When demand is high for metal, injecting efficiencies into metal scrap recycling processes can create a definitive financial reward for metal scrap recyclers and machine shops alike. One pathway to realizing that reward? Briquetting metal scrap.
How Briquetters Work
Briquetting machines compress metal chips, loose turnings, and swarf to create compact, dense, uniform pucks that decrease metal scrap volume and increase metal scrap value. While puck density will vary from briquetter to briquetter, an average aluminum puck is about 10 times more dense than loose chips.
The machines are engineered to modify a variety of metal scrap including ferrous metals such as steel and cast iron and nonferrous metals such as aluminum, magnesium, brass and copper.
During compression, cutting fluids are squeezed out of the metal scrap to produce an almost completely dry, solid briquette. The machines are designed to capture the fluids in a reclamation tank and once recovered, the oil or water-based coolant can be recycled and reused.
In some instances, metal scrap may require preconditioning prior to briquetting to create a flowable stream of material. This is usually accomplished by a crusher or shredder. Some machines use a single ram to compress the metal scrap – more advanced machines use two in order to compress the material from both ends.
A word of caution about briquetter hydraulics: avoid running them at or near their failure point. Although the machine’s hydraulic system may be rated for 5,000 psi, operating the machine at maximum psi can strain the equipment, which could result in extended downtime, increased maintenance costs, and decreased equipment service life.
Creating Value at the Scrap Yard
Briquetters can benefit recycling operations in several ways.
Unlike loose metal scrap, pucks optimize container fill, which significantly reduces the space needed to store metal scrap. It is not unreasonable to expect that two drums of turnings briquetted into pucks would only fill half of a single drum after compression. Because they can be up to 99 percent dry, the need to utilize drying racks or centrifugal dryers is typically not necessary. Also, once briquetted, the potential for metal scrap pucks to cross-contaminate with other materials is greatly reduced.
Dry, compact pucks also melt more efficiently than loose, wet metal scrap. While loose chips and turnings can retain 10 percent to 15 percent of residual cutting fluids, moisture in briquettes can be reduced to an estimated 1 percent to 5 percent depending on the machine and metal. Pucks lend themselves to a more consistent feed rate and they sink into the molten metal. As a result, the burn-off loss is reduced and the melting process is more consistent. This contributes to lower energy consumption and melt times.
The ability to create dry, uniform pucks can also lower expenses. If the recycling facility outsources melting, purification, and solidification to a third party, transportation costs will typically be lower than the costs to haul loose chips, turnings, and swarf because a higher volume of metal scrap can be hauled in a single trip. Heavy-duty vehicle fleets still primarily rely on fossil fuels, therefore fewer trips may even translate to a lower carbon footprint.
Briquetting metal scrap can also create a resale advantage. Because the pucks are compact and easy to store, the recycling facility can potentially store more briquettes on-site than loose material. This may empower recyclers to sell or process the material when it is most advantageous for them – for instance, when specific metals command higher prices.
Creating Value for Metal Recycling Customers
Many machining businesses still use a centrifuge/wringer to spin cutting fluid from metal machining scrap because the primary objective is to reclaim the fluid to lower fluid replacement costs. However, as the circular economy grows, demand for metal increases, and transportation costs rise, recyclers who collaborate with metalworking operations to pursue more advanced metal scrap modification at the source will afford several benefits to both parties.
First and foremost, fabricators and manufacturers who supply pucks to recyclers reap more value from metal scrap – up to 25 percent higher. Briquettes are more efficient than loose chips in most re-melt applications. Finally, the significant reduction in the volume of metal scrap will fill fewer containers with high-density metal scrap, resulting in lower haul-away costs.
Efficiently processing metals and an ability to quickly respond to market conditions is vital for recyclers to maximize margins. Partnering with a metalworking customer to install a briquetter at the machining facility can essentially outsource the initial processing that would otherwise need to take place at the scrap yard. In turn, this can give the recycler increased processing capacity and the fluid that is a waste stream at the scrapyard can be recycled and reused at the source. Initiatives such as these not only enrich the value chain, they can also spread costs and benefits across multiple parties, driving mutual success for both metalworking businesses and recyclers.
About the Author
Mike Hook is the sales and marketing director for PRAB and has over 15 years of mechanical design and application experience. PRAB is a supplier of engineered conveyors, equipment for processing stamping scrap, turnings, chips and spent metalworking fluids, as well as wastewater treatment solutions.
Published in the July 2022 Edition