Pharmaceutical Catalyst Recovery
August 1, 2013
How to select—and work with—the right refiner
to help maximize returns and assure
Many pharmaceutical processors use a variety of precious metal-bearing catalysts for facilitating hydrogenation of various intermediates, and also for eliminating harmful exhaust emissions at end-of-pipe applications. Generally the precious metals that are used in catalytic processes include platinum and palladium, and are part of what are commonly referred to as PGMs, or “Platinum Group Metals.” PGMs also include ruthenium and rhodium as well.
A variety of carriers, or supports for these precious metals are used in pharmaceutical processing depending upon application, including soluble or insoluble alumina, silica/alumina, or zeolites. However, the most common carrier media for precious metal bearing catalysts in the pharmaceutical processing industry are carbon supports.
Precious metal catalyst users typically work with established refining organizations to recover their remaining values after the catalysts lose their efficacy and must be replenished. Occasionally precious metals at pharmaceutical processing plants may also be recovered from process by-products or even protective clothing worn by plant personnel. No matter what the source, the high cost of precious metal-bearing catalysts requires careful thought with regard to their recovery. This should include selecting and working with the right refiner for your particular requirements.
Like virtually all businesses today pharmaceutical manufacturers are faced with profit squeezing in one form or an other, and most people seek ways and means of reducing costs wherever possible. Obviously most cost-cutting methods involve lowering expenses for processing, labor, energy, and other overhead items. Consequently the subject of maximizing returns for the remaining precious metals in spent process catalysts often gets “short changed.” This situation can be avoided, since working with the right refining organization can also be a rewarding experience. Perhaps more important, the implications associated with working with the wrong refiner can be serious — and costly as well.
Many catalyst users may not be aware of the legal requirements concerning effluent or atmospheric discharges by the precious metal refiners they use. Choosing the wrong refiner can become an expensive headache. Legal implications that you must be aware of when working with a precious metals refiner concern possible effluent or atmospheric discharges at the refiner’s facility, since environmental violations are taken seriously by regulatory agencies at all levels. 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, we should look at the various methods used to help maximize returns for your spent precious metals catalysts. Essentially there are three critical factors that the refiner controls, which apply to virtually all precious metal bearing materials. These are sampling, assaying, and processing turnaround time.
To accurately determine the amount of precious metals present in materials for recovery three different sampling techniques are used. These are dry sampling, melt sampling, and solution sampling. 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.
Fundamentally, sampling spent catalysts containing precious metals may be compared to sampling any homogenous mass. The problem is, even new catalysts on substrates (carriers) such as soluble and insoluble alumina, silica-alumina, zeolite, or carbon supports are not homogenous masses — and after years of exposure in harsh environments in which they operate, spent catalysts tend to be far from homogenous. Instead, they typically accumulate many different contaminants of various densities during their useful lives (typically 5-6 years); among them are phosphorous, lead, sulfur, arsenic, nickel, cadmium, and others as well.
What follows is a discussion of a typical sampling procedure for a lot of spent catalyst materials sent to a precious metals refiner. The process begins when incoming catalyst materials are inspected, weighed, assigned tracking numbers, and stored prior to sampling. The assignment of tracking numbers is critical; this specific lot — from the beginning — is segregated from all other materials at the refiner’s facility to eliminate all possibility of mixing in with other lots. Next, these catalysts must first be processed to remove organic contaminants to provide free flowing properties that will assure accurate sampling.
Fundamentally, the principle of sampling involves “reducing” large quantities of precious metal bearing material (as much as many tons) into small quantities (as little as a few grams). Samples are then extracted for analysis from different fractions and/or different stages of the resultant sub-lot. The sampling procedure begins by converting precious metal bearing scrap into a homogenous mass so that molecules of precious metals and other constituents are evenly distributed. Results of sampling the homogenous mass thus represent an accurate ratio of the precious metals content in the overall matrix.
Dry sampling is used whenever materials cannot be dissolved in solution or are inappropriate to melt either because of their structure, or because of the cost associated with melting vs. the possible return. Because it is difficult to achieve homogeneity dry sampling is more complex and potentially less precise than melt or solution sampling; in fact, this method requires more judgmental skills than the others. Materials for dry sampling are homogenized, generally by grinding large pieces into smaller and ever finer particles. The material is allowed to free fall in a stream into a crosscut, timed automatic sampler. Representative samples are also taken periodically and sampling accuracy is typically ±2%. Precious metal bearing catalysts are usually sampled with this technique.
Keep in mind that throughout the sampling procedure the refiner must adhere to all applicable environmental codes and standards with regard to effluent disposal and atmospheric emissions. Therefore, an ideal sampling system would typically be enclosed for dust control and evacuated under a low volume flow into a dedicated baghouse. In addition to the obvious reasons for preventing atmospheric discharge of toxic and/or noxious fumes, the dust collected during this sampling process is also recovered and sampled separately, with its value returned to the catalyst owners, since its value is often substantial.
Dry sampling is both tedious and complex. And while it is your responsibility as a catalyst user (or owner) to understand why it is used, how it works, and how the ultimate value of your precious metals are determined, there are still some issues associated with this technique that many people are not familiar with. Consider some of them here:
During the sampling procedure at the refiner’s, it is in your best interest — and those of the refiner as well — to be represented (by someone from your organization or an independent outside representative) to observe the following procedures:
First, make certain that your material is received and stored properly: it should be assigned a control/tracking number and weighed on certified, inspected scales. Proper documentation must be prepared that should include confirmation of the materials’ description, piece counts (if applicable), and weights. If any irregularities are found (differences between actual numbers vs. your estimates), they must be documented. Your materials then should be segregated into agreed upon lot sizes; lot sizes should be limited based upon the value of the material. Multiple samples will help to improve the statistical accuracy of the sampling. For highest possible precious metal content determination each lot will be sampled individually. For obvious reasons your materials must also be separate from any other customers’ materials.
Accurate and repeatable assaying procedures employ sophisticated diagnostic instruments for measuring precious metals content of materials being reclaimed. A well equipped analytical laboratory utilizes advanced X-ray fluorescence equipment, atomic absorption (AA) and inductively coupled plasma (ICP) emission spectroscopy, and many classic volumetric, gravimetric, and fire assay techniques. When all methods are used together they provide the most thorough and precise approach for determining precious metals content in spent catalyst materials, thus assuring you highest possible returns. In general, the specific techniques used for assaying are determined by the types of materials being processed.
When this process is completed, the samples are assayed using a wide variety of analytical instruments and techniques. Essentially the contaminants in the spent lots (which may influence the samples’ analysis) must be defined, and an explanation provided as to how they would influence the ultimate value determination. The assay must be accurate, precise, and, most important, repeatable. Materials’ owners and their refiners usually assay the final samples independently. If the assays agree to within predetermined limits they are usually averaged to arrive at a payable “settlement” (the value of all precious metals in the total lot). If they do not agree, the refiner will send a sealed “umpire” sample to an independent laboratory (the umpire). Those three resulting assays are used (again by an agreed upon procedure) to determine the final settlement.
The speed at which catalysts are processed — and their precious metal recovered (reclamation turnaround time) — is the third 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. Costs for many precious metals have risen — and fallen — sharply over the past few years, at one point reaching as high as $1100 an ounce for palladium, and about the same for platinum. Obviously these high costs add to the overall expenses for any pharmaceutical processor using PGM bearing catalysts. While palladium prices have decreased since these highs, platinum is still valued at $1100 an ounce. Thus it is still prudent to seek out a precious metals refiner who will return maximum value to you — based on accurate and precise sampling and assaying procedures, and timely processing steps.
In addition to the financial issues concerned with recovering and refining spent catalysts, you must also consider the legal implications associated with processing procedures at the precious metals refiner, as previously mentioned. Certainly you need to use a refiner which offers maximum recovery and fast processing turnaround; however, choosing the wrong refiner with regard to possible effluent or atmospheric discharges could become a costly mistake.
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 should be your responsibility to determine how any solid, liquid, or gaseous by-product is handled at the processing facility.
Ideally there should be no hazardous waste materials shipped from a precious metals processing facility. Some plants will ship them under approved procedures and conditions; you should learn the difference. In addition, minimal pollutants should be emitted before, during, or after refining. Exhaust air quality should be managed with current technology air pollution control systems. Process water must also be disposed by appropriate legal methods. 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 also help you determine that the refiner you select does not violate any applicable law or regulation. In the United States, the Superfund Act 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. When choosing a precious metals refiner, make sure that the one you select does not violate any applicable environmental laws or regulations. Essentially, the environment must be protected to avoid serious financial and legal consequences; the refiner’s violation of environmental laws or regulations could result in heavy fines and legal costs to you. This is a key reason for you to request copies of all detailed documentation rela tive to legal compliance from your refiner.
One way to determine if a refiner meets these criteria is to check its use of appropriate pollution abatement technology such as afterburners, baghouses, wet scrubbers, and liquid effluent neutralizing equipment. Also, evaluate the refiner’s approval status with all applicable agencies at local, state, and federal levels. Most precious metal refiners will be pleased to provide copies of required documentation which could include permits under the Clean Air and Water Acts and prove that the company qualifies as a bona fide precious metals refiner as specified in the preamble to the Boiler and Industrial Furnace (BIF) Rule and its amendments
Due diligence with regard to selecting a refiner will also likely pay off in a number of ways. First and foremost will be the value returned for the remaining precious metals in your spent catalysts. After all, that is why you’re involved in this process in the first place. How do you assure that you will get the most value for these metals? It’s your obligation to investigate the refiner’s reputation with regard to its environmental policies. For example, is the refiner in compliance with appropriate local, state, or federal environmental regulations? Is it financially sound, with the ability to promptly provide you the return value of your precious metals, whether in cash, credit, or new materials?
You’d also want to learn about the refiner’s customer base. Who and what kinds of organizations are they working for? Talk to existing customers about their own experiences with the refiner as well.
Methods used for recovering precious metals from various types of catalysts should also be discussed with the refiner. Many refiners use different sampling procedures, and some may not be ideally suited for the circumstances with regard to maximizing return values. Because sampling (particularly dry sampling) is considered an art as well as a science, there are applications where one sampling procedure should be used over another depending upon how the spent catalyst was employed.
Another consideration is the refiner’s use of outside services or independent contractors involved in the sampling process. Obviously this will add costs which must be passed on to you; perhaps more important, however, it will take time which will delay your return, and also introduces the possibility of your materials being combined with other customers’ materials. In-house processing is very important (especially for large lots), since extra costs are involved for packing and shipping. You also want to learn more about the refiner’s policies for settlement and assay exchanges; these will obviously have a direct impact on your returns, both from their value as well as the lead times involved.
Based on this information it is in your best interest to seek a precious metals refiner with complete in-house capabilities from beginning to end (preburning through returning new metal or cash on a timely basis). However, keep in mind that the keys to obtaining maximum value (recovering all possible remaining precious metals) from spent catalysts focus on the refiner’s meticulous attention to hundreds of details. These include the thoroughness and accuracy of the materials’ sampling process, with assaying of the sampled lots close behind. Whether you are seeking a new precious metals refiner for your spent catalyst material, 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 your refiner also adhere to the full compliance issues concerning environmental regulations. All else being equal, 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 right precious metals refiner for your organization. In any case, your relationship with the refiner must be viewed as a “partnership” and must be based upon mutual trust and fair treatment.
— By James A. Barrett
Sabin Metal Corp., East Hampton, NY