Recovery Of Gold By Hydrometallurgical Processing From Electronic Components Of Waste Mobile Phone

Because of rapidly short product life cycles,mobile phone has been one of the largest and fastest growing waste stream in the world.Large amounts of metals are found in waste mobile phones,scientific recycling of metal in waste mobile phones could reduce over-exploitation of mines and protect environmental pollution.In this paper,the hydrometallurgical processing was used to recover gold from waste electronic components of mobile phone,the base metals was dissolved in a special solution made of HCl and NaClO.The leaching process of precious metals?gold,palladium?was treated by the leaching system of HCl-CuCl₂-NaClO;Finally,the dissolved Au was extracted by dibutylcarbitol?DBC?,the oxalic acid was used in the reduction of god from organic phase.The results was shown as the following:?1?Under the condition of 2 mol/L HCl,2%?V/V?NaClO,25?,stirring speed 300 rpm and solid / liquid ratio of 1/10?g/mL?,waste electronic components of mobile phone was treated with HCl-NaClO leaching solution,the first leaching for 4 h,repeat one more time,after two consecutive leaching step,more than 93% of base metals?Cu,Fe,Ni,and Sn etc.?was dissolved in leaching solution.The leaching rate was Cu > Sn > Fe > Ni,while,nearly 99% of the gold and palladium was retained in the solid residue.?2?The leaching process of precious metals was treated by the leaching system of HCl-CuCl₂-NaClO.HCl,CuCl₂,NaClO in the appropriate range of concentration could promote the metal leaching rate,the temperature will promote the metal leaching,at conditions of reaction temperature 333 K,2 mol/L HCl,0.05 mol/L CuCl₂,2.5%?V/V?NaClO,300 rpm,1% S/L,over 86% of Au and 93% of Pd dissolution was achieved after 4 h.?3?The multivariate quadratic regression equation was used to fit the relationship between the factors and the response values.Finally,the relationship between the metal leaching rate and the variables was obtained.The results was shown as the following.Y₁ = 92.65 + 18.00 X1 + 11.2 X2 + 23.7 X₃-0.50 X1X2-14.21 X1X₃-21.48 X2X₃-7.80 X12-10.98 X₂²-13.14 X₃²Y₂ = 86.25 + 10.34 X1 + 1.94 X2 + 42.39 X₃ + 0.40 X1X2-1.25 X1X₃-2.61 X2X₃-8.75 X12-8.37 X₂²-30.2 X₃²Y₁ was palladium leaching rate,Y₂ was gold leaching rate,X1 was the concentration of HCl?mol/L?,X2 was the concentration of CuCl₂?mol/L?,X₃ was the concentration of NaClO?%?V/V??.?4?In this paper,the extractant?DBC + sulfonated kerosene?was used to extract Au from the leaching solution.The extraction rate of gold increased with the increase of A/O,when A/O = 2,over 98% gold was extracted in first extraction after 3 min,the extraction rate was still up to 95% in the third extraction.?5?The organic phase was carried out using 5% H2C2O4,the gold reduction rate increaseed with the reaction temperature increaseed,increase the concentration of oxalic acid could increase the rate of gold reduction,at 343 K,using 2% oxalic acid,gold was completely restored after 2 h.