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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 27, Number 3
JKCSEZ 27(3)
June 20, 1983 

 
Title
Effect of Reductive Salts on Dissolution of α-Fe2O3 in Acidic Solutions

산성용액 내에서 α-Fe2O3의 용해에 대한 환원성 염의 효과
Author
Jeong-Ik Lee, Lee-Mook Kwon

이정익, 권이묵
Keywords
Abstract
α-Fe2O3의 HCl 또는 H2SO4에 의한 용해반응에 있어서 금속염의 첨가효과를 분광광도법과 중량법으로 검토하였다. 환원성 금속염은 현저한 반응촉진 효과를 보이나 비환원성 금속염은 부의 효과를 나타내었다. FeCl2와 같은 환원성 금속염을 첨가한 경우에 α-Fe2O3의 용해속도가 크게 촉진되는 것은 Fe3+ 와 Fe2+ 사이에 chloro-brige가 형성되어 전하이동이 일어나면서 α-Fe2O3 표면의 격자에너지를 감소시키기 때문인 것으로 추측된다. 이 전하이동으로 인한 α-Fe2O3 표면의 격자 에너지 변화가 반응의 활성화에너지 변화와 대응된다고 보면 약 0.36e의 부분전하가 Fe3+ 쪽으로 옮겨간 것으로 계산되었다.

Effect of metallic salts added to the α-Fe2O3-HCl or α-Fe2O3-H2SO4 reaction systems were investigated by colorimetric and gravimetric determinations. While reductive salts exhibited remarkably enhanced reaction rate, non-reductive salts showed inhibitive results. We supposed that the improvement of dissolution rate of α-Fe2O3 by the addition of FeCl2, a reductive salt, to the α-Fe2O3-HCl system can be attributed to the formation of chloro-bridge between Fe3+ and Fe2+, and therefore some partial electronic charge transfer from Fe2+ to Fe3+ on the surface of α-Fe2O3 will be easily achieved through the bridged bond. The transferred charge to the surface will reduce the positive charge of initial Fe3+, and also result to reduce the lattice energy of that site. Assuming tothat there is a linear relationship between the lattice energy change and the change of activation energy of the reaction system, the transferred partial electronic charge to Fe3+ of α-Fe2O3 surface was calculated to be ca. 0.36e.

Page
194 - 200
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