Furnaces – Refuse incinerator – With electric heater
Patent
1995-12-28
1997-08-05
Bennett, Henry A.
Furnaces
Refuse incinerator
With electric heater
110345, 110346, 75434, 75958, F23G 500
Patent
active
056531826
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns a method for neutralizing waste, such as fly ash from combustion of house refuse, fluorescent tubes and similar.
BACKGROUND
At the present, there is a high demand to manage environmetally harmful waste in general, and in particular fly ash from combustion of waste and fluorescent tubes. Combustion of e.g. house refuse results in residual materials such as slag and fly ash which contain mercury and heavy metals, such as barium, cadmium, cobolt and chrome, in addition to large quantities of mercury and lead. These materials are considered as hazardous waste in Norway and in the most of the European countries. During the destruction of fluorescent tubes, the powdery fluorescent material therein is separated from the metal, plastic and glass components including mercury. This powder, comprising about 38-40 different elements, is also characterized as hazardous waste in most of the European countries. At the present there is no satisfactory or environmetally safe method to handle such waste, and one has to resort to deposits in special waste storage.
NO Patent 172103 describes a method for treating waste material. According to this process, solid and/or liquid waste is/are combined with a binder material, in this case clay, whereupon the granulated/powdery mixture is subjected to pyrolysis to remove volatile components in the waste. The waste is then fed to a furnace at oxidizing conditions to oxidize remaining volatile components and at least some of the bound carbon, whereupon the waste is passed through a vitrification process to form a solid aggregate.
However, the above process is different from the present in several ways, as the heat treatment is applied to the waste in its solid form. The resultant aggregate will be at least partly porous as a result of the stripping of volatile compounds and carbon. This will allow for water penetration which will result in leaching of environmetally hazardous compounds and elements. The waste treated in accordance with the method of NO Patent 172103 can for that reason not be stored on e.g. waste disposal sites or recovered as recyclable raw materials or products because of the risk of releasing environmetally hazardous components from e.g. water draining from waste disposal sites.
OBJECT
Accordingly, the object of the present invention is to provide a method that permits an environmetally sound treatment of waste, such as ash from refuse incineration (fly ash), and luminescent tubes into a material that can be stored as harmless refuse or recovered as raw material for use in new products, without risk of releasing hazardous components to the environment.
THE INVENTION
The object stated above is fulfilled with a method according to the characterizing part of claim 1. Further beneficial features appear from the accompanying claims.
According to the present invention, waste such as fly ash from refuse incineration, coating from TV screens and similar, and luminescent powder from luminescent tubes, luminescent lamps and similar, is neutralized by embedding the waste in glassified slag, optionally with the removal of heavy metal components.
In more detail, the neutralization occurs by charging, in a first step, waste, such as fly ash from refuse incineration, including SiO.sub.2 -containing material and optionally carbon containing material into a furnace operated at reducing conditions, whereupon compounds of mercury, lead, zinc, cadmium and any other elements are reduced and withdrawn from the furnace along with the exhaust gases.
This first step of reducing heavy metals is, however, not required if: 1) heavy metal compounds/elements are absent in the refuse to be treated, or 2) the neutralized waste is to be left permanently on a waste disposal site and not to be used as recyclable raw material. One example of waste that belongs to category 1) above is waste from luminescent tubes and similar products.
The reduced components escaping with the exhaust gases from the furnace are transformed to oxides in a combustion chamber and sep
Bennett Henry A.
HAS Holding AS
O'Connor Pamela A.
LandOfFree
Method for neutralizing waste does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for neutralizing waste, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for neutralizing waste will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1067767