Chemo-biohydrometallurgy—A hybrid technology to recover metals from obsolete mobile SIM cards

Enhancement of gold and silver recovery from discarded computer printed circuit boards by Pseudomonas balearica SAE1 using response surface methodology (RSM)

“…To obtain particle-free suspension, leachate/solution was first filtered using Whatman grade 1 filter followed by filtration through glass fiber filter (0.45-µm, PALL-GF-A/E-I). The dissolved metals ions were quantified using atomic absorption spectrophotometry (AAS) (AAnalyst 400, PerkinElmer) at 242.8 and 328.1 nm wavelengths for Au and Ag, respectively (Pradhan and Kumar 2012;Sahni et al 2016). The finely ground CPCBs were sterilized in an autoclave at 121 °C, 15 psi for a time period of 30 min in autoclavable bags (HiMedia) and dried at room temperature (25 ± 3 °C) prior to bioleaching (Pradhan and Kumar 2012;Rozas et al 2017).…”

“…Whereas, hydrometallurgical recovery of precious metals from e-waste is being carried using cyanide/non-cyanide (e.g., thiourea and ammonium thiosulphate) leaching and chemical (e.g., HNO 3 , H 2 SO 4 and aqua regia) leaching (Sun et al 2017). However, these processes are expensive, energy intensive, generates large amount of spent acid, toxic gases, sludge, liquid waste, fumes of heavy metals (metals with low melting point like mercury, lead and cadmium), and may lead to formation of mixed halogenated dioxins and furans [especially, if the scrap contains plastic with brominated flame retardants (BFRs)] (Kaya 2016;Sahni et al 2016). The hydrometallurgical/pyrometallurgical methods are rapid but low metal recovery rate, loss of precious metals during recovery, environmental impacts and high cost have push the development of alternative methods of metal recovery from e-waste (Kumar et al 2017b;Priya and Hait 2017;Sun et al 2017).…”

Prospective (Bio)leaching of Historical Copper Slags as an Alternative to Their Disposal

“…In addition, the optimization of bioleaching conditions is more challenging as compared to chemical leaching, mainly due to a possible metal toxicity effect on the microorganisms and the associated concerns with microbial survivors and activity [24]. These shortcomings are often difficult to overcome, which has driven the development of hybrid processes combining chemical and biotic techniques [25]. A hybrid approach can be accomplished in a way that a microbial-derived solution is generated in a reactor and then diverted to a separate slag-containing reactor in order to execute the extraction process.…”

Advances in bioleaching as a sustainable method for metal recovery from e-waste: A review

“…Several studies have shown the bioleaching of miscellaneous e-waste including fluorescent powder obtained from cathode ray tube glass recycling process [44], obsolete SIM cards [31], TV circuit boards [80] and electrolyte manganese slag [79]. However, there are still several other e-wastes for bioleaching which should be investigated for recovery of hazardous heavy metals and also reuse of some precious and economically viable metals.…”

“…This waste contains high quantity of Cu (75.84%), and small amount of precious metals (0.042% Au and 0.01% Ag). In the work that studied the bioleaching of SIM cards [31], C. violaceum was used as microorganism. However, the obtained yield were not satisfactory (13.79% for Cu, 0.44% Au and 2.55% Ag).…”