Simple and efficient process for the preparation of pencil...

Details Simple and efficient process for the preparation of pencil... Simple and efficient process for the preparation of pencil...

2007-05-15

2007-05-15

Johnson, Christina (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

Carbonizing to form article

In specific atmosphere

C401S049000

Reexamination Certificate

active

10659692

ABSTRACT:
The present invention relates to a simple and efficient process for the preparation of pencil lead from the spent or waste pot liners of aluminum industries, said process comprising steps of crushing the liners into small sizes, adding chromic acid to the crushed liners, washing the reacted product with distilled water, thermally shock-treating the dried mass to obtain a fine flowing graphite powder, mixing the powder with binder(s), moistening the mixture with requisite amount of water to form a stiff dough, extruding the dough under pressure to obtain product in the form of a discs, heating the dried discs in an inert/reducing atmosphere in a furnace at temperature ranging between 400–1200° C. for time duration ranging between 1 to 6 hours, and obtaining the pencil lead.

REFERENCES:
patent: 1137373 (1915-04-01), Alysworth
patent: 4091083 (1978-05-01), Hirschvogel et al.
patent: 5118345 (1992-06-01), Handl
patent: 5164174 (1992-11-01), Banker et al.
patent: 5346930 (1994-09-01), Maine et al.
patent: 5496392 (1996-03-01), Sims et al.
patent: 57083570 (1982-05-01), None
patent: 61252278 (1986-11-01), None
patent: 3139578 (1991-06-01), None
patent: 4252281 (1992-08-01), None
patent: 11286643 (1999-10-01), None

Affiliated with

Also associated with

Rating

Simple and efficient process for the preparation of pencil... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Simple and efficient process for the preparation of pencil..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simple and efficient process for the preparation of pencil... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3767274