Improved Process for Hardening Bituminous Substances.
Year: 1896

page_text: Date of Application, 11th Aug., 1896-Accepted, 3rd Oct., 1896
COMPLETE SPECIFICATION.
Improved Process for Hardening Bituminous Substances.
I, EDWIN THEODORE DUMBLE, of 106 West 17th Street Austin, in the
County of Travis and State of Texas, United States of America, Geologist do
hereby declare the nature of my invention, and in what manuer the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My invention relates to a process for hardening or partly solidifying to any
required degree, substances such as liquid or viscid bitumens, tars or asphaltums,
either natural or artificial.
The present ordinary method of rendering a liquid bitumen denser or harder,
consists in expelling therefrom by heat the lighter or more volatile portions, as in
the manufacture of petroleum or in the distillation of coal tar, where the various
light oils of different series and different volatility are driven off, leaving finally
a residuum of pitch whose degree of softness or hardness corresponds to the
degree of heat used. Substantially the same method is applied to the asphaltum
used in street paving. This compound after being mixed with the requisite
amount of sand or other similar material, must be heated until the lighter petrolene
oils are evaporated to give it the necessary consistency and firmness.
My improved method is based upon the discovery of the fact that at suitable
temperatures these oils of liquid or viscid bitumens, tars and asphaltums, are
capable of dissolving bituminous coals and analogous solid bituminous materials,
to such an extent as to render them harder, and even solid on cooling, and without
serious loss of weight by evaporation of the lighter oils.
My process takes advantage of this fact for the purpose named. I find that as
the characters of these liquid materials vary, the temperature at which solution
takes place varies also, as well as the amount of any given bituminous coal or
analogous material that can be dissolved in them.
The principal points of the process are as follows:
The liquid or viscid material is heated in any suitable vessel to a temperature,
near, but below its boiling point. The bituminous coal or analogous bituminous
material, preferably in a pulverized condition, is also heated and the two materials
are mixed, while hot, in suitable proportions and the heat gradually raised to the
boiling point and continued until solution is effected. This part, of the process is
greatly facilitated by constant stirring and in practice a steam-jacketed pug mill,
such as is used in agglomerating coal dust and pitch in the manufacture of artificial
fuel, gives excellent results although any other device which will serve the same
purpose may be used as well. Or, the materials may be mixed with coal and
then brought to a proper temperature for solution. In practice I prefer the
former method.
By regulating the amount of bituminous coal or analogous bituminous material
added, any degree of hardness can be given the product up to that of hard pitch at
least. By this process, the amount of hard pitch produced is greatly increased,
some of the liquid or viscid asphaltums having the power of dissolving twice
their weight of other bituminous material, with but little loss of their own
substance.
To illustrate the process by an example, I will state that an asphaltum from

page_text: Indian Territory was hardened with a coal having the following proximate
analysis:
Moisture
Fixed carbon -
•40
59-63
Volatile matter
Ash -
36.42
3.54.
The asphaltum is fluid at 100 degrees Centigrade. The coal after being
pulverized is heated to the same temperature, and if medium pitch is wanted a
quantity is added weighing from one to one and one-fourth times as much as
the asphaltum; if hard pitch, from one and one-half to twice as much. The heat
is then raised to about 200 degrees Centigrade and the materials thoroughly
stirred until solution takes place, which is known by the smoothness and ropiness
of the mixture. It is then run out into any suitable receptacle to cool.
I desire it to be understood that the same result is obtained whether the solid
material (bituminous coal) and the liquid or viscid material be first heated
separately and then mixed to effect their combination, or the two materials mixed
before heating. These two processes therefore are equivalents, and the appended
claims cover both processes.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,-
1. The herein described method of hardening liquid or viscid bituminous
substances, which consists in mixing them with bituminous coal or analogous
bituminous material, and subjecting them to a temperature below the volatilizing
point of the lighter oils, thereby softening and dissolving the solid bituminous
material and uniting it with the liquid or viscid bituminous substance, as set
forth.
2. The herein described method of hardening liquid or viscid bituminous
substances, which consists in mixing them with bituminous coal or analogous
bituminous material, subjecting the mixture to an initial temperature below the
boiling point of the liquid or viscid bituminous substance, thereby softening and
dissolving the solid bituminous material and uniting it with the liquid or viscid
bituminous substance, and then gradually increasing the temperature to the boiling
point of the compound, as set forth.
Dated this 11th day of August 1896.
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.