Metal Recovery from the Mobile Phone Waste by Chemical and Biological Treatments

Abstract

Abstract:Recycling electronic waste is an important subject not only from the point of view of waste treatment, but also regarding the recovery of valuable metals. This research examined the stepwise recovery of metals in mobile phone waste using chemical treatment via pH swing and the biological method using biomineralization. In chemical treatment, the metal fraction attached to the printed circuit board (PCB) and camera parts were separated from the mobile phone waste and were then pulverized into particles with a size less than~2 mm. The metal fraction was dissolved in aqua regia, and the pH of the solution was increased to 10.5 by adding NH 4 OH. The first precipitate was iron oxide, produced by raising the pH to 3.1~4.2 with NH 4 OH. Sequentially, copper chloride and rare earth-metal complex were produced at pH 5.7~7.7 and 8.3~10.5, respectively. In the biological method, the filtrate at pH 7.7 was added to a metal-reducing bacteria growth medium as a precursor. After two weeks of incubation, rhodochrosite and calcite were precipitated as nano-sized minerals. The results indicate that effective metal recovery of mobile phone waste is feasible using chemical and biological treatments, and the recovered metals and rare earth metals can be recycled into raw materials for various industries.

Review of Methods for Obtaining Rare Earth Elements from Recycling and Their Impact on the Environment and Human Health

“…Mixed rare earth oxide (from roasted rare earth oxalate) and FeC 2 O4• 2 H2O with purities of 99.49% and 97.17%, respectively, were obtained [114]. Additionally, a method for separating metals from waste mobile phones using aqua regia leaching and pH-based precipitation was described, with iron precipitated at pH 3.1-4.2, copper at pH 5.7-7.7, and rare metals at pH 8.3-10.5 [115].…”

Material Measurement Units for a Circular Economy: Foundations through a Review

“…Allrecipes, RecipeSource); • research papers reporting the material composition of specific products such as the ones in Table 2; • documentaries such as "How It's Made" 1 ; • performing a chemical composition analysis of the product of interest. Reference Analyzed products [62] LCD screens [92] fluorescent lamps [95] computer monitors [58] mobile phones [107] headset, HDD, SSD [40] vehicle batteries An analogy between water networks and manufacturing networks can be seen considering both an intuitive and a physical explanation. The intuitive explanation is that both networks are made of nodes (i.e.…”

Insights into the Selective Transformation of Ceria Sulfation and Iron/Manganese Mineralization for Enhancing the Selective Recovery of Rare Earth Elements

“…10,11 The recovery of REEs from wasted mobile phones through leaching with aqua regia suffered from the coextraction of Fe, Cu, Ni, and Zn. 12 All of these cases indicate the indiscrimination of conventional metallurgy on REE recoveries, resulting in environmentally unfavorable artificial treatments. Thus, a selective and industrially viable solution should be developed to recover or separate REEs from the impurity, especially the transition metals, reducing the burden of downstream processing.…”

“…More than 80% of REEs was localized at glass and hematite phases of coal fly ash (CFA), necessitating the alkaline pretreatment followed by the acidic dissolution. Although this process could yield a mildly acidic REE-rich solution, the coextraction of Fe required further purification. , The recovery of REEs from wasted mobile phones through leaching with aqua regia suffered from the coextraction of Fe, Cu, Ni, and Zn . All of these cases indicate the indiscrimination of conventional metallurgy on REE recoveries, resulting in environmentally unfavorable artificial treatments.…”