• 제목/요약/키워드: gypsum content

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Combustion and Mechanical Properties of Fire Retardant Treated Waste Paper-Waste Acrylic Raw Fiber Composite Board

  • Eom, Young Geun;Yang, Han-Seung;Kim, Hyun-Joong
    • Journal of the Korean Wood Science and Technology
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    • 제31권3호
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    • pp.1-10
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    • 2003
  • Shredded waste newspapers, waste acrylic raw fibers, and urea-formaldehyde (UF) adhesives, at 10% by weight on raw material, were used to produce recycled waste paper-waste acrylic raw fiber composite boards in laboratory scale experiments. The physical and mechanical properties of fire retardant treated recycled waste paper-waste acrylic raw fiber composite boards were examined to investigate the possibility of using the composites as internal finishing materials with specific gravities of 0.8 and 1.0, containing 5, 10, 20, and 30(wt.%) of waste acrylic raw fiber and 10, 15, 20, and 25(wt.%) of fire retardant (inorganic chemical, FR-7®) using the fabricating method used by commercial fiberboard manufacturers. The bending modulus of rupture increased as board density increased, decreased as waste acrylic raw fiber content increased, and also decreased as the fire retardant content increased. Mechanical properties were a little inferior to medium density fiberboard (MDF) or hardboard (HB), but significantly superior to gypsum board (GB) and insulation board (IB). The incombustibility of the fire retardant treated composite board increased on increasing the fire retardant content. The study shows that there is a possibility that composites made of recycled waste paper and waste acrylic raw fiber can be use as fire retardant internal finishing materials.

Effects of Decreasing Methods of Salt Content in Root Zone on Soil Properties and Crop Grwoth at the Newly Reclaimed Tidal Soil (신간척지(新干拓地)에서 근권(根圈)의 염농도(鹽濃度) 저하(低下) 방법(方法)이 토양특성(土壤特性)과 작물생육(作物生育)에 미치는 영향(影響))

  • Cho, Yeong-Kil;Jo, In-Sang;Um, Ki-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • 제25권2호
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    • pp.127-132
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    • 1992
  • This experiment was conducted to find out the useful data for upland crop cultivation in the newly reclaimed tidal land. Poseung silty clay loam soil was selected, and cotton(Mogpo VII) and tall fescue were cultivated under different drainage systems and soil ameliorator applications. Soil hardness and bulk density were decreased by subsurface drainage and plastic film installed at 40cm depth of the soil. Red earth application was also effective to loosen the soil, but zeolite and gypsum made the subsoil compact. Water content of the soil was high in surface drain than that of subsurface drain or plastic film curtain plot during dry season. The water content was in order of plastic film curtain, surface drain and subsurface drain. Electrical conductivity(EC) was decreased to lower than 0.4 Simens $meter^{-1}$ ($SM^{-1}$) in the subsurface drain during rainy season, and the EC of subsurface drain was maintained a quater to an half of surface drain. The yield of cotton and tall fescue were high in order of subsurface drain, plastic film curtain and surface drain plot. The yields of cotton were increased to 36-73 % by ameliorator application, and the red earth application was more effective for tall fescue growth compare to gypsum and zeolite.

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Feasibility Study on CLSM for Emergency Recovery of Landfill Bottom Ash (매립장 석탄회의 긴급복구용 CLSM으로 활용 가능성)

  • Ha-Seog Kim;Ki-Suk Kim
    • Land and Housing Review
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    • 제14권2호
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    • pp.137-145
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    • 2023
  • In this study, the characteristics such as flowability, bleeding rate, and strength of the CLSM (Controlled Low Strength Material) according to physical properties such as particle size distribution and particulate content of the pond ash were investigated as part of the practical development of technology for CLSM using pond ash. As a result of analyzing the properties of the collected pond ash, it was found that the density and particle size distribution characteristics were different. And that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for four hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it was determined that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

Corrosion of castable refractory in H2O/N2/H2S mixed gas at 900℃ (H2O/N2/H2S 혼합가스 분위기 900℃에서 캐스타블 내화물의 부식)

  • Shin, Min;Yoon, Jong-Won;Kim, Chang-Sam
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • 제27권2호
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    • pp.99-104
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    • 2017
  • Refractories used in low-rank coal gasification reactors are usually exposed in a highly corrosive $H_2S$ gas at less than $1000^{\circ}C$, and their mechanical properties such as erosion resistance and fracture strength decline with the exposure time. However, the cause of the degradation of the mechanical properties has little reported yet. In this paper, two kinds of castable refractories with different refractoriness had been exposed in a $H_2O/N_2/H_2S$ mixed gas with high $H_2S$ content for 100 hours at $900^{\circ}C$, and the changes of microstructure, crystalline phases and erosion resistance were compared before and after the corrosion test. The weight of the refractories decreases due to the elution of silica in the specimens after the corrosion test. The capillary porosities of the samples are reduced, but the erosion resistance of the samples is fatally weakened after the corrosion test. There also are changes in constituent phases; dmitryivanovite ($CaAl_2O_4$) and amorphous silica ($SiO_2$) disappear, and gypsum ($CaSO_4{\cdot}2H_2OS$) and kaolinite ($Al_2Si_2O_5(OH)_4$) newly appear after the corrosion test. It is obvious that the phase change from dmitryivanovite that works as a binding agent in the castable refractory to gypsum is the main reason of the degradation of the erosion resistance, because the mechanical properties of gypsum are much poorer than those of dmitryivanovite.

Effects of Phospho-gypsum Fertilizer as Reclamation Material in the Newly Reclaimed Paddy Fields (간척지 논의 부산석고비료 시용효과)

  • Sohn, Bo-Kyoon;Lee, Do-Jin;Park, Bum-Ki;Chae, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • 제40권2호
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    • pp.145-150
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    • 2007
  • This study was conducted to evaluate the application effects of phospho-gypsum fertilizer (PGF) as reclamation material in the newly reclaimed paddy fields located in Goheung and Youngam, Jeonnam province in Korea. The PGF used in this experiment was produced by Namhae Chemical Co. as the name of Soil-Saver$^{TM}$. Prior to rice transplanting, the PGF was applied as soil amendment as the amount of $3,000kg\;ha^{-1}$. The PGF increases rice plant height and number of tiller at the heading stage by 119.9 cm and 9.1, respectively, in Youngam area. The harvest index of brown rice increased up to 5 and 13% more in the PGF applied paddy field from both sites than in the non-application of PGF at paddy field before rice transplanting, and the ripening ratio in increased in both sites to 81 and 90%. Protein content of brown rice was also greater than in the non-application of PGF at the both sites. For the effects of the reclamation by PGF in the paddy field soils, we found that PGF reduced exchangeable Na to 18 and 28% for both sites, respectively, and increased exchangeable Ca and $SO_4$. And we found relatively higher amounts of $K_2O$, CaO and MgO in the rice plants from both sites applied with PGF.

Characteristics of Direct Aqueous Carbonation Reaction Using Incinerated Ash and Industrial By-Products (소각재 및 산업부산물을 이용한 직접 수성탄산화 반응 특성)

  • Dong Kyoo Park;Seungman Han;Changsik Choi
    • Clean Technology
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    • 제30권2호
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    • pp.113-122
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    • 2024
  • In order to better understand carbon dioxide recycling, the carbon dioxide capture characteristics of six different alkaline industrial by-products, including incineration ash, desulfurized gypsum, low-grade quicklime, and steelmaking slag were investigated using a laboratory-scale direct aqueous carbonation reactor. In addition to the dissolution characteristics of each sample, the main reaction structure was confirmed through thermogravimetric analysis before and after the reaction, and the reactive CaO content was also defined through thermogravimetric analysis. The carbon dioxide capture capacity and efficiency of quicklime were determined to be 473 g/kg and 86.9%, respectively, and desulfurized gypsum and incineration ash were also evaluated to be relatively high at 51.1 to 131.7 g/kg and 51.2 to 87.7%, respectively. On the other hand, the capture efficiency of steelmaking slag was found to be less than 10% due to the influence of the production and post-cooling conditions. Therefore, in order to apply the carbonation process to steelmaking slag, it is necessary to optimize the slag production conditions. Through this study, it was confirmed that the carbon dioxide capture characteristics of incineration ash, quicklime, and desulfurized gypsum are at levels suitable for carbonation processes. Furthermore, this study was able to secure basic data for resource development technology that utilize carbon dioxide conversion to produce calcium carbonate for construction materials.

Analysis of Characteristics of Slurry and Thermal Insulation Materials Using Hauyne Cement

  • Kim, Tae Yeon;Jo, Ki Sic;Chu, Yong Sik
    • Journal of the Korean Ceramic Society
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    • 제56권5호
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    • pp.468-473
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    • 2019
  • This study focused on manufacturing an inorganic insulation material set with various amounts of calcium-sulfoaluminate (CSA) (hauyne) content for enhancing both workability (demolding, handling) and the high thermal insulating property. To carry out the experiment, the amounts of CSA utilized were 5%, 10%, 15%, and 20%, with anhydrous gypsum added in equal proportion to produce a stable formation. As the content of CSA increased, a sinking phenomenon occurred because of the hydration reaction from the slurry, so it was difficult to utilize a retarder normally used in the cement manufacturing process. However, an RCOOM surfactant was able to solve the local clumping problem from cement and CSA and obtain a rapid retarding effect, so it was included in this process at 0.3%. Furthermore, the cement fineness was not 7000 ㎠/g but rather 3300 ~ 4000 ㎠/g to prevent a rapid temperature increase in the slurry. The specific gravity of the sample manufactured with 20% CSA was approximately 0.11 g/㎤, and its thermal conductivity was 0.041 W/m·K, providing an excellent insulating property.

A Study on the Capability to Use with Admixture Material of Paper Sludge Ash (제지 슬러지 소각회의 시멘트 혼화 재료로서의 이용 가능성에 관한 연구)

  • 김재진;문경주;노병남;문성필;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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    • pp.89-92
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    • 1999
  • The purpose of this study is to evaluate the capability to use with cement admixture materials because Paper Sludge Ash consists of Si, Ca and Al which are chief content in Pozzolan. For the derivation of Pozzolanic reaction in Paper Sludge Ash, it is measured compressive strength on cement mortar which is replaced mixing of Paper Sludge Ash and inorganic admixture ; ie, gypsum, lime and slaked lime, regularly. In the result of test, the strength decrease remarkably when cement is only replaced with Paper Sludge Ash, but the strength is almost equal when cement is replaced with Paper Sludge Ash is mixed with inorganic admixture material in proportions of 5~15%. Consequently, It is possible to use Paper Sluge Ash with admixture materials of cement.

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X-ray and gamma ray shielding behavior of concrete blocks

  • Hernandez-Murillo, Christian Geovanni;Contreras, J. Rafael Molina;Escalera-Velasco, Luis Alberto;de Leon-Martineza, Hector Asael;Rodriguez-Rodriguez, Jose Antonio;Vega-Carrillo, Hector Rene
    • Nuclear Engineering and Technology
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    • 제52권8호
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    • pp.1792-1797
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    • 2020
  • The shielding characteristics of two concrete blocks, widely used in the building industry in Mexico have been determined. These characteristics include the mass interaction coefficients, the linear attenuation coefficients and the half-value layers. The energy-dispersed X-ray fluorescence shows that the percentage mass content of each atom in the sample, and the atomic volume of the constituent elements of a material, plays an important role in its shielding capabilities. The total linear attenuation coefficients and the half-value layers were analyzed for a set of photon energies related to X-rays for diagnosis and cancer treatment with linear accelerators. Our results show that the concrete blocks have similar photon attenuation coefficients than the Portland concrete and better features than gypsum.

Effect of Impurities Included in the Domestic Waste Phosphogypsum on Hydration of Portland Cement (국산 인산석고에 함유된 불순물들이 Portland Cement의 수경성에 미치는 영향)

  • 인식환;정형진
    • Journal of the Korean Ceramic Society
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    • 제18권4호
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    • pp.237-246
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    • 1981
  • The effects of impurities, included in the by-produced phosphogypsum from the dihydrate process, on the hydration of portland cement were studied. Six gypsums were adopted in this study; four different raw phosphogypsums from domestic fertilizer plants, a reprocessed phosphogypsum and a reagent grade pure gypsum. Cements with differing $SO_3$ content, were synthesized by grinding two different commercial clinkers and the above six gypsums together. The effects of the impurities were investigated by measuring the setting time, the non-evaporable water coatent, X-ray phase analysis of cement pastes and the compressive strength of cement mortar specimens. It was found that the soluble $P_2O_5$ known as one of injurious impurities on the hydration of portland cement, included in the demestic raw phosghoypsum cxneedigply by far the specified amounts of the Korean Industrial Standards (L9005), and retarded the setting time severely, thus the strength development of cement was delayed at the earlier stage of hydration.

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