Recovery of Waste Materials: Technological Research and Industrial Scale-Up

Abstract

An increase in population, booming economy, rapid urbanization and the rise in living standards have exponentially accelerated waste production [...]

Bioleaching Techniques for Sustainable Recovery of Metals from Solid Matrices

“…More than 12 billion tons of solid waste are produced annually worldwide [31], including approximately 1.55 billion tons of agricultural waste [32] and about 2 billion tons of municipal solid waste [31]. The generation of industrial waste is almost 18 times greater than that of municipal solid waste [33].…”

“…The wastes mentioned above contain metals in various concentrations [3,6,[33][34][35][36][37][38][39][40], which have the potential as matrices to be subjected to the process of extraction of metals in the form of dissolution using the bioleaching process.…”

“…These wastes contain metals due to industrial and anthropic activities [47], involving metals such as Zn, Pb, Cu, Cr, Hg [37,[48][49][50], Cd [37,48,49], Ni [49], Co and As [37]. In addition, household wastes such as eggshells are rich in Ca [33]. In the study by Kuusiola et al, the compositions of the metal fractions of 54% tinned steel, 15% stainless steel, 24% aluminum, and 8% other metals are shown [6]; likewise, in landfills, the concentrations of leached metals are 108.5 g/Mg of Pb, 90 g/Mg of Cu, 560 g/Mg of Zn, 101.5 g/Mg of Cr and 2.24 g/Mg of Cd [48].…”

“…The WEEE, commonly called e-waste, contains up to 60 different elements in various concentrations, comprising base metals, critical metals, and platinum group metals mixed in a complex matrix of metallic and non-metallic materials [11,55]. For example, Au, Ag and Pd, Cu, and Ni are recovered from used cell phone printed circuit boards, with 540-880 mg/kg Ag, 168 mg/kg Au and 110 mg/kg Pd [33,34].…”

Selective Recovery of Cerium as High-Purity Oxides via Reactive Separation Using CO2-Responsive Structured Ligands

“…Only a small fraction of WEEE, 20% (WEEE = waste electrical and electronic equipment), is recycled, with the vast majority ending up in landfills or used as feedstocks in waste-to-energy plants . Thus, with the increased WEEE fraction in the domestic waste stream, ash generated from waste-to-energy plants often contains critical elements, including REEs, Cu, Ni, or Zn, and other elements with significant carbon storage potential. ,,, The combination of these sources promises to provide more environmentally friendly resources (even if the REEs are in low concentrations) that can be used for future innovations while storing CO 2 as useful Ca or Mg carbonates, creating a circular economy with reduced landfilling.…”