The proton-driven multi-stage system represents the cutting edge of current PCB gold recovery technology. This system is based on polyacrylamide oxime (PAO) hydrogel and achieves cascaded separation of gold (Au(III)) and palladium (Pd(II)) through a proton concentration gradient in a strong acidic environment (pH=0). Its advantages include ultra-high adsorption capacity (2165.75 mg·g⁻¹) and ultra-fast kinetics (<10 minutes), while the separation factor (kAu(III)/Pd(II) = 36.5) significantly enhances selectivity. The key to this technology lies in the proton-mediated differential capture mechanism: under strong acidic conditions, the H₂N-C=N-OH groups of PAO preferentially reduce Au(III) to elemental gold (accounting for 91.17%), while Pd(II) is primarily captured through coordination, with a reduction rate of only 6.62%.
The Royal Mint of the United Kingdom employs Excir's patented chemical technology to process 4,400 tons of electronic waste annually, extracting approximately 0.45 tons of high-purity gold (999.9‰). The core of this process is an environmentally friendly chemical leaching method that replaces traditional cyanide-based techniques, reducing pollution risks and enhancing efficiency. Additionally, novel leaching agents such as ionic liquids (ILs) and deep eutectic solvents (DESs) achieve gold recovery rates exceeding 90% in laboratory settings and are reusable, but large-scale application still requires cost optimization.
The value of PCB gold recovery is directly linked to precious metal content. Take server motherboards as an example: their gold-plated components, such as CPU sockets and memory interfaces, are densely concentrated, yielding over 300 grams of gold per ton—far exceeding ordinary consumer electronics boards (100–300 grams per ton)—resulting in recycling quotes as high as $10–30 per kilogram. Military-grade or communication equipment-specific PCB recovery, with their high gold layer purity (99.9%) and complex substrate materials, can command a recycling premium of up to 60 USD per kilogram.
In contrast, ordinary multilayer boards (such as computer motherboards) have lower gold content, with recycling prices of approximately 5–12.5 USD per kilogram, while low-end categories like television circuit boards fetch only 1–4 USD per kilogram. Price fluctuations are significantly influenced by the gold futures market: during the period of rising international gold prices in 2025, the PCB recovery price of high-end PCBs increased by 15–20% month-on-month.
The above data is sourced from DONGSHENG Precious Metals Recycling Company. For precise quotes, please contact our PCB scrap procurement specialists.
Large-scale crushing and sorting is the core of PCB recovery pretreatment. Taking GreenJet Environmental Protection's automated system as an example, three-stage crushing (shredding to 3–5 cm → hammer crushing to 0.5–1 cm → grinding into 30–80 mesh powder) combined with airflow/specific gravity/electrostatic sorting achieves a copper recovery rate of ≥99% and non-metal residue of <1%. Electrostatic separators use high-voltage electric fields to separate metal and non-metal powders, with a processing capacity of 500 kg/h, and dust emissions compliant with international environmental standards.
Acid leaching and purification is the key step in PCB gold recovery. HONGKONG DONGSHENG's dynamic acid leaching apparatus uses a rotating perforated inner cylinder to mix crushed PCB with aqua regia (hydrochloric acid + nitric acid), accelerating the reaction through mechanical stirring. This design improves gold extraction efficiency by 40% and integrates an exhaust gas treatment module to reduce nitrogen oxide emissions. While pyrometallurgy has a high processing capacity, it is energy-intensive (relying on fossil fuel-based electricity). In contrast, mixed leaching (biological leaching for copper + chemical leaching for gold) can reduce global warming potential by 70% when powered by carbon-free electricity.
The end-use applications for gold recovery from PCB board focus on high-value-added products. The Royal Mint in the UK directly casts the extracted gold into jewelry (such as bracelets and pendants) and commemorative coins, with unit prices ranging from 275 to 110,000 pounds. In the industrial sector, a closed-loop system is employed: the stripped gold is electrolytically purified (to 99.99% purity) and then re-plated onto new PCBs, reducing the demand for primary metal mining—recycling 1 ton of server motherboards avoids the carbon emissions associated with mining 3 tons of copper ore and refining 200 grams of gold.
Innovative technologies like soluble substrate PCBs are driving the recycling revolution. Water-soluble polyvinyl alcohol (PVA) substrates dissolve when exposed to water, allowing components to detach intact and be reused directly, while liquid metal circuits can be filtered and recycled. Although this technology is still in the laboratory stage, it has already opened new pathways for “no-disassembly” PCB recycling.
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