| Me-NaHCO3-NH3-H2O体系和Me-NaOH-NaHCO3-H2O体系的热力学分析 |
| Thermodynamic Analysis on the Me-NaHCO3-NH3-H2O and Me-NaOH-NaHCO3-H2O Systems |
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| 摘要: 通过对Me(Fe2+, Ni2+, Cu2+, Zn2+)-NaHCO3-NH3-H2O体系以及Me-NaOH-NaHCO3-H2O体系的热力学分析，得到各金属离子总浓度cMe与pH值的关系，确定了2种体系的完全共沉淀区域。热力学分析结果表明：在Me-NaHCO3-NH3-H2O体系中，Ni2+，Cu2+，Zn2+这3种离子和氨的配位能力很强。当总碳的浓度cC=1 mol·L-1且总氮的浓度cN=0.01 mol·L-1时，在pH=7.5～11范围内可实现完全共沉淀；当cN=0.05 mol·L-1且cC=3 mol·L-1时，在pH=70.5时可实现完全沉淀，但共沉淀范围较窄，不利于铁氧体组分的精确控制。在Me-NaOH-NaHCO3-H2O体系中，共沉淀区域由cC决定，当cC=1 mol·L-1，pH=7.5～11时可实现完全共沉淀。 |
| 关键词: 镍铜锌铁氧体 化学共沉淀 热力学分析 |
| 基金项目: |
| Abstract: Through thermodynamic analysis for different Me2+ ions (Me refers to Fe, Ni, Cu, Zn) in NaHCO3-NH3-H2O and NaOH-NaHCO3-H2O systems, the total Me2+ concentration cMe as a function of pH was obtained, and hence the pH window of complete co-precipitation for several of Me2+ ions is determined. The results show that Ni2+, Cu2+ and Zn2+ ions are difficult to completely co-precipitate in the system containing NH3 because of their strong complexing ability with NH3，When the total carbon concentration cC is 1 mol·L-1 and the total nitrogen concentration cN is smaller than 0.01 mol·L-1, the four kinds of metal ions can be completely co-precipitated in the pH range from 7.5 to 11. Though they can also be co-precipitated entirely at pH of 6.5～7.5, while keeping cN 0.05 mol·L-1 and cC greater than 3 mol·L-1, the pH window of complete co-precipitation is so narrow that it is disadvantage for ensuring the desired composition. In the system of Me-NaHC03-NaOH-H2O, the pH window of complete co-precipitation is determined by the total carbon concentration cC. When cC is 1 mol·L-1, they can complete co-precipitate at the pH of 7.5～11. |
| Keywords: nickel copper zinc ferrite chemical co-precipitation thermodynamic analysis |
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| 周小兵,代建清,陈 辉,蔡进红.Me-NaHCO3-NH3-H2O体系和Me-NaOH-NaHCO3-H2O体系的热力学分析[J].无机化学学报,2009,25(4):602-608. |
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