Adding Profits From Spent Processing Catalysts
August 1, 2013
Recovering precious metals from spent pharmaceutical and chemical processing catalysts can pay big dividends if it’s done right
Precious metal-bearing catalysts are widely used to speed reactions for producing many pharmaceutical, nutraceutical, and chemical products. They are also used to eliminate harmful end-of-pipe emissions during the process cycle. As an example, heterogeneous palladium on carbon, platinum on carbon, palladium on alumina, palladium on calcium carbonate catalysts, and various gold compounds are employed for hydrogenation and other reactions of intermediates. Although these catalysts typically represent a small portion of overall pharmaceutical/chemical manufacturing costs, they are by no means insignificant considering the value of the precious metals incorporated in the catalyst. Most precious metals used in these catalysts—typically platinum, palladium, rhodium and ruthenium—are commonly referred to as “PGMs,” or Platinum Group Metals.
At the end of a catalysts useful life, the value of its remaining precious metals could easily be worth in excess of many hundreds of thousands of dollars. When you consider the high costs associated with developing, producing and successfully marketing new pharmaceutical-based products, prudent managers always look at ways to lower costs—and add profits—wherever possible. One often neglected approach concerns methods to maximize recovered value of the remaining precious metals in spent process catalysts.
Many organizations recover and refine PGMs and other precious metals from spent catalysts. While they all essentially perform the same tasks, there are also considerable differences among them. Some of these differences can have a significant impact on your returns, and your risk of litigation through exposure to many government authorities (Table 1). Therefore, it is in your best interest to learn as much as possible about the precious metals refiner you are considering. For example, you should know how the organization processes spent catalysts and what equipment and procedures it uses.
As a concerned precious metals refiner, Sabin must maintain awareness of all applicable environmental regulations, and watch for new laws that may affect us—and you. As a general guideline, here are a few typical regulations that impact our organization:
Resource Conservation and Recovery Act (RCRA)—Concerns generation, storage, transportation, treatment and disposal of solid and hazardous waste.
Requires generators and transporters of hazardous wastes, as well as disposal site owners and operators to beheld responsible for the cost of evaluating and remediating contaminated sites.
Added provisions set requirements for emergency planning, notification, and community “right-to-know” reporting on chemical and toxic emissions.
The CAA Amendments consist of 11 major provisions associated with toxic, noxious, or otherwise harmful atmospheric discharges.
This EPA mandated act involves water quality standards including hazardous wastewater discharges.
The TSCA regulates the manufacture, distribution, use, and disposal of chemicals considered a risk to human health or the environment.
The DOT regulates transportation of hazardous materials via air, rail, sea, and road.
Critical areas of interest include the refiners’ contamination removal processes, material sampling and assaying methods, environmental protection policies and systems; and—perhaps most important—the refiner’s reputation with its long-term customers. All of these issues—and there are others as well which will be described here—will have an impact on the relationship you establish with your precious metal refiner.
There are legal implications that you must be aware of when working with a precious metals refiner. They concern possible effluent or atmospheric discharges at the refiner’s facility, since violations are taken seriously by controlling organizations. Based on these concerns, choosing the wrong refiner could result in a costly mistake. The question is, how do you go about choosing the right refiner? There are many criteria to consider when selecting a precious metals refiner. Before that discussion, however, consider the various methods used to help maximize returns for your spent precious metals catalysts. Essentially there are three critical factors under the refiner’s control which apply to virtually all precious metal bearing materials. These are sampling, assaying and processing turnaround time.
The process of reclaiming precious metals in spent catalysts is referred to as “recovery and refining.” Included in the process are many specialized procedures such as materials documentation, contamination removal, sampling, assaying, recovery, refining, environmental considerations, and turnaround time. Each of these is independent; however, together they will have a dramatic affect on how much of the remaining PGMs are recovered, the speed at which they are recovered, and the value returned.
Consequently, these procedures impact the overall costs associated with an organization’s precious metals management program. While each of these functions is important, sampling procedures for spent catalyst materials are perhaps the most critical elements with regard to recovering maximum remaining precious metals. As a user of these materials, it is in your best interest to understand how sampling is used to determine the precious metals content of spent catalysts, and, ultimately, the value of these metals which is returned to their owners.
To accurately determine the amount of precious metals present in materials for recovery the spent catalysts must first be sampled. The three most common sampling techniques used in precious metals sampling are dry sampling, melt sampling, and solution sampling. As each of these techniques offers specific advantages, determining the most appropriate sampling method depends upon the type of material being processed as well as its estimated precious metals content.
Some precious metal bearing materials can be sampled only by one of the three methods described; however, others may be processed by more than one method. In this case the method chosen will depend on variables such as: the estimated value of the precious metals content; the cost-effectiveness of using one method over another for highest possible returns; and practicality—a function of refining costs, materials value, and other factors.
Because precious metal bearing catalysts are made with various substrates and in many sizes and configurations—powder, granulated, and extrudates, for example—determining the best sampling technique is crucial to recovering the most value from your spent catalyst. Most catalysts used for pharmaceutical/chemical processing are carbon based—90% or greater carbon content—and therefore are best suited for dry sampling because of their structure.
Since it is difficult to achieve homogeneity, dry sampling is more complex and potentially less precise than other sampling techniques (melt or solution); in fact, this method requires more judgmental skills than the others. Because of this, it is essential that the material is properly prepared prior to dry sampling in order to reduce sampling error. This process typically begins with a thermal oxidation step used to eliminate contaminants and results in large quantities of spent catalysts—as much as many tons—being “reduced” into smaller quantities—as little as a few pounds.
Once the contaminants are eliminated as completely as possible, the final step of proper preparation generally includes grinding large pieces into smaller and ever finer particles. and passing the material through a predetermined sized screen. The goal is to reduce sampling error by eliminating contaminants and produce a material that is free flowing. This will help generate as precise a representative sample of the overall material lot as possible, and thus permit as accurate a determination as possible of the actual value of recoverable precious metals within the lot.
Following the preparation steps a proper sampling procedure would then allow the fine material from the screening step—oversize material is handled separately—to free-fall in a stream into a crosscut, timed automatic sampler. An ideal dry sampling system would be capable of drawing representative samples from free flowing catalyst according to the principles of Pitard (1) and Gy (2) and the practices of Merks (3). Proper preparation (which will be expanded on later) and sampling will result in representative samples where sampling accuracy is typically ±2% (Figure 1).
Like most concise descriptions of complex procedures, this is easier said than done, since there are many processes, evaluations, equipment, and systems involved in the preparation and sampling process, and there are also vastly different sampling methods used depending upon circumstances. The refiner’s experience and expertise play a major role here, since some sampling procedures and their ultimate outcome can be affected by judgment. Therefore, it is critical that the catalyst user understands the preparation and sampling methods of the refiner to ensure that they properly minimize sampling error and variability. Because of this, a refiner should have detailed documented procedures describing their preparation and sampling protocols. An example of proper preparation and sampling procedures and what to look for follows.
A proper dry sampling procedure for spent catalysts should include an organized identification and tracking system as well as approved preparation and sampling procedures based on sound sampling principles. In a typical precious metal refinery, incoming catalyst materials are inspected, weighed, assigned tracking numbers, and stored prior to sampling. The assignment of tracking numbers is critical; a specific lot— from its arrival at the loading dock—is segregated from all other materials at the refiner’s facility to eliminate the possibility of mixing with other lots.
Spent catalysts are contaminated with organic materials that must be removed to assure accurate evaluation of their remaining precious metals. Removal of those contaminants helps provide free flowing properties to help assure accurate sampling. The removal of organic contaminants is typically done in a box furnace where the carbon catalyst is placed in a tray which is subsequently placed in the furnace and heated until its initial burn off is complete. From there, the catalyst tray is transferred to a cooling area where the “roasting” is completed and the remaining carbon is reduced to as low as 1-2%. Burning virtually all the carbon and liquid from the entire catalyst lot is a key factor towards achieving highest possible sample accuracy.
With regard to contamination removal, spent catalysts typically contain sulfur, carbon, moisture, and other unwanted elements. Consequently, “pre-burning” (the process of removing these and other contaminants) is critical to assure highest possible sampling accuracy which ultimately means highest possible return value for the PGMs in the catalysts. Because of the importance of this process, the precious metals refiner should provide catalyst users with complete in-house “pre-burning” “capabilities and services.
Throughout the sampling procedure the refiner must adhere to all applicable environmental codes and standards with regard to effluent disposal and atmospheric emissions. This is a critical area, and one with which you should be familiar. For instance, thermal oxidation systems should be equipped with adequately sized afterburners to ensure complete combustion of organic contaminates, and the off-gases should be evacuated to a baghouse and scrubber system (Figure 2).
Because sampling is such a critical part of the precious metal recovery and refining process, it has been discussed in detail. However, additional topics need to be considered when choosing the proper precious metals refiner to obtain maximum value from spent pharmaceutical process catalyst.
In conjunction with spent catalyst sampling procedures, accurate and repeatable assaying procedures also play a major role in determining precise values of remaining precious metals. Once the final samples are obtained, sophisticated instrumentation is used to measure their precise precious metals content. Among the equipment and methods used in a well-equipped analytical laboratory is X-ray fluorescence (Figure 3), which is helpful in identifying contaminates that may have an affect on the assaying or refining steps. This is especially important since a refiner has many different customers that use a variety of catalysts for different processes.
Other instrumentation and methods employed by a well-equipped analytical laboratory include: atomic absorption (AA) and inductively coupled plasma (ICP) emission spectroscopy (Figure 4) as well as classical volumetric, gravimetric, and fire assay techniques. By utilizing a combination of these methods, an assayer is able to provide the most thorough and precise approach for determining precious metals content in spent catalyst materials. In general, the types of materials being analyzed determine the specific techniques used for assaying. After sampling and analysis, the total value of the entire spent catalyst lot is determined, and agreed upon between the refiner and its customer.
The speed at which catalysts are processed—and their precious metals recovered (reclamation turnaround time)—is also a key factor of the “maximum return” equation. Logically, faster processing turnaround minimizes interest charges a user accrues for leasing replacement precious metals to eliminate process downtime. It also avoids the necessity of purchasing PGMs on a volatile spot market for use in the timely manufacture of catalysts to permit uninterrupted processing or production.
Values of precious metals can be volatile, fluctuating wildly over a short period of time. For example, palladium at today’s cost is nearly $ 600/oz (€ 14/g), and platinum is almost at $ 2300/oz (€ 53/g). Obviously these high values add to the overall expenses for processing and production of many pharmaceutical products.
As prices for PGMs rise, recovery/refining processing turnaround times increase, and the lease rates— the most common method for financing PGMs—move up, the stage is set for a classic profit squeeze. While any of these factors will decrease profits, the combination of all three can have a dramatically negative effect. At high PGM prices users are forced to seek relief in a number of different directions. Since you are not likely to influence metal market prices, the best place to turn is to your precious metals refiner. The refiner, at least, has some control over precious metals management, certainly as far as your returns are concerned.
Obviously, it is in the best interest of precious metal catalyst users to 1) obtain the highest possible percent recovery for their precious metals; and 2) to work with a refiner that offers fastest possible processing turnaround time so as to minimize lease charges.
By providing faster spent catalyst reclamation turnaround times, substantial cost savings may be realized, in many cases translating into thousands or hundreds of thousands of dollars each year. These are serious numbers of course, and because of this, there is a clear trend towards establishing independent asset recovery programs (or departments) functioning as profit centers for the recovery of precious metals within an organization.
As previously mentioned, you must also consider the legal implications associated with processing procedures at your precious metals refiner. In addition to choosing the wrong refiner with regard to maximum recovery and fastest possible turnaround, choosing the wrong refiner with regard to possible unlawful effluent or atmospheric discharges could become even more costly.
When selecting a refiner, you must not only be aware of how your materials will be processed, but those of the refiner’s other customers as well. It is your responsibility to determine how any solid, liquid, or gaseous by-product is handled at the processing facility.
For instance, exhaust air quality should be managed with state-of-the-art pollution control systems resulting in minimal pollutants being emitted before, during, or after refining. In addition the process water treatment procedure should minimize all causes of pollution. While each of these functions is fundamental, there are many hidden pitfalls surrounding them with regard to environmental compliance.
Requesting detailed documentation on environmental law compliance may help you determine that the refiner you select does not violate any applicable law or regulation. In the United States, the Superfund Act (CERCLA) addresses the direct responsibility of customer and refiner. This law mandates that both the company that is the source of the materials for precious metals recovery and the precious metals refiner share in the “cradle-to-grave” responsibility, as well as future liability for the proper treatment and/or disposal of any materials. Most European countries have similar—if not stricter—laws.
When choosing a precious metals refiner, make sure that the one you select does not violate any applicable environmental laws or regulations. Ask the refiner to provide you with copies of all detailed documentation relative to regulatory compliance. Essentially, the environment must be protected to avoid serious financial and legal consequences and the refiner’s violation of environmental laws or regulations could result in heavy fines and legal costs to you.
One way to determine if a refiner meets these criteria is to check its use of appropriate pollution abatement technology such as afterburners, bag houses, wet scrubbers, and liquid effluent neutralizing equipment. Also, evaluate the refiner’s approval status with all applicable governing agencies. Most precious metals refiners will be pleased to provide copies of required documentation.
The keys to obtaining maximum value from spent pharmaceutical and chemical process catalysts focus on the refiner’s meticulous attention to hundreds of details, all of which influence the final outcome. Possibly most important, these include the thoroughness and accuracy of the materials sampling process, with assaying of the sample lots close behind. Whether you are seeking a new precious metals refiner for your spent catalyst materials, or working with one presently, you must look carefully into these areas, and work closely with the refiner whenever possible.
It’s most important that you adhere to the full compliance issues concerning environmental regulations. All else being equal (i.e., highest possible returns and fastest possible turnaround time), environmental violations at your refiner could create problems for you. These steps—and the refiner’s overall policies with regard to applicable pollution codes and standards compliance—should provide you with the knowledge and confidence to select—and work with—the proper precious metals refiner. In any case, your relationship with the refiner must be viewed as a “partnership,” and must be based upon mutual trust and fair treatment.
- Pitard F.F. Sampling and Process Control for Precious Metals; Francis Pitard Sampling Consultants: Broomfield, CO. USA. 2001: www.fpscamplinjg.com
- GY P.M. Sampling of Particulate Materials. Theory and Practice: Developments in Geomathematics, 4; Elsevier Scientific Publishing Co: Amsterdam, The Netherlands—, 1982
- MERKS J.W. Sampling and Weighing of Bulk Solids: Trans Tech Publications: Clausthal—Zellerfield, Germany, 1985