Tire Recycling Basics

The United States generates approximately 300 million scrap tires per year. Through government interaction and entrepreneurial initiative, tire recycling has become a big business. From TDF (tire-derived fuel) to playground cover to landscaping mulch to asphalt additives, the uses for recycled tires are growing.


Points to Consider
Developing a business plan for recycling tires involves many aspects that can easily be overlooked, such as:

• The number of tires you can gain access to within a 200-mile radius;
• The type of tires you can access—passenger tires, light truck tires or both;
• The amount you can charge to collect the tires;
• Finding customers who will purchase the shredded tires; and
• The ultimate end market use—TDF, landscaping material, playground cover or engineering grade powders.

It is my experience that you need to have access to about 500,000 tires per year to begin working on a successful business model. Anything less than this will not justify the initial capital investment required.

The next thing you need is a customer (preferably a large group of customers) that will purchase the ground rubber from you. The price you can get for ground rubber is a simple, relatively linear formula. The finer you grind the tires, the more money you can sell the material for. However, the finer you grind the tires, the more equipment you will require. You cannot, for example, make chips or crumb (1/4-inch minus down to 200 mesh) with a single shredder. In fact, getting down to 30 or 40 mesh typically involves as many as four steps in the shredding process.


Processing Pointers
Below, I provide a general overview on the process used to make TDF, wire-free chip and crumb rubber as small as 1/4 inch in size.


Step 1 — The Primary Shredder. As of today, approximately 50 percent of recycled tires are used as  TDF. TDF is defined as a 2-inch-by-2-inch (sometimes even a 1-inch-by-1-inch) particle that still contains the steel wire. You can make TDF with a single shredder, called a “primary shredder,” a vibratory screener and some conveyors.

Primary shredders to handle passenger tires start at about $130,000 to $150,000. If you want to handle passenger tires and truck tires (but not OTR, or off-the-road, tires), then you can plan on spending roughly $300,000 for the primary shredder.

You should plan to spend $200,000 to $250,000 for the vibratory screener and conveyors required for your TDF production system.

Whole tires are loaded onto a roller belt conveyor that takes the tires up into the primary shredder. After passing through the primary shredder, the “shreds” fall onto the vibratory screener. Pieces larger than 2 inches by 2 inches are carried onto a “return conveyor” that brings them back to the primary shredder where they are shredded again (and again and again, if necessary) until they are 2 inches by 2 inches or smaller.

The “unders” (the pieces sized 2 inches by 2 inches or smaller) are now TDF and are removed from the vibratory screener via another belt conveyor.

A system like this, laid out in a straight line, would be approximately 80 feet long and about 20 feet wide, at maximum. The approximate investment would be $300,000 to $500,000, depending on whether you are processing passenger tires only or passenger and truck tires. The approximate operating costs of the system as described is $12 to $15 per ton, and the end product value could range from $25 to $50 per ton, depending on your market, the quality of the TDF, customer demand, etc.

 

A secondary shredder is required to liberate tire wire (top) from rubber (bottom) when processing tires.

Step 2 — The Secondary Shredder. Some markets require a particle size of less than 2 inches by 2 inches and, more importantly, they require the material to be “wire free.” To produce a wire-free product, a secondary shredder must be added to the processing line.

Vecoplan offers a rotary tire re-shredder, or RTR, that has a single rotating head (called the “rotor”) that has knives (or “cutters”) mounted on it. The RTR has a hydraulic ram that pushes the pre-shred into the rotor and a PLC program that controls the feed rate of that ram based on the amp load of the main drive motor. The cutters on the rotor pass through a stationary bed knife, cutting the rubber and pulling the wire from the pre-shred.

A stationary screen controls the particle size of the material. The smaller the screen, the longer the material stays inside the machine. Screens are offered in various sizes and are interchangeable.

The rubber and wire come out of the RTR in the same stream, so the product gets carried away via a drag chain conveyor that is equipped with a self-cleaning, rotary drum magnet. The wire is separated from the rubber at this point. The rubber, now mostly “wire free,” is dropped into super sacks.

The approximate investment to add this second shredder is $250,000 to $500,000, while the approximate operating cost for this equipment is $9 to $15 per ton. The typical size of product ranges from 5/8 inches to 1 inch and it is suitable for a range of markets, including playground cover, landscaping mulch, arena cover, wire-free TDF and an engineering grade replacement for gravel at a value of $150 to $200 per ton, depending on market, material quality, customer demand, etc.

The wire derived through this processing step can be valued at $40 to $120 per ton, again depending on market, quality, customer demand, etc.


Step 3 — Granulation. You can demand more money for your final product the smaller it is. And now that you have the wire out of the rubber, further size reduction is easier. Granulators can take the 3/4-inch-minus material out of the secondary shredder and reduce it down to about 1/4 inch to 1/2 inch, depending on the need. If additional size reduction is required after the granulator, then it is necessary to reduce the material down to at least 1/2 inch to 1/4 inch to prepare the material for the next step.

In addition to the further size reduction this step offers, it also aids in removing the loose fabric from the shredded material. (Passenger tires have about 10 to 15 percent nylon or polyester fabric in them by weight.) Separating the fabric from the rubber is typically done using an air system, which “lifts” the loose fabric out of the material stream. Each time the material is downsized, more fabric will be liberated from the rubber, and fabric separation will be required. However, some of the fabric can (and will) stay embedded in the rubber.

The approximate investment for the third processing step is $350,000 to $500,000, while the typical product size is 1/4 inch to 1/2 inch. Suitable end markets include horse arena cover and sports field additive, among others. The typical product value ranges from $200 to $300 per ton, depending on factors such as market, quality and customer demand.



Rusty Angel is regional sales manager for Vecoplan LLC (www.vecoplanllc.com), High Point, N.C.