A Cleaner Process for Selective Recovery of Valuable Metals from Electronic Waste of Complex Mixtures of End-of-Life Electronic Products

Abstract

In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency.

Recovery of Lanthanum(III) and Nickel(II) Ions from Acidic Solutions by the Highly Effective Ion Exchanger

“…There are millions of old and disused electronic and electrical devices around the world, so-called Waste Electrical & Electronic Equipment (WEEE) at our homes, i.e., old cell phones, smartphones, laptops, computers, non-working printers, and many others. At present, WEEE is becoming the fastest growing waste stream in the world [1][2][3]. In 2016 the total e-waste was 44.7 Mt worldwide, and it is expected to grow to 52.2 Mt in 2021 [4].…”

Comprehensive process for the recovery of value and critical materials from electronic waste

“…Hydrometallurgical treatment of e-waste has been found to be more efficient and environmentally friendly than other recovery processes, such as physical separation and pyrometallurgical processes [4]. With a hydrometallurgical approach, the low leaching selectivity and the low concentration of precious metals, relative to the total metal content, lead to a significant use of chemicals in the dissolution of the most abundant metals, such as Cu or Sn [4,22,23].…”

Finding the Most Efficient Way to Remove Residual Copper from Steel Scrap

“…Chlorine gas is the most problematic, as it is toxic and corrosive. Alternatively, an ammonia-based leachant has a low toxicity, and Sun et al [70] demonstrate that copper could be deposited, while re-generating the leachant with electrowinning. Handling molten metals can be hazardous, but processes performed at high temperature could be operated at steelmaking sites, with the appropriate safety provisions and expertise.…”