Acetic Acid Leaching of Calcium-based Active Components from Converter Steel Slag
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摘要: 以转炉钢渣为浸出对象, 乙酸作为浸出剂, 在热力学研究的基础上考察了不同粒度下浸出温度、时间、乙酸浓度和固液比对转炉钢渣中钙离子浸出率的影响规律。研究结果表明, 在273.15~373.15 K的温度区间内, 钢渣中CaO、Ca2SiO4物相的钙离子浸出反应的吉布斯自由能ΔG<0, 而CaTiO3物相的钙离子浸出反应的吉布斯自由能ΔG>0。转炉钢渣中钙基活性组元的浸出迅速, 粒度越细、固液比越小, 钙基活性组元的浸出率越高;乙酸浓度越高, 钙的浸出率越大。在乙酸浓度为1 mol/L、固液比为1∶20、浸出时间为60 min、浸出温度为70℃条件下, 钙的浸出率高达87.52%。XRD和SEM分析表明, 转炉钢渣中活性氧化钙全部浸出, 转炉钢渣表面形成不规则孔隙, 而钛酸钙 (CaTiO3) 则留在渣相中。Abstract: On the basis of thermodynamic study,with converter steel slag as the leaching object and acetic acid as leaching agent,the effects of leaching temperature,leaching time,concentration of acetic acid and the ratio of solid to liquid on the leaching rate of calcium in converter steel slag having different particle sizes were investigated.The results show that the Gibbs free energy change for leaching reaction of CaO and Ca2SiO4 phase is negative while it’s positive for the leaching reaction of the CaTiO3 phase in the converter steel slag with temperature range of 273.15~373.15 K.The leaching rate of calcium-based active components in the slag are very rapid.The smaller the particle size and the solid-liquid ratio,the higher the leaching rate of the calcium-based active components. Meanwhile,a higher leaching rate of calcium can be obtained at higher concentration of acetic acid.The leaching rate of calcium ion reaches to 87.52% at 1 mol/L of acetic acid,1 ∶ 20 of solid to liquid ratio,70 °C of leaching temperature for 60 min.XRD and SEM analysis shows that the active calcium oxide in the converter steel slag is completely leached with irregular pores formed on the surface of the slag,while calcium titanate (CaTiO3) stays in the slag.
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Key words:
- converter steel slag /
- acetic acid /
- leaching /
- calcium based active components /
- leaching rate
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