Copper's Nine Lives

Cerro Copper Products Co. transforms copper scrap into gleaming new tube products. Take a tour of its Illinois operation and find out how.

By Kristina Rundquist
Kristina Rundquist is an associate editor of Scrap.

Most people don’t spend much time thinking about the copper tubes in the plumbing, air conditioners, and refrigerators in their homes.

But the employees at Cerro Copper Products Co. (St. Louis) spend a lot of time thinking about just such things. They live and breathe them, in fact. And no wonder. The firm’s Sauget, Ill., refinery and extruding operation and its three sister facilities—in Shelbina and Mexico, Mo., and Bossier City, La.—expect to produce in excess of 300 million pounds of more than 350 types of tubing in the coming year.

That’s a lot of tube, enough to make Cerro the largest producer of copper-tube products in the world. And what are all these products made of? Copper, yes, but more specifically, a large part is copper scrap. And how does this scrap get transformed into gleaming new products? A visit to Cerro provides a glimpse of one of the many lives of copper.

In With the Old ...

 A copper tube begins its life in an office at Cerro’s 61-acre Sauget plant. It’s here, at the beginning of each month, that Bill Rickher, the firm’s vice president of raw materials, sits down with other managers and charts the raw material plan for the month. Together, they examine the plant’s operating schedule—projected downtimes and the like—to determine what scrap inventory they’ll need on hand. “We try to start planning our metal requirements one, two, and three months out,” says Rickher. “We have to consider our projected sales, inventories, metal due to be delivered, and production to determine whether we need more scrap or more cathode and how much of each we need.”

Cathode is the pure raw material used to make Cerro’s products. The firm produces its own cathode from No. 2 scrap. Cerro buys No. 1 and No. 2 copper scrap from a national network of scrap suppliers. The company prefers to buy direct from processors, as opposed to brokers, because of issues of quality.

 Every morning, the tangible results of Rickher’s purchases line up outside the Sauget plant’s gate. It’s not unusual, in fact, to find more than 50 trucks waiting each morning, poised to roll into one of the 11 truck bays at the facility’s covered receiving dock. A fleet of forklifts then begins the long process of unloading the 40,000 pounds or so of copper scrap from each truck. For every 25 trucks unloaded, a million pounds of scrap enters the plant.

While most scrap arrives loose or in bales, some is delivered in corrugated gaylord boxes, a practice Cerro discourages. These containers, once emptied, pose a disposal burden for the company, which helps explain why it charges a $5 disposal fee per box. 
After being delivered to the dock, all scrap is given an initial visual inspection by a grader and, if necessary, is sampled for chemical analysis. All quality problems are relayed to the purchasing office daily. If the load in question is boxed or baled, it’s set aside in the sampling room until one of the firm’s buyers can come down for disposition. However, should the load be loose, the buyer is immediately called to make a decision, which will keep the material from inadvertently becoming mixed in with other scrap shipments.

 All loose scrap, which is gathered in a collection pit near the truck docks, is transported by an overhead crane to the hopper of a “bricking,” or baling, machine capable of producing up to 900 bricks a day, each weighing roughly 3,500 pounds. These bricks are then stored with already-prepared scrap in a large concrete lot behind the receiving area. At this point, the grades of scrap diverge, with No. 1 material heading straight for the furnace for making logs and No. 2 bricks beginning a two-week cycle of electrolytic refining.

... Out With the New

The furnace dedicated to No. 1 scrap cranks out 470,000 pounds of molten copper 24 hours a day, seven days a week. Run on either gas or oil, the furnace blends a charge using between 200,000 and 300,000 pounds of No. 1 scrap each day.

The melting process begins when a layer—or “mattress”—of approximately 60,000 pounds of loose material is laid on the bottom of the furnace before the bricks are charged, explains Rickher. Once the charge is fully melted, a sample is taken to check the purity levels. 

When the bath reaches the proper temperature, blow pipes are inserted in the rear of the furnace and air is injected into the molten copper. As the air is introduced, all oxidizable elements are released into slag. 

The slag, which contains about 20 percent copper, is skimmed off and poured into vats to cool outside before being broken up and sold.

Even after the slag has been removed, the copper bath isn’t ready for pouring because it contains microscopic bubbles. To eliminate these bubbles, tree trunks—yes, tree trunks—are shoved into the furnace. As they are pushed under the bath, the combustion uses up the remaining air bubbles. “It’s how we deoxidize our bath,” Rickher notes.

After this deoxidation stage, the copper is poured at approximately 2,150oF into the water-cooled molds of one of two semi-continuous casters. Each caster can produce six logs that, when fully cooled, are sawed into billets about 251/2 inches long. A billet is a casting suitable for extrusion. Samples are taken every two feet, and each billet is stamped with the heat number.

Cerro’s copper billet casting operation in Mexico, Mo., is devoted solely to the production of such billets and is the most modern billet casting facility in the world, the company says. With two continuous-strand casting lines operating at all times, this plant supplies the Sauget, Shelbina, and Bossier City facilities with approximately 120 million pounds of billet a year, an amount that can easily be doubled, states Cerro. These billets are made only from full-plate cathode supplied primarily by the Sauget operation.

Creating Cathode

Cerro’s No. 2 scrap, meanwhile, takes an entirely different melting path, passing through the company’s anode furnace, a 100-percent-scrap-fed colossus that consumes 570,000 pounds of No. 2 copper scrap a day, six days a week. In contrast to the No. 1 scrap, which is cast into billets, No. 2 scrap is destined to become anode, the raw material used in cathode production.

As the molten metal exits the furnace, it fills a ladle that tips when its contents reach a predetermined weight, based on the desired thickness of the anode. A carousel of anode molds rotates slowly underneath the ladle’s mouth, stopping to allow each mold to be filled. As the carousel turns, the newly poured anodes begin to cool and pass through a chamber where water is sprayed from both the top and bottom to hasten the cooling process. When the metal has solidified sufficiently, a peg at the bottom of the mold begins to push the anode up and out of the form.

An air-operated donkey crane swiftly picks up each anode by protrusions called ears and places it in a rack submerged in a vat of water. When the rack’s 25 slots have been filled, a remote-operated crane lifts the rack from the bath and moves it to the final air-cooling area.

Meanwhile, empty anode carousel molds are sprayed with a mold wash, and the ejection pins are hammered down and sealed with mold wash to prevent molten metal from seeping around the pin. At this point, the molds are ready to be filled again.

Once anodes have completed the cooling process, they’re ready for the plating process, which transforms anode copper into cathode.

In the first step of the plating process, anodes are moved to the tankhouse, so-called because it contains cells of sulfuric acid solution into which the anodes are lowered. These cells are then charged with electricity. As current passes through the anode, copper leaches into the solution and plates onto a stainless steel plate, forming a thin copper foil that is peeled off and removed every 12 hours to produce a starter sheet. These sheets of pure copper are placed into other cells where they will continue the plating process to complete the transformation into cathode.

Wait two weeks, and a 99.96-percent-pure copper cathode is born.

Cerro consumes most of the cathode it produces, sending much of the metal to its Mexico, Mo., plant to be cast into billets. Depending on markets and metal requirements, Cerro sometimes sells the remainder of its cathode on commodity exchanges.

Ruby’s Red Billets

Cerro is well-known for being the world’s biggest producer of copper tube, one of the largest copper scrap consumers in the country, and the only fully integrated U.S. copper tube producer, meaning that it has both refining and extruding operations under one roof.

But more than this, even, the company is known for Ruby, a 5,700-ton, high-ratio extrusion press that is capable of extruding in excess of 1,000 billets every day. So well-known and admired is this press that most Japanese copper tube producers have copied it, Cerro says.

Ruby is the machine that takes billets and begins the process of turning them into Cerro’s finished tube products.  Before entering Ruby, billets are heated to more than 1,000°F and then passed along a series of rollers and mini-grapples. Each glowing-orange billet is then pushed inside the press between a die and stem. Then a long lance-like tool called a mandrel pierces the billet, creating a cavity inside the malleable metal and forcing it to within 1/10 of an inch of the die.

The rest of the extrusion process (a Cerro innovation) is all wet—that is, the metal goes under water. At this point, the log-shaped billet is now a long hollow shell with both ends plugged. This initial extrusion will be anywhere between 180 and 220 feet in length, depending on the initial size of the billet and the desired thickness of the shell. After the ends are cut off, the shells pass through bull blocks that reduce the tube’s diameter and wall thickness even further.

While the product looks finished at this point, the coils still must go through several stages. During annealing, for instance, the tube is exposed to an inert gas, which changes the grain structure of the metal. In this regard, Cerro is planning to add a new $7-million annealing furnace to its Shelbina plant. This state-of-the art furnace will eliminate even minute amounts of contaminants through a patented, continuous purging system that removes all gases, lubricants, and oxidants from the tube’s interior, according to Cerro.

From the annealing stage, the coils are loaded, boxed, and shrink-wrapped. If the tube is to be shipped as coil, it heads straight to the shipping and storage area, where it waits to be sent by truck to its final destination.

Coils for straight-line tube production, on the other hand, bypass the annealing process and instead pass into a machine that straightens the tube and cuts it to the desired length. The tubes are then bundled and sent to the storage warehouse. Cerro can store up to 5 million pounds of straight-length tubing in its nearly 3-acre warehouse. 

Both coiled and straight tube are warehoused until their time comes to be shipped out to a plumbing wholesaler and, from there, perhaps even straight to your kitchen sink.

And so begins a new life for the copper tube.

The Cerro Chronicles

 Cerro’s corporate roots extend back to the early 1900s when L.J. Cohen established a metal recycling firm—L.J. Cohen Co.—in Kansas City, Mo., eventually moving the operation to St. Louis. When Cohen died in 1918, his partner, William Lewin, took over and changed both the company’s name and its focus.

With his brother Tannie, Lewin ventured into the brass ingot smelting business. Soon thereafter, Lewin Metals, as it was called, began experimenting with electrolysis, the process used to produce purer grades of copper. The brothers set up a pilot plant, secured a patent for their process, and in 1927 built a full-scale electrolytic refinery in Sauget, Ill. Four years later, the firm merged with G. Mathes Co., another metals dealer, and became Lewin-Mathes Co.

As the 1930s dawned, copper began to replace iron as the pipe of choice in home-building. In response, Lewin-Mathes constructed its first copper tube mill in 1939. Demand for copper tube accelerated after World War II, thanks to the subsequent housing boom, as well as the growing use of refrigerators and air conditioners.

In 1957, the company was sold to Cerro de Pasco Corp., which owned mines in Peru, and in 1975 became a member of the Marmon Group (Chicago), an international conglomerate of more than 60 autonomously operated companies.

In 1981, the company expanded by opening a production plant in Shelbina, Mo., under the name Cerro Copper Tube Co. In 1996, this sister company acquired the Bossier City, La., copper tube mill of Heatcraft Inc. (Grenada, Miss.). And that same year, Cerro opened a copper billet mill in Mexico, Mo., under the name Cerro Copper Casting Co. •