도진영 Jin Young Do , 이태종 Tae Jong Lee

DOI:10.22807/KJMP.2026.39.2.1 Vol.39(No.2) 1-11, 2026

This study investigated the mineralogical mechanisms of exfoliation and granular disintegration induced by salt weathering to establish fundamental conservation data for the Stupa of State Preceptor Jigwang from Beopcheonsa Temple Site, Wonju. Wonju granite, selected as the replacement stone for the stupa's restoration, was thermally pre-treated to simulate various weathering grades and subjected to 130 cycles of artificial weathering tests using gypsum and sodium sulfate solutions. The results demonstrated that highly soluble sodium sulfate deeply penetrated the rock matrix, where repeated crystallization pressure caused severe granular disintegration. This phenomenon resulted in a maximum weight loss of 19.45% and a 76.5% reduction in compressive strength compared to the unweathered rock. Conversely, gypsum, a low-solubility salt, primarily formed a surface crust that inhibited internal penetration, exhibiting a weathering pattern dominated by surface exfoliation rather than severe internal structural degradation. Due to the extreme loss of surface material, sodium sulfate was not detected in the X-ray diffraction (XRD) analysis; however, SEM-EDS and Ion Chromatography (IC) analyses mutually confirmed a distinct increasing trend in the content of Na and S components (such as Na⁺ and SO₄²⁻). This indicates that the salt remained entrapped within the pore network in an amorphous state. Furthermore, the simultaneous leaching of K⁺ and the consequent decrease in K₂O content revealed that salt weathering acts as a complex mechanism, accelerating both the physical breakdown and chemical dissolution of rock-forming minerals. In conclusion, the weathering behavior of granite is fundamentally governed by the solubility and crystallization characteristics of the involved sulfate salts. Therefore, the effective extraction of soluble sulfates and the implementation of strict environmental controls are essential prerequisites for ensuring the long-term structural stability of stone cultural heritage.

원주석, 황산염, 박리, 입상분해, 복합풍화, Wonju granite, Sulfate, Exfoliation, Granular disintegration, Complex weathering

김찬석 Chan-souk Kim , 박현용 Hyun-yong Park , 김성용 Seong-yong Kim

DOI:10.22807/KJMP.2026.39.2.13 Vol.39(No.2) 13-29, 2026

The purpose of this study is to analyze media coverage of national critical minerals issues and derive policy measures for critical minerals. The analysis covered a total of 232 articles related to critical minerals published in conservative and progressive media from January 1 to December 19, 2025, employing keyword network analysis and topic modeling (LDA) analysis on the textual data. The analysis revealed that conservative media strongly tended to frame critical minerals issues around industrial competitiveness, supply chain restructuring, trade, and economic security, with keywords such as minerals, critical minerals, supply chain, and tariffs forming the core of the discourse. In contrast, progressive media tended to interpret critical minerals issues within the context of Korea-U.S. relations, resource security, and international political constraints, with keywords related to government, president, cooperation, and security showing high centrality. Topic modeling analysis also showed that conservative media predominantly featured topics on ‘critical minerals industrial supply chain’ and ‘U.S. tariff negotiations’, while progressive media was dominated by the ‘Korea-U.S. resource security’ topic. Based on these findings, the study proposed government policy measures including the establishment of an integrated policy framework for critical minerals, science communication considering media characteristics, sustainable policy agenda-setting for national critical minerals, and strengthening of international cooperation networks.

핵심광물, 미디어, 정책방안, 키워드 네트워크 분석, 토픽 모델링, critical minerals, media, policy measures, keyword network analysis, topic modeling

김후식 Hu Sik Kim , 유호연 Ho Yeon Yoo , 임우택 Woo Taik Lim

DOI:10.22807/KJMP.2026.39.2.31 Vol.39(No.2) 31-43, 2026

This study investigates the effect of competitive Mg²⁺ cations on the ion-exchange behavior, site occupancy, and distribution of Cs⁺ ions in zeolite Y (FAU-type). Ion exchange was performed using a mixed aqueous solution containing Cs⁺ (100 ppm) and Mg²⁺ (1000 ppm) on single crystals of zeolite Y (Si/Al = 1.56), followed by dehydration under dynamic vacuum conditions. The resulting structures were analyzed by single-crystal synchrotron X-ray diffraction. The crystal structure was determined in the cubic space group Fd3 m at 100(1) K and refined to final error indices of R1wR2 = 0.0639/0.1869. The unit-cell composition was determined as |Cs₆Mg₂₉Na₁₁|[Si₁₁₇Al₇₅O₃₈₄]-FAU. Structural analysis revealed that Mg²⁺, Na⁺, and Cs⁺ ions occupy distinct crystallographic sites. Mg²⁺ ions predominantly occupy the internal sites I, I′, and II′ with occupancies of approximately 14, 4, and 3.5 per unit cell, respectively, indicating preferential occupation of energetically favorable framework positions. In contrast, site II is co-occupied by Mg²⁺ (7.5), Na⁺ (11), and Cs⁺ (0.5), with Cs+ showing significantly reduced occupancy. Cs⁺ ions are mainly located at site III in the supercage (5.5 per unit cell), indicating a distribution limited to more accessible regions of the framework. These results demonstrate that the preferential occupation of internal sites by Mg²⁺ significantly restricts Cs⁺ incorporation into the zeolite framework, leading to a redistribution of Cs⁺ from internal sites to external supercage regions.

제올라이트 Y, 이온교환, 경쟁이온, 세슘이온, 마그네슘이온, 결정학, Zeolite Y, FAU, Ion exchange, Competitive cations, Cesium, Cs⁺, Magnesium, Mg²⁺, Crystallography

이선용 Seon Yong Lee , 전철민 Chul-min Chon , 이영재 Young Jae Lee

DOI:10.22807/KJMP.2026.39.2.45 Vol.39(No.2) 45-64, 2026

This study comparatively evaluated hydroxyapatite and struvite crystallization processes for phosphorus recovery from high-salinity phosphate solutions and investigated the applicability of hydroxyapatite crystallization under strongly acidic conditions. The effects of ion molar ratio, cation source, pH, background electrolytes, and seed materials on crystallization performance were examined, and the resulting products were characterized using X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). In hydroxyapatite crystallization, phosphorus removal efficiency increased with increasing Ca:P ion molar ratio and pH, achieving removal efficiencies greater than 99% under optimal conditions (Ca ≥ 1.8:1 and pH ≥ 10). CaO and Ca(OH)₂ exhibited phosphorus removal performances comparable to that of CaCl₂, whereas the effects of background electrolytes and seed materials were limited. In struvite crystallization, phosphorus removal efficiency also increased with increasing Mg:NH4:P ion molar ratio and pH, reaching a maximum removal efficiency of 97.3% when MgCl₂ was used as the magnesium source. XRD analysis confirmed hydroxyapatite and struvite as the dominant crystalline phases in the recovered products. Applicability tests under strongly acidic conditions demonstrated that the addition of CaO increased solution pH and induced hydroxyapatite crystallization in both 10% HCl and 10% H₂SO₄ solutions, reducing the residual phosphorus concentrations to 2.2 and 2.6 mg/L, respectively. These results indicate that both hydroxyapatite and struvite crystallization are effective technologies for phosphorus recovery, while hydroxyapatite crystallization shows particular potential for recovering phosphorus from strongly acidic phosphorus-containing solutions.

수산화인회석, 스트루바이트, 수용액 조건, 결정화, 인 제거, hydroxyapatite, struvite, aqueous solution conditions, crystallization, phosphorus removal

정원석 Wonseok Cheong

DOI:10.22807/KJMP.2026.39.2.65 Vol.39(No.2) 65-68, 2026

김태환 Taehwan Kim

DOI:10.22807/KJMP.2026.39.2.69 Vol.39(No.2) 69-74, 2026