Basic Research On The Application Of Comprehensive Recovery Of Valuable Elements From Gold Smelting Wastewater Enhanced By Ultrasoun

The carbon pulp process（CIP）is one of the gold treatment processes that produces a large amount of gold smelting wastewater during actual industrial production,which contains cyanide,gold,silver and copper ions and poses a potential risk to the environment.The wastewater generated not only allows for the recovery of heavy metals and the decomposition of cyanide,but the treated wastewater also allows for the recycling of water resources.In response to the current situation that traditional methods cannot efficiently decompose cyanide and recover metal ions,an ultrasonic-enhanced ozone oxidation process is proposed to decompose cyanide and recover copper,and ultrasonic-enhanced replacement of gold and silver in the wastewater.The effects of gas flow rate,oxidation time and ultrasonic power density factors on cyanide decomposition rate and copper recovery rate,and the effects of replacement dose,replacement time,rotational speed and ultrasonic power density factors on gold and silver replacement rate were investigated.The gold-silver-copper recovery and cyanide oxidation mechanism were investigated using infrared spectral analysis,Raman spectral analysis,X-ray diffraction,electron paramagnetic resonance spectrometry,scanning electron microscopy and gas chromatography methods.The main findings are as follows:（1）Cyanide decomposition and copper recovery in gold smelting wastewater:By investigating the effects of gas flow rate,oxidation time and ultrasonic power density on the decomposition rate of cyanide and copper recovery,it was found that the decomposition rate of cyanide and copper recovery were 99.96%and 99.3%,respectively,under the optimum oxidation conditions.The kinetic analysis of the oxidation process showed that the ultrasonically enhanced ozone（US/O₃）oxidation process and the ozone oxidation process conformed to the quasi first order kinetic model.Ultrasonically enhanced ozone（US/O₃）oxidation accelerated the reaction and improved the decomposition rate of cyanide and the recovery of copper.The copper content of the copper slag obtained by oxidation exceeded 32%.（2）The oxidised gold smelting wastewater was used as the study object:by studying the replacement dose,replacement time,rotational speed and ultrasonic power density,it was found that the replacement rate of gold and silver reached 99.12%and99.95%respectively.Kinetic analysis showed that the ultrasonic enhanced replacement of gold and silver in the wastewater was consistent with the diffusion control model.The replacement products were characterised by TEM,SEM,EPMA and particle size analysis and ultrasound was found to refine the particles and increase the reaction rate.（3）Expanded experiments were studied to verify the stability and feasibility of the ultrasound-enhanced ozone oxidation and ultrasound-enhanced replacement processes,and it was found that the recovery of gold,silver and copper and the decomposition of cyanide achieved better results.In summary,ultrasound can increase the rate of ozone decomposition of cyanide and reduce the amount of ozone used.The decomposition of cyanide is accompanied by the recovery of the valuable metal copper,and the pretreated wastewater can be subjected to ultrasonic enhanced replacement for the recovery of gold and silver.The treated wastewater can be recycled and has industrial application prospects.