Recycling Palladium from Monolithic Ceramic Capacitors
Published: December 3, 2011
E-scrap Source for Palladium
Most e-scrap digital electronic printed circuit boards contain trace amounts of Palladium in monolithic ceramic capacitors but this Palladium is possibly the most overlooked e-scrap recycler resource. A monolithic ceramic capacitor contains Palladium or a mix of Silver and Palladium. These capacitors are quite small but exist on most digital circuit boards disposed of as e-scrap, including memory sticks.
Monolithic ceramic capacitors may be identified by a light brown or tan color but they may be other colors as well. The photo below, courtesy of Jeff Keyser (2011), shows a monolithic capacitor in a microscopic view. Toward the center of the photo is a component with two silver-colored bars surrounding a tan area. This component is a monolithic ceramic capacitor.
The silver-colored bars are the electrodes that connect the capacitor to the circuit board; the Palladium resides in the tan area between the silver bars. One can derive from the fact that the photo is from a microscopic view that many of these capacitors are quite small. They were developed as part of a manufacturing process known as surface-mount, which uses robotics to populate the boards.
Palladium Processing Alternatives
Two alternatives exist for the recycler to take advantage of the Palladium content of monolithic ceramic capacitors. The first alternative comprises selling e-scrap circuit boards to board processors or arranging a sort of assay process. The second alternative is for the recycler to process the circuit boards.
When a recycler sends off e-scrap printed circuit boards for recycling to a processing plant, the processor will most likely recover the Palladium and silver from the capacitors on the boards as a separate step from reclaiming the gold. Unfortunately, the recycler who sends the circuit boards to the processing plant will not receive a line item accounting of the materials recovered from the boards.
The recycler sells the boards to the processing plant by bulk weight and receives the money up-front before any recovery processes take place. Because the processing plant pays a minimal amount to the recycler, the processing plant receives most of the money for the precious metals. This is an equitable arrangement, however, because the recycler does not take on the time, effort, expense, and risk of recovering the gold, silver, Palladium, and other precious metals.
A recycler with very large amounts of e-scrap circuit boards may arrange for an assay of the materials contained in those boards and the processor would perform an assay of the materials. In this case, the recycler pays the assay fees then the processor returns the precious metals back to the recycler after recovery; including the gold, silver, and Palladium contained in the capacitors. The processor may offer to buy the precious metals from the recycler according to the spot prices for the individual metals. The precious metals market controls the prices for gold, platinum, Palladium, and silver and these prices change periodically; the price for a precious metal at a given instant in time is that metal's spot price.
Cleaning E-scrap Circuit Boards
If a recycler cleans circuit boards (removes the components from the boards) before sending them for processing then the recycler removes these capacitors along with the other components and saves them in separate bins until enough individual components stockpile for processing. Processing plants often pay more for stripped boards than for those containing components.
The reason for this is that printed circuit board processing plants tool up to reclaim the gold, silver, and other precious metals from the boards themselves and the components contained on the boards detract from the processing. The plant grinds up the boards then processes the chips to extract the precious metals.
Cleaning the boards does provide an advantage to the recycler, however. The cleaned boards take up less space and weigh less than the populated boards. This means that the recycler will get more bang for the buck when shipping the boards to a processor. Good business practices would require the recycler to get the most for the money; sending five pounds of stripped boards yields more than shipping five pounds of populated boards.
Reclaiming the Palladium
Like gold, there are ways for a home chemist to reclaim Palladium. However, the Palladium content of e-scrap is limited to the Palladium contained in the monolithic ceramic capacitors contained on printed circuit boards.
Palladium and other platinum related precious metals are normally collected and sold in either a powder, salt, or button form. To profit from the extraction process after paying for the necessary chemicals, a home chemist should process monolithic ceramic capacitor batches weighing at least 100 grams. Since the capacitors are quite small, this weight correlates to a fair number of capacitors collected from many e-scrap printed circuit boards.
Important Safety Tip
The author originally believed that the procedures to reclaim precious metals would involve pulverizing and melting the components; this is not the case.
The procedures to extract and refine Palladium require using heated acids, which generate poisonous fumes so extreme safety precautions should be taken and only the most competent home chemist should attempt the procedures. A suitable vented fume hood is highly recommended and the recycler should contact the authorities about necessary licenses or permits if that recycler plans to process large quantities of e-scrap to extract Palladium.
The result of the Palladium recovery procedure detailed in the above video is an acid solution containing the dissolved precious metal. This solution is suitable for refining to extract the Palladium metal, which may be done by a home chemist following the procedures in the two videos that follow. An alternative is to sell the solution to a refiner.
Note: Selling the solution would require special handling procedures because the solution is toxic and corrosive. Shipping restrictions may apply.
A home chemist who performed the recovery process would probably be better off refining the solution rather than sending the solution off for refinement, unless the individual lives close enough to the refiner to hand-deliver the solution.
Refining Palladium: Part 2
Disclaimer: The preceding recovery and refinement procedures were presented by the author as an illustration of the processes involved. The procedures were not presented as step-by-step instructions and these procedures should not be attempted using only what was presented here. The author provides no warranty; any procedures attempted by the reader are strictly the readers responsibility.
The above disclaimer should inform any reader of the dangers involved in these procedures and why the author feels that only a qualified home chemist should attempt them. As a matter of fact, this is the first hub written by the author that prompted the necessity for including such a disclaimer. However, if this hub peaked enough interest in a reader to motivate that reader to attempt the procedures then the reader should obtain detailed instructions. Sources for the procedures are available from Amazon.com below.
More by this Author
Much of the gold contained in escrap computers resides in the CPU chips. The CPU chips often contain gold plated pins because of the high frequencies involved in computer clocking. Gold may also connect the CPU chip...
The bulk of gold content within escrap computers resides within the gold fingers or the edge connectors that connect printed circuit boards together. Recyclers recover this gold from the escrap computers to earn a home...
Risk identification may be accomplished using a number of techniques, including brainstorming and the Delphi Technique.