Gold recovery from copper anode slime by means of magnetite nanoparticles (MNPs)

• Electrostatic attraction caused the gold ions adsorption on MNPs.
• MNPs show the stability after separation and recycling process.
• MNPs is effective alternate to conventional adsorbents for gold complex adsorption.
• MNPs is effective adsorbents for obtaining high purity gold from secondary sources.

Despite cyanidation currently being the conventional gold recovery process, researchers are looking for alternative methods for the recovery of gold from its sources without using cyanide. The current work attempts to study the recovery of gold from copper anode slime by means of a novel process utilizing magnetite nanoparticles (MNPs).In this process, MNPs were first synthesized by the co-precipitation method, and the characterization of the product was then carried out using the X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibration sample magnetometer (VSM) methods.Thiourea solution was employed as leachant. All the gold content of copper anode slime was dissolved in thiourea solution and a positive complex of gold and thiourea was obtained as a result. At a pH value higher than the pH of point of zero charge (PZC), the nanoparticles (NPs) were added to the gold solution. The gold complex adsorbed on the NPs due to their negative surface charge. At the last stage, ammonia was added to the gold-attached NP suspension and gold was consequently precipitated in metallic form. The results obtained from the method indicate the high efficiency of the method for the recovery of gold from copper anode slime.

Figure optionsDownload as PowerPoint slide