IMPROVEMENTS IN THE MANUFACTURE AND PURIFICATION OF LAMPBLACK, AND IN APPARATUS EMPLOYED THEREIN
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Richard Archibald Brooman at
the Office of the Commissioners of Patents, with his Petition, on the
10th January 1866.-A communication from abroad by Benoit Perra,
of Petit Vanves, France.
1, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Inven
tion for "IMPROVEMENTS IN THE MANUFACTURE AND PURIFICATION OF LAMPBLACK,
AND IN APPARATUS EMPLOYED THEREIN," to be as follows:-
Lampblack has hitherto been produced by burning incompletely matters
such as resin, pitch, tar, heavy oils, naphthaline, and others. The black
thus obtained varies in quality according to the mode of combustion and
the materials employed. If it is obtained from resin it is called vegetable
black in contradistinction to that manufactured from products arising from
residues of coal, tar, boghead, and similar materials. According to whether
the black is obtained by burning directly the raw materials in pans (chau-
dières), or in chambers, or in ovens communicating with chambers, or in
small lamp-like apparatus, it varies considerably in its qualities. The
black obtained by the lamp-like apparatus is less flat, lighter, dryer, more
divided and finer than those obtained by the other processes. Inde-
pendently of the water and carbonic acid which are produced, resinous
matters, heavy oils, and other matters are formed, and are drawn by the
current of air which carries off the lampblack. As these apparatus, which
are furnished with wicks, only take up the materials as fast as they are

page_text: consumed, it follows that very little of the raw materials is burnt during
combustion. It is different when the raw materials are placed in pans
with a large surface for the direct action of combustion; in this case a
considerable proportion of these materials is drawn and volatilized in the
current of air and injures the black obtained by rendering it compact,
heavy, fat, and very odoriferous. To purify raw and impure black of bad
quality, or to improve black, it has been usual simply to re-burn the black
in sheet iron vessels. Black thus treated loses sometimes from 40 to 75
per cent. of its weight. If the products volatilized and drawn off during
the combustion of the black are re-burnt by this method of slow combus-
tion, the slow combustion itself also produces tarry, resinous, and similar
matters, which remain condensed in the black. The purity of the re-burnt
black is only relative. The foregoing explanations are considered neces-
sary to enable the present Invention, which consists in a method of and
apparatus for burning materials to manufacture black and in a method of
purifying the black, to be fully understood. The apparatus I employ ís
similar to the old lamp apparatus of constant flow and level. I intro-
duce into the reservoir of the lamp resin dissolvet, naphthaline, heavy
oils, or similar materials. The burner of the lamp where combustion
is effected is not provided with a wick as ordinary apparatus, but is in the
form of an open pan similar to that before referred to.
The apparatus is
furnished with a double jacket containing boiling water to keep the
materials always in a fluid state; or instead of a double jacket any other
convenient arrangement answering the same purpose may be adopted.
The pan of the apparatus is placed in a chamber or an oven communi-
cating with a chamber, and the outer jacket of the apparatus is contiguous
to a cast-iron plate, serving as a wall to the oven, which naturally becomes
heated during combustion and permits of the flow of the materials. The
advantages arising from this improved apparatus are that it serves to burn
any material from which black can be obtained; it renders the production
of the black regular and continuous and of uniform quality; it increases
the production without augmenting manual labor; and it does away with
the risk of explosion or fire.
The second part of this Invention relates to the purification of lamp-
black. I do not purify it by calcination or slow combustion, which
produces black of only relative purity, but by a process which permits of
obtaining a black chemically pure and really black. By analyzing black
as hitherto manufactured it will generally be found to contain, in addition
to various salts, earthy matters and water, the following bodies, viz.,

page_text: resinous, tarry, and bituminous matters, pitch, heavy oil, carburet of
hydrogen, little volatile, naphthaline, paranaphthaline, and other sub-
The hydrocarburets of coal schist, boghead, petroleum, essence
of turpentine, ether, chloroform, methylene, amylene, alcohol, sulphuret
of carbon, and similar materials dissolve perfectly all the impurities
above mentioned which the black contains. It is sufficient to agitate
the black with one of these solvents, to place the whole in a filter,
and to submit it to washing operations in order to obtain a black
chemically pure, of a perfectly black appearance, and deprived of all
odour, if ether, chloroform, or sulphuret of carbon, that is to say, a solvent
easy of evaporation, has been employed. The several impurities above
mentioned are the cause of ordinary lampblack being never quite black;
according to which of the impurities predominates the lampblack is brown,
grey, red, maroon, greenish, yellowish, and so on. The lampblack purified
by means of solvents as before named is quite black. I proceed as follows
in order to purify the black :-I mix the raw black with ten times at least
of its weight of sulphuret of carbon; I agitate it well and leave the
mixture in contact some time. Then I put this mixture of black and
sulphuret of carbon into a turbine or centrifugal apparatus provided inter-
nally with close woven canvas forming a filter. The turbine is furnished
with a double metallic jacket to prevent the sulphuret of carbon evaporat-
ing. I impart motion to the turbine, and the sulphuret of carbon is
thrown by centrifugal force out of the black, carrying with it the dissolved
impurities. I repeat this operation as many times as found desirable.
The sulphuret of carbon which has been employed in these washings is
put into a still to be regenerated. The black washed and still wet with
sulphuret of carbon is put into a still heated by a bain-marie or water bath,
which allows the last traces of sulphuret of carbon to be separated and
collected.