Precious metal recovery from spent catalysts not only requires “leaching out” the precious metals, but more importantly to achieve high recovery rates, high treatment capacity, low energy consumption, low environmental impact, and low investment. Metalcess provides full package solution with core process flow including: high-efficiency pyro metallurgical metal collection → TBRC deep enrichment →slag circulation → water atomization-enhanced leaching → precise hydrometallurgical separation.

This process fully leverages the advantages of pyrometallurgy—high throughput, high recovery rates, and strong adaptability—while utilizing hydrometallurgy to achieve the final separation of precious metals and the production of high-purity products. Through the process route of “initial significant enrichment via pyrometallurgy followed by fine separation via hydrometallurgy,” the scale of the hydrometallurgical system and the wastewater treatment load can be significantly reduced, enabling the efficient, low-cost, and environmentally friendly recovery of platinum-group precious metals.

Electric Arc Furnace Smelting—Large-Scale Precious Metal Enrichment

After crushing and blending, waste catalysts or PGM ore are fed into an electric furnace for smelting.

In the electric furnace, by adding appropriate collectors and reducing agents, the platinum group metals in the waste catalysts and PGM ore are transferred from the low-grade feedstock into a specially designed collector alloy. Following smelting in the electric furnace, the concentration of precious metals is increased by a factor of 10 to 20.

At the same time, the carrier materials, oxides, and gangue components in the spent catalysts and ore form conventional smelting slag.

This slag has a stable mineral composition and can be safely disposed of in accordance with local environmental regulations and leaching test requirements at the project site; when requirements are met, it may be safely landfilled or further recycled.

TBRC Intensive Refining and Enrichment of PGMs

TBRC stands for Top Blown Rotary Converter.

The collector alloy obtained from the electric furnace is fed into the Metalcess TBRC furnace for intensive refining. Through top-blown oxidation and enhanced rotation of the converter, base metal impurities in the collector alloy are gradually oxidized and incorporated into the slag, while platinum group metals (PGMs)—such as platinum, palladium, rhodium, and iridium—are further concentrated in the alloy phase due to their unique metallurgical behavior. After TBRC refining, the PGM content in the alloy is typically concentrated by 10 to 15 times.

This means that through Metalcess’s two-stage pyrometallurgical enrichment process—“electric furnace scavenging + TBRC refining”—PGMs in low-grade spent catalysts can be concentrated 100 to 150 times before entering the hydrometallurgical system.

TBRC slag recovered by internal recycling

Traditional precious metal recovery processes often face the challenge of handling complex precious metal-containing slag. Metalcess employs a closed-loop pyrometallurgical design. The slag generated during the BRC furnace smelting process is not discharged as final solid waste; instead, it is entirely returned to the electric furnace for re-reduction and collection.

The precious metals remaining in the TBRC slag re-enter the collector alloy.

Consequently, TBRC slag is recycled within the entire system:

This closed-loop design is of significant importance:

Ø  Minimizes the loss of precious metals in the slag;

Ø  Improves the overall PGM recovery rate;

Ø  The TBRC system generates virtually no final solid waste;

Ø  Reduces slag disposal costs;

Ø  Reduces environmental risks associated with the project.

The primary slag ultimately discharged is ordinary electric furnace smelting slag. The process flow is clear, and solid waste management is straightforward.

PGM recovery rate 99.95% above

For high-value precious metal projects, the recovery rate directly determines the project’s economic benefits.

Metalcess employs a comprehensive technical approach that includes: high-efficiency collector recovery in an electric furnace; TBRC-enhanced enrichment; internal slag recirculation; and fine separation via hydrometallurgical processes.Through multi-stage enrichment and internal recirculation, losses of PGM in pyrometallurgical slag are minimized.

Depending on the feed composition and specific process conditions, the overall PGM recovery rate typically reaches 99.95% or higher.

When processing high-value secondary resources such as automotive and petrochemical waste catalysts, even a 0.01% increase in recovery rate can yield significant economic benefits. Therefore, Metalcess not only focuses on the metal recovery rate of individual equipment but also enhances the system’s overall precious metal recovery level through closed-loop design across the entire process.

Reduced Investment in Hydrometallurgical Processes

Traditional hydrometallurgical processes that directly treat spent catalysts must handle large volumes of ceramic supports, alumina, siliceous materials, impurity metals, and solid residues. Not only do these processes require large-scale equipment, but they also involve high acid consumption, large volumes of waste liquid, and complex slag disposal.

Metalcess employs a “pyrometallurgical pre-concentration” approach, ensuring that PGMs are already concentrated by approximately 100 to 150 times before entering the hydrometallurgical system. Consequently, the subsequent hydrometallurgical system only needs to process a very small amount of high-value concentrated alloy.

The resulting advantages include:

Ø  Significantly reduced capital investment in hydrometallurgical equipment;

Ø  Significantly reduced acid consumption;

Ø  Reduced reagent consumption;

Ø  A simpler process flow;

Ø  Lower volume of waste liquid generated;

Ø  High precious metal separation efficiency;

Ø  Easier automated control.

For large-scale spent catalyst project of treatment 3,000–10,000tpy, this combination of “high-throughput pyrometallurgical processing + small-scale hydrometallurgical refining” has engineering and economic advantages.

High-efficiency wet separation for the fine purification of Pt, Pd, Rh, and Ir

The atomized alloy powder enters the hydrometallurgical system.

Based on the chemical properties of different precious metals and impurity metals, selective leaching is performed using different acid systems. The final product will be purified Pt, Pd, Rh, Ir.

Depending on customer requirements, the products can be further processed into:

Precious metal powders; Sponge metals; Precious metal salts; High-purity metal products.

Low-Energy-Consumption, Reducing Project Operating Costs

Metalcess PGM recovery process for spent catalysts not only achieves high recovery rates but also features low energy consumption.

Electric arc furnace energy consumption: approximately 800 kWh/t Catalyst

The electric furnace first separates precious metals from a large amount of worthless carrier material, significantly reducing the volume of subsequent processing.

TBRC Refining Energy Consumption: Natural gas: 100 Nm³; Oxygen: 400 Nm³

Through enhanced oxidative refining using TBRC, deep enrichment of the collector alloys can be achieved in a shorter period of time.

Since the feedstock entering the TBRC consists of small quantities of high-value alloys that have already undergone initial pyrometallurgical enrichment, the TBRC performs a highly efficient, high-value refining task rather than processing all spent catalysts.

This tiered processing approach helps reduce the cost per unit of precious metal recovered.

Low Wastewater or Even Zero Liquid Discharge

Before entering the hydrometallurgical system, the vast majority of the worthless carrier has already been separated through pyrometallurgical processing.As a result, the amount of material processed by the hydrometallurgical system is very small. At the same time, the material entering the hydrometallurgical system is a highly concentrated alloy with few impurities, rather than the original spent catalyst.

This significantly reduces:

•    The volume of acid leach solution;

•    the volume of wash water;

•    consumption of purification chemicals;

•    the scale of waste liquid treatment;

•    discharge of saline wastewater.

Through the proper design of the solution recirculation system, the project can achieve extremely low wastewater discharge and meets the engineering conditions for further implementation of Zero Liquid Discharge (ZLD).

This feature is of significant value in regions with strict environmental requirements and limited wastewater treatment capacity in industrial parks.

Key Advantages of Metalcess’s PGM Recovery Solution for Spent Catalysts

Ø  Extremely high overall PGM recovery rate, typically reaching 99.95% or higher.

Ø  PGM enrichment of 100 to 150 times; after two stages of pyrometallurgical enrichment, the PGM content in the alloy entering the hydrometallurgical system can reach 20 to 30%.

Ø  Low capital investment in hydrometallurgical equipment: Following high-concentration pyrometallurgical processing, the hydrometallurgical system processes only a small amount of high-value alloy, significantly reducing capital investment and plant size.

Ø  High processing capacity: A single production line can process 3,000–10,000 metric tons of spent catalysts per year.

Ø  Short process flow: electric furnace scavenging → TBRC enrichment → water atomization → hydrometallurgical refining, thereby avoiding the direct entry of large amounts of low-value carrier material into the complex hydrometallurgical system.

Ø  Low energy consumption: Typical electricity consumption for the electric furnace is approximately 800 kWh/t of spent catalysts; typical consumption for the TBRC process is approximately 100 Nm³ of natural gas + 400 Nm³ of oxygen.

Ø  TBRC slag is recycled. All TBRC slag is returned to the electric furnace for re-reduction and collection, minimizing precious metal losses.

Ø  Low solid waste generation. The primary final discharge from the pyrometallurgical system is ordinary smelter slag from the electric furnace, which can be safely disposed of or recycled based on environmental testing results.

Ø  Extremely low wastewater volume. Following pyrometallurgical pre-enrichment, the volume of wet processing is significantly reduced. The solution recirculation system is simple, enabling low wastewater discharge and meeting the design requirements for zero liquid discharge.

Metalcess- a provider of comprehensive solutions for the recovery of high-value secondary resources.

We helps customers maximize the recovery of high-value platinum group metals—such as platinum, palladium, rhodium, and iridium—while reducing energy consumption, capital expenditures, and environmental compliance costs. From low-grade spent catalysts to high-purity platinum group metal products, Metalcess offers complete, efficient, and environmentally friendly industrial solutions.