Cryogenic Rubber Crumb

DDR Recycling offer a range of cryogenically produced rubber crumb to the market at preferential market rates.

Cryogenic material is available in five size ranges, with each referred to be a specific colour code:

· Red = 4 – 10 mesh (2.0mm – 4.0mm)

· Blue = 10 – 14 mesh (1.6mm – 2.0mm)

· Green = 14 – 30 mesh (0.6mm – 1.6mm)

· White = 30 – 40 mesh (0.4mm – 0.6mm)

· Yellow = -40 mesh (0mm – 0.4mm)

Material Source

Material is provided to processing sites as used car tyres. These tyres are source segregated and fed into a conveyor system.

Cryogenic Produced Material

Material is subject to an initial mechanical cut to reduce tyres to 50mm x 50mm strips. This material is fed into a freeze chamber where it is cooled using quantities of inert liquid nitrogen. The chamber takes the chip and cools it before the material arrives at a bank of mechanical hammers.

The material temperature by the time it arrives at the hammers is -80 degrees centigrade and the rubber is very brittle. The hammers are enclosed in large steel chambers mounted 2.5 metres below ground level. Drive shafts running through the chambers propel the hammers to strike against themselves thousands of times each minute.

As these hammers hit the frozen tyre chip they smash rubber off in pieces of various sizes of tyre ‘crumb’. This crumb is then extracts from the hammer chambers and sorted into one of 6 grades of crumb for further treatment or direct use.

Other materials, including steel and fibre are recovered through the process and these are also recycled making the process 100% environmentally efficient.

Packaging

Materials are bagged into hessian sacks which are loaded into 40 foot high cube shipping containers.

Cryogenic vs Ambient (mechanical) Rubber Crumb

Characteristics

Ambient:- irregular in shape, often elongated particle with considerable surface dust (due to process)

Cryogenic:- a cubic smooth-sided regular shape

Advantages

Ambient:- cheap, perceived to give a mechanical ‘lock’ in bonded products, readily available around the world

Cryogenic:- cleanliness and freedom from wire and steel, low dust content, sinks in water, mixes well with bonded products, uses less additive when bonded due to shape (5 times less surface area than ambient material means that less additive is required)

Disadvantages

Ambient:- can be dusty, difficult to size accurately, does not flow or mix easily

Cryogenic:- cost

For the purpose of sales, DDR classify all material by the colour codes provided above. DDR seek to sell material on an ex-works, FOB or CIF basis. Please email richard.cook@ddrrecycling.com for further details.