Refining scrap catalysts

Catalytic converter recycling is big business and plays a significant role in the effort to feed the constant demand for Platinum Group Metals (PGMs), all of which are in scarce supply. In its early days, this recycling was both logistically and technically complex, and whilst this, to an extent, remains the same today, improved efficiencies and technical advancements have helped the industry burgeon.

At the top of the food chain sits the refining operation, the removal of the PGM’s from the catalyst ceramic and metallic substrates. Smelters are the “real” refiners, melting metals to separate the alloy from its impurities, in order to recover the actual precious metals. The technology of the recycling process is rather complex and consist of many stages. It requires heavy investment, and, hence, has traditionally been carried out by large organizations, usually located in USA, Europe, Japan, that are capable of refining an extensive range of metals. Reimbursement is one of two ways:

Refining Flat Offers - a simple and straightforward method with the refining company charging a percentage of the final value of the precious metal. Thus, although you will not be “charged” as such for the actual service, you will not receive back the full value of your precious metals.

Toll Refining Offers - whereby you will be charged a combination of  “lot charge”, “treatment charge”, and “refining charge”. To offset this, companies will offer a higher return rate for your material.

Processrefining process for scrap catalysts

Once collected, catalytic converters are de-canned and the substrate crushed to a fine powder. Specialist refiners then undertake the complex work of extracting the PGMs.

The preferred method for recovering PGM-bearing materials such as catalytic converters is a pyrometallurgical process, which delivers high recovery rates. This involves the thermal treatment of mineral and metallurgical ores to bring about physical and chemical transformations in the materials to enable the recovery of the precious metals. The nature of the operation usually has meant that large quantities of substrates - in excess of 1 ton - have been required to make up a “load”.

After primary extraction, the precious metals are separated from base metals by chemical refining techniques including dissolution, solvent extraction, and selective precipitation. Alternatively, the ceramic substrate of some catalysts can be dissolved in acid leaving behind a concentrated residue of precious metals.

Whilst this is the basic process, and originally was carried out by major smelting companies with a background in handling metals that are in much higher demand (quantity-wise at least), technological advancements and growing demand have led to more forward-looking organizations entering the market. These offer a broader range of services and, importantly, the flexibility and efficiency to handle the wide range of catalyst types on the market today, as well as the ability to operate economically with smaller batch sizes. We have talked in previous articles about the impact that the diversity of catalyst types is having on the recycling market - these new players are looking to be the solution.

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