Recovery of metals from chloride leach solutions of waste of printed circuit boards by adsorption and precipitation
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Tarih
2014
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Gecamin
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The downstream treatment of chloride leach solutions of WPCB for recovery of base and precious metals by a combination of adsorption and precipitation processes were carried out. A synthetic leach solution (1 M HCl, 116.5 g/L Cl-, 30 g/L Cu2+, 2.5 g/L Fe3+, 5 mg/L Au3+, 10 mg/L Ag+ and 20 mg/L Pd2+), which was prepared based on the composition of the pregnant leach solution obtained in the previous study was used in the tests. The leach solution was initially subjected to activated carbon (AC) adsorption #y(20 g/L AC, 80°C) in which gold was selectively recovered over silver and palladium i.e., 88% Au recovery at 0.5 h (92% at 3.5 h) compared with only 3-6% for Ag/Pd. Copper and iron were also observed to adsorb on AC as indicated by 1.4% and 17% decline, in their respective concentrations. Following the adsorption and filtration stage, metallic copper was added into the gold-barren solution to allow reduction of Cu2+ to Cu+, and to cement Pd on metallic copper. Over the mixing period (1 h), 93% of the Pd was recovered while only 1.4% of silver was cemented onto metallic copper. Subsequently, the leach solution was gradually neutralised by NaOH to pH 4, 7.5 and 9.5 for the precipitation of copper as cuprite (Cu2O). It was found that 41% and 46% of Cu and Ag, respectively, were precipitated at pH 4 at which iron was almost totally (99.8%) removed from solution. Precipitation of copper and silver was increased further at high pHs. At pH 9.5, cumulative recoveries for copper and silver were 91% and 85%, respectively. XRD analysis of the precipitates confirmed the presence of cupric copper oxides/hydroxides and revealed that copper losses occurred at pH 4 was due to the undesired presence of cupric copper in the solution.
Açıklama
Antofagasta Minerals; Edemet; et al.; Outotec; Russell; ThyssenKrupp Industrial Solutions
27th International Mineral Processing Congress, IMPC 2014 -- 20 October 2014 through 24 October 2014 -- Santiago -- 112722
27th International Mineral Processing Congress, IMPC 2014 -- 20 October 2014 through 24 October 2014 -- Santiago -- 112722
Anahtar Kelimeler
Activated carbon, Adsorption, Carbon, Copper, Copper metallurgy, Gold, Leaching, Metal recovery, Metals, Printed circuit boards, Printed circuits, Recovery, Silver, Chloride leach, Copper loss, Cumulative recovery, Leach solutions, Metallic copper, Precipitation process, Pregnant leach solutions, XRD analysis, Copper oxides
Kaynak
IMPC 2014 - 27th International Mineral Processing Congress
