What Are The Stages in the Catalytic Converter Recycling Process?

Catalytic converter recycling doesn’t start and end at a scrap yard. The metals they contain–platinum, palladium, and rhodium–need to be extracted. And that’s only possible through toll refining.

Toll refining is a complicated process that involves multiple steps to extract platinum group metals (PGMs) from scrap catalytic converters. And for many people, this process is a mystery.

That’s why we’re here to shed some light on the entire process, from the moment your converters arrive at a processor’s facility to the sale of your precious metals.

The toll refining process

Toll-refining converters is the only way to extract the valuable metals that they contain. Here’s how the process works.

Grading

After a toll refiner receives your used catalytic converters, the units are counted or graded. This is an important step because processors will use the grading report for comparison once the assay is complete. But we’ll get to that later!

During grading, processors look for total units, unit fullness, and material types (DPFs, OEMs, Aftermarkets, foil, etc).

Decanning

Decanning is the process of removing any pipes, shields, and metal shells from your converters. During this step, dust is produced, and it’s vital that your processor has the proper equipment and methods to capture catalyst dust effectively. That’s because the dust produced during this stage often has twice the concentration of precious metals.

Crushing & milling

The loose ceramic is then crushed, milled, and commingled. The result is a homogenous powder with equal particle size. That means each particle has an equal chance of being analyzed. Once the crushing and milling phase is over, multiple samples are taken for laboratory analysis.

Assay

A laboratory assay is the only possible method to determine the composition of precious metal content in your converters. A proper analysis uses both theX-ray Fluorescence (XRF) and Inductive Coupled Plasma (ICP) methods to determine precious metal content.

X-ray fluorescence

XRF is the most common method used in assay laboratories. XRF is a non-destructive technique that measures fluorescent secondary x-rays emitted by a sample.

Inductive coupled plasma

While many companies claim they can sample converters, most of them might have an XRF machine at best, or even an XRF gun. The Gold Standard for toll refining companies is the ICP machine, which is much more precise.

The powder sample is converted into a liquid, and the component elements are separated. Plasma flame is then used to make the elements visible. Then the precious metal content is measured against the ceramic substrate by light intensity and the results are indicated as parts per million (PPMs).

Determining the value of your material

With the completion of laboratory analysis, the value of your converters is determined. Processors do this by combining the PPMs of precious metals, net weight of the ceramic, and the market prices for the metals at the time of sale. It’s at this stage that all recyclers are paid, whether the company who assayed the material has a smelter or not.

After the processor: the smelter

Your material moves to the furnace once you’ve been paid and the toll refining process is over. Material is smelted in an arc or plasma.

During this process, the catalyst ceramic floats on top of the furnace and needs to be released in two stages. The first stage of the tap-out is the ceramic. The second stage is to release the metal in the form of slag. It’s important to remember that furnaces need to be fed material constantly in order to work effectively.

Once the initial smelting process is finished, the metals are combined into one mass. Then, the metals are ground down into a fine powder and subjected to chemical leaching. This means that the precious metals are separated from each other into a usable form, or what we call a sponge.

Now they’re ready to be sold on the market.

Metals are returned to the global economy

When these precious metals are sold on the market, they typically return to the automotive industry. But PGMs are versatile metals and have uses across many industries.

Platinum, for example, is used in the production of medical equipment, electronics, and jewelry.

Palladium is used in fuel cells, dental fillings/crowns, and jewelry.

The majority of rhodium’s use is in catalytic converters but it can also be seen in catalysts for the chemical industry and acids like nitric and acetic.

Why is recycling converters important?

Around 40% of the PGM supply for the automotive industry comes from recycled catalytic converters. That means that a significant proportion of the PGM supply still comes from mining, which damages our environment and depletes our natural resources. There’s also a high cost to mining precious metals, so recycling converters is both beneficial for the environment and a cost-saving measure.

Your place in the catalytic converter processing pipeline is crucial. Working directly with a toll refiner not only ensures you get paid for your materials true worth but also ensures those metals return to the global economy and to the industries that depend on them.

To start dealing direct, contact us now or book a free consultation.