• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.390-393
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• 2010

The thermal decomposition rate of ammonium perchlorate with 3% of yellow iron oxide, FeOOH was found to be much faster than with red iron oxide, $Fe_2O_3$. By applying yellow and red iron oxide as a burning rate modifier to HTPB/AP propellant, burning rate of the HTPB/AP propellant with yellow iron oxide was shown to be 10 ~ 25% faster than with red iron oxide. There was no special difference in viscosity and hardness buildup of yellow and red oxide added HTPB/AP formulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.65-71
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• 2018

There is no significant difference in the initial viscosity of a propellant applied with yellow iron oxide and red iron oxide. In addition, the thermal decomposition rate of the material with added yellow iron oxide is faster than that with the addition of red iron oxide. Specifically, it was confirmed that the pressure exponent was 18% lower at high temperature and high pressure with yellow iron oxide than with red iron oxide. The initial viscosity was lowest at 71% of the large particle to small particle ratio.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.498-503
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• 2017

There is no unusual difference in the initial viscosity of the propellant applied with yellow iron oxide and red iron oxide. In addition, the thermal decomposition rate of the material added with yellow iron oxide is faster than that of the addition of red iron oxide. Especially, it was confirmed that the pressure exponent was 18% lower at high temperature and high pressure. The initial viscosity was lowest at 71% of large particle/small particle ratio

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.12-17
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• 2020

The mechanical properties of the propellant with yellow iron oxide were slightly increased compared to the propellant with red iron oxide. The propellant with yellow iron oxide used two types of AP. As the ratio of small particles of AP increased, the burning rate increased. The propellant may be applied to the propellant under operating conditions of 17.5 mm/sec or less having a pressure index of 0.5. The burning rate downs in the mixer scale-up. The stress at maximum load of propellant decreased and the strain at maximum load increased in the mixer scale-up. The yellow iron oxide did not affect the adhesive force between the insulation/liner/propellant.

• Resources Recycling
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• v.11 no.5
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• pp.24-29
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• 2002

In this study, to improve the color of iron oxide from waste pickling acid at the cold rolling mill, the quality control technologies especially about color were investigated on the spray roaster and iron oxide powder. At the operation condition of the spray roaster, the charge amount of waste acid per hour, temperature, numbers of spray nozzle were investigated. At admixing process, titanium oxide, silica, goethite were tested. Color character of iron oxide can be improved by process control at spray roaster and by admixing process at a pigment factory Iron oxide from results of this study is enough to use as the colorant of concrete product.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.137-144
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• 2012

Soil pan typically presents the problems in soil water movement or in aeration which is not appropriate for a plant root growth, In this study physico-chemical characteristics of soils and micromorphological characteristic of clay accumulated zone were investigated to identify redox characteristic and evolution of a fragipan of Gangreung series commonly developed in coastal terraces. Gangreung series is classified as Aquic Fragiudalfs according to the USDA soil taxonomy. It is known that sedimentary ocean floor results in soil pan having parallel liner soil structure due to landscape evolution around 200 to 250 million years ago. it is considered that illite, kaolinite, and vermiculite are major clay minerals contained in a fragipan of Gangreung series. Mixed gray and reddish brown colored band around soil pores was found and would be the redoxmorphic features of fragipan. It is possibly due to accumulated illuvial clay and ferriargillans in soil pores and aggregates in reducing conditions eluding ferrous material. Therefore, mixed colored band around pores in soils of Gangreung series would be developed from the eluted ferrous materials which were accumulated in fragipan during the emerged land formation.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.239-254
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• 2016

The Hwangto cave is a sea cave which is located near shore in the Taeha-ri, Ulleung Island, being composed of the reddish tuff wall rock, the topic of this study, and the trachyte ceiling rock. The chemical compositions of the red tuff layer are 49.81-63.63% of $SiO_2$, 13.05-24.91% of $Al_2O_3$, 2.67-5.82% of $Fe_2O_3$, 2.87-6.92% of $Na_2O$, 2.37-3.85% of $K_2O$, 0.55-0.81% of $TiO_2$, 0-0.53% of MnO, 0.39-1.75% of MgO, and 0.60-1.40% of CaO with a pH ranging from 4.5 to 8. The reddish tuff are composed of 23.7-39.4% of anorthoclase, 16.9-33.3% of sanidine, 15.8-26.1% of illite, 5.1-9.0% of hematite, 0-3.7% of goethite, 6.9-9.9% of titanium oxide, and 0.9-9.5% of halite in mineral composition. Although it only includes anorthoclase, sanidine, and illite as major minerals, there can be additional vitric minerals that could not detected by the XRD. The mineralogy and textures of the tuff layer indicate that it became reddish due to the formation of amorphous palagonite and the oxidation of the iron as a heat from the trachytic lava affects the underlying tuff to altered. This iron oxides are enriched in the palagonite, or form microcrystalline or amorphous minerals. We thus suggest that the red tuff layer was generated by the combination of the thermal oxidation involved in the trachytic lava flow on the tuff layer, the palagonitization of the matrix of the tuff, and the oxidation of iron-bearing minerals.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.145-152
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• 2004

Red sedimentation substance contains large portion of Fe. The earth retaining structure of a tunnel and ground water containing more portion of Fe than other area are the major factor of this substance In case of white sedimentation substance, the most frequently founded ingredient is CaO, which is occurred in case grouting injection materials for ground reinforcement is transmitted into a tunnel system by ground water. This substance is doesn't affect safety of a tunnel Black sedimentation substance is often found in tunnels near station. This substance is a mixture of either white or red sedimentation substance and detergent material in station transmitted to a tunnel drainage system.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.10-15
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• 2020

This study is about the changes in mechanical and combustion properties after the production of the combustion catalysts FeOOH and Fe₂O₃ having the same manufacturing method and application to the solid propellant. In order to make the FeOOH and Fe₂O₃ having the same manufacturing method, FeOOH was calcined at 200, 300, 400, 500℃ for 2 h, and the XRD results were confirmed. In addition, after applying the prepared catalyst to a solid propellant, it exhibited change in mechanical and combustion properties. As result of XRD, FeOOH was confirmed to change the crystal phase from Geothtie to Hematite between 200 and 300℃. The stress of the propellant hardly changed as the calcination temperature of the combustion catalyst incredsed, but the elongation increased when catalyst was calcined. the maximum value at 300℃. The burning rate confirmed that FeOOH without calcination was about 3~5% faster than other catalysts.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.153-162
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• 2009

The main compositions of "Seokganju", a Korean traditional red mineral pigment, are iron oxides. To investigate its mineralogical and functional properties, we had got its ore from Juto cave in Ulreoung island, which was a famous field of it in Korean documents. The ore occurs as a paleosol between the olivine basalt and amphibole trachyte in discontinuously. It is reddish brown and yellowish brown and consists mainly of clay minerals with minor debris. Its reddish and yellowish brown color are due to the hematite and ferrihydrate, respectively. These iron oxides are precipitated as ferrihydrate from the ferrous water in the paleosol and partly changed to hematite. The color reproduced in timber by using seokganju pigment with traditional tools and methods is similar to that in heritage building. The moistureproofing and fire resistance of Ulreungdo seokganju is far better than that of artificial seokganju. Moreover, the combustion tests show that the artificial seokganju promote the ignition and combustion of the timber. Ulreungdo seokganju is regarded as a pigment with fungicidal efficacy because growth of two wood decay fungi (cov. and typ.) are inhibited in solid medium with it.