A PROCES AND INSTALLATION FOR DESTROYING HAZARDOUS WASTES

Abstract: Hazardous waste containing organic compound having covalently bound oxygen, nitrogen, sulfur and/or phosphor­ us is reduced preferably in a reactor (5) with aluminium to less hazardous form.

Description: A Process and Installation for Destroying Hazardous-Wastes This invention is directed to a process and installation for destroying hazardous wastes containing organic compounds which contain covalently bound -element selected from the group consisting of oxygen, nitrogen, sulfur, and/or phosphorus. Many hazardous wastes have been disposed of improperly during the years since the chemical age began. Some of these resulted from incomplete reactions at chemical manufacturing plants; others were isomeric or sidereaction products which were not suitable for use. Still others are compounds which had been manufactured and in use, but had been discovered to present a real or potential hazard to workers in the plants manufacturing them, to their users, or to people exposed to them. Little notice was paid these discarded materials until recently, when the magnitude of their quantity has made it a problem which can no longer be ignored. Many were buried in improperly secured landfills; some in open dumps; some simply left standing in drums; some dumped on the ground. Some companies early in the "waste management" business charged generators for disposing of their wastes, and merely stockpiled them, without making any attempt to effect a proper, environmentally safe treatment or disposal. Thousands of these dumps are known to exist, and much attention is being given to methods of containment or disposal of their contents. More recently, much effort has gone into devising processes for their destruction or disposal. Methods for their disposal include: secured landfills; incineration in lime or cement kilns; incineration in specially constructed incinerators designed to retain the combustion gases for long periods of time in order to insure complete oxidation; oxidation in molten salt baths which utilize the molten salt to retain the combustion products and maintain the high temperature necessary. Recently adopted processes involve reaction of polychlorinated biphenyls (PCB's) with a sodium alkyl, a process which has been in use for a long time as an analytical tool. This is a reductive process in which the sodium in the sodium alkyl abstracts the chlorine from the PCB molecule. This can result in addition of the alkyl to the biphenyl ring structure, or it may be done in a medium which can supply substituents to the fragments. Sodium metal has also been applied to the analytical determination of organically bound halogens; reducing the covalently bound halogen and forming the negative halide ion. Starting from these facts it is the problem ofthe invention to make available a simple, economic and safe process and installation outlined above. The solution according the invention utilizes molten metallic aluminum or powdered aluminum and heating to react with the covalently bound oxygen, nitrogen, sulfur, and phosphorus in hazardous organic compounds containing these to reduce the compounds, for example, to form ionic inorganic salts or oxides, causing the organic residues to become dehydrated, combined, or rearranged into innocuous gaseous compounds. Preferred embodiments and a preferred installation are outlined in-the subclaimes. Hazardous compounds containing covalently bound oxygen which are treatable in the process herein include, for example, alcohols, aldehydes, ketones, carboxylic acids, esters and ethers. By such treatment, the compounds are reduced to unsaturated hydrocarbons, hydrogen and carbon; the aluminum becomes oxidized to aluminum oxide. Such compounds include: 3-(alpha-Acetonylbenzyl)-4-hydroxycoumarin and salts Ac role in Allyl alcohol Bis(chloromethyl) ether Bromoacetone 2-Butanone peroxide Chloroacetaldehyde Endrin Fluoroacetic acid, sodium salt 1,2,3,4,10, 10-Hexachloro-1 ,4,4a,5,8,8a-hexahydro- 1,4,5,8-endo, endo-dimethanonaphthalene Dimethodte Methomyl Oleyl alcohol condensed with 2 moled ethylene oxide 7-Oxabicyclo (2,2,1)heptane-2,3-dicarboxylic acid Pentachlorophenol Phenylmercury acetate Phosgene 1 ,2-Propanedlol 2 Propyn-7-Ol Acetone Acetyl chloride Acrylic acid Bis (2-chlorethoxyl) methane Acetone Bis (2-chloroethyl) ether Bis (2-chloroisopropyl) ether Bis (2-ethylhexyl) phthalate 4-Bromophenyl phenyl ether n-Butyl alcohol Carbonyl fluoride Chloral Chlordane Chlorobenzilate p-Chloro-m-cresol l-Chloro-2,3-epoxypropane Chlorethyl vinyl ether Cresols Crotonaldehyde Cresylic acid Cyclohexanone Di-n-butyl phthalate 2,4-Dichlorophenol 2,6-Dichlorophenol Diepoxybutane Diethyl phthalate Diethylstilbestrol Dihydrosafrole Alpha, alpha-dimethylbenzylhydroperoxide 2,4-Dimethylphenol Dimethyl phthalate Di-n-octyl phthalate 1 ,4-Dioxane Ethyl acetate Ethyl acrylate Ethylene oxide Ethyl ether Ethylmethacryl ate Formaldehyde Formic acid Fur,an Furfural GEycidylaldehyde Hexachlorophene Hydroxydimethyl arsine oxide Iron Dextran Isobutyl alcohol Isosafrole Kepone Maleic anhydride Methanol Methyl chlorocarbonate Methyl ethyl ketone Methyl ethyl ketone peroxide Methyl isobutyl ketone Methyl methacrylate 1,4-Naphthoquinone Oxalic acid Paraldehyde Phenol Phthalic anhydride Quinones Resorcinol Safrole 2,3,4, 6-Tetrachlorophenol Tetrahydrofuran Toxaphene 2,3,5-TP 2,4,5-Trichiorophenol 2,4,6-Trichiorophenol 2,4,5-Trichlorophenoxyacetic acid 2,4,5-Trichlorophenoxy propionic acid Hazardous compounds containing covalently bound nitrogen which are treatable by the process herein include, for example, amines and nitriles (cyanides). In the treatment herein, these are reduced to hydrocarbons, hydrogen, nitrogen and carbon, while the aluminum is converted to the nitride. Such compounds include: 4-Aminopyridine p-Chloroaniline 3-Chioropropionitri le Cyanogen Cyanogen bromide Cyanogen chloride Alpha, alpha-dimethylphenethylamine Ethylcyanide Ethylenediamine Ethyleneimine Hydrocyanic acid 2-Methylaziridine Methyl hydrazine 2-Methyllactonitrile Nicotine and salts Propionitrile Acetonitri le Acetylaminofluorene Acrylonitri le Amitrole Aniline Auramine Benz(c)acridine N,N-Bls (2-chloroethyl)-2-naphthylamine 3,3-Dichlorobenzidine 1,2-Diethylhydrazine Dimethylamine p-Dimethylaminoazobenzene 3,3-Dimethylbenzidine 1,2-Diethylhydrazine Dipropylamine Maleic hydrazide Malononitrile Melphalan Methacrylonitrile 4,4-Methylene-bis-(2-chloroaniiine) 1,4-Naphthylamine 2-Naphthylamine 2-Picoline n-Propylamine Pyridine Toluenediamine Toluldine hydrochloride Hazardous organic compounds containing covalently bound sulfur which are treatable by the process herein include sulfides, thiols, thiocarbonyls, thioketones and mercaptans. In the treatment herein, these are reduced to hydrocarbons, carbon and hydrogen while the aluminum is oxidized to the sulfide. These compounds include: Thiocarbonyl chlorine Carbon disulfide Thioacetone trimer Methyl mercaptan Endosulfan Tri chioromethaneth iol Hazardous organic wastes containing covalently bound phosphorous which are treatable by the process herein include, for example, phosphines, e. g. methyl phoshine. Treatment hen results in formation of hydrocarbons, hydrogen and carbon while aluminum phosphide is formed. The hazardous organic compounds containing both covalently bound oxygen and covalently bound nitrogen which are treatable by the process herin include, for example, nitro and nitroso compounds, amides, oximes, amino alcohols, and amino acides. By the treatment herein such compounds are reduced to hydrocarbons, hydrogen, nitrogen and carbon, while the aluminum is converted to oxide and nitride. Such compounds include: 5-(Aminomethyl )-3- isoxazolol Ammonium picrate Brucine 2-Sec-Butyl-4,6-dinitrophenol 1-(p-Chlorobenzoyl )-5-methoxy-methylindole-3-acetic acid Dieldrin 4,6-Dinitro-o-cresol and salts 2,4-Dinitrophenol 2-Fluoroacetamide Isocyanic acid, methyl ester 2-Methyl -2- (methylthlo)propionaldehyde-o- (methylcarbonyl) oxime N-Methyl-N-nitro-N-nitrosoguanidine p-Nitroaniline Nitrobenzene Nitroglycerine N-Nltrosodimethylamine N-Nitrosodiphenylamine N-Nitrosomethylvinylamine 6-Amino-1,1a,2,8,8a,8b-hexahydro-8-(hydroxymethyl) 8-methoxy-5-methylcarbamate azirino(2',3',3,4) pyrrolo(1,2-a) indole-4,7-dione(ester) Azaserine Chlorambucil Daunomycin 3,3-Dimethylbenzidine Dimethylcarbamoyl chloride Dimethylnitrosamine 2,4-Dinitrotoluene 2,6-Dinitrotoluene Di-n-propylnltrosamlne Maleic hydazide 4-Nitrophenol 2-Nitropropane N-Nitrosodi-n-butylamine N-NitrosodiethanoIamine N-Nitrosodiethylamine N-Nitrosodi-n-propylamine N-Nitroso-n-ethylurea N-Nitroso-n-methylurea N-Nitroso-n-methylurethane N-Nitrosopiperidine N-Nitrosopyrrolidine 5-Nitro-o-toluidine Pentachloronitrobenzene Phenacetin Pronamide Reserpine Saccharin Streptozoticin Toluene diisocyanate Trinitcobenzene Uracil mustard Urethane Hazardous organic compounds containing both covalently bound oxygen and covalently bound sulfur which are treatable by the process herein include, for example, sulfonic acids, sulfonates, thiols and sulfones. In the treatment herein, these are converted to hydrocarbons, carbon and hydrogen and the aluminum is oxidized to oxide and sulfide. Such compounds include: Benzenethlol Dimethyl sulfate Dodecylbenzene sulfonic acid Endosulfan Ethyl methanesulfonate 1,3-Propane sulfone Hazardous organic compounds containing both covalently bound oxygen and covalently bound phosphorus which are treatable by the process herein include, for example, phosphates, phosphonates and phosphine oxides. By the treatment by the process herein, these are reduced to hydrocarbons, carbon and hydrogen and the aluminum is oxidized to oxide and phosphide. Such compounds include: Hexaethyl tetraphosphate Methylene diphosphonate Tetraethylpyrophosphate Tris-(2,3-dibromopropyl) phosphate Hazardous organic wastes containing both covalently bound nitrogen and covalently bound sulfur which are treatable by the process herein include, for example, thioamides, and aminothiols. These reaction the process herein to form hydrocarbons, hydrogen carbons and nitrogen while the aluminum forms nitride and sulfide. Compounds of this type are: 1-(o-Chlorophenyl)thiourea 2,4-Dithiobiuret Ethylene bis dithiocarbamate Ethylene thiourea Methyl pyrilene Methyl thiouracil 1-Naphthyl-2-thiourea N-Phenylthiourea Thioacetamide Thiosemicarbazide Thiourea Thiouram Trichloromethanethiol Hazardous organic wastes containing oxygen and nitrogen and sulfur; oxygen and phosphorus and sulfur; oxygen and nitrogen and phosphorus, those containing all four; including those which additionally contain halogen; react with molten aluminum to either carbonize or degrade the compound into simpler hydrocarbons or hydrogen and carbon. The aluminum reactent forms the appropriate salt or salts Hazardous organic wastes having more than two of these elements as substituents are as follows: 1-Acetyl-2-thourea Dial late Dimethoate Ethylenebisdithfocarbamate Methylthiouracil Trypan blue O,O-Diethyl-S-(2-(ethylthio)ethyl)ester of phosphorothioic acid Phorate Tetraethyldithiopyrophosphate O,O-Diethyl-S-methyl ester of phosporodlthiolc acid Octamethylpyrophosphoramide 3,3-Dimethyl-l-(methylthio)-2-butanone-0 (methyl amino) carbonyl oxime Methyl parathion Parathion As indicated above the hazardous organic compounds treated herein sometimes additionally contain halogen, e.g. chlorine, bromine, iodine or fluorine. The use of powdered aluminum coupled with heating or molten aluminum for hazardous waste destruction combines the strong reducing power of this active metal with the naturally destructive tendency of heat. A presently preferred process and installation for carrying out the invention are schematically illustrated in Fig. 1 and comprise the following: Incoming solid hazardous wastes are placed in a receiving hopper 1, which is covered and sealed when not being loaded. The waste Is then conveyed by a horizontal screw conveyor 2 to a feed hopper 3. A vertical screw conveyor 4 feeds the waste downward through an open tube which has its terminus near the bottom of a reactor 5 into the bath of molten aluminum 6 with the upper surface of both being benoted by reference numeral 20. Vapors rising from the reaction zone pass into a water trap 7 via pipe 23 and then are compressed by compressor 8 and stored for fuel in pressure tank 9, or else are flared to the atmosphere through a fire screen 13. Liquid hazardous wastes are stored in a storage tank 10, and a pump 11 pumps them through the apertures in the inlet pipe 12 into the reactor 5. Liquids or vapors--either from vaporization of the liquids, or from reaction, rise through the aluminum 6 and react completely. In a less preferred embodiment, hazardous waste is treated with powdered aluminum and heating. This is readily carried out in either a continuous or a batch process. Continuous processing can involve, for example, mixing and/or milling hazardous waste and powdered aluminum, and conveying the resulting admixture through a tube furnace. Batch processing can involve mixing hazardous waste and powdered aluminum, and heating the resulting admixture in a sealed chamber Preferably, the heating is to procide a temperature of at least about 250 C. In processing with molten aluminum, the temperature is at least 6600C, which is the melting point of aluminum. Temperatures up to the boiling point of aluminum of 2 4500C are readily used. Preferably, the temperature ranges from 680"C to about 2 3000C and very preferably from about 7800C to about 1 000 C. The amount of molten aluminum utilized is preferably many times that needed to react with the waste being processed, e.g. 100 times or more, i.e. -an amount which is in overwhelming excess. In the processing herein, as indicated above, hydrocarbons and hydrogen can be formed. The hydrocarbons can include combustible gases such as methane, propane, acetylene, and ethene. The hydrogen and gaseous hydrocarbons which are formed are readily utilized for combustion to provide the molten aluminum reactant or to provide the heating when processing with powdered aluminum. Hazardous waste which is treated can contain one of Åa plurality of hazardous organic compounds. The following specific examples illustrate the invention. The apparatus for use in Examples II, III, IV, VII and XI is adapted for use in destroying the liquid wastes treated in these examples. In these examples* the liquid waste to be destroyed is vaporized in a preheater chÅamber heated by a furnace and the formed vapor is routed into a bath of molten aluminum via a delivery tube andsager which is located in a bell reactor in a bat of molten aluminum in a crucible. The vapor passes into and reacts with the molten aluminum in:the bell reactor and gaseous products of the reaction rise and leave the molten aluminum bath and accummulate at the top of'the bell reactor from where they are routed by a discharge tube to the mouth of a water trap located in a reservoir for holding the water displaced from the trap by entering gas. the discharge tube is equipped with a check valve to prevent water from the trap and reservoir from syphoning into the reactor. The apparatus for use in Examples I, V, VI, VIII, IX, X, XII and XIII is adapted for use in destroying the solid wastes treated in these examples. In these examples, the solid waste to be destroyed is placed in an aluminum tube which is sealed to form a capsule and the capsule is fastened with a screw to the inside of a pipe welded to an open end of a larger pipe which is capped at the other end where it communicates with an exit pipe. The assembly is lowered into a bath of molten aluminum contained in a crucible so that the aluminum tube is immersed in the molten aluminum whereby the aluminum tube melts to expose the solid waste to the molten aluminum bath whereby reaction between the waste and the molten aluminum occurs. The gaseous products of the reaction leave the bath and the larger pipe via the exit pipe and are recovered in a water trap. Example I Twenty grams of a waste oxalic acid are treated and constitute the solid waste placed in the aluminum tube and processed in the apparatus for solid waste destruction described above. The aluminum bath is held at a temperature of 8500C by means of an electric furnace. The aluminum is used in an overwhelming excess over that required for this quantity of oxalic acid. Reaction occurs and produces 4,2 liters of hydrogen gas in the trap; and both carbon and aluminum oxide on the surface of the molten metal. No residual oxalic acid is found in the slag or in the trapped gas. Example II Seventy-four (72) grams of contaminated n-butyl alcohol from pathological preparations is vaporized and treated in the apparatus for liquid waste destruction described above. The aluminum bath is held at 8500C. The aluminum is used in an overwhelming excess over that required to react with the waste. The butyl alcohol waste reacts with the molten aluminum and Is completely destroyed, producing 41,2 liters of gas, and aluminum oxide. The gas consists of a mixture of hydrogen and butene-1, with less than 1% each of butane and propene-1. Example III Fifty-eight (58) grams (idol) of waste acetone solvent is substituted for the butanol in Example II and reacts with the molten aluminum. No trace of acetone could be found in any of the raction products. The reaction produces 18,3 liters of gas, consisting of 82% methyl acetylene (propyne-1), and 7% 2,3-dimethylbutene-2, and minor quantities of other unidentified gases. Example IV Sixty (60) grams of waste formaldehyde (embalming fluid) is substituted for the n-butanol in Example II and reacts with the molten aluminum. Less than 0,01% of the total is found in the water in the vapor trap. Hydrogen gas is formed, (41,7 liters), leaving carbon and aluminum oxide on the surface of the molten metal. Example V Forty-six (46) grams (Imol) of waste diethyl ether from fat extractions is substituted for the butanol in Example I, with the result that the ether is destroyed and 64,4 liters of gaseous product is formed. The gas consists of 98% hydrogen and about 1% each of methane and ethane. Example VI Waste dimethyl phthalate (19,4 grams) from a polyester resin formulation is substituted for the oxalic acid In Example I, with the result that the dimethyl phthalate is destroyed, producing 10,1 liters of gas, comprising 35% acetylene and 63X hydrogen. The water trap also contains dissolved acetylene, but no dimethyl phthalate is detected in any of the products. Example VII A 41ml sample of waste acetonitrile used in preparation of thin-layer chromatographic samples is substituted for the butanol in Example II. The acetonitrile is completely destroyed, producing 31,3 liters of hydrogen gas with a trace of a higher molecular weight hydrocarbon gas believed to be butyne-2. Both slag and metal yield ammonia when treated with caustic. Example VIII Thirteen (13) grams of naphthylamine which is too impure for use in chemical synthesis is substituted for the oxalic acid in Example I. The naphthylamine is destroyed, producing 9,2 liters of gas comprising 62% acetylene and 34% hydrogen. Treatment of the slag with water produces ammonia gas. A sample of the molten metal is dissolved in acid and the resulting solution made alkaline with sodium hydroxide; upon mild heating, ammonia evolves from the solution. Example IX Seventy-six (76) grams (Imol) of used carbon disulfide from pesticide sample dilutions is substituted for the butanol in Example I. The carbon disulfide is completely destroyed. No gas is formed. Both slag and metal emit the characteristic odor of hydrogen sulfide when exposed to atmosheric moisture. Example X Waste tri-n-octyl phosphine oxide (19,39) left over from a research project, is substituted for the oxalic acid in Example I. The tri-n-octyl phosphine oxide is completely destroyed, yielding 4,8 liters of gas, comprising 33% hydrogen and 66% propene-1. Both the slag and a sample of the metal yield phosphine when treated with acid. Example XI A mixture containing contaminated methyl benzenersulfonate and ethyl benzene sulfonate is destroyed by distilling 91 grams of the mixture and passing the vapor through molten aluminum as in Example II. The sulfonates are completely destroyed, producing 21,7 liters of gas comprising ethylene, acetylene and hydrogen. The slag contains aluminum oxide, aluminum sulfide and carbon. Example XII Waste p-nitrophenol (13,99) is immersed in molten aluminum as in Example I. Reaction occurs to produce 5,5 liters of gas which is 80X acetylene and 20X hydrogen. The slag contains carbon and releases ammonia upon treatment with 10% caistic solution, demonstrating complete reduction of the nitro group, and destruction of the p-nitrophenol. Tests for phenols in the slag, aluminum, water trap and gas indicate below 1 part per million. Example XIII Twenty (20) grams) of a polyglycol ester of phosphoric acid (a waste detergent) is substituted for the oxalic acid in Example, with the result that it is completely decomposed, forming 11,5 lieters of a mixture of ethylene and acetylene. No phosphate or detergent can be detected in the metal, slag, or vapor; or in the water trap. Phosphene is detected in both slag and metal samples upon adding acid, igniting the gas stream and playing the flame on a cold surface. Example XIV p-Nitrophenol Is treated with powdered aluminum at 3000C. The resulting reaction is exothermic reducing the nitro group to form a compound in the residue which hydrolyzes to ammonia A gas tentatively identified as acetylene is given off during the reaction. Example XV Triphenyl phosphine is immersed in molten aluminum and gaseous hydrocarbon and hydrogen evolves. While the foregoing describes preferred embodiments, modifications within the scope of the invention will be evident to those skilled in the art. Thus, the scope of the invention is intended to be defined by the claims.

Claims: C I a i m s 1. A process for destroying hazardous wastes containing hazardous organic compounds which contain covalently bound element selected from the group consisting of oxygen, nitrogen, sulfur and/or phosphorus, said process is caracterlzed in contacting such compound with metallic aluminum to react with the covalently bound element to reduce the compounds thereby destroying the compounds and forming less hazardous product. 2. A process as recited in claim 1 where molten aluminum is used. 3. A process as recited in claim 1, wherein hazardous waste is treated with powdered aluminum and heating. 4. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound oxygen and is selected from the group consisting of alcohols, aldehydes, ketones, carboxylic acides, esters, and ethers. 5. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound nitrogen and is selected from the group consisting of nitriles and amines. 6. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound sulfur and is selected from the group consisting of sulfides, thiols, thioketones, thiocarbonyls and mercaptans. 7. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound phosphorus and is a phosphine. 8. A process as recited in claim 2 or-3, in which the hazardous organic compound contains both covalently bound oxygen and covalently bound nitrogen and is selected from the group consisting of nitro compounds, nitroso compounds, amides, oximes, amino alcohols and amino acids. 9. A process as recited in claim 2 or 3, in which the hazardous organic compound contains both covalently bound sulfur and covalently bound oxygen and is selected from the group consisting of sulfonic acids, sulfonates, thiols and sulfones. 10. A process as recited in claim 2 or 3, in which the hazardous organic compound contains both covalently bound oxygen and covalently bound phosphorus and is selected from the group consisting of phoshates, phosphonates and phosphine oxides. 11. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound sulfur and covalently bound nitrogen and is selected from the group consisting of thioamides and amino thiols. 12. A process as recited in claim 2 or 3, in which the hazardous organic compound additionally contains halogen. 13. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound oxygen, nitrogen and sulfur. 14. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound oxygen, sulfur and phosphorus. 15. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound nitrogen, phosphorus and oxygen. 16. A process as recited in claim 2 or 3, in which the hazardous organic compound contains covalently bound oxygen, nitrogen, phosphorus ans sulfur. 17. Installation for the performance of the process accord ing claim 2, characterized in a solid waste receiving hopper (1), a horizontal screw conveyor (2) connecting the receiving hopper (1) with a feed hopper (3), a reactor (5) containing a bathbf molten aluminum, a vertical screw conveyor (4) feeding the waste downward through an open tube which has its terminus near the bottom of the reactor (5),-a liquid waste storage tank (10) connected with the reactor (5) by a pipe (12) charged by a pump (11) and introduced in the reactor and having there apertures, a water trap (7) the bottomslde of which is connected with the head region of the reactor (5) by a pipe (23) and the head region of which is connected to an outlet leading to a fire screen (13) and/or a pressure tank (9) preferably charged by a compressor (8).

Inventors: SHULTZ, CLIFFORD G.
Applicants: SHULTZ, CLIFFORD G.
Application year: 1985
Main classification: A62D3
IPC codes: B09B3, A62D101, A62D3