Ferrocyanide wastewater treated by precipitation-electrolytic oxidation process
ZHAO Lingling1,, SONG Yonghui1,2,,, ZENG Xinhui1, LI Yifan1, LAN Xinzhe1,2 1.School of Metallurgical Engineering, Xi′an University of Architecture and Technology, Xi′an 710055, China 2.Key Laboratory of Gold and Resource of Shaanxi Province, Xi′an 710055, China
Abstract:The precipitation-electrolytic oxidation combined technology was used to treat high-ferric cyanide gold-lifting wastewater, and the effects of factors such as the dosage of precipitant, precipitation time, temperature, electrolysis voltage, and electrolytic time on the removal rates of total cyanide, free cyanide, and ferric cyanide complex were investigated. The results showed that with the increase of the dosage of CuCl2, the precipitation rate of the main ions in the cyanide wastewater increased gradually. At the CuCl2 dosage of 3.0 g to 100 mL of cyanide-containing wastewater, 40 min-stirring and room temperature, the removal rates of CNT, CN?, and Fe ions could reach 95.29%, 98.00% and 100%, respectively. The titanium plate was used as the cathode and anode, and the electrode parallel system (one cathode and two anodes) was used to conduct electrolytic oxidation experiments on the precipitated solution. When the voltage was 6 V, the electrode spacing was 15 mm, electrolysis time was 5 hours and the initial concentration was 60%, the removal rates of CNT and CN? could reach 99.76% and 99.90%, respectively. XRD analysis showed that the removal of copper cyanide and iron cyanide complex ions during precipitation was mainly attributed to the formation of CuCN, Cu2Fe(CN)6, CuSCN and other precipitates. With the increase of the applied voltage and chloride ion concentration during electrolytic oxidation, the removal rates of residual free cyanide and metal cyanide complex ions in wastewater increased gradually, which was mainly due to the strong oxidation of Cl2/ClO? produced during the anode reaction. The research results can provide a reference for the treatment of high-ferric cyanide gold-lifting wastewater. Key words:cyanide/ ferricyanide complex/ chemical precipitation/ electrolytic oxidation.
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1.School of Metallurgical Engineering, Xi′an University of Architecture and Technology, Xi′an 710055, China 2.Key Laboratory of Gold and Resource of Shaanxi Province, Xi′an 710055, China Received Date: 2020-01-14 Accepted Date: 2020-05-12 Available Online: 2020-12-08 Keywords:cyanide/ ferricyanide complex/ chemical precipitation/ electrolytic oxidation Abstract:The precipitation-electrolytic oxidation combined technology was used to treat high-ferric cyanide gold-lifting wastewater, and the effects of factors such as the dosage of precipitant, precipitation time, temperature, electrolysis voltage, and electrolytic time on the removal rates of total cyanide, free cyanide, and ferric cyanide complex were investigated. The results showed that with the increase of the dosage of CuCl2, the precipitation rate of the main ions in the cyanide wastewater increased gradually. At the CuCl2 dosage of 3.0 g to 100 mL of cyanide-containing wastewater, 40 min-stirring and room temperature, the removal rates of CNT, CN?, and Fe ions could reach 95.29%, 98.00% and 100%, respectively. The titanium plate was used as the cathode and anode, and the electrode parallel system (one cathode and two anodes) was used to conduct electrolytic oxidation experiments on the precipitated solution. When the voltage was 6 V, the electrode spacing was 15 mm, electrolysis time was 5 hours and the initial concentration was 60%, the removal rates of CNT and CN? could reach 99.76% and 99.90%, respectively. XRD analysis showed that the removal of copper cyanide and iron cyanide complex ions during precipitation was mainly attributed to the formation of CuCN, Cu2Fe(CN)6, CuSCN and other precipitates. With the increase of the applied voltage and chloride ion concentration during electrolytic oxidation, the removal rates of residual free cyanide and metal cyanide complex ions in wastewater increased gradually, which was mainly due to the strong oxidation of Cl2/ClO? produced during the anode reaction. The research results can provide a reference for the treatment of high-ferric cyanide gold-lifting wastewater.