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metallurgical, hydrometallurgical, and electrometallurgical processes to recycle
waste to recover about 20 precious metals and nonferrous metals (Kasper 2011;
Santanilla 2012).
10.3.2.4 Technology for the Management and Conservation
of Geochemically Scarce Resources
The topics discussed below address the technologies currently used to recover rare
earth elements. If urban mining is to become a feasible alternative, it is extremely
important that reverse logistics and recovery technologies are consolidated on a
higher scale.
The main processes used to recycle rare earth elements are pretreatment (which
consists of the screening and disassembly of devices), mechanical processing, and
metallurgical processing. This step is divided into pyrometallurgical and hydrometallurgical processes (Veit 2001; Vivas and Costa 2013; Oliveira 2012).
10.3.2.4.1 Disassembly
Disassembly is the first process used to obtain rare earth elements. It consists of the
removal of toxic compounds and the selection of valuable elements that may be
separated manually or automatically as a means to simplify the further stages in the
recovery of elements (de Moraes 2011). Therefore, the objective of this stage is to
optimize the next recycling or recovery stages, whether these are mechanical or
metallurgical in nature (de Moraes 2011; Silvas 2014).
For Cui and Forssberg (2003), most recycling organizations use manual disassembly as the first step. For Knoth et al. (2000), disassembly is the first and most
important step in recycling and is carried out manually. This makes disassembly
more time-consuming and hazardous, increasing the difficulty to perform the process on an industrial scale. The lack of standardized equipment, which is produced
by different manufacturers, is another aspect that hinders any move toward perfecting disassembly. Significant improvements in this important step will have to be
considered in the next few years. Knoth et al. (2000) also claim that due to increasing amount of products that are recycled, it is necessary to automatize processes as
a means to increase efficiency both in technical and economic aspects.
After disassembly, materials are treated according to their characteristics. For
Oliveira (2012), the advantages of disassembly and screening include the recovery
of components, the removal of potentially hazardous materials, and the segregation
of fractions of different added values.
10 E-waste Management and the Conservation of Geochemical Scarce Resources
metallurgical, hydrometallurgical, and electrometallurgical processes to recycle
waste to recover about 20 precious metals and nonferrous metals (Kasper 2011;
Santanilla 2012).
10.3.2.4 Technology for the Management and Conservation
of Geochemically Scarce Resources
The topics discussed below address the technologies currently used to recover rare
earth elements. If urban mining is to become a feasible alternative, it is extremely
important that reverse logistics and recovery technologies are consolidated on a
higher scale.
The main processes used to recycle rare earth elements are pretreatment (which
consists of the screening and disassembly of devices), mechanical processing, and
metallurgical processing. This step is divided into pyrometallurgical and hydrometallurgical processes (Veit 2001; Vivas and Costa 2013; Oliveira 2012).
10.3.2.4.1 Disassembly
Disassembly is the first process used to obtain rare earth elements. It consists of the
removal of toxic compounds and the selection of valuable elements that may be
separated manually or automatically as a means to simplify the further stages in the
recovery of elements (de Moraes 2011). Therefore, the objective of this stage is to
optimize the next recycling or recovery stages, whether these are mechanical or
metallurgical in nature (de Moraes 2011; Silvas 2014).
For Cui and Forssberg (2003), most recycling organizations use manual disassembly as the first step. For Knoth et al. (2000), disassembly is the first and most
important step in recycling and is carried out manually. This makes disassembly
more time-consuming and hazardous, increasing the difficulty to perform the process on an industrial scale. The lack of standardized equipment, which is produced
by different manufacturers, is another aspect that hinders any move toward perfecting disassembly. Significant improvements in this important step will have to be
considered in the next few years. Knoth et al. (2000) also claim that due to increasing amount of products that are recycled, it is necessary to automatize processes as
a means to increase efficiency both in technical and economic aspects.
After disassembly, materials are treated according to their characteristics. For
Oliveira (2012), the advantages of disassembly and screening include the recovery
of components, the removal of potentially hazardous materials, and the segregation
of fractions of different added values.
10 E-waste Management and the Conservation of Geochemical Scarce Resources