AU664454B2 - Destruction of halogenated organic compounds - Google Patents

Description

64454

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

C. C

C.

C

TO BE COMPLETED BY APPLICANT Name of Applicant: BRAMBLES AUSTRALIA LTD Actual Inventor: ANTONY JOHN HENDRY Address for Service: WRAY ASSOCIATES, Primary Industry House, 239 Adelaide Terrace, Perth, Western Australia, 6000.

Attorney code: WR Invention Title: "Destruction Compounds" of Halogenated Organic 'Details of Associated Provisional Application No: PL3010 The following statement is a full description of this invention, including the best method of performing it known to me:- 1 2 This invention relates to a method for the destruction of halogenated organic compounds, and is particularly suited to destruction of halogenated organic compounds contained in a polluted medium.

In recent years there has been a growing awareness of the toxicity of halogenated hydrocarbons, and their detrimental effect on the environment. Such compounds include poly chlorinated biphenyls (PCB's), dichlorodiphenyl trichloroethane (DDT), dieldrin, lindane and chlordane.

S 10 Polychlorinated biphenyls were originally utilised in the electrical and electronic industries as a dielectric in capacitors, and as a coolant oil in high voltage electrical equipment. These compounds were favoured for this purpose because of their apparent inertness and their insulating 15 properties, however with the passage of time it became apparent that they were stored cumulatively in the human body, and were highly toxic. Various authorities have stockpiled containers of polychlorinated biphenyls, and quantities of these compounds have been destroyed by high 20 temperature incineration; however there is some resistance to the process of high temperature incineration from people living near the sites of such incinerators, due to the risks posed by the process. For example, if the reaction temperature falls below that required for destruction of the compounds, there will be emissions of halogenated hydrocarbons. Similarly there is some opposition to the transport of these compounds to the sites of destruction where these sites are overseas, due to the risks posed to wildlife should there be an accident resulting in a spillage.

Dichlorodiphenyl trichloroethane (DDT) and dieldrin have been utilised as insecticides. While the use of DDT ceased in most places in the world during the 1960's, and dieldrin 3 has been banned in the United States of America, the use of dieldrin as an insecticide has been practised in Australia quite recently. There have been instances where premises have been rendered uninhabitable when dieldrin has been misused, and where soil and ground water have been contaminated when an excessive quantity has been sprayed.

In these circumstance, there is a need to render the soil safe, before there -is any threat to the ground water.

Furthermore, in situations where industry has polluted its site soil, there is a need to clean this soil so that the site may be safely utilised.

The present invention seeks to provide a method for the destruction of halogenated organic compounds present in a polluted medium. The present invention is especially 15 advantageous as the polluted medium may also be contaminated with cationic heavy metals or other organic waste or both.

0e In accordance with one aspect of the present invention there is provided a method of treating halogenated hydrocarbon containing material to dehalogenate the hydrocarbon contained therein, comprising adding to said material, per mole of halogen group the following 6 reagents:group 1 or group 2 cation values in quantity at least sufficient to form metal halides with said halogen, 0* silicate anion values, and at least one mole of -OH group contained in a polyol; mixing said reagents and said material together, and raising the temperature to beyond 100°C for sufficient time to dehalogenate said hydrocarbon.

4 The method is especially advantageous as it can deal with heavy metal contaminants present in the material, precipitating them out as insoluble metal silicates.

Preferably said reagents are solubilised in a solvent such as water before mixing with said material, to ensure more thorough mixing. The solvent may conveniently be water.

Alternatively, said reagents are added directly to said material, with agitation to ensure thorough mixing.

Preferably prior to the step of raising the temperature, 10 the temperature is maintained at a level sufficient to drive off said solvent and/or any water present, before being raised to the final temperature to dehalogenate said hydrocarbon.

Preferably at least some of said cation values and said 15 aPAion values are provided by an alkali metal .silicate such as sodium silicate. Normal, meta, or ortho forms may be utilised. Where necessary, if further cations are required to satisfy stoichiometric requirements, these may be provided as inter alia hydroxide or silicate.

20 Preferably said polyol comprises inter alia glycerol, ethylene glycol, polymers thereof, or sugars, or a mix thereof.

Preferably prior to said reagents and material being heated to dehalogenate said hydrocarbon, a catalytic amount of a hydride such as sodium borohydride is added to the mixture.

Preferably where said material comprises an organic non aqueous liquid, an organic catalyst such as a bitumen, a bituminous oil, or a non aromatic cyclic organic compound is added to said material and reagents prior to heating to 5 dehalogenate said hydrocarbon. In this manner the temperature at which dehalogenation takes place may be reduced by up to 100 0

C.

When dehalogenation of the hydrocarbon is complete, the reaction products may be neutralised with an acid for handling and disposal purposes. Where the material comprises soil from a contaminated site, consideration should be given to using an acid which results in an environmentally acceptable neutralisation byproduct.

The above method gives rise to a number of processes for the destruction of halogenated organic compounds, depending on the volatility of the halogenated organic compounds and on the physical state of the contaminated medium. The halogenated organic compounds could range from relatively volatile solvents trichloro ethylene, perchloro ethylene, chlorofluoro carbons (CFC's), ethylene dibromide, tetrabromo ethane) to non volatile compounds, e.g., polychlorinated biphenyls (PCB's), dichloro diphenyl trichloro ethane (DDT), dieldrin, lindane and chlordane.

The physical state of the polluted medium may comprise soil, sediment, crushed concrete, charcoal, sludge, paper, wood, cork, oil, solvent, solution, or other liquids, slurries or solids. The method is suitable for use with contaminated mediums which contain up to 200,000ppm of halogenated organic compounds, or even higher levels, depending on the halogen content of the compounds. Where the quantity of halogen is excessive, it may be necessary to add further material to lower the proportion of halogen present in the mix.

In accordance with a second aspect of the present invention thee is provided a method of treating halogenated hydrocarbon containing liquid and a spent oil mixture, to 6 dehalogenate the hydrocarbon contained'therein, and recover the oil for reuse, comprising adding to said material, per mole of halogen group the following reagents:group 1 or group 2 cation values in quantity at least sufficient to form metal halides with said halogen, silicate anion values, and at least one mole of -OH group contained in a polyol; mixing said 'reagents, said liquid, and said spent oil together, and raising the temperature to beyond 100 0 C for 10 sufficient time to dehalogenate said hydrocarbon, and recovering the oil for reuse subsequent to dehalogenating said hydrocarbon.

The silicate in the reagents will deal with heavy metal contaminants present in the spent oil in the mixture, precipitating them out as insoluble metal silicates. In order to deal with the heavy metal contaminants, it will be necessary to ensure that sufficient silicate anions are present in the reaction.

Preferably said reagents are added directly to said 20 mixture, with agitation to ensure thorough mixing.

Preferably prior to the step of raising the temperature, the temperature is maintained at a level sufficient to drive off any water present, before being raised to the final temperature to dehalogenate said hydrocarbon.

-Preferably at least some of said cation values and said anion values are provided by an alkali metal silicate such as sodium silicate. Normal, meta, or ortho forms may be Sj utilised. Where necessary, if further cations are required to satisfy stoichiometric requirements, these may be supplied as inter alia hydroxide or silicate.

Preferably said polyol comprises inter alia glycerol ethylene glycol, polymers thereof, or sugars, or a mix thereof.

Preferably prior to the reagents being heated to dehalogenate said hydrocarbon, a catalytic amount of a hydride such as sodium borohydride is added to the mixture.

Preferably an organic catalyst such as a bitumen, a 10 bituminous oil, or a non aromatic cyclic organic compound is added to said mixture prior to heating to dehalogenate said hydrocarbon. In this manner the temperature at which dehaJogenation takes place may be reduced by up to 100 0

C.

The process of the invention will now be described by way 15 of a number of specific examples thereof.

Typically, for the treatment of nonvolatile halogenated organic compounds, the process comprises the addition oi an aqueous solution of soluble sodium silicate plus a polyol conveniently in the form of glycerol to the polluted medium. Where the medium comprises particulate solids, the aqueous nature of the reagents helps to evenly distribute them throughout the medium.

The material is then dehydrated by heating off the moisture between 80 0 C and 1200C at atmospheric pressure, or at lower temperature under reduced pressure.

For hydrophobic slurries or oils, the reagents are added dry; however this dehydration step will still be necessary to remove native moisture. In these circumstances, this step must be accompanied by agitation or stirring to effect 8 even distribution of reagents throughout the medium.

After dehydration, a catalytic amount of hydride source, sodium borohydride dissolved in glycerol, which acts as on hydride initiator, may be added to the reaction.

This step is thought to speed up the dehalogenation process.

The reaction then is heated further to a temperature of between 300 0 C and 350 0 C, with agitation. In the case of solids, a rotary reactor will be suitable to provide the necessary agitation, whereas for oils, liquids or slurries o a stirred reactor will most probably be required.

For the treatment of volatile and semi-volatile halogenated compounds, or volatile and semi-volatile halogenated compounds in solvents or oils, the medium may be dehydrated prior to the addition of reagents. The sodium silicate and glycerol are added to the previously dried contaminated medium, optionally with a catalytic amount of hydride initiator, sodium borohydride dissolved in glycerol.

Depending on volatility the reaction can be performed in a stirred high pressure reactor, utilising temperatures up to 300 0 C. As will be appreciated, caution must be exercised with high vapour pressure solvents and high pressure reactors must have adequate pressure safety margins for the solvent or the resultant degradation products.

The amount of reagents added depends on the physical nature of the mediul and the level of contamination of halogenated organic compound. In general, the reagents are added in an amount sufficient to provide from about 2g to 12g of polyol and about 1 to 6g of sodium silicate per gram of halogen, which is derived from the halogenated organic compounds in the medium and depending on the halogen. The sodium 9 borohydride is added in an amount of about 5 to 20mg per gram of halogen.

The time required to destroy the halogenated organic compounds is concentration dependant in the 300 0 C 350 0

C

temperature range. Generally, however, a medium containing less than 1% of halogenated organic compound requires about one hour for destruction. Each additional percentage of halogenated organic compound requires approximately an additional incremental hour to effect destruction at 3000C 350 0

C.

After heat treatment, the medium is neutralised with an acid, to produce a final medium in the pH range from about 7 to about 9. Sulphuric, nitric, phosphoric or hydrochloric acids can be used in this step.

t 15 The presence of sodium silicate in the process achieves the further objective of insolubilising and immobilising many soluble cationic heavy metals cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, tin, zinc), which may co-contaminate the medium. The general conditions, including heat treatment ensures that these cationic heavy metal ions precipitate out as insoluble metal-silicate complexes.

The addition of a catalysing amount of an organic catalyst such as a bitumen, a bituminous oil, or a non aromatic cyclic organic compound added to the medium and reagents prior to heating to dehalogenate said hydrocarbon may be advantageous in certain circumstances, particularly where the dehalogenation takes place in an organic liquid phase.

In these circumstances, the temperature at which dehalogenation takes place may be reduced by up to 100 0

C.

An example which follows will demonstrate that dehalogenation of halogenated hydrocarbons took place at 10 250 0 C when bunker oil tesidue recovered from a ship was added to the medium.

The processes that result from this method are demonstrated in the following examples EXAMPLE 1 This example demonstrates the application of the method according to the present invention which exemplifies a solids treatment process.

A polluted medium sample comprising organochlorine pesticide contaminated soil from a contaminated pesticide site owned by a pesticide company in Perth, Western Australia was gathered. This soil contained a cocktail of pesticides made up of an average (12 samples) of 72ppm aldrin, 1,210ppm "chlordane, 45ppm dieldrin and 73ppm heptachlor, that is a total of 1,400ppm of identified organochlorine pesticides.

200g of the contaminated soil was placed in a 500ml roundbottom flask and a solution of 50ml of water containing 2 mL of glycerol and Ig of sodium ortho-silicate was added

*.SS

20 to the contaminated soil. The resulting mixture was tumbled until homogenous. The flask was then placed in a heating mantle and equipped with a distillation head, condenser and receiving flask. A thermoprobe was inserted through a side-arm of the flask so that the probe-tip contacted the soil. Water was then distilled off over a period of 1 hour, during which time the temperature was raised to 120 0 C. GC analysis revealed less than Img of organochlorine in this aqueous distillate.

A catalytic amount of 5mg of sodium borohydride in glycerol was then added into the soil and then the 11 temperature was increased to 340 0 C 350 0 C over the following hour and maintained at 340 0 C 350°C for half an hour.

A sample of 50g of this treated soil was acidified with 50ml of 0.1 M HC1 and the mixture was evaporated to dryness on a steambath prior to hexane extraction and preconcentration. GC analysis of the treated soil showed that the residual total organochlorine pesticide residual was less than ippm.

10 EXAMPLE 2 fl This example further demonstrates the application of the S" method according to the present invention which exemplifies a solids treatment process.

A polluted medium comprising a contaminated soil was spiked with a known amount of PCB, having the commercial designation Aroclor 1260. This additional 200g sample of organochlorine pesticide contaminated soil described in Example 1 was spiked with 2g of Aroclor 1260, giving a soil sample that was effectively contaminated with 1,400ppm of total organochlorine pesticides plus 10,000ppm of PCB.

This sample was placed in a 500ml round-bottom flask to which was added 50ml of water containing 4g of glycerol and 4g of sodium ortho-silicate.

After homogenising the slurry by mixing, the flask was placed in a heating mantle, equipped with a distillation head, condenser and receiving flask and a thermoprobe was inserted through a sidearm of the flask so that the probe tip contacted the soil. The flask temperature was raised to 120 0 C and the water was evaporated off in 1 hour. This initial condensate contained less than Img of PCB congeners on GC analysis.

12 A catalytic amount of 5mg of sodium borohydride in 0.5ml of glycerol was then added to the soil and the temperature was raised to 340 0 C 350 0 C for two hours. The total sample was then cooled, and the condenser glassware flushed with 20ml of acetone to wash any condensate into the soil. The soil was then treated with 200ml of 0.1 M HC1 and the mixture was evaporated to dryness on a steambath prior to hexane extraction, preconcentration and analysis by capillary GC against relevant standards. Results revealed that the total organochlorine residual was less than Ippm.

EXAMPLE 3 (a) This example demonstrates the application of the method according to the present invention which exemplifies a liquid oil treatment process.

15 A polluted medium sample comprising a waste lubricating oil was gathered from the mixed waste oil storage tank from the oil recycling operation at the Cleanaway Technical Services Treatment Plant in Perth, Western Australia. This oil was initially free of PCB congeners but contained 3,500ppm of soluble lead.

A 90g sample of this oil was introduced to a 250ml roundbottom flask and then spiked with 10g of PCB in the form of Aroclor 1260. An iron magnetic follower was introduced to the flask, which was then placed in a magnetically stirred heating mantle, equipped with a Dean-Stark distillation system, and a thermometer was inserted through a sidearm of the flask so that the tip contacted the top of the oil.

While the oil was vigorously stirred, 24g of glycerol and 24g of powdered sodium ortho-silicate was introduced to the oil. A further 20ml of white spirits was introduced to the mixture to assist in the azeotropic distillation of water from the original waste oil.

13 The flask temperature was then slowly raised from 60 0 C 120 0 C over two hours whilst the water and lighter hydrocarbons were azeotropically distilled from the liquid.

GC analysis revealed less than 1mg of PCB congeners in this distilled condensate.

After dehydration, a catalytic amount of 100mg of sodium borohydride in 2 mL of glycerol was added to the stirred reactor and the temperature was raised to 340 0 C 350 0

C.

After 16 hours of stirring under these conditions, the reaction was cooled and the oil filtered from the solids.

The oil was analysed on GC which revealed that the residual PCB's in the oil was less than Ippm. Metals analysis of the oil by AAS revealed that the lead levels also had been reduced, from 3,500ppm to 3ppm, due to the formation of a .i15 sparingly soluble lead silicate complex.

The reactor solids were filtered, acidified in 50ml of M HC1 and evaporated to dryness on a steambath and then hexane extracted and the concentrate was analysed on GC, which revealed less than 1mg of PCB in the solids.

20 EXAMPLE 3 (b) This example demoiicrates the application of the method according to the present invention which exemplifies a liquid oil treatment process.

A sample was prepared comprising a clean high boiling point (340 410 0 C) lubricating oil contaminated with 10g of the PCB Aroclor 1260 was prepared in the following manner. A sample of the oil was introduced into a 250ml roundbottom flask and then spiked with 10g of PCB in the form of Aroclor 1260. An iron magnetic follower was introduced to the flask, which was then placed in a magnetically stirred 14 heating mantle, equipped with a Dean-Stark distillation system, and a thermometer was inserted through a sidearm of the flask so that the tip contacted the top of the oil.

While the oil was vigorously stirred, 24g of glycerol and 24g of powdered sodium ortho-silicate was introduced to the oil. A further 20ml of white spirits was introduced to the mixture to assist in the azeotropic distillation of water from the original waste oil. The flask temperature was then slowly raised from 60 0 C 120 0 C over two hours whilst the water and lighter hydrocarbons were azeotropically distilled from the liquid.

GC analysis revealed less than 1mg of PCB congeners in this distilled condensate. After dehydration, a catalytic amount of 100mg of sodium borohydride in 2 mL of glycerol 15 was added to the stirred reactor and the temperature was raised to 240 0 C -250 0 C. After 4 hours at this temperature, the oil was analysed for PCBs but the analysis showed no dehalogenation.

The oil temperature was then increased to 340°C 350 0

C.

After 16 hours of stirring under these conditions, the reaction was cooled and the oil filtered from the solids.

The oil was analysed on GC which revealed that the residual PCB's in the oil was less than Ippm. The reactor solids were filtered, acidified in 50ml of 1.0 M HCl and 25 evaporated to dryness on a steambath and then hexane extracted and the concentrate was analysed on GC, which revealed less than Img of PCB in the solids.

EXAMPLE 3 (c) This example demonstrates the application of the method according to the present invention which exemplifies a liquid oil treatment process.

15 A sample was taken from a polluted medium comprising a mixture of waste lubricating oil which originated from the mixed waste oil storage tank from the oil recycling operation at the Cleanaway Technical Services Treatment Plant in Perth, Western Australia, and bitumen. This oil was initially free of PCB congeners.

A 90g sample of this viscous oil/bitumen was introduced to a 250ml round-bottom flask and then spiked with O1g of PCB in the form of Aroclor 1260. An iron magnetic follower was introduced to the flask, which was then placed in a magnetically stirred heating mantle, equipped with a Dean- Stark distillation system, and a thermometer was inserted Sthrough a sidearm of the flask so that the tip contacted the top of the oil. While the oil was vigorously stirred, 24g of glycerol and 24g of powdered sodium ortho-silicate .i was introduced to the oil. A further 20ml of white spirits was introduced to the mixture to assist in the azeotropic distillation of water from the original waste oil.

The flask temperature was then slowly raised from 60 0 C 20 120 0 C over two hours whilst the water and lighter hydrocarbons were azeotropically distilled from the liquid.

GC analysis revealed less than Img of PCB congeners in this distilled condensate.

*After dehydration, a catalytic amount of 100mg of sodium 25 borohyc.iide in 2 mL of glycerol was added to the stirred reactor and the temperature was raised to 240 0 C -250 0

C.

After 4 hours at this temperature, analysis of the oil indicated that about 30% destruction of the PCBs in the reactor. The reaction was continued at 240 2500C for a further 10 hours and then the reaction was cooled and the oil filtered from the solids. The oil was analysed on GC which revealed that the residual PCB's in the oil was less than ppm.

16 The reactor solids were filtered, acidified in 50ml of M HC1 and evaporated to dryness on a steambath and then hexane extracted and the concentrate was analysed on GC, which revealed less than 1mg of PCB in the solids.

EXAMPLE 3 (d) This example demonstrates the application of the method according to the present invention which exemplifies a liquid oil treatment process.

A sample was prepared comprising 80g of a clean high boiling point (340-410 0 C) lubricating oil mixed with 10g of bitumen and subsequently contaminated with a 10g of PCB mixture Aroclor 1260. This oil was initially free of PCB congeners.

The sample was placed in a 250ml round-bottom flask, with 15 an iron magnetic follower and then placed in a magnetically stirred heating mantle, equipped with a Dean-Stark distillation system. A thermometer was inserted through a sidearm of the flask so that the tip contacted the top of the oil.

*e S 20 While the oil was vigorously stirred, 24g of glycerol and 24g of powdered sodium ortho-silicate was introduced to the oil. A further 20ml of white spirits was introduced to the mixture to assist in the azeotropic distillation of water from the original waste oil. The flask temperature was then slowly raised from 60 0 C 120°C over two hours whilst the water and lighter hydrocarbons were azeotropically distilled from the liquid. GC analysis revealed less than 1mg of PCB congeners in this distilled condensate.

After dehydration, a catalytic amount of 100mg of sodium borohydride in 2 mL of glycerol was added to the stirred 17 reactor and the temperature was raised to 240 0 C 250 0

C.

After 12 hours of stirring under these conditions, the reaction was cooled and the oil filtered from the solids.

The oil was analysed on GC which revealed that the residual PCB's in the oil was less than Ippm.

The reactor solids were filtered, acidified in 50ml of M HC1 and evaporated to dryness on a steambath and then hexane extracted and the concentrate was analysed on GC, which revealed less than Img of PCB in the solids.

EXAMPLE 4 This example further demonstrates the application of the method according to the present invention which exemplifies another liquid treatment process.

A sample was prepared comprising a polluted medium in the 15 form of a waste semi volatile solvent 1,1,2,2tetrabromoethane (TBE) which boils at 243.50C under atmospheric pressure. A 20g (6.75ml) sample of TBE was placed in a 250ml round-bottom flask with 93.25ml of high boiling point (3400C 410 0 C) mineral oil. An iron .20 magnetic follower was introduced to the flask, which was .ooe o. *then placed in a magnetically stirred heating mantle, equipped with reflux condenser, and a thermometer was inserted through a sidearm of the flask so that the tip •contacted the top of the liquid.

While the liquid was stirred, 60ml of glycerol plus 40g of powered sodium ortho-silicate and 100mg of sodium borohydride were introduced to the flask. The system was heated to 100 0 C with rapid stirring and the heat source was then turned off. The temperature of the reaction rapidly increased to 1500C, indicative of an exothermic reaction.

On stabilising, the heating mantle was are activated and 18 the liquid was refluxed at 180 0 C 200°C for 10 hours, with magnetic stirring. After 10 hours the slurry was cooled and the filtered oil was analysed by GC, which revealed less than Ippm of TBE in the oil.

As should be readily appreciated from the above examples, the process provides a convenient and safe method of dehalogenating organo-halides, which may be concurrently performed with the recovery of heavy metals from the same waste, and recovery of waste oils, where those oils are not subject to thermal degradation by the process. As can be seen, the bituminous waste or fresh bitumen may be introduced to catalyse the dehalogenation, lowering the temperature at which de- halogenation occurs.

It should be appreciated that the invention is not limited 15 to the scope of these specific examples or embodiments described herein.

*o *eo

Claims (13)

1. A method of treating halogenated hydrocarbon containing material to dehalogenate the hydrocarbon contained therein, comprising adding to said material, per mole of halogen group the following reagents:- group 1 or group 2 cation values in quantity at least sufficient to form metal halides with said halogen, silicate anion values, and at least one mole of -OH group contained in a polyol; e. mixing said reagents and said material together, and raising the temperature to beyond 100 0 C for sufficient time to dehalogenate said hydrocarbon.

2. The method as claimed in claim 1 wherein said reagents are solubilised in a solvent such as water before mixing with said material, to ensure thorough mixing with said material.

3. The method as claimed in claim 1 wherein, said reagents are added directly to said material, with agitation to ensure thorough mixing.

4. The method as claimed in any one of the preceding *f claims where prior to the step of raising the temperature, the temperature is maintained at a level sufficient to drive off said solvent and/or any water present, before being raised to the final temperature to dehalogenate said hydrocarbon. The method as claimed in any one of the preceding Sclaims wherein at least some of said cation values and said 20 anion values are provided by from an al-kali metal silicate such as sodium silicate.

6. The method as claimed in any one of the preceding claims wherein said polyol comprises inter alia glycerol, ethylene glycol, polymers thereof, or sugars, or a mix thereof.

7. The method as claimed in any one of the preceding claims where prior to said reagents and material being heated to dehalogenate said hydrocarbon, a catalytic amount of a hydride such as sodium borohydride is added to the mixture.

8. The method as claimed in any one of the preceding claims where said material comprises an organic non aqueous liquid, wherein an organic catalyst such as a bitumen, a bituminous oil, or a non aromatic cyclic organic compound is added to said material and reagents prior to heating to dehalogenate said hydrocarbon, to lower the temperature at which dehalogenation takes place.

9. A method of treating halogenated hydrocarbon containing liquid and a spent oil mixture, to dehalogenate e* the hydrocarbon contained therein, and recover the oil for reuse, comprising adding to said mixture, per mole of halogen group, the following reagents:- group 1 or group 2 cation values in quantity at least boo sufficient to form metal halides with said halogen, silicate anion values, and at least one mole of -OH group contained in a polyol; T mixing said reagents, and said mixture together, and 21 raising the temperature to beyond 100 0 C for sufficient time to dehalogenate said hydrocarbon, and recovering the oil for reuse subsequent to said hydrocarbon being dehalogenated. The method as claimed in claim 9 wherein said reagents are added directly to said mixture, with agitation to ensure thorough mixing.

11. The method as claimed in claim 9 or claim 10 where prior to the step of raising the temperature, the temperature is maintained at a level sufficient to drive off any water present, before being raised to the final temperature to dehalogenate said hydrocarbon.

12. The method as claimed in any one of claims 9 to 11 wherein at least some of said cation values and said anion values are provided by an alkali metal silicate such as sodium silicate. 4 S13. The method as claimed in any one of claims 9 to 12 wherein said polyol comprises inter alia glycerol, ethylene glycol, polymers thereof, or sugars, or a mix thereof.

14. The method as claimed in any one of claims 9 to 13 where prior to the reagents being heated to dehalogenate said hydrocarbon, a catalytic amount of a hydride such as sodium borohydride is added to the mixture. The method as claimed in any one of claims 9 to 14 wherein an organic catalyst such as a bitumen, a bituminous oil, or a non aromatic cyclic organic compound is added to said mixture prior to heating to dehalogenate said hydrocarbon, to lower the temperature at which dehalogenation takes place. 22

16. A method of dehalogenating an organohalide substantially as herein described with reference to the description of the embodiment.

17. A method of dehalogenating an organohalide and simultaneously re-refining used oil substantially as herein described with reference to the description of the embodiment. Dated this SIXTEENTH day of JUNE 1993. BRAMBLES AUSTRALIA LTD Applicant WRAY ASSOCIATES, •Perth, Western Austi 'ia, Patent Attorneys fox ie Applicant. *to o Sooo *o*o I ABSTRACT A method of treating halogenated hydrocarbon containing material to dehalogenate the hydrocarbon contained therein. The method comprises adding the following reagents to the material, per mole of halogen group:- S group I or group II cation values in a quantity at least sufficient to form metal halides with the halogen, silicate anion values, and O at least one mole of -OH group contained in a polyol. *The method also comprises mixing the reagents and the material together, and raising the temperature to beyond 100 0 C for sufficient time to dehalogenate the hydrocarbon. A method of treating halogenated hydrocarbon containing S: liquid and a spent oil mixture, so as to dehalogenate the hydrocarbon and recover the oil for reuse is also described. *oo