How to Process Electronic Waste: Dismantling, Granulation, and Metal Recovery Workflow
Introduction
Electronic waste has the highest recovery value — and the most complex processing workflow — of any industrial waste category. A single circuit board contains copper, gold, silver, and palladium; a desktop computer contains steel, aluminum, copper, various plastics, and fiberglass substrate. These materials are intermixed: simply feeding a whole computer into a granulator not only damages the equipment, but the precious metals end up blended into waste granules that are nearly impossible to recover — a direct loss of recovery value.
The logic for processing electronic waste is fundamentally different from general plastic waste. Granulation is not the end goal — it is a means of making downstream material sorting more efficient. This article explains the dismantling process, mechanical granulation methods, material sorting technologies, and final metal recovery value for three categories of electronic waste: circuit boards, computer and appliance components, and batteries.
Composition and Recovery Value of Electronic Waste
Understanding what is worth recovering in electronic waste is very helpful for planning the processing workflow.
Precious metals
Circuit boards and electronic components contain copper, gold, silver, palladium, and platinum. Copper has the highest content — one ton of circuit board waste may contain 100–300 kg of copper. Gold and palladium are present in much smaller quantities, but their unit value is extremely high, making them one of the main sources of profit in electronic waste recovery.
Ferrous and non-ferrous metals
Steel and aluminum in housings, heat sinks, and structural components have lower recovery value per unit than precious metals, but the quantities are large and total recovered volume is substantial. These can usually be separated during the manual dismantling stage without entering the granulation process.
Plastic regrind
The housings and outer packaging of electronic equipment are typically ABS, PC, or PC/ABS alloy — granulatable for use as plastic regrind. However, electronics-grade plastics with brominated flame retardants have restricted downstream applications for the regrind.
Step 1: Manual Dismantling and Pre-Processing
Manual dismantling is the non-negotiable first step before any electronic waste enters mechanical equipment. This step has three objectives: extracting high-value components, separating hazardous materials, and removing metal structural elements that would damage equipment.
High-value components: separate recovery
CPUs, memory modules, GPUs, and capacitors — these high-density precious-metal components are worth far more sold directly to precious-metal recovery specialists than their contribution to value if shredded and then refined from mixed granules. The first manual dismantling action is to remove these components from the motherboard for separate handling.
Connectors, slots, and high-pin-count IC chips also fall into this category. Handle them carefully during dismantling — damaged components command much lower precious metal recovery prices.
Hazardous material separation
Electronic waste contains multiple hazardous materials that must be separated before mechanical granulation. If left in, they spread during granulation and contaminate other materials, also increasing downstream waste disposal difficulty and cost.
Hazardous materials requiring special attention: mercury-containing LCD backlight tubes (CCFL); high-lead-content solder concentrated areas; nickel-cadmium batteries and lithium batteries (batteries must be handled separately under all circumstances — they must never enter a granulator).
Large metal structural components
Computer cases, TV metal frames, appliance steel chassis — large metal structural elements should be removed during manual dismantling and sent directly to metal recycling. They do not need granulation. Allowing large metal parts into a granulator wastes machine capacity and can instantly damage blades when they encounter thick steel plate.
Step 2: Mechanical Shredding
Electronic waste after manual dismantling is fed into a shredder for initial size reduction, breaking circuit boards, plastic housings, cables, and other materials into 5–10 cm chunks.
Circuit board shredding considerations
PCB (printed circuit board) FR4 fiberglass substrate is very hard, causing far more blade wear than general plastics — similar to the situation with glass-fiber-reinforced engineering plastics. Powder-metallurgy high-speed steel or carbide blade materials are recommended; shorten sharpening intervals. See: How to Granulate Glass-Fiber-Reinforced Engineering Plastics.
Circuit boards generate fiberglass dust during shredding. Dust collection equipment is mandatory on-site; operators must wear protective clothing and N95 or higher rated dust masks throughout. The long-term respiratory hazard from fiberglass dust inhalation is serious — protective measures cannot be treated casually.
Mixed-material shredding strategy
After dismantling, computer and appliance components typically consist of multiple mixed materials. These do not need to be separated before shredding. Mixed-material shredding actually helps — mechanical connections between different materials loosen and separate during shredding, which is beneficial preparation for downstream sorting.
Step 3: Granulator Refining
Shredded chunks are fed into a granulator for further size reduction. The key at this stage is controlling particle size within the range most efficient for downstream sorting equipment.
Too coarse and metals and plastics are still partially encased together — sorting efficiency suffers. Too fine and some sorting methods become less effective, and the cost of handling fine dust increases. Generally, 2–5 mm particle size is optimal for downstream electrostatic and density separation.
Circuit board granulation requires the same fiberglass dust management — equipment sealing and dust collection airflow must effectively contain dust dispersal.
Step 4: Material Sorting
Mixed granules from the granulator pass through three main sorting stages to progressively separate valuable metals from non-metallic waste.
Magnetic separation
The first sorting stage, used to separate ferromagnetic metals (iron, nickel). Equipment is simple and operating cost is low — typically a magnet or magnetic roller mounted above a conveyor belt, attracting ferromagnetic metal particles while other materials continue through. Magnetic separation primarily removes screws, iron component fragments, and some nickel alloy material — low recovery value individually, but removing them improves the precision of subsequent stages.
Eddy current separation
The second stage, specifically for separating non-ferromagnetic conductive metals — primarily copper and aluminum. An eddy current separator uses a high-frequency alternating magnetic field to induce eddy currents in conductive metal particles; the interaction between eddy currents and the magnetic field generates a repulsive force that propels conductive metal particles away from non-conductive material.
Copper is the highest-content precious metal in electronic waste, and eddy current separation is the core step in copper recovery. Separation effectiveness is directly related to particle size — copper particles below approximately 1 mm experience significantly reduced eddy current separation efficiency, which is one reason granulation particle size should not be set too fine.
Electrostatic separation
The third and most precise sorting stage. In a high-voltage electrostatic field, conductors and non-conductors charge differently and follow different trajectories — allowing residual fine metal particles to be further separated from the mixed granule stream.
Electrostatic separation is particularly effective at recovering fine copper particles not fully captured by the first two stages, as well as gold, palladium, and other precious metal particles. Equipment cost and operating/maintenance cost are both higher than the first two stages. This stage is typically only justified when electronic waste volumes are large enough for precious metal recovery value to support the equipment cost.
Battery Handling: Special Requirements
Batteries are the item in electronic waste that most absolutely must be handled separately. They must never be mixed into a standard electronic waste granulation workflow.
Lithium batteries
Lithium batteries can catch fire or even explode when subjected to impact or breach. Feeding lithium batteries into a granulator is an extremely dangerous operation. All lithium batteries must be completely removed during manual dismantling and sent to a professional battery recycling facility — they must not be crushed in-house under any circumstances.
Taiwan's Environmental Protection Administration operates an approved waste battery recovery system. Waste lithium batteries should be channeled through this system to qualified processing facilities. This is both a safety requirement and a legal obligation.
Nickel-cadmium and lead-acid batteries
Nickel-cadmium batteries contain highly toxic cadmium; lead-acid batteries contain large amounts of lead. Both require separate collection and must not enter general granulation processes. Strict environmental regulations govern the processing of these battery types — all should be sent to qualified waste battery processors.
Hazardous Materials and Environmental Regulations
Taiwan has explicit regulatory requirements for electronic waste processing. Waste electrical and electronic equipment falls under "designated recyclable waste" — processors must register with the environmental regulatory authority, and both the processing procedure and the final destination of waste materials must comply with requirements and be documented.
Post-granulation non-metallic waste (fiberglass powder, plastics granules containing brominated flame retardants) constitutes industrial waste and cannot be directly landfilled or discarded. It must be entrusted to a licensed waste removal and disposal company, with relevant documentation retained.
Before formally entering the electronic waste processing business, confirm with your local Environmental Protection Bureau what permits are required and what regulations must be followed, and incorporate compliance costs into the overall cost assessment.
Metal Recovery Value from Granulated Output
Electronic waste recovery revenue comes primarily from the precious metals separated during sorting. Recovery value varies significantly by metal:
Copper is the highest-volume precious metal. Recoverable copper per ton of circuit board waste ranges from tens to several hundred kilograms depending on board type. Copper market prices are relatively stable and form the revenue foundation of electronic waste recovery.
Gold and palladium are present in gram quantities, but their unit value is extremely high. High-end server motherboards and telecommunications equipment circuit boards contain significantly more precious metals than typical consumer electronics — if your waste source is such equipment, recovery value is higher.
Aluminum from heat sinks, housings, and aluminum structural components is generally present in smaller quantities than copper, but the recovery process is straightforward — eddy current separation is effective.
Overall, the investment threshold for electronic waste processing is relatively high: manual dismantling labor, multi-stage sorting equipment investment, and environmental compliance costs are all substantial. Before entering this field, carefully calculate the stability of your waste supply and total recoverable metal volume to confirm that revenues can support these costs.
Conclusion
Electronic waste processing is not something a single granulator can solve. The quality of manual dismantling determines precious component recovery value; granulation particle size determines sorting efficiency; the configuration of sorting equipment determines the completeness of metal recovery. The entire workflow must be planned as an integrated system, not evaluated stage by stage in isolation.
Battery handling is the safety non-negotiable in electronic waste operations — under no circumstances can batteries be allowed into granulating equipment. Environmental compliance is the baseline requirement for this field; confirm regulatory requirements before formally beginning operations to avoid post-hoc fines and rectification costs.
For guidance on glass-fiber material impact on blades and corresponding blade selection, see: How to Granulate Glass-Fiber-Reinforced Engineering Plastics. For day-to-day equipment maintenance, see: Granulator Maintenance and Care Guide.