Hun Song

Extraction of Mg ion and Fabrication of Mg Compound from Ferro-Nickel Slag

Ferro-Nickel slag is one of the by-products in Ferro-Nickel manufacturing process. The slag is composed of SiO₂, MgO, Fe₂O₃ and others. But the slag has been buried at landfill despite having valuable elements. This study tried to extract Mg ion and fabricate Mg compound from ferro-nickel slag using hydrochloric acid solution. Mg ion was extracted with Si, Fe and other ions in HCl solution. So reprocess was needed for gaining high purity Mg ion. It was thought that Si ion or SiO₂ precipitated in HCl solution and removed from solution in filtering process. Fe ion converted into Fe(OH)₃ after reacted with NH4OH and precipitated in HCl solution. After these process, the filtrate was composed of high purity Mg ion. MgCl₂·NH₄Cl·6H₂O was obtained through drying of filtrate and this product was changed into MgO by burning process (600℃-30 min). That is, 1st material or solution for manufacturing 2nd product was fabricated using acid dissolution method and other treatments.

Flame Resistance Performance of Architectural Membranes Using Basalt Woven Fabric

The membrane structure provides high satisfaction with lightweight, improved workability, reduced cost, and a free shape. Thus, its applications expanding. On the other hand, in an architectural membrane that is vulnerable to fire, the development of various architectural membranes with flame resistance is in demand. Therefore, this study applied basalt woven fabric safety for flame resistance, excellent heat insulation and thermal properties on an architectural membrane. The PTFEcoated basalt woven fabric membrane was compared with a PTFE coated glass fiber membrane by DSC/TGA, strength properties, flammability, and incombustibility properties. In addition, this study confirmed the membrane applicability of basalt woven fabric and basalt-glass hybrid woven fabric through a comparison with existing architectural membranes.

Image and Phase Analysis of Low Carbon Type Recycled Cement Using Waste Concrete Powder

, recycling waste concrete to manufacture recycled aggregate or recycling waste concrete powder, which is the material for cement can be considered optimally environment-friendly practices. This study contributes to the aim of manufa cturinghigh value added materials that exploits the chemical properties of the waste concrete powder. From the research results, waste concrete powder is feasible to use to produce low carbon type recycled cement.키워드 : 저탄소형 시멘트, 콘크리트 미분말, 콘크리트 리사이클 Keywords : Low carbon type cement, Waste concrete powder, Recycled concrete* Corresponding author E-mail: songhun@kicet.re.kr

Carbonation and Cl − Penetration Resistance of Alkali Silicate Impregnant of Concrete

Every concrete structure should continue to perform its intended functions such as to maintain the required strength and durability during its lifetime. Deterioration of the concrete structure, however, occurs more progressively from the outside of the concrete exposed to severe conditions. Main deteriorations in concrete structures result from carbonation, chloride ion attack and frost attack. Concrete can therefore be more durable by applying surface protection to increase its durability using impregnants, which are normally classified into two large groups in polymeric and silicate materials. Concrete impregnants are composed of silanes and alkali silicates (sodium, potassium and lithium silicate). Thus, this study is concerned with elevating the carbonation and Cl- penetration resistance of concrete structures by applying alkali silicate hydrophilic impregnants including lithium and potassium silicates. From the experimental test results, lithium and potassium silicates produced a good improvement in carbonation resistance and are expected to be used as hydrophilic impregnants of concrete structures.

Hygroscopic Characteristic of Gypsum Boards Using Porous Materials

Active clays, Diatomite, bentonite and zeolite were used as porous materials for fabricating hygroscopic gypsum boards. Pohang active clay and Cheolwon diatomite showed excellent characteristics of moisture adsorption and desorption. These characteristics were caused by higher surface area and pore volume of porous materials. Moisture adsorption content of gypsum board with 10% active clay(P1) was 62.0 g/m, and moisture desorption content was 50.2 g/m. Moisture adsorption content of gypsum board with 10% diatomite(P) was 59.5 g/m, and moisture desorption content was 49.0 g/m. Moisture adsorption contents of gypsum boards with porous materials were higher than that moisture desorption contents of gypsum board without porous materials. Correlation coefficient between surface area and moisture adsorption content of gypsum boards was 0.98. Also, correlation coefficient between surface area and moisture desorption content of gypsum boards was 0.97. Moisture adsorption and desorption contents were influenced by surface area and pore volume of the gypsum boards, and surface area had a larger effect on moisture adsorption and desorption.

Physical Properties of Light Weight Foamed Glass Using Waste Glass Powder and Fly Ash

Building insulation materials use for the purpose of energy saving. Insulation materials can be classified inorganic and organic insulation materials. Inorganic insulation is used for fire resistive performance parts and organic insulation is used for thermal performance parts. Meanwhile, organic insulation is due to toxic gas emission in fire. Inorganic insulation is too heavy and low thermal performance than organic materials. This study is focused on evaluation of the physical properties of inorganic foam material using industrial by-products such as waste glass powder and fly ash. From the test result, inorganic foam materials for the applicability of fire-resistance and insulation light-weight materials.

Property of Concrete Surface layer Using Self-Cleaning Silicate Concrete Impregnant

This study is interested in manufacturing the self-cleaning silicate concrete surface impregnant including tetra ethyl ortho silicate, lithium silicate for the repair of the exposed concrete surface and the color concrete requiring the advanced function in view of the concrete appearance. The concrete surface layer change and static contact angel was tested for the review of application. The result of this study shows that the effective silicate is tetra ethyl ortho silicate and lithium silicate. The adhesion in tension is satisfied with performance requirement of KS standard but the reinforcement of concrete substrate is slight. So, The self-cleaning silicate concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.

A Study on Fabrication and Characterization of Inorganic Insulation Material by Hydrothermal Synthesis Method (1)

In this study, the inorganic insulating material was fabricated with quartzite, ordinary portland cement(OPC), lime and anhydrous gypsum. After characteristic analysis of slurry, the optimum mixing ratio was derived with different CaO/SiO2 mole ratio. Based on derived mixing ratio, the inorganic insulating material was fabricated at different water content and hydrothermal synthesis conditions. Specific gravity was 0.26 g/cm 3 , compressive strength was 0.4 MPa, and thermal conductivity was 0.064 W/mK. This properties were enhanced performance of conventional ALC (Autoclaved Lightweight Concrete). And it can replace organic insulation with harmless inorganic insulation through continues research and development.

Leaching Properties of Water-Soluble Hexavalent Chromium by Manufacturing Condition of Cement Clinker

One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The purpose of the present study was to investigate leaching properties of water-soluble hexavalent chromium by different manufacturing conditions of cement clinker. Raw materials were prepared to add different , and sources. After the raw materials, such as limestone, sand and clay, iron ore was pulverized and mixed, and the raw meal was burnt at in a furnace with an oxidizing atmosphere. Leaching of soluble hexavalent chromium showed a tendency to decrease with an increasing LSF and IM. However, leaching of soluble hexavalent chromium increased with an increasing S.M. Alkali contents of iron source minerals is closely related to the leaching properties of soluble hexavalent chromium. Green sludge has the highest content of alkali added; leaching of water-soluble hexavalent chromium was mostly high. In order to reduce the water-soluble hexavalent chromium in cement, reducing the alkali content in raw materials is important.

Adhesion Characteristic and Porosity Change of Alkali Silicate Impregnant of Concrete

There are the impregnating layer formation by surface protective materials or impregnants and the adhesion method by polymer, FRP sheet or steel plate in the surface protective method of concrete structure. The surface impregnation method by impregnants improves the durability of concrete structure by modifying the structure of the concrete surface and also have a merit that can be shortly applied in place without the decrease of concrete surface appearance and is easily applied again. This study is interested in manufacturing the concrete surface impregnants including lithium and potassium silicate for the repair of the exposed concrete and the color concrete requiring the advanced function in view of the concrete appearance. The durability and porosity properties was tested for the review of application. The result of this study show that the effective content of silicate ranges 5 to 20% and the separate application of the first impregnant and the second impregnant is effective for the optimum performance. The adhesion in tension is slightly increased but the reinforcement of concrete substrate is slight. So, the concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.