Through its use of a catalyst in a patented process, a Canadian company is recycling PE and PP into a variety of industrial waxes.
The technology employed by Brantford, Ontario-based GreenMantra Technologies could provide a valuable market for plastics that are hard to mechanically recycle.
“This is now a potential technology that can get [plastics] out of the re-introduction into the PE space and now into a specialty chemical market, which has much better margins,” said Ryan L’Abbe, vice president of operations at GreenMantra Technologies.
For example, he said a plastics processor might buy a bale for 25 cents to 30 cents per pound and sell pellets to a plastic-products manufacturer in the 40- to 45-cents-per-pound range. But GreenMantra is selling into a wax market with prices in the $1- to $1.05-per-pound range, said L’Abbe, former general manager of the Blue Mountain Plastics Division of Ice River Springs bottled water. Of course, even with higher selling prices for wax, the GreenMantra technology will have to be cost-efficient if the company wants to see significant profit margins.
The waxes can be used in coating, plastics, adhesives, asphalt roofing, paving and inks. The technology can also be used to create greases, lubricants and other specialty chemicals.
The company is now working to expand its technology and production capabilities, aiming to create an outlet for difficult-to-recycle polyolefin plastics.
Part secret, part patented technology
First developed at the Indian Institute of Technology in Kanpur, India, the GreenMantra technology uses a thermocatalytic process, which combines heat, pressure and a proprietary catalyst, to depolymerize post-consumer plastics to create synthetic waxes, said Domenic di Mondo, the company’s technical director. The catalysts used by the company are trade secrets. The process received U.S. patent approval in March 2014.
Depending on the type of wax to be produced, the recycling process can take as little as 10 minutes and as long as two hours, although most waxes made by the company take anywhere from 10 to 60 minutes, he said. The company is also getting close to achieving a 100 percent recycling efficiency, without residuals.
“We’re able to achieve a very efficient conversion to wax,” he said.
GreenMantra can fine-tune the properties of the final wax product, including the melting points, viscosities and crystallinity, di Mondo said. Such steps allow for a customized end product.
For example, L’Abbe said, GreenMantra provided a customer with “drop in” waxes with profiles similar to those they were already buying from existing suppliers. GreenMantra was then able to modify the waxes so the customer could create a better product.
The process also uses a heterogenous catalyst that will not dissolve into the polymer, eliminating any worries about leaching later on, he said. Currently able to recycle HDPE, LDPE and PP plastics, the company is researching recycling other polymers.
Expanding production
GreenMantra, founded in 2010, recently announced the completion of a production plant in Brantford, Ontario, where its pilot plant and research-and-development facility are located.
Using funds from private equity investors and provincial and federal grants, GreenMantra added two new semi-continuous batch lines with a total capacity of 5,000 metric tons per year, adding to the 750-metric-tons-per-year capacity of the existing pilot plant, L’Abbe said. The plants are working on four-day, 24-hour schedules.
“The unique configuration of our manufacturing plant is a prototype for future plants using our proprietary technology,” Kousay Said, president and CEO, stated in a press release. “The small size and modular design will enable us to locate similarly designed plants alongside feedstock suppliers such as plastics recyclers, or within the operations of large wax customers.”
The company has developed a pilot project testing a continuous batch process it is hoping to commercialize in a year, di Mondo said.
Finding feedstocks
GreenMantra isn’t like plastics-to-oil technologies, which traditionally recycle mixed plastics into a variety of fuel products, L’Abbe said.
“We selectively pick the feedstock, we selectively pick the profile for depolymerization, and that results in a very significant improvement in yield,” he said.
GreenMantra doesn’t require the same degree of feedstock cleanliness other plastics reclaimers may need, he said. Color doesn’t usually matter, because the waxes are going into applications such as asphalt roofing and paving, and the company can easily filter out charred organic contaminants. But the process does require a single resin in a stream.
GreenMantra purchases all of its feedstock. Because it doesn’t yet have a wash line, it’s buying pellets on an ongoing basis from half a dozen to a dozen North American plastics processors.
“Our business model is buying recycled plastics at competitive, current pricing for our feedstock,” L’Abbe said.
In the future, the company plans to cut out a middleman by purchasing bales directly from MRFs and sorting the plastics itself, further improving the economics, he said.
