Hazardous or toxic waste destruction or containment – Containment
Patent
1994-11-28
1996-10-08
Suchfield, George A.
Hazardous or toxic waste destruction or containment
Containment
405128, 588254, A62D 300, B09B 300
Patent
active
055625851
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for the disposal of asbestos or materials containing asbestos, wherein the asbestos or materials containing asbestos are transformed by grinding into a material which comprises non-fibrous, stable, mineral phases.
2. Description of the Related Art
As is known, fine-fibrous asbestos aggregates such as serpentine asbestos (chrysotile) and amphibole asbestos cause tissues to become diseased, and in particular lung cancer. The safe disposal of asbestos or materials containing asbestos is, therefore, of great importance. At present the disposal of asbestos or materials containing asbestos takes place by dumping. If need be, the waste material is solidified with cement before it is dumped. A great disadvantage of this type of disposal is that a later release of asbestos into the environment cannot be excluded.
It is known, it is true, to treat asbestos thermally and/or chemically with acids to destroy its health-endangering fiber structure, and if need be to influence it mechanically. However, the known methods used for this require a relatively large amount of energy, a considerable outlay on equipment and/or relatively long treatment times. In particular, treatment parameters such as time and temperature must be very accurately adjusted relative to one another. There also exists a particular treatment relationship for the various types of asbestos. When comminuting asbestos, a health-endangering dust occurs, and with some chemical reactions waste gases occur that must be collected. As a result thereof, known methods, which are specified in greater detail below, have not proved successful in practice and do not permit the desired large-scale industrial application in a satisfactory manner. According to Kirk-Othmer, Encyclopaedia of Chemical Technology, 1978, Wiley-Interscience, New York, US, 3rd edition, vol. 3, p. 272, chrysotile is first subjected at high temperatures to a thermal decomposition to ensure a dehydroxylation, and then to an intensive grinding. From DE-A-3 914 553 it is known to sinter the fibres of chrysotile and crocidolite at relatively high sintering temperatures whilst at the same time influencing them mechanically. Some methods propose to treat asbestos with acids to dissolve the fiber structure (WO-A-8 906 167; WO-A-8 810 234) and if need be to heat it at the same time to high temperatures (DE-A-3 728 787) or to influence it mechanically (JP-A-2 311 381). According to WO-A-9 100 123 it is provided that moistened asbestos should be treated with a water-soluble mineralising agent, e.g. in particular borate, to transform it into a non-asbestos containing product. To this end, the asbestos may, if necessary, be shredded before the coarsely comminuted asbestos fragments are exposed to the mineralising agent.
SUMMARY OF THE INVENTION
In contrast thereto, it is the object of the invention to provide a technically simple method for the final and safe disposal of asbestos or materials containing asbestos which is suitable for all types of asbestos and can at a favourable cost be performed on an industrial scale, wherein the end product, which is to be dumped or used for other purposes, should no longer contain any asbestos.
According to the invention this object is achieved in that the grinding is carried out in the form of a pulverizing in an aqueous suspension, together with at least one substance which in water releases OH.sup.- -ions. With this method the asbestos material is transformed into a material with mineral phases which differ from the mineral phase of the asbestos wherein the transformation is irreversible. As end product of the method a suspension of fine-crystalline and gel-like substances is obtained, which no longer have a fiber structure. The wet grinding according to the invention produces the transformation of the asbestos or the material containing asbestos in a relatively short time. After a grinding time of, for example, 30 minutes asbestos is no longer detectable with the X-ray diffr
REFERENCES:
patent: 4432666 (1984-02-01), Frey et al.
patent: 4818143 (1989-04-01), Chou
patent: 5096692 (1992-03-01), Ek
patent: 5258131 (1993-11-01), Mirick et al.
patent: 5258562 (1993-11-01), Mirick et al.
Kirk-Othmer, Encyclopedia of Chemical Technology, 1978, Wiley-Interscience, New York, US 3rd Edition, vol. 3, p. 272.
C. Wieker, "Chemische, electronenmikroskopische und rontgenographische Untersuchungen an Chrysotil-Asbest-Proben unter verschiedenen hydrothermalen Bedingungen in Gegenwart von Ca(OH)2", Silikattechnik, vol. 35, No. 5, 1984, Berlin DD, pp. 140-142.
Karl-Heinrich Lemmerbrock
Suchfield George A.
LandOfFree
Process for disposal of asbestos or substances containing it does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for disposal of asbestos or substances containing it, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for disposal of asbestos or substances containing it will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-53600