Asbestos commercial

Boric acid/alkaU spinning has been commercialized in Kuraray Co. and Unitika Co. in Japan, and is reportedly under research and development also in the People s RepubHc of China as a process for producing high strength PVA fiber to be used for replacing asbestos (9). 

The usual definition of asbestos fiber excludes numerous other fibrous minerals which could be qualified as asbestiform following the criteria Hsted above. However, it appears the term asbestos has traditionally been attributed only to those varieties which are commercially exploited (1,2). 

Asbestos and other fibers in a wide variety of bundle sizes or even individual fibrils are in commercial usage. The handling of asbestos and other fibers causes degradation of the larger fiber bundles to fibers having diameters less than two micrometers that remain airborne for extended periods of time. These airborne fibers are prone to inhalation and lung entrapment. The exact definition of harmfiil fibers and the mechanism by which they affect the body is not accurately known. 

There are now commercially available a large range of laminated plastics materials. Resins used include the phenolics, the aminoplastics, polyesters, epoxies, silicones and the furane resins, whilst reinforcements may be of paper, cotton fibre, other organic fibres, asbestos, carbon fibre or glass fibre. Of these the phenolics were the first to achieve commercial significance and they are still of considerable importance. 

Silicone-asbestos laminates are inferior mechanically to the glass-reinforced laminates and have not found wide commercial use. Interesting laminates have. 

Similar routes are available for the production of HBr and HI, The catalysed combination of H2 and Br2 at elevated temperatures (200-400°C in the presence of Pt/asbestos, etc.) is the principal industrial route for HBr, and is also used, though on a relatively small scale, for the energetically less-favoured combination of H2 and I2 (Pt catalyst above 300°C). Commercially HI is more often prepared by the reaction of I2 with H2S or hydrazine, e.g. ... 

Asbestos It is not the name of a distinct mineral species but is a commercial term applied to fibrous varieties of several silicate minerals such as amosite and crocido-lite. These extremely fine fibers are useful as fillers and/or reinforcements in plastics. Property performances include withstanding wear and high temperatures, chemical resistance, and strengths with high modulus of elasticity. When not properly handled or used, like other fibrous materials, they can be hazardous. 

Adverse effects associated with multiple chemical exposures associated with rocket testing at a commercial defense test facility. This study evaluated the excess mortality of workers employed at a rocket test site over a period beginning in the 1950s. Excess lung cancer was identified in this cohort of workers and their health outcomes were possibly associated with exposure to hydrazines, nitrosamines, asbestos, trichloroethylene, and other chemicals. 

Worldwide, there are numerous plasma system designs for treatment of all types of wastes. Economical considerations limit their commercial applications to the most profitable actions. Presently they commercially operate in Switzerland and Germany for low level nuclear waste vitrification, in France and the USA for asbestos waste vitrification, in the USA and Australia for hazardous waste treatment, in Japan and France for municipal fly ash vitrification. The most of installations is working in Japan because there 70% of municipal waste is incinerated and the ash can not be used as landfill. EU Regulations banning the disposal to landfill of toxic and hazardous wastes after year 2002 may cause wider use of plasma waste destruction technology in Europe. 

Asbestos was a relatively economieal produet for a mass market of commercial customers. In other markets better quality also achieves a better market price. This quality may also mean for customers being free of hazardous components (textiles, cosmetics, children s toys). 

Dr. Joachim Breuer, CEO of the association of commercial and industrial statutory accident insurance, stated in a press release on 17.12.2002 We do not expect deaths to reach their peak until between 2005 and 2015 . Breuer estimates that the overall expenditure of the iability insurance carriers could probably rise to well in excess of 10,000 million. By 2020 up to 20,000 deaths in Germany could be due to asbestos. 

Fig. I.IB illustrates fibers typical of commercial asbestos, while Fig. l.ll shows Fiberglas and Fig. I.IJ silicon carbide whiskers. Some of the fibers in these examples are bent, occasionally through 180°, indicating considerable flexibility. Whiskers of other compounds can also bend but the tensile strength of these materials is their most remarkable feature. The measured values (Table 1.2) are at least ten times higher than those observed for the same compounds in bulk or in another morphology (Walker and Zoltai, 1979). The numerous investigations into the causes of this unique response have produced several hypotheses.

Intermediate members of the series that contain both Mg and Fe, may be identified as iron-rich cummingtonite, for example. Alternatively, a fibrous species whose composition and structure resembles grunerite occurs in South Africa. It is mined as asbestos and known commercially as amosite. Amosite is a varietal mineral name that has been used in the trade to describe mineral materials within the cummingtonite-grunerite series. The name is an acronym for asbestos mines of South Africa. Because it is not a proper mineral name, it may not be found in lists of minerals in standard miner-alogical texts. 

Table 2.3 Chemical Analyses and Calculation of Formulas for Commercial Chrysotile Asbestos Samples from Four Countries...

Table 2.4 lists the major amphibole mineral series and illustrates the chemical range of the group. The five commercial asbestos varieties are starred. Idealized chemical formulas for the amphibole asbestos minerals are as follows ... 

Table 2.5 presents chemical analyses of selected materials from commercial deposits. These data illustrate the chemical range of minerals that have been mined as asbestos. 

Occurrences in the United States were known as early as 1698 with numerous finds along Brandywine Creek in Pennsylvania (Frondel, 1988). The celebrated purse made from asbestos that Benjamin Franklin took to London in 1724, and which now resides in the British Museum of Natural History, may have been made of long-fiber asbestos from Newbury, Massachusetts. As a journeyman printer, Franklin made paper from asbestos, as did many Europeans. It was also used in making lamp wicks and cloth. Commercial mining in the United States took place some time after the first discovery of asbestos on Staten Island, New York, in 1818. (Asbestos continued to be mined at the site until 1876.) By 1825 more than seventy localities were known to produce asbestos in the United States (Robinson, 1825). However, as early as 1804 Jameson had recorded the mineralogy of the species and listed the numerous university, societal, and private mineral collections containing specimens of asbestos from U.S. localities and asbestos products of local manufacture. 

Over the past several decades six different silicate minerals have been mined as asbestos and processed for industrial and commercial applications. The most commonly encountered asbestos mineral today is chrysotile. The five other minerals are tremolite, actinolite, anthophyllite, grunerite, and rie-beckite. All five are members of the amphibole group of minerals, and each can occur as chunky, acicular, or equant crystals, as well as in fibrous form. When found as fine fibrous aggregates, in quantities appropriate for mining, they are usually distinguished as a special variety—for example, tremolite-asbestos. 

After a thousand years of use, asbestos is being replaeed by other, often fibrous, materials. It remains to be seen whether the substitutes will be as successful, commercially and financially, or more or less hazardous. We are certainly not going to do without fibrous inorganic materials nor expunge them from our environment. 

Amosite A commercial term for a type of amphibole-asbestos from South Africa consisting chiefly of fibrous members of the cummingtonite-grunerite series. Variable amounts of several fibrous members of the amphibole group and other minerals may be included in a particular sample. The name is an acronym derived from asbestos mines of 5outh Africa. 

---