Recycled rubber carbon black

N. Mandal, S. Dasgupta, and R. Mukhopadhyay, Regeneration of carbon black from waste automobile tires and its use in carcass compound. Progress in Rubber, Plastics and Recycling Technology, 21(1), 55, 2005. 

Rubber tyres are by far the most visible of rubber products. Identification is trivial and collection is well organized. Recycling and disposal, however, are less evident. A major route for tyres is their use as a supplemental fuel in cement kilns. Major compounds in tyres are styrene-butadiene rubber (SBR), synthetic and natural polyisoprene rubber, steel cord, carbon black, zinc oxide, sulphur and vulcanization-controlling chemicals. Tyres can be retreaded, which is economic for large sizes (truck tyres), or ground to crumb or powder (cryogenic grinding). Such materials have some limited market potential as an additive in asphalt, and in surfaces for tennis courts or athletics. 

A pyrolysis system has been developed to recover useful material from scrap tires. An actual plant was constructed in 1979 The plant will be on a trial for a year to demonstrate that the equipment of the plant satisfies the test specifications and that the recovered carbon black has the quality demanded by the rubber industry. After passing one year tests, it will be put into commercial operation. This project is a full scale recycling for scrap tires supported by public agencies which also supported the pulverizing plant in Osaka. It is expected that the completion of the project will open a new course for recycling and disposal of waste. 

Tires are one of the most durable technological products manufactured today. They are a resilient, durable composite of fabric, steel, carbon black, natural rubber, and synthetic polymers. The qualities that make tires or other engineered rubber products a high-value item create a special challenge of disposal. Tires and other rubber products, such as conveyor belts and hydrauUc hoses, are not biodegradable and cannot be recycled like glass, aluminum, or plastic. Four potential applications for such products entering the solid waste stream have been identified ... 

NR composites and nanocomposites can be fabricated by three main techniques, namely latex compounding, solution mixing and melt blending. A variety of nanofillers, such as carbon black, silica, carbon nanotubes, graphene, calcium carbonate, organomodified clay, reclaimed rubber powder, recycled poly(ethylene terephthalate) powder, cellulose whiskers, starch nanocrystals, etc. have been used to reinforce NR composites and nanocomposites over the past two decades. In this chapter, we discuss the preparation and properties of NR composites and nanocomposites from the viewpoint of nanofillers. We divide nanofillers into four different types conventional fillers, natural fillers, metal or compound fillers and hybrid fillers, and the following discussion is based on this classification. 

BR, butyl rubber CB, carbon black CBS, cyclohexyl-2-benzothiazolefulfenamide CNT, carbon nanotube CSPE, chlorosulfonate polyethylene CIP, carbonyl-iron powder EPM, ethylene propylene monomer EPDM, ethylene propylene diene monomer EVA, ethylene-vinyl acetate FSR, fluorosilane rubber GRP, graphite powder HGM, hollow glass microsphere lONP, iron oxide nanoparticle LDH, layered double hydroxide MBT, 2-mercaptobenzothiazol MMT, modified montmorillonite NR, natural rubber PAMAM, polyamidoamine R-EPDM, recycled ethylene propylene diene monomer SR, silicon rubber SBR, styrene-butadiene rubber TBBS, iV-tert-butyl-2-benzothiazolesulfenamide. 

Recycl Blacks. The pyrolysis of carbon black containing rubber goods has been promoted as a solution to the accumulation of waste tires. In the processes in question, tires are pyrolyzed in the absence of oxygen, usually in indirect fired rotary kiln-type units. The mbber and extender oils are cracked to hydrocarbons which are collected and sold as fuels or petrochemical feedstocks. The gaseous pyrolysis products are burned as fuel for the process. Steel tire cord is removed magnetically and the remainder of the residue is milled into a pyrolysis black. This contains the carbon black, silica, and other metal oxides from the rubber and some newly created char. Typically these materials have 8-10% ash, and contain... 

Some studies have looked at producing useful products, effectively fillers, from waste rubber by using methods that use a partial pyrolysis approach. Silica is being used as a part replacement for carbon black as a filler in the production of green tyres . As this practice increases, there will be a corresponding increase in the total recoverable inorganic fraction from waste tyres, and so this recycling route could become more attractive. Examples of partial pyrolysis processes are described below. 

Testing methods and quality protocols essential to ensuring rubber recycling can take Its place In today s quality conscious world are described. Also Included Is using waste rubber to generate energy and manufacture new materials such as fuel oils and recovered carbon black. 

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