Special bitumens

The low-level and intermediate-level wastes are to be capsulated in bitiun, concrete or glass. The bitumen would be highly water resistant, but it ages with time and begins to lose strength in 10 — 20 years. Special bitumen materials have to be developed for wastes which must be contained in >50 years. The bitumen drums are normally stored in a containment building, e.g. of concrete. 

Special bitumens, according to CEN EN 12597 (2000), are bitumens manufactured by processes and from feedstocks chosen to confer special properties that meet stringent requirements for paving or industrial applications. 

Use of Modified Bituminous Binders, Special Bitumens and Bitumens with Additives in Pavement Applications, World Road Association (PIARC) Technical Committee Flexible Roads (C8), Labo-ratoire central des Fonts et Chaussees, September 1999. 

Road paving. This includes bitumen, cutbacks and fluxed bitumen as well as emulsions. Each of these products is subject to very special application techniques. This list is completed by the use of poured asphalt, even though this product is better suited to smaller surfaces sidewalks, courts, etc., than to pavements. Since the middle of the 1980 s, air-blown bitumen is no longer used for road construction. 

Distinctions between tar sands bitumens and heavy oils are based largely on differences in viscosities. The bitumen in oil sand has a specific gravity of less than 0.986 g/mL (12°API), and thus oil sands may be regarded as a source of extremely heavy cmde oil. Whereas heavy oils might be produced by the same techniques used for the lighter cmde oils, the bitumens in tar sands are too viscous for these techniques. Consequently these oil-bearing stones have to be mined and specially processed to recover contained hydrocarbon. 

For many years atactic polypropylene was an unwanted by-product but today it finds use in a number of markets and is specially made for these purposes rather than being a by-product. In Europe the main use has been in conjuction with bitumen as coating compounds for roofing materials, for sealing strips where it confers improved aging properties and in road construction where it improves the stability of asphalt surfaces. Less important in Europe but more important in USA is its use for paper laminating for which low-viscosity polymers are used, often in conjunction with other resins. Limestone/atactic... 

Macdonald, D.D., Greidanus, J.W., Hyne, J.B., Hydrothermal (Water) Reactions of Athabasca Bitumen Organosulphur Model Compounds and Asphaltene , The Oil Sands of Canada-Venezuela 1977, CIM Special Volume 17. 

Organic S/S (use of thermoplastics or polymers) is often more expensive than other S/S methods. The urea formaldehyde and bitumen processes are likely the least expensive of this type but are still usually more costly than the more common inorganic processes. The waste often requires more pretreatment, and processing can be more difficult because of the higher temperatures and specialized equipment involved (D150141, p. 7.89). 

Floors call for special consideration. They need to be protected against moisture and chemical action. The best material is concrete with a chemical-resistant coating. The next best is good-quality linoleum, which should be kept clean and well waxed to help prevent the penetration of spilled solutions.This can be underlain with bitumen paper as an extra precaution against liquids getting through and damaging the sub-floor. A drain is useful but not entirely necessary if the floor is dried after spills. 

Figure 3 indicate the stififness modulus versus bitumen percent. As it can be seen clearly, the waste rubber reinforcement can improve the stiffness modulus, in contrast to non-reinforced samples. According to the experiments with certain bitumen percent, the value of stiffness modulus in reinforced specimen is more than the value of stiffness modulus in non-reinforced specimen, specially, when bitumen percent increased the cohesion between waste rubber, talus material and bitumen will increase, therefore, difference between stiffness... 

Asphalts of Farukhabad and the bitumen of Ain Gir assume special importance in view of these inferences. Farukhabad and neighboring settlements were so close to Ain Gir and other nearby sources that they could hardly fail to interact. Evidence for development of asphalt technology would more likely be found in this area than in any other studied. 

The classic definition of asphaltenes is based on the solution properties of petroleum residuum in various solvents. This generalized concept has been extended to fractions derived from other carbonaceous sources, such as coal and oil shale. With this extension there has been much effort to define asphaltenes in terms of chemical structure and elemental analysis as well as by the carbonaceous source. This effort is summarized by Speight and Moschope-dis (i) in their chapter in this volume along with a good summary of the current thinking. Thus, there are petroleum asphaltenes, coal tar asphaltenes, shale oil asphaltenes, tar sands bitumen asphaltenes, and so on. In this chapter I will attempt to show how these materials are special cases of an overall concept based directly on the physical chemistry of solutions and that the idea that they have a specific chemical composition and molecular weight is incorrect even for different crude oil sources. 

Dismantling of decommissioned nuclear reactors requires special procedures. The outer parts can be handled like normal industrial waste, whereas the inner parts, mainly the reactor vessel and some core components, exhibit high radioactivity due to activation. Radioactive deposits on the inner surface of the reactor vessel may be removed by chemical decontamination. Altogether, the relatively large volumes of LLM and MLW which are obtained by dismantling are further processed and then preferably enclosed in concrete or bitumen. 

Bleeding. Discoloration caused by migration of components from the underlying film. Substrates that can cause problems are those coated with tar- or bitumen-based materials, paints made on certain red and yellow organic pigments (which are partially soluble in solvent), some wallpapers, and timber stains that contain soluble dyes. The remedy is to use a specially formulated sealer or an aluminum paint. 

Application of DLVO Theory. Some of the concepts and expressions of Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory of colloid stabihty have been described in Chapter 1, or can be found in many different textbooks 4, 5). The application of DLVO theory to oil-in-water colloids with special reference to the stability of bitumen-in-water emulsions will be discussed here. 

Production costs per tonne of base oil are calculated by dividing the total annual costs by the total annual production of base oils. Net feedstock cost can be calculated in several ways, but it will not necessarily be identical to the cost of crude oil. As the base oil plant in a sense competes with fuel production units for feedstock, the basic feedstock cost to the lubricant base oil complex should be determined by the alternative value of that feedstock if it were used to make mainstream fuels products. The by-products of base oil manufacture also have values for blending into fuel streams or in some cases for direct sale as speciality products, such as waxes and bitumen. Credit must be given for these products so that the net value of the hydrocarbon content of the base oil can be calculated. Refineries use sophisticated linear programming computer models to optimise refinery operations based on different crude oil input, process yields, market prices, production targets, etc. 

It is unlikely that the sludges and waste resins from the exchangers will require having any of their chemical components removed before disposal and the treatment envisaged is therefore a direct incorporation of the waste into a cement or bitumen matrix followed by packaging for disposal. These techniques, now often referred to as waste solidification, have been developed specially in the nuclear industry to aid in the disposal of radioactive wastes. 

Although the gasoline fraction is almost absent in this crude, it is nevertheless a valuable stock-feed for production of diesel fuel and of special kerosenes, also as source of high quality bitumens. In tests, this crude showed a shift in its limit of stress T, equal to 28 kg/cm, and on that basis, it was classified as a liquid of non-Newtonian type. 

Petroleum reservoirs, however, occur in a gray facies of the Lyons found in the deep basin (Levandowski et al., 1973). This facies contains no ferric oxides or calcite. Many grains in the facies are coated with bitumen, the remnants of oil that migrated through the rock, and the rock is cemented with anhydrite and dolomite. The anhydrite and dolomite cements occupy as much as 25% and 15%, respectively, of the rock s precement pore volume. The origin of these cements is of special interest because of their relationship to the distribution of petroleum reservoirs in the basin. 

Bitumens are residues of the vacuum distillation of suitable crude oils (distillation bitumen). Residues of less suitable crudes must be partially oxidized by blowing to achieve the desired technical properties (semi-blown bitumen). Blown bitumens for special purposes can also be produced from vacuum residues. The process is executed by blowing a stream of finely distributed air through the molten bitumen (sometimes reduced in viscosity by addition of flux oil) at temperatures of 250-290 "C. 

---