Pitch bonded carbon electrode

Claim 2

A process for preparing chemical pitch which comprises stripping under reduced pressure steam cracker tar to obtain a pitch having an initial boiling point of between 350° C and 400° C at atmospheric pressure, heat soaking the pitch at 360° C to 420° C in the absence of air or oxygen at a pressure in the range of from sub-atmospheric to 4 atmospheres absolute and stripping under reduced pressure the soaked pitch to obtain a product having a minimum softening point (R and B) of 75° C.

Claim 3

A process according to claim 1 wherein the steam cracker tar has the following characteristics: ______________________________________ Sp. gr. at 20° C 1.10 - 1.15 Toluene insolubles (wt.%) 0.020-0.200 Ash content (wt.%) 0.010-0.004 Viscosity (cps) at 210° F 20 - 200 n-heptane insoluble 10 - 25 Coking value of n-heptane insoluble wt.% 50 - 65 Aromatic carbon atom % 71 - 72 Aliphatic/aromatic proton ratio 1.3 - 1.6 Number average molecular weight 250 - 310 Sulphur content (wt.%) 1.0 - 5.0 ______________________________________

Claim 4

A process according to claim 1 wherein the steam cracker tar is stripped by vacuum stripping.

Claim 5

A process according to claim 1 wherein the steam cracker is stripped at a temperature between 200° C and 400° C at a pressure of 10 to 100 mm Hg.

Claim 6

A process according to claim 1 wherein the pitch obtained after stripping the steam cracker tar has a softening point of between 60° and 95° C (R and B).

Claim 7

A process according to claim 5 wherein the pitch is heat soaked at a temperature of 380° C to 390° C and at about atmospheric pressure.

Claim 8

A process according to claim 1 wherein the pitch obtained from the heat soaking step has a softening point of 60° to 90° C (R and B).

Claim 9

A process according to claim 7 wherein the final product obtained after stripping has a softening point (R and B) of 100° C to 130° C.

Claim 10

A process according to claim 7 wherein the final product obtained after stripping has an aromatic carbon content of 73% to 80% and a coking value of 50% to 58%.

Claim 11

A process according to claim 7 wherein the final product obtained after stripping has a C:H atomic ratio of 1.35 to 1.50 and a benzene insolubles (wt.%) of 15 to 32.

Claim 12

Chemical pitch whenever prepared by a process claimed in claim 1.

Claim 13

An electrode comprising coke and 14 to 17 wt.% based on the weight of coke of chemical pitch as claimed in claim 11.

Claim 14

An electrode comprising coke and 26 to 32 wt.% based on the weight of coke of chemical pitch as claimed in claim 11.