Carbon fibers from kraft softwood lignin

1. The process of forming a carbon fiber from kraft softwood lignin comprising:

a) acetylating lignin obtained from softwood alkaline black liquor to provide a lignin acetate until the acetyl content of the dry lignin acetate is between 16% and 22% by weight as measured by deacetylation in alkali followed by ion chromatography wherein the lignin acetate melts when heated

b) melt extruding the acetylated softwood acetylated lignin to provide a coherent “green” lignin fiber

c) thermally stabilizing the melt extruded green lignin acetate fiber to a state that does not melt on subsequent heating

d) carbonizing thermally stabilized softwood lignin acetate fiber.

2. The process of claim 1 wherein the acetylation step is performed using acetyl chloride, acetic anhydride or acetic acid.

3. The process of claim 1 wherein the acetylation step is performed without using a catalyst.

4. The process of claim 3 wherein the acetylation step is performed at a temperature in the range of 70 to 100° C.

5. The process of claim 3 wherein the acetylation step is performed at a temperature in the range of 75 to 85° C.

6. The process of claim 2 wherein the acetylation step is performed using a catalyst.

7. The process of claim 6 wherein the catalyst is an organic amine.

8. The process of claim 6 wherein the catalyst is pyridine, tri-ethyl amine or tri-methyl amine.

9. The process of claim 6 wherein the acetylation step is performed at a temperature of 100° C. or less.

10. The process of claim 8 wherein the acetylation step is performed at a temperature of 45 to 55° C.

11. The process of claim 1 wherein the green lignin fiber has a diameter of 5 to 100 microns.

12. The process of claim 11 wherein the green lignin fiber has a diameter of 10 to 50 microns.