• Economic and Environmental Geology
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• v.42 no.5
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• pp.395-401
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• 2009

The smectite-illite (SI) reaction is a ubiquitous process in siliciclastic sedimentary environments. For the last 4 decades the importance of smectite to illite (S-I) reaction was described in research papers and reports, as the degree of the (S-I) reaction, termed "smectite illitization", is linked to the exploration of hydrocarbons, and geochemical/petrophysical indicators. The S-I transformation has been thought that the reaction, explained either by layer-by-layer mechanism in the solid state or dissolution/reprecipitation process, was entirely abiotic and to require burial, heat, and time to proceed, however few studies have taken into account the bacterial activity. Recent laboratory studies showed evidence suggesting that the structural ferric iron (Fe(III)) in clay minerals can be reduced by microbial activity and the role of microorganisms is to link organic matter oxidation to metal reduction, resulting in the S-I transformation. In abiotic systems, elevated temperatures are typically used in laboratory experiments to accelerate the smectite to illite reaction in order to compensate for a long geological time in nature. However, in biotic systems, bacteria may catalyze the reaction and elevated temperature or prolonged time may not be necessary. Despite the important role of microbe in S-I reaction, factors that control the reaction mechanism are not clearly addressed yet. This paper, therefore, overviews the current status of microbially mediated smectite-to-illite reaction studies and characterization techniques.

• Journal of the Mineralogical Society of Korea
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• v.18 no.1
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• pp.19-31
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• 2005

A study on the beneficiation of illite occurring in Youngdong province is performed with applying selective grinding and air classification techniques. Quartz and illite are occurred as major components, and sulfide minerals such as pyrite, chalcopyrite are associated as minor components. The result of sieving test shows that contents of Al₂O₃, K₂O and ignition loss are increased, whereas SiO₂ is decreased with particle size decrease. Fe₂O₃ content is almost same in all the particle size range but slightly lower at coarse particles. The yield of fine particles is increased with increasing rotor speed in both grinding stage and air classification stage. When the selective grinding and air classification are carried out at optimal condition, yield of the concentrate is 76.16 wt.%. The chemical compositions of the concentrate are SiO₂70.13%, Al₂O₃ 19.40%, Fe₂O₃ 1.62%, K₂O 5.20%, and ignition loss 2.77%. The beneficiation process developed in the current study is very effective method which purification and particle size control can be achieved simultaneously.

• The Korean Journal of Petroleum Geology
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• v.2 no.2 s.3
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• pp.83-90
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• 1994

Thermal maturation and diagenesis of the Gyeongsang Supergroup in the Euiseong area are studied by means of organic geochemical techniques and illite crystallinity. Black mudrocks of the Singdong Group contain organic matter of $0.5{\~}2{\%}$ derived from higher plants, being compared to type Ⅲ. Thermal maturity of organic matter reached dry gas generation phase. Tmax by Rock Eval pyrolysis varies between $578^{\circ}C$ and $593^{\circ}C$ regardless of stratigraphic position and localities, and vitrinite reflectance is about 2.9 and $3{\~}4{\%}Ro$ in the Jinju and the Nagdong Formations, respectively. Vitrinite reflectance measurements indicate that the maturation is mainly due to burial and partly to be affected by post-depositional intrusions. Illite crystallinity values from the Nagdong, Hasandong, Jiniu Formations and part of the Iljig Formation are plotted around the boundary between diagenesis and anchizone, indicating dry gas generation stage. However, the values are not dependent on stratigraphic position. The values from the Iljig, Hupyeongdong, Geomgog, and Sagog Formations fall into the range of anchizone, probably resulted from the post-depositional intrusions which occur locally. Both organic geochemical and illite crystallinity data indicate thermal maturation stage of dry gas generation. Diagenesis of the Gyeongsang strata is mostly controlled by burial, and partly affected by post-depositional intrusions. Paleotemperature of the Sindong Group is estimated at around $200^{\circ}C$ on the basis of illite crystallinity.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.259-271
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• 2023

Since the short-wave infrared spectrum has a significant range of variation depending on the production environment, countries with advanced resource exploration are collecting the spectrum and building a database. Representative organizations include the USGS and CSIRO, and they are currently carrying out a project in China that can synthesize and use a large number of existing data. The USGS library provides a total of 2,457 spectra targeting not only minerals but also various materials that respond to infrared radiation. Among these, there are 1,276 mineral spectra, which are about half of the total. The spectrum title includes information, such as analysis devices (NIC4, BECK, ASDNG, etc.), purity codes (a, b, c, d, u), and measurement methods (AREF, RREF, RTGC, TRAN). Analyzed raw data are provided in ASCII and GIF format. The CSIRO library has a total of 502 spectra, of which the majority, 493, correspond to mineral spectra. The USGS library is a free, publically available resource, while the CSIRO library is bundled with TSG8 or must be purchased separately. Among these, when comparing the eight spectra whose spectral shapes can be analyzed with the spectra of domestic illite, the positions of the absorption peaks are significantly different from those of domestic illite, except for one Japanese illite. Additional research will be needed to determine the causes of such differences, and the domestically relevant databases should be established as well.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.163-173
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• 2012

In this study, we determined the relative clay mineral composition of 51 surface sediments from SEYSM (Southeastern Yellow Sea Mud) (northern part 25, southern part 26) and 30 river sediments inflow to Yellow Sea using the semi-quantitative X-ray diffraction analyses. In addition to we analyzed illite characteristics of the same samples. The clay-mineral assemblage is composed of illite (61~75%), chlorite (14~24%), kaolinite (9~14%), and smectite (1~7%), in decreasing order. The average composition of each clay mineral is not different from northern part to southern part of SEYSM except a little higher kaolinite and lower smectite content in northern part. Smectite content generally has reverse relationship with illite content. Mineralogical characteristics of illite such as illite crystallinity index also is not different between two areas and show very narrow range (0.18~0.24 ${\Delta}^{\circ}2{\theta}$). Our results reveal that clay mineral composition and illite characteristics are nearly the same between northern and southern part of SEYSM. Characteristics of surface sediments in SEYSM is closer to Korean river sediments than Chinese Hanghe sediments, however it is necessary to investigate further study including Yangtze river sediments. This study conclude that most of surface sediments in SEYSM attribute to the supply of considerable amount of sediments from the nearby Korean rivers. The large sediment budget and high accumulation rate in the SEYSM can be explained by erosion and reworking of surface sediments in this area. Tidal and regional current system around SEYSM might contribute these erosional and depositional regimes.

• Journal of the Korean Geophysical Society
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• v.4 no.4
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• pp.251-256
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• 2001

Korean natura1 zeolite with fe1dspar and illite as impurities was purified by an air c1assification method. X-ray powder diffraction ana1yses showed that the air c1assification effectively separated zeolite and impurities, and reduce the amount of impurity of the natura1 zeolite. The zeolite with air c1assification was treated with 1N NaOH solutions at temperatures at 100, 150, 200 ℃ for 17hours. The obtained hydrotherma1 treatment of phase change to philli1site and ana1cime from mordenite and clinopti10lite.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.182-183
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• 2017

This research identifies radon gas absorption mechanism by adsorption materials, replacing gypsum board with radon emissions, the density and absorption rates of magnesium were carried out using vermiculite, anthracite, powdered active carbon, bentonite, illite, diatomite as a basic study on the fire resistance type of radon Gas reduction type with absorption and decomposition. As a result of the experiment, diatomite showed the lowest density, and the highestt value was the highest. For the absorption rate, bentonite showed the highest absorption rate, and the anthracite showed the lowest absorption rate.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1495-1506
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• 2023

For the safe disposal of high-level radioactive waste using Engineered Barrier Systems (EBS), bentonite buffer is used by its high swelling capability and low hydraulic conductivity. When the bentonite buffer is contacted to heated pore water containing ions by radioactive decay, chemical alterations of minerals such as illitization reaction occur. Illitization of bentonite indicates the alteration of expandable smectite into non-expandable illite, which threatens the stability and integrity of EBS. This study intends to provide a thorough review on the information underlying in the illitization of bentonite, by covering basic clay mineralogy, smectite expansion, mechanisms and observation of illitization, and illitization in EBS. Since understanding of smectite illitization is crucial for securing the safety and integrity of nuclear waste disposal systems using bentonite buffer, this thorough review study is expected to provide essential and concise information for the preventive EBS design.

• Proceedings of the Petrological Society of Korea Conference
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• 2009.05a
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• pp.15-17
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• 2009

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.154.1-154.1
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• 2001