不同类型有机酸-磷矿粉复合物对土法炼锌废渣中重金属的固定作用

为分析利用不同类型有机酸活化低品位磷矿粉形成的"有机酸-磷矿粉复合物"对铅锌冶炼废渣中重金属的固定作用,以黔西北历史遗留土法炼锌废渣为对象,研究3种类型有机酸(草酸、酒石酸及柠檬酸)活化低品位磷矿粉对土法炼锌废渣中4种主要重金属(Pd、Cd、Cu、Zn)的固定效果。结果表明:不同类型有机酸作用下土法炼锌废渣中重金属的释放存在明显差异,3种有机酸对铅锌废渣中4种重金属的活化能力表现为酒石酸柠檬酸草酸。草酸、酒石酸和柠檬酸浓度分别在0. 8、0. 8、0. 4 mol/L时对低品位磷矿粉中磷素的活化能力最强,但各有机酸-磷矿粉复合物在有机酸浓度分别为1. 2、0. 8、0. 4 mol/L时对铅锌废渣中各重金属的固定效果最好,其中,草酸-磷矿粉复合物对4种重金属的降低率为90. 67%、99. 64%、13. 63%、5. 99%,酒石酸-磷矿粉复合物对4种铅锌废渣中重金属的降低率为91. 72%、44. 2%、34. 37%、7. 51%,柠檬酸-磷矿粉复合物对4种重金属的降低率为60. 39%、8. 15%、5. 03%、-6. 12%,综合来看,浓度为1. 2 mol/L的草酸-磷矿粉复合物可更好地固定铅锌冶炼废渣中的重金属。

Effects of Different Organic Acid-Phosphate Rock Powder Composites on the Immobilization of Heavy Metals in Waste Slags of Indigenous Smelting Zinc

In order to understand immobilization effects of different types of organic acid activated low-grade phosphate rock composite on heavy metals in lead-zinc slags, indigenous zinc smelting waste slags from northwest Guizhou were selected to explore immobilization effects of phosphate rock powder composites treated by three different organic acids (oxalic acid, tartaric acid and citric acid) on four heavy metals (Pd, Cd, Cu and Zn). The results showed that the releases of heavy metals from indigenous zinc smelting waste slags were different significantly after been treated by different organic acids. The abilities of three organic acids to activate four heavy metals from lead-zinc slags followed the trend of tartaric>citric>oxalic acid. Phosphorus in low-grade phosphate rocks was activated the most when treated concentrations of oxalic acid, tartaric acid and citric acid were 0.8, 0.8 and 0.4 mol/L, respectively, but the immobilization effect of the organic acid-phosphate rock powder composite to heavy metals in lead-zinc slags reached the strongest when concentrations of oxalic acid, tartaric acid and citric acid were 1.2, 0.8, and 0.4 mol/L, respectively. Under such conditions, the oxalic acid-phosphate rock powder composite reduced the releases of four heavy metals by ratios of 99.64%, 90.67%, 13.63%, 5.99%, respectively; the tartaric acid-phosphate rock powder composite reduced the releases of four heavy metals by ratios of 91.72%, 44.2%, 34.37%, 7.51%, respectively; the citric acid-phosphate rock powder composites reduced the releases of four heavy metals by ratios of 60.39%, 8.15%, 5.03%, -6.12%, respectively. In summary, the composite of phosphate rock with 1.2 mol/L oxalic acid is the best to immobilize heavy metals in lead-zinc smelting slags.