Apparatus and method for recovering carbon black from pyrolysis byproducts

1. A method for purification and refinement of carbon black comprising the steps of:

providing a feedstock comprising a physical combination of particulate carbon black, metal oxides, and sulfur;

removing the metal oxide particles from the feedstock by introducing the feedstock into an aqueous acidic solution, wherein the aqueous acidic solution dissolves the metal oxide particles from the feedstock; and,

removing the sulfur particles from the feedstock by introducing the feedstock into a sulfur-dissolving solvent to produce a sulfur-containing slurry, wherein the sulfur-dissolving solvent dissolves the sulfur from the feedstock;

separating the feedstock from the sulfur-containing slurry;

evaporating all sulfur-dissolving solvent from the sulfur-containing slurry;

removing the sulfur remaining after evaporation of the sulfur-dissolving solvent; and

reusing the sulfur-dissolving solvent.

2. The method of claim 1 wherein the step of removing metal oxide particles comprises the steps of:

mixing the feedstock with an aqueous acidic solution to chemically react with the metal oxides and form an acidic slurry comprising metal salts in solution; and

separating the acidic slurry and the feedstock.

3. The method of claim 2 , wherein the aqueous acidic solution is hydrochloric acid.

4. The method of claim 3 , wherein the aqueous acidic solution has a concentration of 2N.

5. The method of claim 1 , wherein the step of removing sulfur particles further comprises

heating the sulfur-containing slurry to a selected temperature of less than 110° C.

6. The method of claim 1 , further comprising the steps of:

agitating the sulfur-containing slurry at a temperature selected to maintain the sulfur and admixed carbon black particles in solution;

removing the feedstock from the sulfur-containing slurry;

separating the dissolved sulfur from the sulfur-containing slurry by evaporating the sulfur-containing solvent; and

recycling the resultant sulfur-dissolving solvent.

7. The method of claim 6 , wherein the step of separating the dissolved sulfur from the sulfur-containing slurry is accomplishing by evaporating the sulfur-dissolving slurry to produce sulfur-dissolving solvent vapor and sulfur solids.

8. The method of claim 1 wherein the step of removing the sulfur particles from the feedstock by introducing the feedstock into a sulfur-dissolving solvent to produce a sulfur-containing slurry comprises the step of:

agitating the sulfur-containing slurry at a temperature in a range of between approximately 60° C. and approximately 80° C., wherein the carbon black particles are admixed in the sulfur-dissolving solvent containing dissolved sulfur.

9. The method of claim 1 , further comprising the step of:

mixing toner black components to the feedstock to form a toner portion.

10. The method of claim 9 , wherein the toner black components are comprised of magnetite and a resin.

11. The method of claim 10 , further comprising the step of:

extruding the toner portion to form pellets.

12. The method of claim 11 , further comprising the step of:

pulverizing the pellets to form a powder.

13. A process for purification and refinement of a carbon black feedstock comprised of a physical mixture of carbon black, metal oxide, and sulfur particles, the process comprising the steps of:

providing the feedstock at a continuous and uniform rate;

mixing the feedstock with an aqueous solution containing an acid to chemically react with the metal oxide particles contained in the feedstock and form a first liquid portion and a first solid portion, the first liquid portion comprising an acid slurry comprising metal salts in solution, the first solid portion comprising feedstock particles;

separating the first liquid portion from the first solid portion;

adding the first solid portion to a sulfur-dissolving solvent to form a solvent slurry, wherein the sulfur particles contained in the first solid portion are dissolved by the sulfur-dissolving solvent;

agitating the solvent slurry at a temperature in a range of between approximately 60° C. and approximately 800° C., in order to maintain the solvent slurry having a second liquid portion comprising a solution of sulfur-dissolving solvent and the sulfur and a second solid portion comprising admixed feedstock particles;

removing the second solid portion;

evaporating the sulfur-dissolving solvent from the remaining solvent slurry to provide solid sulfur; and

condensing the sulfur-dissolving solvent for reuse.

14. The method of claim 13 , further corriprising the step of:

neutralizing the first liquid portion with an alkaline solution.

15. The method of claim 14 , wherein the alkaline solution is comprised of sodium hydroxide.

16. The method of claim 13 , wherein the sulfur is separated from the sulfur-dissolving solvent by an evaporation means within a closed system.

17. A method for purification and refinement of carbon black comprising the steps of:

providing a feedstock comprising a physical combination of particulate carbon black, metal oxides, and sulfur;

removing the metal oxide particles from the feedstock by introducing the feedstock into an aqueous acidic solution, wherein the aqueous acidic solution dissolves the metal oxide particles from the feedstock;

removing the sulfur particles from the feedstock by introducing the feedstock into a sulfur-dissolving solvent to produce a sulfur-containing slurry, wherein the sulfur-dissolving solvent dissolves the sulfur from the feedstock; and,

neutralizing the aqueous acidic solution with an alkaline solution.

18. The method of claim 17 , wherein the sulfur-dissolving solvent is selected from a group composed of xylene, benzene, and toluene.

19. The method of claim 17 , wherein the alkaline solution is comprised of sodium hydroxide.

20. The method of claim 17 , further comprising the step of filtering the feedstock from the sulfur-containing slurry; and

evaporating the sulfur-dissolving solvent from the sulfur-containing slurry from which the feedstock has been removed, wherein the sulfur is removed and the sulfur-dissolving solvent is reused.

21. The method of claim 20 , wherein the step of evaporating the sulfur-dissolving solvent from the sulfur-containing slurry further comprises

heating the sulfur-containing slurry to a selected temperature of less than 110° C.