Method and composition for neutralizing hazardous material spills

Description

Background of the Invention

[0001] This invention relates to compositions and methods useful to neutralize both acidic materials and alkaline materials. More particularly, the invention relates to compositions and methods useful to neutralize or reduce the acidic character or the alkaline character of an acidic or alkaline material, for example, a quantity of hazardous material resulting from an accidental spill.

[0002] Materials which are at least potentially hazardous to human and/or animal health and/or to the environment are necessarily used or produced throughout industry. The use, production, storage, transportation and/or disposal of such hazardous materials are often closely regulated and monitored to reduce risks associated with these materials. However, instances do arise in which hazardous materials are spilled or otherwise escape entrapment. In these instances, in order to avoid or reduce health/environmental risks and damage, it is often necessary to "clean up" this material.

[0003] Hazardous materials are often acidic or alkaline. Thus, one approach to "cleaning up" such hazardous materials has been to neutralize this acidic or alkaline character. For example, if the material is acidic, a strong base, such as sodium hydroxide, can be mixed with the material. If the material is alkaline, a strong acid, such as sulfuric acid, can be combined with the material.

[0004] Several problems exist with this approach. First, it is often not apparent whether a particular hazardous material is acidic or alkaline. Thus, substantial time may be spent in determining whether a particular material is acidic or alkaline. Also, workers using the approach outlined above must come prepared for two separate treatments. That is, a supply of strong acid and a separate supply of strong base must be available. The need to carry both an acid and a separate base, one of which will not be used in any one particular application, disadvantageously burdens such workers, and adds to the cost of the clean up. In addition, the use of a strong acid or a strong base can result in violent reactions, generation of excessive amounts of heat and the production of products, for example, gases, which are themselves toxic or otherwise hazardous.

[0005] Clearly, it would be advantageous to provide a new system for reducing the acidity or alkalinity of materials, such as hazardous materials.

Summary of the Invention

[0006] New compositions and methods useful for neutralizing both acidic materials, for example, acidic hazardous materials, and alkaline materials, for example, alkaline hazardous materials, have been discovered. The present system employs a single composition effective to reduce the acidity or the alkalinity of the material with which it is contacted. Therefore, no valuable time need be spent before treatment in determining whether the material is acidic or alkaline. Also, only a single, relatively inexpensive composition need be available, thus saving on costs and the amount of equipment needed to treat the material.

[0007] In addition, the present compositions are designed for controlled rates of reaction, for example, neutralization, thus reducing the risks of violent reactions and excessive generation of heat. The present compositions are usable with a wide variety of materials, e.g., hazardous materials, to provide treated materials which are more environmentally acceptable (relative to the original, untreated material) and which preferably are substantially non-toxic, non-hazardous and stable. The treated material may be amenable to disposal as a non-hazardous waste. The present compositions are preferably non-toxic to man and are non-hazardous under U.S. Environmental Protection Agency (EPA), National Fire Protection Association (NFPA) and U.S. Department of Transportation (DOT) guidelines. Further, these compositions can be stored for prolonged periods of time without substantial decomposition or other deterioration.

[0008] In short, the present invention relatively inexpensively provides for the effective reduction of the acidity or alkalinity of a material, e.g., a hazardous material spill, preferably in an environmentally suitable manner to produce a more environmentally acceptable treated material.

[0009] In one broad aspect, the present invention is directed to compositions useful for neutralizing both acidic materials and alkaline materials which compositions comprise an admixture of a first alkaline earth metal component and a second alkaline earth metal component. The first alkaline earth component is present in an amount effective to at least partially neutralize an acidic material which is contacted by the composition. This first alkaline earth metal component has a limited degree of solubility in the acidic material at the conditions of use. The second alkaline earth metal component is present in an amount effective to at least partially neutralize an alkaline material which is contacted by the composition. The composition is preferably present in a solid form, more preferably as a mixture of solid particles of the first and second alkaline earth metal components. Both of these components are preferably magnesium components. In a particularly useful embodiment, the first magnesium component is selected from magnesium oxide, magnesium hydroxide and mixtures thereof, while the second magnesium component is selected from magnesium sulfate, magnesium sulfate hydrates and mixtures thereof. Such compositions have been found to very effectively reduce the acidity or alkalinity of a material, preferably rendering the treated material more environmentally acceptable than the original, untreated material.

[0010] In another broad aspect of the present invention, methods for increasing the environmental acceptability of a material having either an acidic character or an alkaline character are provided. These methods comprise contacting the material, the environmentally acceptable nature of which is to be increased, with a composition comprising both first and second alkaline earth metal components, as described herein.

[0011] The invention also includes methods for increasing the environmental acceptability of a material having an alkaline nature, by contacting the material with a composition including only the second alkaline earth metal component, such as water soluble magnesium sulfate.

[0012] These methods are effective to reduce either the acidic character or the alkaline character of the material and to form a treated material which is more environmentally acceptable than the original, untreated material. In a preferred embodiment, the treated material is disposed of, for example, in a landfill or other location, in an environmentally suitable or sensitive manner.

[0013] In general, the present invention is applicable to a wide variety of materials to provide treated materials which are more environmentally acceptable relative to the original, untreated material. By "environmental acceptability" is meant the measure of a given material's overall effect on the environment. Thus, a material which has increased environmental acceptability is one which overall has a reduced detrimental effect on the environment relative to a reference material. Put another way, a material which has increased environmental acceptability has increased environmental quality relative to a reference material.

Detailed Description of the Invention

[0014] The present compositions comprise admixtures of first and second alkaline earth metal components.

[0015] The first alkaline earth metal components useful in the present invention are present in an amount effective to at least partially neutralize an acidic material which is contacted by the present composition. In other words, the first alkaline earth metal component is effective to reduce the acidic character of an acidic material. This first alkaline earth metal component has a limited degree of solubility in the acidic material at the conditions of use. In a preferred embodiment, the second alkaline earth metal component has an increased solubility in water at 25° C. relative to the solubility of the first alkaline earth metal component in water at 25° C.

[0016] This limited degree of solubility of the first alkaline earth metal component is advantageous in controlling the rate at which the acidity of the material being treated is reduced. Thus, with the rate of acidity reduction effectively controlled by the limited solubility of the first alkaline earth metal component of the present compositions, the risks of violent reactions with the acid or acids present in the materials being treated is reduced. In addition, the risk of generating heat at an excessively high rate is reduced. This limited solubility feature of the present invention is important since it reduces the risks to the workers treating the material and to the environment surrounding the material being treated.

[0017] Any suitable alkaline earth metal component which is capable of functioning as a first alkaline earth metal component, as described herein, may be used as such in the present invention. The alkaline earth metals include beryllium, magnesium, calcium, strontium and barium. Because of their generally good environmental acceptability, components of calcium and magnesium are advantageously used in the present invention. Preferably, the first alkaline earth metal component is a first magnesium component. Particularly useful first magnesium components are selected from magnesium oxide (magnesia), magnesium hydroxide and mixtures thereof. These particularly useful first magnesium components are practically insoluble (magnesium oxide) or have very low solubility (magnesium hydroxide) in water, for example, at 25° C.

[0018] The second alkaline earth metal component is present in an amount effective to at least partially neutralize an alkaline material which is contacted by the present composition.

[0019] It has been discovered that the second alkaline earth metal component can also be used in the methods described herein by itself, and without the first alkaline earth metal component. In these methods, a composition of the second alkaline earth metal component is effective at least partially to neutralize an alkaline material.

[0020] Any suitable alkaline earth metal component which is capable of functioning as a second alkaline earth metal component as described herein, may be used as such in the present invention. Preferably, the second alkaline earth metal component is a second magnesium component. Particularly useful second magnesium components are selected from magnesium salts of acids, hydrates of magnesium salts of acids and mixtures thereof. Examples of acids the magnesium salts of which can be employed as the second magnesium component include hydrochloric acid, sulfuric acid, thiosulfuric acid, phosphoric acid, sulfurous acid, carboxylic acids, for example, acetic acid, and the like. More preferably, the second magnesium component is selected from magnesium sulfate, magnesium sulfate hydrates and mixtures thereof, and still more preferably from hydrates of magnesium sulfate.

[0021] Particularly useful magnesium sulfate hydrates have the following formula:



        MgSO₄ · xH₂O



wherein x is an integer from 1 to 7, preferably 1 or 7.

[0022] In a particularly useful embodiment, the first alkaline earth metal component is present in an amount in the range of about 10% to about 80%, more preferably about 20% to about 60%m and still more preferably about 25% to about 40% by weight of the total composition; while the second alkaline earth metal component is preferably present in an amount in the range of about 20% to about 90%, more preferably about 40% to about 80% and still more preferably about 60% to about 75% by weight of the composition.

[0023] The present compositions are preferably present in the form of admixtures comprising solid particles of the first alkaline earth metal component and solid particles of the second alkaline earth metal component.

[0024] The present compositions can be made very conveniently and easily, for example, from the individual components which are often plentiful and readily available, using conventional blending techniques, for example, solid powder blending procedures. Each of the components may be ground and/or milled and/or otherwise processed to provide the desired particle size. The present compositions may be formed by blending together the two components.

[0025] Additional materials can be included in the present compositions to provide one or more beneficial properties to the compositions. Examples of such additional components include fillers, drying agents, absorbants, reducing agents, and the like. A particularly useful embodiment of the present invention involves the compositions which consist essentially of the first alkaline earth metal component and the second alkaline earth metal component as described herein.

[0026] The present compositions are useful in methods for increasing the environmental acceptability of a material having either an acidic character or an alkaline character. These methods comprise contacting the material to be treated with a composition in accordance with the present invention at conditions effective to reduce the acidic character or the alkaline character of the material and form a treated material which is more environmentally acceptable than the original, untreated material.

[0027] Another form of the compositions described herein is useful in methods for increasing the environmental acceptability of a material having an alkaline character. Preferably such compositions would include a major portion, such as 50% by weight, of the second alkaline earth metal component. In any event, the second alkaline earth metal component should be present in the composition in sufficient amounts at least partially to neutralize and treat an alkaline material which is contacted by the composition.

[0028] The treated material is preferably further processed, for example, is recovered and/or otherwise removed from the place where the original, untreated material was located, for disposal in an environmentally acceptable manner, for example, by incineration, placement in landfill, or other suitable disposal methodology.

[0029] The conditions of the above-noted contacting may be selected to provide for the desired reaction or reactions between the present composition and the material to be treated. Often, such conditionsl are dictated by the location of the material to be treated. For example, if the material to be treated is the result of a spill, then the contacting with the present composition most probably will occur at the site of the spill.

[0030] The types of materials, e.g., hazardous materials, which can be treated in accordance with the present invention may have widely varying compositions, and may have an acidic character or an alkaline character. Such acidic character or alkaline character can be derived from any acidic or alkaline component, respectively, which is included in the material. Examples of such acidic components include sulfuric acid, nitric acid, hydrochloric acid, carboxylic acids, phosphoric acid, acidic derivatives, e.g., acidic salts, of such acids and the like and mixtures thereof. Examples of alkaline components include sodium hydroxide, e.g., in form of lye, caustic soda and the like, potassium hydroxide, ammonium hydroxide, other well known hydroxides and other bases, alkaline derivatives, e.g., basic salts, of such bases and the like and mixtures thereof. The material to be treated in accordance with the present invention may be a waste material, for example, caused by spillage or produced as part of a manufacturing or other process.

[0031] The materials which are treated in accordance with the present invention preferably contain a liquid phase, more preferably an aqueous liquid phase.

[0032] The following non-limiting examples illustrate certain aspects of the present invention.

EXAMPLE 1

[0033] The composition in accordance with the present invention used in the Examples was prepared as follows. Magnesium sulfate heptahydrate (MgSO₄ · 7H₂O) was ground in a mortar and pestle until there were no apparent lumps. Then magnesium oxide was added to this ground material in an amount equal to one half (1/2) the weight of the original amount of magnesium sulfate heptahydrate. These ingredients were thoroughly mixed until an even, substantially homogenous mixture was obtained. No more than 90 grams of this mixture were prepared at any one time.

[0034] An aqueous solution of concentrated sulfuric acid (18.00 grams) was placed in a 600 ml glass beaker. The initial pH of this concentrated sulfuric acid solution was less than zero. With the acid being subjected to stiring using a conventional magnetic stirrer, 28.77 grams of the above-noted mixture was added to the acid. This caused the generation of a minor amount of heat. An additional 500 ml of distilled water was added into the beaker to facilitate measuring the pH. The final pH of this combined mixture was 9.16.

[0035] Throughout the experiments reported here as Examples, the room temperature was maintained between about 22° C and about 24° C.

EXAMPLE 2

[0036] An aqueous solution of concentrated nitric acid (13.18 grams) was placed in a 600 ml glass beaker. The initial pH of this concentrated nitric acid solution was less than zero. With the acid being subjected to stirring using a conventional magnetic stirrer, 20.38 grams of a mixture prepared as set forth in Example 1 was added to the acid. This caused the generation of a minor amount of heat and some fumes. An additional 500 ml of distilled water was added into the beaker to facilitate measuring the pH. The final pH of this combined mixture was 9.67.

EXAMPLE 3

[0037] An aqueous solution of concentrated hydrochloric acid (76.30 grams) was placed in a 600 ml glass beaker. The initial pH of this concentrated hydrochloric acid solution was less than zero. With the acid being subjected to stirring using a conventional magnetic stirrer, 70.16 grams of a mixture prepared as set forth in Example 1 was added to the acid. This caused the generation of a minor amount of heat, but no major generation of fumes. An additional 500 ml of distilled water was added into the beaker to facilitate measuring the pH. The final pH of this combined mixture was 6.12.

EXAMPLE 4

[0038] A quantity (11.38 grams) of an aqueous solution containing 50% by weight of sodium hydroxide was placed in a 600 ml glass beaker. The initial pH of this sodium hydroxide solution was greater than 14. With the sodium hydroxide solution being subjected to stirring using a conventional magnetic stirrer, 57.94 grams of a mixture prepared as set forth in Example 1 was added to the sodium hydroxide solution. This resulted in good mixing and absorbing of the mixture into the aqueous medium. An additional 500 ml of distilled water was added into the beaker to facilitate measuring the pH. The final pH of this combined mixture was 9.70.

EXAMPLE 5

[0039] A concentrated aqueous solution of ammonium hydroxide (56.0 grams) was placed in a 600 ml glass beaker. The initial pH of this concentrated ammonium hydroxide solution was 13.65. With the ammonium hydroxide solution being subjected to stirring using a conventional magnetic stirrer, 116.75 grams of a mixture prepared as set forth in Example 1 was added to the solution. This caused the characteristic ammonia odor to vanish and resulted in a somewhat thick solution. The final pH of this mixture was 10.76.

EXAMPLE 6

[0040] An aqueous solution containing 23% by weight of sodium metasilicate pentahydrate (130.86 grams) was placed in a 600 ml glass beaker. The initial pH of this silicate-containing solution was 13.47. With this solution being subjected to stirring using a conventional magnetic stirrer, 59.0 grams of a mixture prepared as set forth in Example 1 was added to the silicate-containing solution. This caused the generation of no significant amount of heat. The final pH of this combined mixture was 9.55.

[0041] The results of these Examples demonstrate that compositions in accordance with the present invention are suitable for neutralizing both acidic media and alkaline media. Thus, in each of the Examples, the pH of the final combined mixture was substantially closer to a neutral pH, that is a pH of 7, relative to the pH of the original starting material. In addition, and quite importantly, no violent reactions were observed, only relatively minor amounts of heat were generated and, in most instances, little or no fumes were observed.

[0042] The present compositions, for example, the mixture used in the Examples, are very effective for treating industrial wastes, for example, spills, to reduce the environmental harm which may potentially be caused by such wastes. To illustrate, if a railroad tanker car filled with concentrated sulfuric acid spills over an area adjacent to the ruptured car. After the car has been repaired and/or removed, the area of the acid spill is contacted with a composition in accordance with the present invention. For example, the mixture used in the Examples may be spread over the spill area. The spill area may be plowed or otherwise mixed , with the addition of more of the present composition, to ensure that the spilled acid has been neutralized. After the spilled acid has been neutralized, the affected area can be recovered, for example, in environmentally secure containers, and removed to a permanent disposal site, for example, a regulated and approved landfill area. In this manner, the detrimental effects of the acid spill on the environment are reduced without creating further substantial risks, for example, in terms of violent chemical reactions, excessive amounts of heat generation and toxic fume generation, as a result of this spill cleanup.

[0043] In effect, the present invention provides relatively inexpensive and straightforward compositions and methods for neutralizing acidic and alkaline materials in a effective and environmentally sound manner.

[0044] While this invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.

[0045] Compositions and methods for using the compositions useful for neutralizing both acidic materials, e.g., acidic spills, and alkaline materials, e.g., alkaline spills, are disclosed. In one embodiment, such a composition comprises an admixture of a first alkaline earth metal component in an amount effective to at least partially neutralize an acidic material which is contacted by the composition, the first alkaline earth metal component having a limited degree of solubility in the acidic material at the conditions of use, and a second alkaline earth metal component in an amount effective to at least partially neutralize an alkaline material which is contacted by the composition. In a second embodiment the composition includes a sufficient amount of the second alkaline earth metal component to at least partially neutralize an alkaline material contacted thereby.

Claims

1. A method for increasing the environmental acceptability of a material having an alkaline character which comprises:
   contacting said material with a composition comprising an effective amount of an alkaline earth metal component capable of at least partially neutralizing an alkaline material which is contacted with said composition, said contacting occurring at conditions effective to reduce the alkaline character of said material and form a treated material which is more environmentally acceptable than said material.

2. The method of claim 1 wherein said alkaline earth metal component is a magnesium component.

3. The method of claim 2 wherein said magnesium component is selected from the group consisting of magnesium salts of acids, hydrates of magnesium salts of acids and mixture thereof.

4. The method of claim 3 wherein said magnesium component is selected from the group consisting of magnesium salts of mineral acids, hydrates of magnesium salts of mineral acids and mixtures thereof.

5. The method of claim 3 wherein said magnesium component is selected from the group consisting of mineral salts, hydrates of magnesium salts of mineral acids and mixtures thereof.

6. The method of claim 3 wherein said magnesium component is selected from the group consisting of magnesium sulfate hydrates and mixtures thereof.

7. A method for increasing the environmental acceptability of a material having either an acidic character or an alkaline character which comprises;
   contacting said material with a composition comprising an admixture of a first alkaline earth metal component in an amount effective to at least partially neutralize an acidic material which is contacted by said composition, said first alkaline earth metal component having a limited degree of solubility in said material at the conditions of said contacting, and a second alkaline earth metal component in an amount effective to at least partially neutralize an alkaline material which is contacted by said composition, said contacting occurring at conditions effective to reduce the acidic character or the alkaline character of said material and form a treated material which is more environmentally acceptable than said material.

8. The method of claim 7 wherein said admixture comprises solid particles of said first alkaline earth metal component and solid particles of said second alkaline earth metal component.

9. The method of claim 7 wherein said first alkaline earth metal component is present in an amount in the range of about 10% to about 80% by weight of said composition and said second alkaline earth metal component is present in an amount in the range of about 20% to about 90% by weight of said composition.

10. The method of claim 7 wherein said first alkaline earth metal component is a first magnesium component and said second alkaline earth metal component is a second magnesium component, said first magnesium component is selected from the group consisting of magnesium oxide, magnesium hydroxide and mixtures thereof and said second magnesium component is selected from the group consisting of magnesium salts of acids, hydrates of magnesium salts of acids and mixtures thereof.

11. A composition useful for neutralizing both acidic materials and alkaline materials which comprises an admixture of:
   a first alkaline earth metal component in an amount effective to at least partially neutralize an acidic material which is contacted by said composition, said first alkaline earth metal component having a limited degree of solubility in the acidic material at the conditions of use; and,
   a second alkaline earth metal component in an amount effective to at least partially neutralize an alkaline material which is contacted by said composition.

12. The composition of claim 11 which is solid and wherein said second alkaline earth metal component has an increased solubility in water at 25° C relative to the solubility of said first alkaline earth metal component in water at 25° C.

13. The composition of claim 11 wherein said admixture comprises solid particles of said first alkaline earth metal component and solid particles of said second alkaline earth metal component.

14. The composition of claim 11 wherein said first alkaline earth metal component is present in an amount in the range of about 10% to about 80% by weight of said composition and said second alkaline earth metal component is present in an amount in the range of about 20% to about 90% by weight of said composition.

15. The composition of claim 11 wherein said first alkaline earth metal component is present in an amount in the range of about 20% to about 60% by weight of said composition and said second alkaline earth metal component is present in an amount in the range of about 40% to about 80% by weight of said composition.

16. The composition of claim 11 wherein said first alkaline earth metal component is present in an amount in the range of about 25% to about 40% by weight of said composition and said second alkaline earth metal component is present in an amount in the range of about 60% to about 75% by weight of said composition.

17. The composition of claim 11 wherein said first alkaline earth metal component is a first magnesium component and said second alkaline earth metal component is a second magnesium component.

18. The composition of claim 17 wherein said first magnesium component is selected from the group consisting of magnesium oxide, magnesium hydroxide and mixtures thereof.

19. The composition of claim 17 wherein said second magnesium component is selected from the group consisting of magnesium salts of acids, hydrates of magnesium salts of acids and mixtures thereof.

20. The composition of claim 17 wherein said second magnesium component is selected from the group consisting of magnesium sulfate, magnesium sulfate hydrates and mixtures thereof.

21. The composition of claim 18 wherein said second magnesium component is selected from the group consisting of magnesium sulfate hydrates and mixtures thereof.

22. The composition of claim 17 wherein said first magnesium component has a limited degree of solubility in the acidic material at the conditions of use; and said second magnesium component having an increased solubility in water at 25° C relative to the solubility of said first magnesium component in water at 25° C.

23. The composition of claim 22 wherein said first magnesium component is selected from the group consisting of magnesium oxide, magnesium hydroxide and mixtures thereof and said second magnesium component is selected from the group consisting of magnesium salts of acids, hydrates of magnesium salts of acids and mixtures thereof.

24. The composition of claim 23 wherein said second magnesium component is selected from the group consisting of magnesium sulfate hydrates and mixtures thereof.