Often referred to as "black pollution" of discarded tires are melting
or refractory non-polymer elastic material, with a strong heat,
anti-biological, anti-mechanical, and difficult to degrade. The
long-term open-air piling up, not only occupy large areas of land, but
also can easily create a mosquito-borne diseases, posing a fire. On the
other hand, waste tires as a renewable resource known as the "black
gold." After repeated refurbished a used tires is equivalent to 2 ~ 3
tires, while the renovation is only the equivalent of the raw materials
consumed in production of a new tire with the specifications of 15% ~
30%, the price of new tires is only 20% to 50%. Tires contain 22% ~ 24%
of nylon and other synthetic fibers can be processed into plastic
products, 16% ~ 24% of high-quality spring steel for the raw materials,
58% ~ 60% of the rubber mixture of recycled rubber to produce rubber
powder and its products and extension products can be widely used in
rubber, chemical, transportation, and urban construction and other
important industry in the national economy, has become an important
secondary resources. Therefore, how to make full use of discarded tires
in China, saving rubber resources, prevent environmental pollution,
China's sustainable socio-economic development must be addressed. At
present, China Resources Comprehensive Utilization of discarded tires
to the following several ways: (1) prototype transformation of
discarded tires. Through bundling, cutting, punching, etc., will be
discarded tires to transform the port terminal and the ship's fenders,
anti-wave protection dams, floating lighthouse, road traffic wall
screens, signs, and reef fish aquaculture, recreational and other
playground equipment. Prototype transformation is a very valuable
collection methods, but the method does not consume large amount of
discarded tires, accounting for only 1% of the amount of discarded
tires, it can only serve as a complementary way. (2) pyrolysis waste
tires. Tires at high temperature cracking can be extracted with high
heat value of gas, rich in aromatic oil, carbon black and steel and so
on, but the method is technically complex, high cost and could easily
lead to secondary pollution, and poor quality of recycled material and
unstable, There is no promotion in the country. (3) The renovation of
old tires. Tire renovation means the tire by the local repair,
processing, re-posted review tread rubber, for vulcanization, a process
to restore its value. Automobile tire in the course of the destruction
of the most common way is the tread of the damage, so tire renovation
is one of the main ways to use old tires. In use, well-maintained under
the conditions of a tire can be refurbished several times, at least
make the tire to extend the overall life of a ~ 2-fold. Each
refurbished once the new tires can be re-paid the equivalent of the
life of 60% to 90% of the life of the average mileage of about
50000-70000 km. Tire renovation not only extended the life of
automobile tires, used tires contributed to the reduction, but also
reduce environmental pollution, is an important industry of circular
economy. At present there are about more than 500 tire retread business
more than 90% belong to small and medium enterprises, the annual
capacity to 15 million refurbishment, renovation and new tire
production volume of about 4%. (4) the use of old tires and production
of renewable rubber. Recycled rubber tires is milled into rubber
granules, water and other chemical substances, in the pressurized,
heated under the conditions of its "anti-hardening", and then by
mechanical squeezing to restore its original state. Reclaimed rubber
production of the existence of low profits, labor-intensive production
processes long, energy consumption, and pollution were serious
shortcomings, so the developed countries had gradually reduce its
output of reclaimed rubber, there are plans to shut down reclaimed
rubber factory. Due to historical reasons, China's production of
reclaimed rubber is still the major means of waste
tire recycling,
annual production of more than 100 million tons, is truly "renewable
rubber kingdom." (5) the use of old tires and production of vulcanized
rubber powder. Vulcanized rubber powder is milled into the tires a good
dispersion of rubber particles, in which metal, textiles and material
has been removed, the nature of light and dry, with a good surface
area. Compared with the traditional reclaimed rubber, rubber powder
production is not secondary pollution, waste tire utilization rate of
100%, can be extended into high value-added and new products can be
recycled, for example, the production of new tires to replace tires;
production of rubber products , waterproof material; production of
rubber and plastic ties instead of cement, timber sleepers, etc.;
production of powder modified bitumen, SBS can replace synthetic
rubber, and has lower noise, lower costs and extend the life of the
advantages of the road. So this is a set of environmental protection
and resource
tire recycling and the use of
tire recycling
as one model, which is the best use of the development of circular
economy approach. Powder manufacturing industry in China has just
started, only dozens of manufacturers, annual output of less than 50000
t, have not formed the emerging industry. From the perspective of
circular economy, waste
tire recycling of
resources should first consider the cycle of materials (such as the
renovation of the old tires), and then consider the chemical
tire recycling
(such as the production of reclaimed rubber), and finally to consider
energy recovery (combustion power generation). Therefore, because of
all these advantages and disadvantages, the comprehensive utilization
of waste tires should be vigorously promoted tires refurbished and
powder production technology, restricting the use of thermal energy
utilization technologies, eliminating the use of reclaimed rubber
production and pyrolysis technologies.