arsenic compounds, chromium (VI) compounds, trichloroethylene, cadmium and cadmium compounds, vinyl chloride, ethylene oxide, wood dust, beryllium and beryllium compounds, 1,3 butadiene, benzene, and others. Among them, the carcinogens (Group 1) exceeding the acceptable standard were trichloroethylene, formaldehyde, and ethylene oxide. The working environment measurement system as regulated by Occupational Safety and Health Act is not properly assessed and managed for occupational carcinogens in South Korea. A component analysis for all materials used should be set up to practically reduce occupational carcinogens. A ban on the use of occupational carcinogens and the development of alternative materials are needed. The occupational carcinogens below the acceptable standards should be carefully examined and a new standard for exposure needs to be established. Conclusions: The Occupational Safety and Health Act should be improved to identify and monitor occupational carcinogens at work sites. A strategy for occupational safety and health systems should be provided to give direction to workers' needs and right to know.

• Analytical Science and Technology
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• v.36 no.6
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• pp.315-323
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• 2023

This study is to quantify α-quartz, cristobalite and kaolinite using by FTIR in respirable dust generated in the mining workplace. Various minerals in mines can interfere with peaks when quantifying respirable crystalline silica by FTIR. Therefore, for accurate quantification, it is necessary to remove interfering substances or correct the peaks that cause interference. To confirm the peaks occurring in α-quartz, cristobalite and kaolinite, each standard material was diluted with KBr and scanned in the range of 400 cm^-1 to 4000 cm^-1 using by FTIR. As a result of scanning the analytes, it was decided to use the peaks of 797.66 cm^-1 and 695.25 cm^-1 for α-quartz, 621.58 cm^-1 for cristobalite, and 3696.47 cm^-1 for kaolinite. When the above materials are mixed, interference occurs at the peak for quantification, which is corrected by the calculation formula. The analysis of the mixture of α-quartz and cristobalite shows the average bias (%) of 2.64 (corrected) at α-quartz (797.66 cm^-1), 5.61 (uncorrected) at α-quartz (695.25 cm^-1) and 1.51 (uncorrected) at cristobalite (621.58 cm^-1). The analysis of the mixture of α-quartz and kaolinite shows the average bias(%) of 1.79(corrected) at α-quartz (797.66 cm^-1), 3.92 (corrected) at α-quartz (695.25 cm^-1) and 2.58 (uncorrected) at kaolinite (3696.47 cm^-1). The analysis of the mixture of cristobalite and kaolinite shows the average bias (%) of 2.15 (corrected) at cristobalite (621.58 cm^-1), 4.32 (uncorrected) at kaolinite (3696.47 cm^-1). The analysis of the mixture of αquartz and cristobalite and kaolinite shows the average bias (%) of 1.93(corrected) at α-quartz (797.66 cm^-1), 6.47 (corrected) at α-quartz (695.25 cm^-1) and 1.77 (corrected) at cristobalite (621.58 cm^-1) and 2.61 (uncorrected) at kaolinite (3696.47 cm^-1). The experimental results showed that the deviation caused by peak interference by two or three substances could be corrected to less than 6 % of the average deviation. This study showed the possibility of correcting and quantifying when various interfering substances that are difficult to remove are mixed.