An Improved Method of Producing Pure Cellulose.
Year: 1888

page_text: Date of Application, 8th Aug., 1888
Complete Specification Left, 6th May, 1889-Accepted, 27th July. 1889
ROVISIONAL SPECIFICATION.
An Improved Method of Producing Pure Cellulose.
We, HARTWIG BAOHE-WEG, and CARL BACHE-WUG, Factory Owners, and VIGGO
BENTNER DREWSEN, Doctor of Philosophy, all of Bóhn pr Eidsvold, in the Kingdom
of Norway, do hereby declare the nature of this invention to be as follows :—
Our invention relates to a method of producing pure cellulose suitable to be employed
as raw material for the manufacture of paper by treating crude cellulose with a
suitable permanganate in a sulphuric acid solution and precipitating the resulting oxide
of manganese by means of a reducing agent.
"
•
In carrying out our invention we proceed substantially as follows:-
We place the crude material which it is intended to purify in a rag engine or
similar apparatus and we add thereto permanganate of potassium or sodium in a diluted
solution of sulphuric acid until the well known red colour ceases to disappear quickly
but remains for say a quarter of an hour or until the material has attained the
required whiteness. The greator part of the permanganate is reduced to sulphate of the
monoxide of manganese but towards the termination of the process one part of oxide;
of manganese or peroxide of manganese is produced. The oxidation being completed
the oxides which as is well known are a deep brown colour are dissolved by means of
a reducing agent such for example as sulphurous acid, thiosulphate of sodium, oxalic.
acid, etc.
1
In some cases the crude material contains so much hard matter that the treatment
with the comparatively expensive permanganate is too costly. In this case we use
chloride of lime for effecting most of the oxidation and employ the permanganate to
remove the remaining impurities.
This method of treating the crude cellulose is intended to be a continuation of the
original solution-process for the complete removal of all hard or crusty matters.
That the material produced is quite a different substance from the crude cellulose is
proved by its considerably smaller weight, its dazzling white colour and paper manu-
factured from this pulp will turn a dead white and not be transparent like paper,
manufactured from common crude cellulose.
་་་
Duted the 8th da.
Amount 1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improved Method of Producing Pure Cellulose.
We, HARTWIG BACHE-WEG, and CARL BACHE WÜG, Factory Owners, and VIGGO
BENTNER DREWSEN, Doctor of Philosophy, all of Bohn pr Eidsvold, in the Kingdom
of Norway, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by-the following
statement:-
Our invention relates to a method of producing pure cellulose suitable to be employed
as raw material for the manufacture of paper, by treating crude cellulose (such for
example as crude sulphite sulphate and soda cellulose) with a suitable permanganate
in a sulphuric acid solution and dissolving the resulting oxide of manganese, by means
of a reducing agent.
In carrying out our invention we proceed substantially as follows:
We place the crude material (such as wood, straw, esparto grass and similar
vegetable substances in a state of completely dissolved cellulose, that is to say, cellulose
EDI

page_text: thoroughly mixed with water) which it is intended to purify in a rag engine or similar
apparatus and we add thereto permanganate of potassium or sodium in a diluted
solution of sulphuric acid until the well known red color coases to disappear quickly
but remains for say a quarter of an hour or until the material has attained the required
whiteness. The greater part of the permanganate is reduced to sulphate of the
monoxide of manganese but towards the termination of the process one part of oxide
of manganese or peroxide of manganese is produced. The oxidation being completed
the oxides which as is well known are of a deep brown color are dissolved, by means
of a reducing agent, such for example as sulphurons acid, ibiosulphate of sodium,
oxalic acid, etc.
In some cases the crude material contains so much hard matter that the treatinent
with the comparatively expensive permanganate is too costly. In this case, we use
chloride of lime for effecting mest of the oxidation and employ the permanganate to
remove the remaining impurities.
This method of treating the crude cellulose is intended to be a continuation of the
original solution-process for the complete removal of all hard or crusty matters.
That the material produced is quite a different substance from the crude cellulose is
proved by its considerably smaller weight and its dazzling white color; paper mann-
factured from this pulp will turn a dead white and not be transparent like paper
manufactured from common crude cellulose.
-
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what we
claim. is :-
1. The method or process of producing pure cellulose consisting in treating wood,
straw, esparto grass and similar vegetable substances in a state of completely dissolved
cellulose, that is to say, cellulose thoroughly mixed with water (such for example as
crude sulphite sulphate and soda cellulose) with a suitable permanganate in a sulphuric.
acid solution and then dissolving the resulting oxide of manganese, by means of a
suitable reducing agent, such as sulphurous acid.
2. The method or process of producing pure cellulose consisting in successively
treating wood, straw, esparto grass and similar vegetable substances in a state of
completely dissolved cellulose, that is to say, cellulose thoroughly mixed with water,
with chloride of lime and a suitable permanganate in a sulphuric acid solution and
then dissolving the resulting oxide of manganese, by means of a suitable reducing
agent, such as sulphurous acid.
Dated the 6th day of May 1889.