The Midas Touch

Tour two plants of the Handy & Harman Refining Group Inc. and learn how it recovers precious metals from a variety of low- and high-grade scrap.

By Kristina Rundquist

Kristina Rundquist is an associate editor of Scrap.

If you have gold jewelry, chances are you think it was made from newly mined gold. But seeing as how 97 percent of all gold ever mined is still in use today, it could be made from recycled gold—perhaps from old jewelry, a contact point on an electronic circuit board, even an old dental filling.

Such is the life of gold and other precious metals such as silver and platinum-group metals—their monetary value virtually ensures their recycling.

Given the allure of precious metals, you’d think there’d be hundreds of companies recycling them. The truth is that precious metal refiners are few and far between for the simple reason that recycling precious metals is no easy feat. It’s a highly technical, precise art that requires experience in how to extract the most metal from a variety of scrap.

Among the few and the proud is the Handy & Harman Refining Group Inc. (HHRG), the largest precious metal refiner in North America, with its headquarters operation in South Windsor, Conn., and additional refining operations in Attleboro, Mass., Phoenix, and Villa Park, Ill.

HHRG traces its roots to Handy & Harman (New York City), which entered the metals business in 1867 as bullion traders. Around the turn of the century, the company expanded to include fabrication and refinery services—and thus began the Handy & Harman Refining Group.

In 1996, Handy & Harman sold HHRG to Golden West Refining Corp. Ltd. (Perth, Australia), an international precious metal refiner and fabricator with sites in Canada, Papua New Guinea, and Australia. The change couldn’t have been better for HHRG. “Not only are we global now, but this association has enabled us to expand our refining expertise even further,” says Brian Gates, vice president of refinery operations. “Now we’re with a company whose sole purpose is the refining of precious metals.”

 That purpose defines all of HHRG’s activities, as this tour of its South Windsor and Attleboro operations shows.

A Feeling of Security

The first thing you notice when visiting HHRG’s facilities is that the security is, shall we say, tight—which makes sense. When you’re dealing with precious metals worth millions of dollars, you can’t be too cautious.

It’s not unusual for incoming material to arrive in armored cars. Once inside South Windsor’s 170,000-square-foot facility, this precious cargo is met by several HHRG employees, each of whom has undergone a thorough background check. Nearby, a member of the company’s security team watches, as do surveillance cameras located both inside and outside the building. Anyone leaving the refining area is subject to metal detection so rigorous even their shoes must pass through an X-ray machine. As Matt Fischer, South Windsor plant manager, says, “we made a commitment that every plant will have the same level of security even though the levels of exposure to theft vary. The security protects our customers’ assets and ours.”

All four of the company’s facilities are reminded repeatedly that the material they handle doesn’t belong to HHRG. In fact, explains Fischer, 90 percent of the time the material is in the South Windsor facility, it remains the customer’s property. Not until sampling has been completed does HHRG purchase it. As such, Gates states, HHRG has “zero tolerance for errors. It’s not like we can mess up with one customer in 10 or even a 100 because if we do, we’ll never see that company again.”

Success Through Sampling

HHRG’s South Windsor and Attleboro plants have clearly defined and distinct, yet complementary, roles. The South Windsor plant is a sampling operation. It takes in material, processes it into a homogeneous product—usually fine powder or copper-based bullion bars—samples it, assays the sample to determine its precious-metal content, then settles with the customer. The Attleboro facility, on the other hand, is a refining operation, taking precious-metal-bearing material from South Windsor as well as other customers and refining it to 99.99-percent-pure metal.

Electronic scrap represents the bulk of precious-metal bearing material that arrives at the 28-acre South Windsor site for sampling. Some companies even send in complete computers, monitors, and hard drives that must be disassembled by hand.

The remaining material is broken down fairly evenly among industrial scrap such as polishing rags, jewelry sweeps, photographic material, spent solutions, baghouse dust containing trace amounts of precious metals, wooden floors from plating shops, and even syringes containing silver. “We’ll take anything that contains precious metal unless it has asbestos, radioactive waste, or free-flowing mercury,” Fischer says.

Many of these items have precious little precious-metal content. “It’s like a toothpaste tube in that you can never get the last bit out, so the customer sends it here because they still want that last bit,” he notes.

Upon arrival, materials must first be weighed. The weight must come within 2 percent of the customer’s reported weight, otherwise HHRG will place the material on hold. A piece count is also done to verify the client’s count.

If HHRG accepts the shipment, it’s assigned a lot number and bar code that describes the material and follows the load through every step of the sampling process. The bar coding, Fischer says, has the double advantage of not only indicating a lot’s location in the system at any given time, but also how long it stays at each stage, allowing HHRG to analyze the total duration and cost of the job.

Since different materials require different processing and sampling treatment, experienced employees must decide which approach is needed. Once that decision has been made, the material is stored in front of the chosen operation, explains Fischer. Materials are stored in their original shipping containers and any hazardous waste stickers are left on until the drum is empty, at which time the drum is triple-rinsed before being crushed and sold as steel scrap.

For most material, the first stop is one of five thermal-reduction units. Unlike incinerators, these units create little turbulence throughout their burning cycle, allowing the metals to settle into the ash. Once the ash has been cooled, it’s sent to ball mills for crushing. The material is poured into a rotating steel cylinder containing steel balls. As the cylinder turns, the tumbling balls crush material such as fiberglass ash and ceramics into a fine dust, leaving behind uncrushables such as aluminum caps, wire, and anything that’s solid metal.

From the ball mills, the dust is passed over a 40-mesh screen. Whatever passes through is ready for further processing, while oversized material is returned to the ball mills. The powder then enters a blender, where it becomes a homogeneous mixture. This is critical to providing an accurate sample of the material’s precious- metal content. As Fischer explains, “accurate sampling is critical to our business. We must take a sample that’s representative of the customer’s lot.” After being blended, the material is poured into drums from which a sample is taken. Each drum is sampled, the samples combined, then sent to Attleboro’s assay lab for testing.

Meanwhile, the metal that couldn’t be crushed in the ball mills is sent to the melt area where copper is added to the mix. Copper, Fischer notes, acts much like soap will in a bucket of oil and water. Silver and gold won’t mix with steel and nickel, two elements contained in electronic scrap, and for this reason copper is added to dilute the effect of the steel and allow the precious metals to become homogeneous.

Now, the unmillable metal-copper mixture is poured into one of 10 electric-induction furnaces of varying sizes. Upon melting, the slag is skimmed off, and a sample of the molten metal is taken, with the remaining metal being poured into ingot molds. From the sample, a mini-ingot—about the size of a postage stamp and 1/8-inch thick—is made and sent to Attleboro to be cut in half and polished. If stratification appears, the melt was not homogeneous and the ingots must be remelted.

Once the results from Attleboro’s assay lab are known, HHRG’s salespeople can calculate the total percentage of precious metal in a given lot and calculate the payment to the customer. Not until this point does HHRG own the material. “The metal percentages are downloaded to South Windsor,” explains Joe Peixoto, Attleboro plant manager, “and if the customer agrees to the price, the material is no longer his. From that point on it loses the lot number and will get refined as we see best.”

The South Windsor plant ships high-grade material to the Attleboro site for refining. Low-grade material is sent to any one of five international copper smelters. In the production of copper cathode, the precious metals settle into a sludge at the bottom of the plating tanks. This sludge is then chemically refined to recover the precious metals.

Depending on the material, the size of the lot, and HHRG’s capacity at the time, electronic scrap can pass through the facility in four to six weeks, including assaying time and settlement with the customer. Some jobs HHRG will complete in two weeks. “Turnaround time is important for our customers,” says Gates. “It’s a competitive issue, and we work on improving our turnaround time.”

The Art of Refining

In addition to what HHRG’s South Windsor and Phoenix plants send for refining, the 90,000-square-foot Attleboro refining facility also receives material from outside clients. Much of it comes from businesses that use precious metals, while some comes from mines in the form of doré that’s been mined and preprocessed so it’s 90 percent precious metals containing silver and/or gold. Spent plating baths and gold-plated contacts from the electronics industry also make their way here. No matter what the material, it’s met at the loading dock with the same degree of security as one finds in South Windsor or any other HHRG plant.

Depending on the product, says Peixoto, incoming material will either be stored in one of four vaults (Peixoto and the plant’s 100 employees like to think of the entire facility as a vault) or go straight into processing. Either way, a stop is made in the metal control room for weighing and assigning of a lot number.

Material ready for processing is divided into two groups based on whether it’s primarily gold- or silver-bearing. Ingots and coins are melted for sampling, whereas anything electronic or in an acid or cyanide solution is sent to the chemical refining department.

Gold-plated material is run through an automated stripping line. Placed into baskets, the material is passed through a series of four tanks in approximately four minutes: two strip tanks and then two clear-water rinses to remove residual solution. The metal-rich solution then spends 24 hours running through plate-out units that collect the remaining precious metal before being sent to the melting area. While this occurs, the barren solution is passed through a filter press, where the sludge is removed and then sent to South Windsor for drying, incineration, and eventual destruction. Everything within the HHRG family, it seems, is a closed-loop process.

Products arriving in acid solutions take a different route and first enter Attleboro’s hydrometallurgical plant, says Peixoto, explaining that this material is loaded in the morning into tanks filled with sulfuric acid to leach out the base metals. The precious metal-bearing powder is filtered and dried before entering the refining process. Meanwhile, the copper solution is pumped into the tanks to be precipitated out with sodium hydroxide. The resulting copper sludge, explains Peixoto, is a wet oxide powder that is shipped to smelters, while the remaining water from this tank is passed through a sand filter and then an activated carbon filter to remove any remaining odor and color. From there it travels through two ion-exchange columns to remove any base metals. 

“The water quality at this point is purer than our city water,” says Peixoto.

Eventually all material ends up in the melt area, where the metal-coated cathodes and metal-bearing sludge are melted in induction furnaces. As the metal melts, it turns into a homogeneous mix from which a sample is taken and cooled before being sent to the assay lab.

Now the actual refining process begins. In the case of low-grade silver sweeps and 20-to-50-percent-silver powders, the material is measured into a gas-powered rotating furnace to which a fluxing compound is added to absorb impurities. The material will reach 2,200oF, at which point the impurity-laden slag is skimmed off and cooled. Because trace amounts of silver remain, the slag will be sent to South Windsor for crushing before heading to a smelter. What’s left in the furnace is poured into ingots of 80-percent-pure silver.

When the time comes, these ingots are placed in a reverberatory furnace capable of holding six tons of metal. The furnace is filled in the afternoon and heated overnight to 2,100oF. Impurities such as copper, zinc, and nickel float to the top as oxides and are skimmed off in the morning to be crushed and milled into a fine powder and re-enter the system at the hydrometallurgical plant (where impurities will be leached out and the silver returned to the refining process). Now, 99-percent-pure silver remains in the furnace and high-grade anodes are poured.

These anodes then enter what HHRG says is the world’s largest electrolytic refining center to be plated onto a stainless steel cathode in a solution of silver nitrate. The silver forms crystalline layers on each cathode, which are scraped off and sent through several rinses. From the cell room, the silver heads to the steam table for drying before being packaged into steel drums to await shipping or before being melted and poured into ingots.

Gold takes a slightly different path through the refining process. Anything that arrives at the Attleboro plant containing 5 percent or more gold heads straight for the gold refinery. High-grade gold is sent immediately to the aqua regia dissolving area, where the gold is dissolved in a hydrochloric and nitric acid solution, then precipitated out. The gold precipitate is then washed, melted, and cast into fine gold ingot. Lower-grade materials are sent to the induction furnace to undergo the Miller chlorination process. Here, metal is melted and a chlorine gas is injected into the furnace, forcing any silver or base metals to the top as salts. The salt is then skimmed and cooled and sent back to the system for eventual refining. Gold bars are continually fed into the furnace until it is brimming with 98-percent-pure gold.

At this point, the gold is poured into anodes and then plated onto cathodes. During this process, the gold forms the equivalent of a 99.995-percent-pure gold sponge on the cathodes over a period of two days. These sponges are then melted and poured into 400-troy-ounce ingots, or more likely cast into water to create fine gold BBs, which jewelers tend to prefer because they can be purchased in small lots.

A Gold Medal for Mettle

While HHRG may make precious metal recycling look easy, what goes on behind the scenes is considerably more complicated. Because any byproduct emerging from HHRG contains some precious metals, everything in the plant is a closed-loop process. As Fischer explains, “No waste products come out of here other than office, sanitary, and cafeteria waste, much of which is recycled. But old uniforms, gloves, floor sweeps—anything that’s in the plant—get burned and sampled and sent to a smelter. When you’re dealing with precious metals, you can’t afford to throw anything out.” That goes for pollutants too, he says, adding, “we have not only an environmental interest but an economic reason to keep them inside the plant.”

For these reasons, the South Windsor plant was built with the environment in mind, says Fischer. “There’s no water effluent and no solid waste effluent. What does come out is an internationally traded commodity.” When South Windsor installed its state-of-the-art environmental control program, the Connecticut Department of Environmental Protection (DEP) said it had 125 percent of what was needed by law. But as Gates explains, “our philosophy is that we want to be as open as possible about our environmental affairs. We don’t want to be perceived as hiding anything from the environmental community.”

So impressive is the company’s environmental safety record that the DEP is sending clients over on recommendations. “When the DEP recommends you, you feel pretty good about your system,” acknowledges Gates.

Employee safety is another concern, and HHRG takes it as seriously as it does the quality of its product. Says Peixoto, “all employees receive an initial safety orientation, and we provide all their personal protective equipment. Our ongoing safety program includes monthly employee meetings as well as monthly safety committee meetings.” Safety courses are also given on specific topics. For example, the company provides training on bloodborne pathogens, lead and cadmium exposure, ergonomics, and hearing conservation. It also offers a range of hazardous materials and machine operation seminars.

In addition, the company has a full-time safety engineer on staff who deals with its safety and environmental concerns and participates in OSHA’s voluntary compliance program. “Not every company likes to do it,” admits Peixoto, “but we feel we’ve been very successful because of it.” The Attleboro plant, he notes, hasn’t had a lost-time accident in six months, while the South Windsor facility has gone a year.

As far as quality control goes, HHRG has no choice but to deliver a Grade A product. That being the case, every lot is sampled. Machinery is cleaned after every lot, and supervisors keep tabs on what enters and leaves their areas. To minimize costs, smaller samples are taken of low-grade materials, says Fischer. “We found that a lot of times the customer would have material that was worth less than the cost of processing it, so to avoid missing out on that market, we decided to take a 10-percent sample and run it through the entire process. It’s a tenth of the cost, and the material can then go to the smelter as is.”

Clearly, safety and quality are hallmarks of HHRG, but equally important is its philosophy of treating customers fairly and with respect. “At the core of this business,” says Gates, “is partnering with the customer and accommodating them the best way we can. That’s how we get and maintain our business.” And that’s what will help ensure that HHRG retains its Midas touch in the future. •