Scrap Tire Management Council

Scrap Tire Characteristics

1. Tire Derived Fuel Analysis
2. Typical Materials Composition of a Tire
3. Typical Composition by Weight
4. Densities of Shredded and Whole Tires
5. Rubber weight by tire component.
6. Tire Derived Fuel By-Products Analysis
7. Steel Tire Cord Analysis

1. Tire Derived Fuel Analysis

Representative Analysis of TDF Produced By WRI

(Source: TDF Produced From Scrap Tires with 96+% Wire Removed)

Description %By Wt, As Received %By Wt, Dry Basis

Proximate Analysis

Moisture 0.62 ----

Ash 4.78 4.81

Volatile Matter 66.64 67.06

Fixed Carbon 27.96 28.13

Total 100.00 100.00

Ultimate Analysis

Moisture 0.62 ----

Ash 4.78 4.81

Carbon 83.87 84.39

Hydrogen 7.09 7.13

Nitrogen 0.24 0.24

Sulfur 1.23 1.24

Oxygen (by difference) 2.17 2.19

Total 100.00 100.00

Elemental Mineral

Analysis (Oxide Form)

Zinc 1.52 1.53

Calcium 0.378 0.380

Iron 0.321 0.323

Chlorine 0.149 0.150

Chromium 0.0097 0.0098

Fluoride 0.0010 0.0010

Cadmium 0.0006 0.0006

Lead 0.0065 0.0065

Others below detectable limits

Heat Value BTU/lb kJ/kg

HHV 16,250 37,798

HV Ave 15,500 36,053

TDF Combustion

Characteristics ° F ° C

Tires ignite (flash point) 550 - 650 288 - 343

Carbon begins to burn 842 450

Carbon completely burnt 1202 650

© 1986 Waste Recovery, Inc.
84% OF A TIRE,S WEIGHT IS FROM RUBBER COMPOUNDS. REMAINDER
IS BEAD AND BELT WIRE PLUS CARCASS AND CHAFER FABRIC

2. Typical Materials Composition of a Tire

This table lists the typical types of materials used to manufacture tires.

Typical Composition of a Tire

Synthetic Rubber
Natural Rubber
Sulfur and sulfur compounds
Silica
Phenolic resin
Oil: aromatic, naphthenic, paraffinic
Fabric: Polyester, Nylon, Etc.
Petroleum waxes
Pigments: zinc oxide, titanium dioxide, etc.
Carbon black
Fatty acids
Inert materials
Steel Wire

3. Typical Composition by Weight

This lists the major classes of materials used to manufacture tires by the percentage of the total weight of the finished tire that each material class represents.

Passenger Tire

Natural rubber 14 %

Synthetic rubber 27%

Carbon black 28%

Steel 14 - 15%

Fabric, fillers, accelerators, antiozonants, etc. 16 - 17%

Average weight: New 25 lbs, Scrap 20 lbs.

Truck Tire

Natural rubber 27 %

Synthetic rubber 14%

Carbon black 28%

Steel 14 - 15%

Fabric, fillers, accelerators, antiozonants, etc. 16 - 17%

Average weight: New 120 lbs., Scrap 100 lbs.

4. Densities of Shredded and Whole Tires

APPROXIMATE DENSITIES

LOOSELY PACKED DENSELY PACKED

550-600 lbs/yd³ single pass 1220-1,300 lbs/yd³

850-950 lbs/yd³ 2" shred 1,350-1,450 lbs/yd³

1,000-1,100 lbs/yd³ 1 1/2" shred 1,500-1,600 lbs/yd³

100/10Yd³ WHOLE TIRES
(PASSENGER/LIGHT TRUCK) 500/10Yd³

10 MESH- 29 lbs/ft³

20 MESH- 28 lbs/ft³

30 MESH- 28 lbs/ft³

40 MESH- 27 lbs/ft³

80 MESH- 25-26 lbs/ft³

5. Rubber weight by tire component.

A tire is manufactured from several separate components, such as tread, innerliner, beads, belts, etc. This table shows which components account for the rubber used to make the tire.

RUBBER PERCENT BY WEIGHT IN A NEW RADIAL PASSENGER TIRE

TREAD 32.6%

BASE 1.7%

SIDEWALL 21.9%

BEAD APEX 5.0%

BEAD INSULATION 1.2%

FABRIC INSULATION 11.8%

INSULATION OF STEEL CORD 9.5%

INNERLINER 12.4%

UNDERCUSHION 3.9%

100.0%

6. Tire Derived Fuel By-Products Analysis

The data presented in the following two tables is analysis of bottom ash and fly ash from a facility combusting only Tire Derived Fuel. It would not be representative of facilities that use TDF as a supplement to another fuel, such as coal or wood.

PRELIMINARY RESULTS OF SLAG
(BOTTOM ASH) ANALYSIS

COMPOUND SAMPLE 1 SAMPLE 2 AVERAGE

Total Carbon -- % 0.071 0.258 0.164

Aluminum 0.128 0.283 0.206

Arsenic 0.002 ---- 0.001

Cadmium 0.001 0.001 0.001

Chromium 0.978 0.068 0.523

Copper 0.255 0.320 0.288

Iron 95.713 96.721 96.217

Lead 0.001 0.001 0.001

Magnesium 0.058 0.059 0.058

Manganese 0.058 0.307 0.416

Nickel 0.241 0.093 0.167

Potassium 0.010 0.015 0.012

Silicon 0.340 0.246 0.293

Sodium 0.851 0.701 0.776

Zinc 0.052 0.160 0.106

Tin 0.007 0.006 0.006

Sulfur 0.766 0.762 0.764

100.0 100.0 100.0

ANALYSIS OF SCRAP TIRE FLY ASH

Contents
Weight by Percentage

Zinc
51.48%

Lead
0.22%

Iron
6.33%

Chromium
0.03%

Copper
0.55%

Nickel
0.03%

Arsenic
0.02%

Aluminum
0.76%

Magnesium
0.50%

Sodium
0.01%

Potassium
0.01%

Magesium Dioxide
0.36%

Tin
0.03%

Silicon
6.85%

Cadmium
0.05%

Carbon
32.20%

Total
99.43%

Note: These results are from incineration of 100% tire fuel.

Sources: Radian Corporation, Results From Sampling and Analysis of Wastes From the Gummi Mayer Tire

Incinerator, May 1985.

7. Steel Tire Cord Analysis

ASTM 1070 Steel Tire Wire

There are approximately 2.5 pounds of steel belts and bead wire in a passenger car tire. This material is made from high carbon steel with a nominal tensile strength of 2,750 MN/m2 and the following typical composition:

STEEL BELTS BEAD WIRE

Carbon 0.67 - 0.73% 0.60% min.

Maganese 0.40 - 0.70% 0.40 - 0.70%

Silicon 0.15 - 0.03% 0.15 - 0.30%

Phosphorus 0.03% max. 0.04% max.

Sulfur 0.03% max. 0.04% max.

Copper Trace Trace

Chromium Trace Trace

Nickel Trace Trace

COATING 66% Copper
34% Zinc 98% Brass
2% Tin