Printed circuit boards (PCBs) are a vital secondary metal resource, rich in copper and high-value precious metals such as gold, silver, palladium, and platinum, along with lead, tin, zinc, and large amounts of organic resins and glass fibers. How can we achieve high metal recovery rates while effectively controlling flue gas emissions and reducing environmental protection investments and operating costs?

Drawing on years of experience in non-ferrous metal pyrometallurgy, Metalcess has developed a comprehensive PCB recycling process centered on the TBRC (Top Blown Rotary Converter). The entire process encompasses feedstock pretreatment, TBRC smelting, flue gas purification, slag depletion, black copper refining, copper electrolysis, and precious metal recovery, enabling the efficient recovery of copper, precious metals, and other valuable metals while meeting strict environmental emission requirements.

TBRC—Core Equipment for achieving high metal recovery rates and low operating costs

The TBRC furnace combines top-blowing enhanced reaction with the mixing effect of furnace rotation, ensuring that oxygen, molten metal and feedstock remain in constant contact, thereby significantly improving heat and mass transfer efficiency.

Compared to traditional equipment such as reflection furnaces and blast furnaces, the TBRC offers the following advantages:

Ø  High comprehensive recovery rates for copper and precious metals;

Ø  Fast smelting speed and high single-furnace processing capacity;

Ø  Compatibility with a wide range of complex feedstocks, including PCBs, electronic components, copper slag, and anode sludge;

Ø  Low copper content in the slag, reducing the burden on subsequent processing;

Ø  High oxygen utilization and low energy consumption;

Ø  High degree of automation and flexible operation.

One of the most distinctive features of the TBRC is its ability to flexibly adjust the oxygen-to-fuel ratio based on the composition of different PCB feedstocks, thereby achieving intensified smelting.

Pure oxygen combustion significantly reducing flue gas treatment costs

PCBs typically contain large amounts of organic materials such as epoxy resins and plastics, which have a high calorific value. Metalcess’s TBRC system utilizes pure oxygen combustion technology and can flexibly adjust the oxygen-to-fuel ratio based on the feedstock and furnace conditions. When processing PCBs with high calorific value, fuel can even be shut off, and only pure oxygen can be fed into the furnace, allowing the chemical energy inherent in the PCBs to serve as the sole heat source for complete combustion within the furnace.

This process offers significant advantages:

Ø  The heat released by the organic compounds in the PCBs directly contributes to the smelting reaction;

Ø  The smelting process maintains thermal equilibrium, enabling stable self-heating operation;

Ø  Natural gas or fuel oil consumption is significantly reduced;

Ø  Since large amounts of nitrogen from the air do not enter the furnace, the volume of flue gas is significantly reduced;

Ø  Subsequent flue gas purification systems require smaller equipment and lower investment;

Ø  Consumption of flue gas treatment chemicals is reduced, leading to significantly lower operating costs.

Compared to traditional air-combustion systems, the pure-oxygen TBRC not only improves energy efficiency but also reduces the flue gas treatment load at the source. During the PCB smelting process, the design of the flue gas purification system is particularly critical due to the presence of a certain amount of organic compounds and halogen elements. Metalcess has established a comprehensive multi-stage flue gas purification process to achieve full-process control of pollutants, ensuring the complete removal of dioxins.

Black Copper refining to produce high-quality anode copper

The metal alloy produced by the TBRC is referred to as black copper. The black copper is fed into the next TBRC furnace for pyrometallurgical refining. During the refining process, by controlling the oxygen potential and reaction conditions within the furnace, the following impurities are gradually removed:

lead (Pb);

tin (Sn);

zinc (Zn);

and other volatile and easily oxidizable impurities.

The refined molten copper is fed into an anode furnace, where the oxygen content is adjusted through reduction to achieve a chemical composition suitable for electrolytic refining. Subsequently, the molten copper is fed into the anode furnace and continuously cast into standard copper anode plates using a disc-type anode casting machine, providing a stable feedstock for subsequent electrolytic refining.

Copper Electrolysis and Precious Metal Recovery for adding-value

After anode copper enters the copper electrolytic refining system, the following occurs during the electrolysis process:

Copper is deposited as high-purity cathode copper; precious metals such as gold, silver, palladium, platinum, selenium, and tellurium are concentrated in the anode slime.

The final products are:

LME Grade A cathode copper; high-value anode slime.

Depending on project scale and product requirements, anode slime can be further processed using pyrometallurgical or hydrometallurgical methods to extract:

Gold (Au)

Silver (Ag)

Palladium (Pd)

Platinum (Pt)

Selenium (Se)

Tellurium (Te)

This enables the efficient and comprehensive recovery of precious metal resources, generating substantial economic returns for the project.

Leveraging proven TBRC smelting technology and a comprehensive flue gas treatment system, Metalcess offers global customers integrated solutions ranging from process design, equipment manufacturing, and engineering construction to commissioning and production startup.

Our PCB recycling systems offer the following core advantages:

Ø  TBRC enhanced smelting, resulting in high overall recovery rates for copper and precious metals;

Ø  Pure oxygen combustion and exothermic reaction technologies significantly reduce energy consumption;

Ø  low flue gas volume leads to significantly lower investment and operating costs for environmental protection systems; a complete system comprising a secondary combustion chamber, quenching, dry desulfurization, baghouse filtration, wet scrubbing, and activated carbon adsorption ensures highly efficient removal of dioxins and acidic pollutants;

Ø  Electric furnace for slag depletion further recovers copper matte, improving the overall utilization rate of valuable metals;

Ø  A full-process configuration encompassing black copper refining, anode casting, copper electrolysis, and precious metal refining maximizes the recovery of resources such as copper, gold, silver, palladium, and platinum;

Ø  process parameters can be flexibly adjusted according to the composition of different electronic waste streams, making the system suitable for PCBs, electronic components, electronic waste, and other complex copper-containing secondary resources.

Metalcess is committed to helping customers achieve efficient resource utilization, environmentally friendly production, and long-term stable operations through advanced metallurgical technologies and reliable engineering capabilities, providing internationally competitive turnkey solutions for the resource recovery of electronic waste.