State Line Shows Significant Progress on Environmental Front

How can a business ensure its green efforts are paying off?  State Line Foundries has a few measuring sticks.

One is sand. “We reclaim and/or reuse about 50,000 tons of sand per year,” states Jesse Milks, president of State Line Foundries.

Another is iron. Castings that previously required 1,000 pounds of new material now need a mere 400 pounds.

Speaking of numbers, it has been more than 365 days without time lost due to an accident, showcasing State Line’s commitment to the safety component of sustainability.

Those are big wins, to be sure. Here is a closer look at State Line’s environmentally friendly advances.

Sand recycling

The green efforts start with transporting silica sand to State Line’s two foundries. The sand is purchased as close to the foundries as possible, limiting the resources used – and emissions created – during transport.

There are two methods of sand molding used: No-bake molding and green-sand molding.

With the no-bake process, the sand is mixed with a liquid resin and catalyst that bond the sand grains together.  When the casting is complete, clumps of sand remain.

“We have to break the big chunks into smaller grain sizes,” Milks says. “If we couldn’t do this, the sand would end up in a landfill.”

Steps are taken to prevent that. First, State Line loads the used no-bake sand into a device that goes by a few names – lump breaker, shaker or attrition mill.

“The shaker vibrates and the grains hit each other and break down,” says Grant Wightman, plant manager for Winnebago Foundry. “It breaks the sand down to a regular grain size from a big, condensed shape.”

The broken-down, no-bake sand is deposited in a giant storage bin and later thermally reclaimed and stripped of its residual resin, Wightman explains. About 90 percent of the no-bake sand is reused.

Used green sand is kept separate from its no-bake counterpart. About 95 percent of green sand is recycled. “It just needs to be refreshed by adding clay and water,” Wightman clarifies.

The volume of materials saved is impressive. When creating green-sand molds, only about 5 percent of the sand is new. With no-bake molds, only about 10 percent.

The savings add up quickly. “We went from getting six to eight truckloads of sand per week to two,” Wightman offers. That means natural resources are preserved – and pressure on landfills reduced.

Despite these processes, the foundries generate waste sand. “You can only use grains for so long before they break down to unusable, fine material,” Milks states.

But even the fine material is repurposed. “The waste sand is hauled away and used for beneficial reuse projects, such as fill material for abandoned quarries,” Milks details.

State Lines’ recycling efforts have come a long ways in a few years, in great part due to investing in new equipment. “Right now, the mix when making new molds is 90 percent old sand and 10 percent new,” Milks asserts. “Five years ago, it was about 50-50.”

Iron recycling

Metallic recycling has increased greatly in recent years. The efforts start with scrap materials created during the casting process.

“When we pour iron into the mold, there are iron gates and risers and runners, which you don’t sell to customers,” Milks says. “We cut those off and melt them and re-use them in the next batch. We’re doing that over and over every day.”

There is a small amount of iron left behind in the ladle after the pouring is complete. It is emptied into a mold that is designed for easy dumping and then reused.

Like the sand, the iron recycling results in eye-popping preservation. “We can produce a thousand-pound pour with only 400 pounds of new material,” Wightman declares.  

State Line further advances sustainability by bringing in scrap steel from outside sources. That includes steel punchings from auto OEMs, sectioned railroad rails and copper wire chops. “We’re taking someone else’s waste and reusing it,” Milks explains.

Energy conservation

Energy consumption has been reduced through the purchase of new equipment, including air compressors, overhead cranes, furnaces, and LED lighting. “They’re the latest and the greatest and the most efficient,” Milks asserts.

The foundry also found a more efficient process regarding furnace linings.

“The linings are made of a ceramic material, which only lasts so long,” Milks emphasizes. State Line began purchasing higher-end linings that last nearly twice as long. That cuts the required ceramic material, and subsequent waste, in half.

Because furnaces must be heated to affix the new linings, the longer replacement schedule also cuts that energy consumption and emissions in half.

Water. State Line uses a closed-loop system to keep furnace coils cooled, drastically reducing the volume of water needed.

Safety. “Safety is always top of mind, whether talking about protective equipment or the operation itself,” Milks avows. 

Recent safety efforts include investing in a new crane system that eliminates loading furnaces by hand. Additional guarding and railings have also been installed.

“Last year, there were no lost-time accidents at either foundry,” Milks states – a statistic he’s clearly very proud of.

Proud of products and processes

The results add up, whether talking about tons of sand or steel saved, or days without time lost to an accident.

“The efforts make a big difference when you look at the numbers,” Milks affirms. “We’re proud of the castings we produce. We’ll stack our products against anyone.”

But it’s more than that. “We’re proud of the way we do it, too,” he concludes.