Compositions – Reductive bleachant – deoxidant – reductant – or generative – Hydrogen generating
Reexamination Certificate
2000-07-20
2001-11-27
Anthony, Joseph D. (Department: 1714)
Compositions
Reductive bleachant, deoxidant, reductant, or generative
Hydrogen generating
C423S657000, C423S658000
Reexamination Certificate
active
06322723
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is broadly concerned with improved methods and products for the thermal degradation of unwanted substances involving contacting such substances with a particulate metal composition in the presence of water and an alkali metal salt. More particularly, the invention pertains to such methods and products wherein the metallic compositions include respective quantities of particulate iron and magnesium, and preferably lesser amounts of particulate aluminum and zinc; such metal compositions can be used to thermally degrade materials such as agricultural manures to a small volume without any adverse environmental impact.
2. Description of the Prior Art
Agricultural areas involved in large-scale swine production face an increasingly difficult problem in disposing of swine manure and wastes. Indeed, in certain locales, government regulations are in place which severely limit the right of swine producers to dispose of such wastes in conventional ways; in some instances, these restrictions threaten to put such producers out of business or impose such costs as to make further production impractical.
There are a number of other industries that give rise to significant waste problems. Among these are packing house operations, oil refineries and the electrical utility industry because of the prior use of polychlorinated biphenols. Here again, these industries face evermore stringent environmental regulations making disposal problems a significant business issue.
Powdered metal compositions have been provided in the past for production of heat and hydrogen gas. For example, U.S. Pat. Nos. 4,017,414 and 3,993,577 describe iron and magnesium-containing compositions designed to generate relatively low temperatures with the evolution of hydrogen gas. The particular utility described in these references is that of replacing lost body heat for undersea divers or combat troops, or for heating machinery or instruments in remote or cold areas.
SUMMARY OF THE INVENTION
The present invention provides improved methods and products especially designed for the thermal degradation of unwanted substances such as manures, blood or blood-derived products, petroleum-based materials and other undesired chemicals such as polychlorinated biphenols. Broadly speaking, the method of the invention involves contacting such a substance with a particulate metal composition in the presence of water and an alkali metal salt, and causing sufficient heat to be generated during the contacting step to degrade the substance. The composition generally includes respective quantities of particulate iron and magnesium.
In preferred forms, the compositions include from about 10-50% by weight elemental particulate iron (more preferably from about 35-45% by weight) and from about 4-90% by weight elemental particulate magnesium (more preferably from about 10-25% by weight). Also, the compositions may include smaller amounts of particulate elemental aluminum and particulate elemental zinc, generally from about 0.1-25% by weight aluminum (more preferably from about 10-20% by weight) and from about 0.1-25% by weight zinc (more preferably from about 10-20% by weight). Where aluminum and zinc are used, it is preferred that at least one of these components be present at a level of about 0.1-10% by weight.
The metal products of the invention are in particulate form, and generally the smallest average particle sizes are preferred (typically around 400 mesh), although sizes up to small chips may be employed. The most preferred powders are in the form of foundry dust from milling or grinding operations, and have an average particle size approximately that of the corresponding pyrotechnic particles ±50%.
In order to generate the desired exothermic reaction, the metal components should be contacted with water and an alkali metal salt, particularly sodium chloride. Where dry compositions are made, the salt may be incorporated directly into the metal ingredients. In such a case, the salt is normally used at a level of from about 0.01-10% by weight, more preferably from about 0.01-2% by weight. Where faster initiation of the exothermic reaction is desired, a minor amount of elemental iodine may be added to the compositions or present along with the salt during the reaction; the iodine is typically used at a level of up to about 5% by weight based upon the weight of the composition.
In one particularly preferred class of compositions, a ball-milled mixture containing from about 10-25% by weight powdered elemental magnesium, from about 35-45% by weight powdered elemental iron is prepared and mixed with from about 0.01-2% by weight sodium chloride, with the balance of the composition being made up of approximately one-half each of powdered elemental aluminum and powdered elemental zinc.
The compositions of the invention may be used directly or can be supported in containers or a synthetic resin matrix. For example, the compositions may be placed in liquid pervious bags for ease of use. Alternately, a self-sustaining body comprising the metal composition interspersed and held within a synthetic resin matrix may be prepared.
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Anthony Joseph D.
Hovey Williams Timmons & Collins
Hydronics, L.L.C.
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