Hydraulic and earth engineering – Soil remediation – In situ contaminant removal or stabilization
Patent
1982-06-04
1984-06-26
Corbin, David H.
Hydraulic and earth engineering
Soil remediation
In situ contaminant removal or stabilization
405266, 405270, B09B 300, E02D 312
Patent
active
044564007
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a national phase application corresponding to PCT/EP/00168 filed Oct. 21, 1981 and based upon German national applications of Oct. 21, 1980 and Nov. 1, 1980 under the International Convention. Priority is claimed as to these earlier applications under the Patent Cooperation Treaty and the International Convention.
Field of the Invention
This invention relates to a process for safely disposing of waste materials which are solid or contained in aqueous liquids, wherein brown coal ash is used.
Background of the Invention
It is known from German Patent Publication 26 52 107 that residues which consist of dust or sludge and contain metal compounds can be agglomerated by a treatment, e.g. quicklime in order to transform them to granular solids, which can be dumped. Owing to their large surface area, their residual porosity and their low bulk density, the polluting constituents of the resulting granular solids which have been dumped may be leached out. In another process, disclosed in German Patent Publication No. 26 38 224, reactive viscous waste materials which have become available in the production of pesticides and contain chlorine and sulfur are mixed with alkaline powders and after an addition of water are transformed to flowable solids. Brown coal ash is not used in that process. German Patent Publication No. 29 25 882 discloses a process in which sulfate-containing brown coal ash is pulped by an addition of water and the resulting pulp is dumped and subsequently hardens. Additional waste materials are not added to the mixture obtained in that process.
Object of the Invention
It is an object of the invention to provide a process in which toxic waste materials or production residues, which may be solid or dissolved or suspended in aqueous liquids, can be transformed in a simple and economical manner to solids which can safely be dumped.
DESCRIPTION OF THE INVENTION
In a process of safely disposing of waste materials which are solid or contained in aqueous liquids, wherein the waste material is treated with alkaline substances and a solid product is formed, that object is accomplished in accordance with the invention in that the waste materials which are solid or dissolved or suspended in aqueous liquids are mixed with brown coal ash and, if desired, water, to form a homogeneous mixture having the consistency of a pulp or a freely flowable slurry and the proportions of the ingredients of the mixture are so selected that the mixture hardens to a virtually waterimpermeable material.
In the process according to the invention, the alkaline substance which is used consists of brown coal ash which becomes available in large quantities in power plants and which also gives rise to dumping problems because it contains sulfates which tend to pollute the ground water.
The ash used in the process according to the invention may consist of unmoistened dustlike ash, which becomes available in the ash bins of the power plants, as well as moistened power plant ash, such as is dumped into brown coal pit mines.
Such power plant ash is composed of the mineral content of pure brown coal and of sand and clay which have been mined together with the brown coal. A major part of said ash consists of very fine-grained ash which has been collected in electrostatic precipitators; a minor part consists of coarse-grained boiler furnace ash, which has a high sand content.
The chemical and physical behavior of brown coal ash depends highly on its calcium content, which is present as the oxide, ferrite and sulfate of calcium. The high reactivity of the ash is increased by its small particle size and its large surface area.
The process according to the invention may be used to bind various waste materials so that they will not pollute the environment. Such waste materials may be available as solids or as aqueous suspensions or sludges or as aqueous solutions and may consist, of solid iron oxide catalysts, which may be enriched with catalyst poisons, such as soluble arse
REFERENCES:
patent: 3718003 (1973-02-01), Cook et al.
patent: 4116705 (1978-09-01), Chappell
patent: 4226630 (1980-10-01), Styron
patent: 4313762 (1982-02-01), Pound
patent: 4374672 (1983-02-01), Funston et al.
Chemical Abstracts, vol. 74 represented by East German Pat. No. 72 998, p. 140.
Heide Gunter
Wagner Hans
Corbin David H.
Dubno Herbert
Ross Karl F.
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