RECYCLING TODAY’S PLASTICS RECYCLING CONFERENCE: Sorting Technology Update

A pre-conference workshop at Recycling Today’s Plastics Recycling Conference & Trade Show in late June addressed advances in optical sorting technology for separating and sorting plastics.

Workshop panelists included Scott Jable of Lubo USA, Stamford, Conn.; Felix Hottensein of MSS Inc., Nashville, Tenn.; and Patrick Nicol of Machinex, Plessisville, Quebec.

Nicol began the session by pointing out that the number of landfills in the United States decreased from 6,000 in 1990 to fewer than 2,000 today, illustrating the growing importance of recycling. And as more curbside programs move to single-stream collection models, material recovery facilities are moving toward the automated separation of materials using optical sorting technology as well as magnets and eddy currents.

Machinex distributes the Pellenc line of optical sorting equipment, which uses infrared detection and air nozzles to sort and separate material. According to Nicol, users can teach their Pellenc equipment the type of sorts they’d like it to perform and easily modify sorts by grade and color. Additionally, optical sorting equipment also is affected by weather conditions and temperature, so it is important for the user to be able to adjust the equipment easily in response to those conditions, Nicol said.

Nicol noted that optical sorting equipment doesn’t completely eliminate the need for hand sorting, but it does drastically reduce it and restrict it to a quality control function.

Hottenstein has been working with optical sorting technology for the last 11 years, and MSS has installed 165 bottle sorting lines since 1991.

Among the advantages of optical sorting are increased throughput, a reduction in processing lines and floor space, improved accuracy and flexibility, he said.        

Like Nicol, Hottenstein said that optical sorting equipment does not reduce the number of hand sorters required as much as it increases an operation’s throughput.

According to Hottenstein, MSS optical sorting equipment provides readouts that can help facilities rate their vendors, do quality control reports or adjust the plant to improve performance.

Hottenstein said the recycling industry could benefit from copying the concepts of the manufacturing industry by focusing on manufacturing a product as opposed to handling garbage.

On the electronics recycling front, MSS will be installing a system beginning in September that sorts plastics from electronics, including PS, HIPS, ABS, PC and POM materials, as well as circuit boards and metal. However, Hottenstein said that while bigger pieces are often easier to ID using optical sorting, when dealing with electronics, these pieces tend to be inter-connected, which prevents good separation. When particles get down to ¼-inches in size, separation is easier, but it is harder to accurately ID the materials, he added.

He closed by saying that black plastics currently present a challenge for optical sorting equipment. While the equipment can identify them by type, it tends to be a “very slow process,” Hottenstein said.

Lubo USA’s Jable began his presentation by announcing that Lubo had acquired ComoDas, a European manufacturer of sorting equipment, which joins the Ti-Tech line the company already distributes.

Like the other presenters, Jable pointed out the advantages of adding optical sorting equipment to a facility. Optical sorting lines take up less space than manual sorting lines and can also be stacked vertically, further maximizing space. Additionally, the equipment can be trained to recognize new materials and can easily be reprogrammed, he said.

According to Jable, the optical sorting equipment that Lubo USA offers can sort up to 10 tons per hour down to a particle size of 10 mm with 95 percent accuracy.

Recycling Today’s Plastics Recycling Conference & Trade Show was June 25-27 at the Hyatt Regency O’Hare in suburban Chicago.