Pyrolytic conversion of paint sludge to useful materials

• US 5,543,367 A
• Filed: 07/28/1995
• Issued: 08/06/1996
• Est. Priority Date: 07/28/1995
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Kim, Byung R., Salmeen, Irving T., Narula, Chaitanya K.
• Primary Examiner(s): LANGEL, WAYNE A
• Application Number:
  US08/508,875
• Time in Patent Office: 375 Days
• Field of Search: 501/155, 501/137, 501/96, 501/134, 501/87
• US Class Current: 501/87
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3843 Titanium carbides
• CPC Class Codes: C04B 2235/422 Carbon
• CPC Class Codes: C04B 2235/465 Ammonia
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/658 Atmosphere during thermal treatment
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 33/1321 Waste slurries, e.g. harbour sludge, industrial muds slurries of specific well-defined waste streams, e.g. phosphate muds, other than red mud, C04B33/132
• CPC Class Codes: C04B 33/30 Drying methods
• CPC Class Codes: C04B 33/32 Burning methods
• CPC Class Codes: C04B 35/46 based on titanium oxides or titanates containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49
• CPC Class Codes: C04B 35/468 based on barium titanates
• CPC Class Codes: C04B 35/58 based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides containing free binder metal C22C29/00
• CPC Class Codes: C04B 35/58014 based on titanium nitrides, e.g. TiAlON
• CPC Class Codes: C04B 35/62204 using waste materials or refuse clay-wares containing waste materials C04B33/132
• CPC Class Codes: C04B 35/62655 Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: Y02P 40/60 Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Abstract

The invention is a process for decomposing dried paint sludge to recover the organic and inorganic components of the paint sludge as gaseous, liquid, and composite materials. The process comprises drying the paint sludge to remove water and organic solvents, pyrolizing the dried paint sludge in an inert atmosphere in an elevated temperature of up to about 600° C. to form gaseous and liquid decomposition materials and a solid residue. The process further comprises collecting the gaseous and liquid decomposition materials and subjecting the solid residue to sintering in an elevated temperate of about 900° to 1300° C. in an atmosphere of nitrogen, argon or ammonia to convert the solid residue to composite materials comprising barium nitranate and titanium compounds such as titanium dioxide, titanium nitride, and titanium carbide. The gaseous and liquid materials may be further pyrolyzed to carbon materials.

Claims

1. A process for decomposing dried paint sludge to recover the organic and inorganic components of the paint sludge as gaseous, liquid, and composite materials, which process comprises the steps of:

drying the paint sludge at a temperature below about 200°

C. for a time sufficient to remove water and organic solvents present in the paint sludge;

pyrolizing the dried paint sludge in an inert atmosphere comprising nitrogen or argon at an elevated temperature of up to about 600°

C. for a time sufficient to form gaseous and liquid decomposition materials and a solid residue;

collecting the gaseous and liquid decomposition materials; and

subjecting the solid residue to further pyrolysis in an atmosphere selected from the group consisting of nitrogen, argon and ammonia at a temperature of between about 900°

C. and 1300°

C. for a time sufficient to sinter the solid residue to form an inorganic composite material comprising barium titanate and titanium compounds.

2. The process according to claim 1 wherein the drying step is carried out under a vacuum.

3. The process according to claim 1, wherein the gaseous decomposition material is cooled to convert it to liquid form.

4. The process according to claim 1, wherein said gaseous and liquid decomposition materials, together or separately, are subjected to further pyrolysis in an inert atmosphere at a temperature above about 800°

C. for a time sufficient to convert the gaseous and liquid decomposition materials to carbon materials.

5. The process according to claim 1, wherein the titanium compound is titanium nitride when said solid residue is sintered in an ammonia atmosphere.

6. The process according to claim 1 wherein said titanium compound comprises titanium dioxide when said solid residue is sintered in an argon atmosphere.

7. The process according to claim 1 wherein said titanium compound comprises titanium nitride and titanium carbide when said solid residue is sintered in a nitrogen atmosphere above about 1000°

C.