塩化金酸水溶液のＳＯ２還元処理による金微粉末の生成

相川 芳和, 木内 弘道

doi:10.2473/shigentosozai.111.1022

The production of fine gold powder with controlled particle size and shape is essential for electrical applications. In this study, the reaction mechanism of gold formation and the morphology of gold particles were investigated in order to establish the reduction of HAuCl₄ solution using Na₂S0₃ solution or SO₂ gas. The experiments were mainly carried out at the concentrations of HAuCl4 solution ranging from 0.2×10^-3 to 0.01kmol·m^-3, at a pH from 0.5 to 10.0, and at room temperature or 343K. When the Na₂SO₃ solution was added to the HAuCl₄ solution, the mixed solution rapidly changed from yellow to colorless solution. Afterwards, gold powder was produced at a pH below 3. It was considered that colorless Au (SO₃) ^5-₄ was produced by generated SO₂ in the mixed solution and its ion turned into Au⁰ at low pH. In the reduction experiments using babbled SO₂ gas, the concentrations of AuCl₄^-, Au (SO₃)^5-₄ and Au⁰ vary with reaction time. The reaction curves suggested that the reaction progressed as an irreversible consecutive first-order reaction, as follows: AuCl₄-k1→Au (SO₃)^5-₄k2→Au⁰ (k1, k2: rate constant) Based on the consecutive reaction model, the changes in the concentrations of the reactant and products were calculated with the reaction time. The calculated results using k1=0.028 sec^-1 and k2=0.019 sec^-1 agreed well with the experimental data. According to the SEM observation and the analysis of particle size distribution, it was found that the gold particles formed by the Na₂S0₃ solutions were spherical at low pH and showed high dispersivility at high concentration of Na₂S0₃ and smooth surfaces at high temperature.

塩化金酸水溶液のＳＯ２還元処理による金微粉末の生成

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塩化金酸水溶液のＳＯ２還元処理による金微粉末の生成

書誌事項

この論文をさがす

説明

収録刊行物

被引用文献 (2)*注記

キーワード

詳細情報 詳細情報について

書き出し

問題の指摘

詳細情報詳細情報について