Road tar

Higher-boiling fractions supply the creosotes, absorbing oils, anthracene, coal tar fuels, road tar, etc. 

Naphthalene, anthracene, carbazole [86-74-8] phenol [108-95-2] and cresyUc acids are found in the tar. Phenol and cresyUc acids are useful as chemical and resin intermediates. The aromatic chemicals are useful in the manufacture of pharmaceuticals, dyes, fragrances, and pesticides. Various grades of pitch are made from residues of tar refining. Coal-tar pitch is used for roofing and road tar, and as a binder mixed with petroleum coke to produce anodes for the aluminum industry. 

Large-scale recovery of light oil was commercialized in England, Germany, and the United States toward the end of the nineteenth century (151). Industrial coal-tar production dates from the earliest operation of coal-gas faciUties. The principal bulk commodities derived from coal tar are wood-preserving oils, road tars, industrial pitches, and coke. Naphthalene is obtained from tar oils by crystallization, tar acids are derived by extraction of tar oils with caustic, and tar bases by extraction with sulfuric acid. Coal tars generally contain less than 1% benzene and toluene, and may contain up to 1% xylene. The total U.S. production of BTX from coke-oven operations is insignificant compared to petroleum product consumptions. 

Liquid tar products, eg, fight oils, cresols, cresyfic acids, creosote oil, and road tars, are generally transported in bulk in insulated mild-steel road or rail tankers. They are loaded at a temperature sufficiently high to ensure delivery at the desired viscosity. Small quantities are generally delivered in dmms that may have to be steam-heated to ensure complete liquidity before discharge. 

The market for tar-based road binders has declined considerably for a variety of reasons. Less cmde tar is available and the profits from the sales of electrode pitch and wood-preservation creosote or creosote as carbon-black feedstock are higher than those from road tar. In most industrial countries, road constmction in more recent years has been concentrated on high speed motorways. Concrete, petroleum bitumen, or lake asphalt are used in the constmction of these motorways. In the United Kingdom, for example, the use of tar products in road making and maintenance had fallen from 330,000 t in 1960 to 100,000 t in 1975 and is less than 100 t in 1994, mainly based on low temperature pitch which is not suitable for electrode or briquetting binders, but which is perfectly satisfactory as the basis for road binders. 

Gilson Road Tar Pits Tar-oil emulsions 2,335 FFTNH 156,000 Total project costs... 

Road Tar Emulsion using Acritamer 941 to help keep the tar suspended and prevent it from settling out. 

With reference Fig. 1, it will be noted that topped tar is the residue remaining from the topping operation where the chemicals are separated as the distillate. The principal use of lopped tar is in road materials. A number of standard grades (RT-I to RT-12) are available, the grade depending on the consistency or viscosity of the tar. Road tar has excellent weather and skid resistance, but its use is limited by availability and price as compared with asphalt. This is borne out by the respective amounts used for road building (United States) with about 90% using asphalt. 

This molten calcium silicate and the other more readily fusible silicates that are always present in the crude iron ores form a slag which floats on the surface of the molten iron. The slag is removed, allowed to solidify, and used in the manufacture of cement or as a road-building material after being mixed with asphalt or road tar. 

Use Coumarone resins solvent for asphalts, road tars, pitches, etc. cleansing compositions process engraving and lithography rubber cements (solvent) naphtha soaps manufacture of ethylene and acetic acid. 

TIR Tar in Road Construction International Road Tar Conference Tokyo, 1967... 

Coke-oven tars contain only minor quantities of nonaromatic hydrocarbons, while the vertical retort tars may have up to 6% of paraffinic compounds. Low-temperature tars are more paraffinic and phenolic (as might be expected from relative lack of secondary reactions) than are the continu-ons vertical retort tars. Coke-oven tars are comparatively rich in naphthalene and anthracene, and distillation is often the means by which various chemicals can be recovered from these particular products. On the other hand, another objective of primary distillation is to obtain a pitch or refined-tar residue of the desired softening point If the main outlet for the jMtch is as a briquetting (Chapter 17) or electrode binder, primary distillation is aimed at achieving a medium-soft pitch as product or for the production of road tar/asphalt (Yan, 1986). 

NFPA Health 2, Flammability 2, Reactivity 0 Uses Road tar fluxing solvent fuel oil wash oil in coal gas purification wood preservative... 

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