화학적 분해법을 이용한 난용성 자원으로부터 희토류 회수 특성 연구

김리나,조희찬,정진안,김지혜,이수경,Kim, Rina,Cho, Heechan,Jeong, Jinan,Kim, Jihye,Lee, Sugyeong 한국자원리싸이클링학회 2020 자원리싸이클링 Vol.29 No.1

In this study, rare earth elements (REE) leaching from a refractory REE ore containing goethite as a major gangue mineral was conducted, introducing a two-stage method of chemical decomposition-acid leaching. At the chemical decomposition step, using one of alkaline agent, NaOH, the ore was decomposed, changing NaOH concentration from 20 to 50 wt% at 10% (w/w) of pulp density and the maximum temperature achieved without boiling at each NaOH concentration. With increasing NaOH concentration, light REE (Ce, La and Nd) and iron were concentrated in the solid phase which is the decomposed product, while aluminum (Al) and phosphorus (P) were removed to the liquid phase, and their concentrations in the solid phase were down to 0.96 and 0.17%, respectively. In addition, through XRD analysis, it was found that the crystallinity of goethite was considerably decreased. At the acid leaching step, the product decomposed by 50 wt% NaOH was leached at 3.0 M HCl and 80 ℃ for 3 hr, then the REE leaching efficiency was above 94% (Ce 80%), and the leaching efficiencies of Al and P were decreased to 12 and 0%, respectively. Therefore, in terms of both REE leaching efficiency and impurity removal, those decomposition and leaching conditions were chosen as optimum processing methods of the investigated material. In terms of REE leaching mechanism, because REE and iron leaching efficiencies showed the positive correlation each other, so it can be concluded that decreasing crystallinity of goethite affect the improvement of REE leaching.

공기와 활성탄 병용에 의한 용액 중 고농도 3가 비소의 산화-침전 거동 연구

김리나,김가희,김관호,유광석,Kim, Rina,Kim, Gahee,Kim, Kwanho,You, Kwang-suk 한국자원리싸이클링학회 2021 자원리싸이클링 Vol.30 No.4

Arsenic (As) oxidation followed by precipitation from a high-As(III)-containing leaching solution derived from a sulfidic ore was investigated in this study to remove aqueous As from the solution using activated carbon (AC) with air injection as an oxidant. To obtain the initial leaching solution, a domestic sulfidic ore was leached in a sulfuric acid solution at pH 1 and 50℃ for 95 h, and approximately 7 g/L of Fe and 3 g/L of As were leached out. To determine the effect of the oxidative reaction utilizing AC with air injection, the leaching solution was tested under the following five oxidative conditions at an initial pH of 1 and 90℃ for 72 h: air-only injection; air injection with 1, 5, and 10 w/v% of AC addition; and H₂O₂ addition. The tests in the presence of both air and AC revealed that the oxidation kinetics and As removal were improved by the reaction between the metallic species and the surface group formed on the AC surface. In addition, the greater the amount of AC added, the better was the reaction efficiency, removing 93-94% of As with more than 5 w/v% of AC addition. Finally, X-ray diffraction analysis confirmed that the precipitate formed from the oxidative reaction was scorodite (FeAsO₄·2H₂O).

초등학교 1학년 학생의 수학 불안 종단 연구

김리나(Rina Kim) 학습자중심교과교육학회 2024 학습자중심교과교육연구 Vol.24 No.8

목적 본 연구에서는 초등학교 1학년 학생들의 수학 불안 상태를 확인하고, 수학 불안이 있는 학생들을 대상으로 그 원인을 조사한다. 이를 통해 초등학교 저학년 시기 수학 불안의 발생 과정에 대해 알아본다. 방법 본 연구에서는 초등학교 1학년 학생 380명을 대상으로 2022년 3월부터 2024년 2월까지 수학 불안에 관한 종단 연구를 시행하였다. 수학 불안 검사지를 활용하여 총 3회에 걸쳐 학생들의 수학 불안 정도를 조사하고 후속 면담을 통해 수학 불안의 원인을 확인하였다. 결과 본 연구에 참여한 초등학교 1학년 대부분은 수학 불안이 없거나 낮았으나, 수학 불안이 높은 소수의 학생도 존재하였다. 특히 1학년 입학 초기 수학 불안이 가장 높았다. 학생들은 두려움 원인으로 수학 학습에서 실패할 것 같다는 걱정을 가장 많이 언급했다. 결론 수학 불안이 1학년 초에 가장 높다는 결과는 학생들이 새로운 수학 학습 상황에 적응하기 전 스스로 어렵다고 생각하는 수학 과제를 마주했을 때 더 불안감을 느끼는 것을 시사한다. 본 연구의 결과는 초등학생의 수학 불안을 이해하고, 학생들의 수학 불안 예방을 위한 교수법을 개발하는 데 도움을 줄 것으로 기대된다. Objectives The purpose of the study in to investigate the state of math-anxiety in first-grade elementary school students and the causes. Methods I conducted a longitudinal study on math-anxiety on 380 first-grade elementary school students from March 2022 to February 2024. Students' level of math-anxiety was investigated three times using the math-anxiety survey items, and the cause of math-anxiety was confirmed through follow-up interviews. Results Most first grade elementary school students who participated in this study had no or low math-anxiety, but there were a small number of students with high math-anxiety. In particular, math-anxiety was highest at the beginning of first grade. Students most frequently cited concerns about failing in mathematics learning as a cause of fear. Conclusions The finding that math-anxiety is highest at the beginning of first grade suggests that students feel more anxious when faced with math tasks they find difficult before they have adapted to new mathematics learning situations. The results of this study are expected to help understand math -anxiety in elementary school students and develop teaching methods to prevent math-anxiety in students.

초등학교 학생의 수학불안 변화 분석: 종단연구

김리나 ( Kim Rina ) 한국수학교육학회 2021 수학교육논문집 Vol.35 No.1

Mathematics anxiety is a term for emotional and physical resistance to mathematics. Understanding students' mathematics anxiety is important not only in terms of improving mathematics academic achievement, but also in nurturing mathematics manpower necessary for the future society. In particular, mathematics anxiety is most likely to occur in elementary school, and it has a negative effect on subsequent learning. Therefore, it is important to understand the aspects of students' mathematics anxiety in elementary school. In this study, I presented the patterns of changes in students' mathematics anxiety over time and statistically verified them. As a result of a follow-up survey of 249 elementary school students' mathematics anxiety for 3 years from 4th to 6th grade, it was found that, rather than having a special pattern related to the formation of math anxiety, it may increase and decrease and vary depending on individual confirmed. Later, in this study, five patterns of Mathematics anxiety patterns were identified through statistical analysis. In addition, I confirmed that the students' interest about teachers’ mathematics lessons was consistently influencing the change in mathematics anxiety. The results of this study will increase students' understanding of the formation of mathematics anxiety and can be used as basic data for the development of teaching and learning materials related to mathematics anxiety in the future and subsequent research.

초등학교 교사의 수학불안과 수학교수불안의 상관관계 분석 연구

김리나 ( Kim¸ Rina ) 한국수학교육학회 2021 초등수학교육 Vol.24 No.2

In this study, I investigate the relationship between mathematics anxiety and mathematics teacher anxiety of elementary school teachers with integrated method. As a result of statistical analysis of the survey of 256 elementary school teachers, there was a statistically significant positive correlation between the two factors (r = .630, p <.05). The analysis show that teaching experience and degree may affect mathematics anxiety and teaching experience, degree, and teacher qualification may affect mathematics teaching anxiety. Subsequently I conduct a qualitative study focusing on interviews with 20 elementary school teachers. As a result of the analysis, I confirm that even if the mathematics anxiety is low, mathematics teaching anxiety may occur due to the teaching environment. As a result of the quantitative and qualitative analysis of this study, Korean elementary school teachers' mathematics anxiety and mathematics teaching anxiety might be regarded as separate factors. From the result of the study, I suggest that mathematics anxiety and mathematics teaching anxiety of elementary school teachers, each emotional state might be considered as independent emotional status. The implication of the study indicate that independent methods might be developed in order to prevent and treat mathematics anxiety and mathematics teaching anxiety in elementary school teachers.

초등학생 수학불안에 관한 문헌연구

김리나 ( Kim Rina ) 한국수학교육학회 2018 초등수학교육 Vol.21 No.2

This literature review focuses on the history of research on elementary students’ mathematics anxiety. The results of analysis shows the characteristics, measurement tools, causes and the treatments of mathematics anxiety. The purpose of this study is to provide analytical views of elementary students’ mathematics anxiety to teachers, researchers and policymakers. I categorize the results of analysis according to the key words of literatures: (1) the relationship between mathematics anxiety and students’ behavior (2) measurements of mathematics anxiety (3) the causes of mathematics anxiety and (4) the treatment of mathematics anxiety.

초등학생의 수학 불안 측정 도구 개발 연구

김리나 ( Kim Rina ) 한국수학교육학회 2018 초등수학교육 Vol.21 No.4

The purpose of this study was to develop and validate a mathematics anxiety scale for elementary students in South Korea. Based on the literature review, I developed two types of survey items measuring elementary students' mathematics anxiety. Teachers or students may use survey measurements selectively according to the students’ participants in mathematics private institutions. In order to assess the reliability and validity of survey items, I conducted surveys with elementary students. The sample consisted of 300 elementary students in public elementary schools in Seoul. A total of 28 items were developed and examined for the internal consistence. The results showed that the proposed scale was appropriate to represent the mathematics anxiety of elementary students. The survey items of this study could be applied for assessing elementary students' mathematics anxiety regardless of their gender and age factors.

초등학교 교사의 수학 교수학적 지식과 수학 불안감 사이의 상관관계 분석 연구

김리나 ( Rina Kim ),신항균 ( Hanggyun Sihn ) 서울교육대학교 초등교육연구원 2015 한국초등교육 Vol.26 No.3

The aim of the study presented in this paper was to explore the relationship between South Korean elementary teachers` mathematical knowledge for teaching (MKT) and their mathematics anxiety. A paired t-test and simple regression analysis are applied to examine elementary teachers` knowledge for teaching mathematics that may influence their mathematics anxiety. Findings of this study suggest that there is a positive correlation between the teachers` mathematical knowledge for teaching mathematics and their positive insights toward mathematics. However, there is a little affect of the increasement of teachers` mathematical knowledge for teaching mathematics on reducing their negative perspectives toward mathematics. The results of this quantitative study help our understanding of the relationship between South Korean elementary teachers’ knowledge for teaching mathematics and their mathematics anxiety, which have a deep impact on their teaching practice.

초등학생의 수학 자기 효능감 검사 도구 개발에 관한 연구

김리나 ( Kim Rina ) 한국수학교육학회 2020 초등수학교육 Vol.23 No.2

The purpose of this study is to develop a mathematics self-efficacy test tool for elementary school students based on the sub-factors of mathematical self-efficacy derived from current studies. In this study, I verified the validity and reliability of the test tool by statistically evaluating the results of applying the test tool to the 3rd-6th grade students. In this study, Principal Component Analysis was performed on the tool for measuring the self efficacy of mathematics for elementary school students. For the validity test, the mathematics anxiety status of the participants was measured. The mathematics anxiety who were known to have a negative correlation with the mathematical self efficacy. The mathematics self efficacy tool developed in this study consists of 16 items with three subcategories: master experience, social persuasions, and emotional and physiological state. The mathematical self efficacy test tool developed in this study is expected to provide grounds for diagnosing the mathematics self-efficacy status of elementary school students and looking for ways to improve it.

Acidithiobacillus ferrooxidans와 Acidithiobacillus thiooxidans를 활용한 고농도 비소 함유 광석 내 중금속 용출 거동 연구

김가희,김리나,김관호,유광석,Kim, Gahee,Kim, Rina,Kim, Kwanho,You, Kwang-suk 한국자원리싸이클링학회 2021 자원리싸이클링 Vol.30 No.2

To investigate the potential for leaching of heavy metals by bacteria from ores stacked on actual mining sites, leaching tests of a complex metallic ore (Pb-Zn-As ore) were conducted over 60 days using acidophile bacteria Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans under initial acidic conditions. Initially, a small amount of heavy metals was leached due to the initial acidic conditions. After 20 days, when A. thiooxidans in the reactor was adapted to the ore, the amount of leached heavy metals rapidly increased; the concentrations of leached arsenic, iron, and zinc reached a maximum of 2800, 3700, and 2500 mg/L, respectively. On the other hand, in the presence of A. ferrooxidans or in the control test without bacteria, heavy metals, except zinc, were barely detected in leaching. Through this study, it was confirmed that (i) bacteria could leach heavy metals at mining sites under acidic conditions and (ii) leaching of heavy metals from a high arsenic-containing ore by A. thiooxidans was more significant than that by A. ferrooxidans.