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5 Recovery of Metals from Electronic Waste
5.7 Thermo-Chemical Methods for Metals Recovery
The goal of thermo-chemical methods is to eliminate the organic materials such
as plastics and leaving non-organic mineral and metallic phases for recovery. The
obtained liquid and gaseous products and chars can be used for energy recovery
[14, 16]. Thermo-chemical processes include pyrolysis, gasification and plasma
technology that are briefly described below.
5.7.1 Pyrolysis
Pyrolysis is the thermal degradation of materials at high temperatures in the absence
of oxygen. During pyrolysis, the organic materials (plastics and resins) of the electronic wastes are converted into gaseous and liquid products and char rich in carbon.
The type of feedstock and process conditions affect the yields and characteristics
of pyrolysis products. Different pyrolysis processes such as microwave-inducted-,
catalytic-, and co-pyrolysis with biomass as well as different types of reactors such
as moving bed, fixed bed, and fluidized bed have been reported for metals recovery
[17]. Figure 5.1 shows a schematic diagram of a fluidized bed reactor for pyrolysis
of e-waste. The solid residue (char) of the process consists of metals (such as Cu, Fe,
Al, Au, Ag, Pt, Pd, etc.) and other inorganic materials that can be recovered through
appropriate physical and chemical processes. The type and content of the metals
Fig. 5.1 Fluidized bed reactor and adsorption scrubber for metals recovery from e-waste. Reprinted
with permission from Elsevier [18]
5 Recovery of Metals from Electronic Waste
5.7 Thermo-Chemical Methods for Metals Recovery
The goal of thermo-chemical methods is to eliminate the organic materials such
as plastics and leaving non-organic mineral and metallic phases for recovery. The
obtained liquid and gaseous products and chars can be used for energy recovery
[14, 16]. Thermo-chemical processes include pyrolysis, gasification and plasma
technology that are briefly described below.
5.7.1 Pyrolysis
Pyrolysis is the thermal degradation of materials at high temperatures in the absence
of oxygen. During pyrolysis, the organic materials (plastics and resins) of the electronic wastes are converted into gaseous and liquid products and char rich in carbon.
The type of feedstock and process conditions affect the yields and characteristics
of pyrolysis products. Different pyrolysis processes such as microwave-inducted-,
catalytic-, and co-pyrolysis with biomass as well as different types of reactors such
as moving bed, fixed bed, and fluidized bed have been reported for metals recovery
[17]. Figure 5.1 shows a schematic diagram of a fluidized bed reactor for pyrolysis
of e-waste. The solid residue (char) of the process consists of metals (such as Cu, Fe,
Al, Au, Ag, Pt, Pd, etc.) and other inorganic materials that can be recovered through
appropriate physical and chemical processes. The type and content of the metals
Fig. 5.1 Fluidized bed reactor and adsorption scrubber for metals recovery from e-waste. Reprinted
with permission from Elsevier [18]