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Laboratories that create high-quality restorations using precious metals, such as gold, silver, and the platinum group metals (PGM) platinum and palladium, have much to gain by making a greater effort to collect the scrap that remains after work is completed on crowns, bridges, partial dentures, implants, inlay/onlays, etc. This valuable by-product of their work should be collected and recycled for ecological, as well as economic reasons.1 Recycling also offers the opportunity to reduce the environmental burden of the metal supply and its impact on climate2 (Figure 1).
Precious Metal Value
The concept of repurposing unused or unwanted fine metals, especially gold, is nothing new. In 2010, the World Gold Report maintained that nearly 30% of the world’s produced gold is processed from recycled gold.3
But gold, the value of which is driven by the economy, is not the only precious metal found in dental laboratory scrap. Most refiners pay for four different metals. In addition to gold, there is silver, platinum (which is currently valued higher than gold), and palladium (which fluctuates according to supply and demand). On April 30, 2013, the Kitco Metals, Inc. website (Kitco.com) quoted these prices for a single ounce of gold, silver, platinum, and palladium—$1468, $24.20, $1500, and $697, respectively.4 Clearly, small additional amounts of these recovered substances can add up to real money for the laboratory.
To receive full and fair value for all their precious metal scrap, laboratories should work directly with a well-qualified refiner to have the scrap melted and assayed for precious metal content.5
Choosing a Refiner
Dental scrap is a valuable commodity and identifying a quality refiner is key to recovering alloy costs.6 This point is underscored by an article in the Platinum Metal Review, “The high technical recyclability of platinum group metals means that over 95% recovery can be achieved once PGM-containing scrap reaches a state-of-the-art refining facility.”2 It is clear from numerous sources1,6,7 that the selection of a refiner, should be made carefully—and should not be based exclusively on price—to ultimately yield the greatest cost recovery. 7
Laboratories are advised to identify a reputable scrap refiner willing to provide references and a tour of the facility. The company selected should be one that processes scrap from start to finish under one roof and does not outsource any of the production processes, which can increase the refining charge.8 Although it may seem convenient to accept an offer by an individual promising on-the-spot scrap evaluation and cash payment, as explained in the below discussion of The Refiner’s Responsibilities, it is not possible to correctly immediately assess value, so payout is almost certain to be considerably less than the scrap is worth.
What to Ask
While vetting various companies, it is important to seek clarification about fees to be paid and received.5,8 First among them is the accountability charges, which represent the percentage of metal recovery that the refiner keeps as one of its fees, which will reduce the recovery payment. Some companies pick up on-site; others require shipping, so the potential client should find out about the costs involved. If there are shipping fees, is there a minimum lot charge, or do they charge by weight? Does the refiner provide insurance, free pickup, online scheduling, and a way to track the package? Do they have dental affiliations or partnerships? Do they charge for the assays necessary to ascertain the value? What methods are used? Most pay for silver, gold, platinum, and palladium, but that should be verified before the first shipment. In addition, it is important to know how they calculate the metal prices used on the settlement report, and the date on which the prices are calculated—whether it is based on when materials are received, assayed, the average, or the date that is most advantageous to the refiner.
Everything should be transparent and conducive to record keeping and verification of value. There should be no hidden charges of any kind, including minimum lots fees. The refiner should provide confirmation of shipment; verify identification and compensation for all four precious metals, not just gold; provide individual assay of the scrap with advanced technologies; provide a certificate of assay or assay report; keep track of customer history; and monitor trends and buying patterns for customers.
As for settlements, they should be handled promptly and the client should be offered several options for payment. There should also be procedures in place in the event that the customer contests settlement.
Once the choice of a refiner has been made, it is the job of the laboratory to maximize the recovery fee by comprehensive retrieval of precious metals. In the past, when a majority of clinical dental scrap was approximately 16 karat and yellow in color, quantifying and qualifying was much easier.9 The industry has since seen the rise of PFM restorations and the increasing shift towards lower noble white alloys, such as palladium-silvers, and non-precious alloys, which makes the spot (visual) assessment of scrap far more difficult than before.9
It is for this reason that the American Dental Association developed its ADA Noble Metal Classification System (Table 1), a precise method of reporting various alloys used in dentistry in which alloys are defined on the basis of the percentage of metal content and listed in order of biocompatibility.10
According to Platinum Metals Review, “The main barriers to recycling PGMs lie in ensuring the collection of scrap.”2 For that reason, the dental laboratory needs to implement collection procedures including a schedule with clear lines of responsibility for specific employees; collection containers and a checklist of all the places scrap can be found7; correct packaging, shipping, and insurance;1,5,9 and keeping a settlement history.5,11
The schedule should be set up in keeping with the needs of the lab; 1,7 it can be monthly, quarterly, or biannually, keeping in mind that the advantages of more frequent and regular shipments include improved liquidity, a better ability to track assets, and the ability to secure the scrap, which is often not covered by the office insurance policy.5 The names and responsibilities of the employees in charge of scheduling duties should be clearly specified.1,7
The dental laboratory offers numerous hiding places for scrap, so recovery efforts should be comprehensive. Follow an established checklist, such as the one below, of all potential scrap sources in the laboratory. The three major categories of scrap are grindings, solids, and sweeps, which should collected and packaged separately.5 Because grindings and solids are the cleanest, careful collection and storage at the bench and casting well is essential.12 Lower grade scrap includes the buildup accumulated through the suction unit and collected in vaccum bags, investment powder, crucibles with metal fused to them, and aluminous oxide.12 Mularski recommends that basically anything that comes into contact with precious metal scrap, including paper towels, disposable floor mats, carpet, vacuum bags, filters, crucibles, torch tips, and pan liners, be included in the shipment for refining.13
Collect all grindings from benches.
Collect all slag from casting well. Be sure to check the well daily.
Collect all floor sweepings from finishing and casting area.
Collect all remakes or crown returns.
Collect all contaminated buttons and spills.
Collect all crucibles used for casting precious metals.
Collect all worn carpet pieces in finishing area.
Wipe all countertops clean with a paper towel, which can be sent with the scrap shipment.
Check all suction units.
Scrap all precious metal crowns or bridges.
Save sink traps.
Collect all grindings from benches and drawers.
Collect all spills and debris (slag) from the casting well areas.
Collect all vacuum system debris including the vacuum bags.
Collect all platinum foil scrap.
Collect all grindings and sweeps from the floor, especially in the casting area.
Vacuum the entire work station, cleaning lights, cracks, crevices, chairs and shoes.
Platinum muffles and Thermocouples in obsolete equipment can be scrapped.
Place carpets at the entrance and exit of finishing areas to collect grindings and dust. Old worn carpet can be collected to be scrapped.
Preparation for Pickup
Once items are collected, they need to be prepared either for retrieval by the refiner or by the facility’s shipping company. If possible, materials should be disinfected, and if applicable, they should be labeled and weighed. Solid crowns, inlays/onlays, and extractions can be packaged together.1
The shipment should also be insured: the person responsible for this task should contact the refiner for advice based on the type and amount of scrap. Some refiners provide preprinted shipping labels that include a standard amount of insurance. Once all these steps are completed, the refiner should be contacted for pickup.1
Keeping a history of settlements provides information about the monetary value of scrap for tax records and also serves as motivation to continue collecting. Some refiners offer a scrap audit.13
The Refiner’s Responsibilities
Receiving and Processing
Once the scrap is received at the facility, it is assigned a lot number by which it will be tracked, then is separated by type and weighed. The materials are then processed—that is, melted—usually in an induction furnace, and stirred to insure homogeneity.12
Gathering a Sample
Gathering a sample that is representative of the melt is essential for an accurate determination of the elemental breakdown. The following two methods are considered to be accurate, as long as the sample is homogeneous. The first involves pulling a sample of the molten metal into a vacuum tube, which is then left to harden. In the second method, a sample is drilled out of the bar once it has hardened.12
The molten metal is then poured into a mold. The melting points for precious metals vary from nearly 2,000°F for gold to over 3,200°F for platinum. Borax added to the mixture to draw out the impurities becomes the “slag,” which should easily separate from the metal after it has cooled and hardened. Once the bar is free of slag, it is weighed. 6,12A representative sample is then taken for assay, which determines which metals are present in the scrap.5
Assaying the Scrap
An assay is a quantitative determination in which a metal or metals are separated from impurities by fusion processes and weighed in order to determine the amount present in the original sample.1
The centuries-old fire assay is still considered the most reliable method for gold assay. With it, a sample is drawn from a homogenous lot and weighted, then added to lead pure silver, weighed, and placed in a crucible. This is heated in a furnace until melted into a bead, which is dissolved with nitric acid, leaving a pure gold residue which is weighed and calculated, divided with the original weight of the sample yields the gold percentage.14
With the advent of more and more PGM in the dental industry, refiners found it necessary to determine methods of assay that are reliable to detect palladium in a sample, such as gravimetrical and spectral means. These methods are used to determine all metals contained in a sample.14,15 At this time, the industry standard for analyzing precious metal content is through the use of an inductively coupled plasma emission spectrometer or ICP.8 The ICP uses an infusion process that is weighted in order to determine the exact amount of precious metals in the sample. The assay sample material is first immersed in a mixture of hydrochloric and nitric acid and totally dissolved (Figure 2). The ICP samples the acid with the dissolved metals and prints out a reading on the amount of gold, platinum, palladium, and silver the sample contains.8 This process provides the exact percentage of each element present. For example, an assay can show that a given sample contains 25% gold, 25% palladium, 5% platinum, 10% silver, 30% copper, 1% indium, 2% nickel, and 2% trace amounts of other elements. Once the percentages of the various elements have been determined, they can be correlated with the weight of the sample.12
Scrap Value Determination
To calculate the dollar value of the scrap, data is entered into the computer, which multiplies those percentages by the fixed price of each metal on that day and by the net weight of the shipment.6 For this, the “London fix” is generally used,16 but the market price used by the refiner should be clarified in advance. As it can make a difference in the ultimate payout, it is important to establish the timing of the valuation. The most common options are to lock in the price on a specific day or to use the average over the time it takes to process your scrap. 3,12
A refiner should not promise settlement in 24 hours. A scrap melt and a complete four element assay (gold, palladium, silver, and platinum) requires 5 to 7 days;8 it typically takes 5 to 10 working days to fully process and assay a lot of scrap to determine an exact settlement figure.8
Each company/refiner establishes its own fees,6,8,9 so it is important to ask specifically about fees while vetting refiners under consideration, but the industry standard is 15% to 18%.8
The most common method of settlement for the value of precious metals recovered is by check, but there is a trend toward compensation with gold, silver, or platinum bullion.15
According to one refinery spokesperson, the average payout to a dental laboratory for scrap gathered over the course of 3 months averages about $4000.
Dental laboratories can maximize their ROI by carefully choosing a refiner that meets exacting standards. The company’s reputation, experience, and use of the most modern technology are paramount. There should be a clear understanding of the scrap evaluation method, and all terms; the settlement report as well as refining terms and policies should be provided in writing. To the best way to determine whether fair market value of scrap has been received is to first track all alloy purchases and break them into each of the four precious metals, then track scrap return. At the end of a year, the amount of precious metals purchased should be compared to the percentage of precious metals in the scrap return. 8 A return on investment of 15% to 18% suggests the laboratory is doing a good job of collecting its scrap and the refiner is doing a good job of recovering the precious metals and offering fair payment.8
1. Circelli T. Set a gold standard in your practice . Inside Dentistry. 2013;9(1).
2. Hagelüken C. Recyling the platinum group metals: a European perspective . Platinum Metals Rev. 2012;56(1):29-35. http://www.platinummetalsreview.com/article/56/1/29-35/ Accessed April 26, 2013.
3. Brady RGP. World Gold Report 2010. London: London Mint Office; 2010.
4. Kitco Metals, Inc. http://www.kitco.com. Accessed April 30, 2013.
5. Weinberg D. Maximizing your dental refining returns. Today’s Florida Dental Association. November 2009. http://fda.cms.memberfuse.com/sites/fda/files/Nov2009TFDA.pdf. Accessed April 26, 2013.
6. Circelli T. Make the most of dental scrap refining . Journal of Dental Technology. 2011;August/September:24. http://www.jdtunbound.com/files/pdf-files/Make%20the%20Most%20of%20Dental%20Scrap%20Refining.pdf. Accessed April 26, 2013.
7. Circelli T. Make the most of your scrap: 9 ways to maximize profits. Lab Management Today. April 2011.
8. An interview with Tony Circelli . Inside Dental Technology. 2011;(2)6:72. http://www.dentalaegis.com/idt/2011/06/an-interview-with-tony-circelli-heraeus-kulzer-precious-metal-refining-manager. Accessed April 26, 2013.
9. Jensen Dental. Choosing the right clinical scrap refiner. http://www.jensendental.com/clinicalrefining/pdf/article.pdf, Accessed April 26, 2013.
10. ADA Revised classification system for alloys for fixed prosthodontics. American Dental Association Web site. http://www.ada.org/2190.aspx. Published March 2003. Accessed April 26, 2013
11. Lund B. A test of metals . Dentaltown. 2010;July:38-42.
12. McKay K. Understanding scrap refining . Inside Dental Technology. 2012;3(1):58. http://www.ddsrefining.com/media/IDT_article.pdf accessed April 26, 2013
13. Mularski LAR. How to maximize your scrap . Inside Dental Technology. 2012;3(9)
14. Circelli T. Setting the gold standard at your laboratory . Focus. 2012;3rd quarter:19-20.
15. Manchanda D. Final analysis: the role of inductively coupled plasma-optical emission spectrometry in determining the fineness of precious metals . Platinum Materials Rev. 2011;55(4):281-283.
16 . What is the London gold fix, and why? Gold News. 2013;March15. http://goldnews.bullionvault.com/gold-fix-031520132. Accessed May 2, 2012.