Improvements in Obtaining Useful Products from the Liquors Resulting from the Manufacture of Cellulose or Fibres by the Sulphite Process.
Year: 1893

page_text: Date of Application, 24th Oct., 1893
Complete Specification Left, 24th July, 1894-Accepted, 8th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Useful Products from the Liquors
Resulting from the Manufacture of Cellulose or Fibres by the
Sulphite Process.
I, CARL DANIEL EKMAN of 57 Old Broad Street in the City of London,
Chemical Engineer, do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to obtain useful products from the liquors resulting
from the manufacture of cellulose or fibres from wood or other fibrous plants by
boiling under pressure with a sulphite solution or a solution containing sulphurous
acid, and a base such as potash, soda, magnesia or lime.
According to this invention after the said sulphite liquor has been clarified by
settling or filtration I first concentrate it by evaporation to a suitable thickness
which will vary according to the purpose for which it is to be used, say for example
a specific gravity of about 63° Twaddel at a temperature of 85° centigrade. The
evaporation should be effected in such manner that the liquor is not burnt or
overheated, a convenient way of obtaining the required heat is to employ a steam
coil or steam jacket, the liquor being placed in a pan or vessel which should be of
a material which will resist the action of the liquor. When a steam coil is used
for beating the liquor either the said coil should be made of lead or other material
which will resist the action of the acid in the liquor or the liquor should be made
slightly alkaline by mixing with it a suitable base such as potash, soda and
magnesia. These can be used in the state of caustics or carbonates, but if magnesia
is employed well burnt magnesite in fine powder answers well when intimately
mixed with the liquor while hot. Sufficient of the base should be added to cause
the liquor to produce an alkaline reaction on red litmus paper. After the liquor
has been concentrated I preferably add a small quantity of a suitable acid to
improve the color. Or when a base is not added to the liquor as before described
before evaporation the acid can even be added before concentration. Sulphuric or
hydrochloric acid is suitable for the purpose and the proportion used can be varied
as desired, it being understood that the greater the amount of acid used up to a
certain point the lighter will be the color of the liquor, but there should be no free
sulphuric or hydrochloric acid in the liquor. Oxalic acid gives a good color, but
it has the disadvantage of forming insoluble compounds with magnesia and lime;
these can, however be removed by settling and decantation if the liquor is not
concentrated to a very thick state, or water can be added to it and the liquor be
again evaporated to the desired degree of concentration. Or alum, sulphate of
alumina or bisulphate of soda can be used instead of an acid in order to improve
the color of the liquor.
The product obtained as above described can be employed as a paste or adhesive
substance for uniting substances together, but in such case the surfaces thus
united should not be exposed to atmospheric influences because the paste is
somewhat hygroscopic and therefore would adhere to other materials with which it
may come in contact.
I therefore preferably employ this paste for the manufacture of further products
and more particularly of a product resembling or having properties similar to those
of dextrine and which for the sake of convenience I will hereinafter call "dextrone."
In order to manufacture or obtain this dextrone I separate it from the organic
substance which gives the liquor the hygroscopic property already mentioned.
For this purpose I add to the liquor (preferably after treatment as hereinbefore

page_text: described but I can also use the liquor in its original state but by preference more
or less concentrated) one or more of certain soluble salts such as sulphates of
potash, soda or magnesia and chlorides of potash and soda. I have obtained the
most satisfactory results and best colors with the sulphates mentioned and of these
I prefer sulphate of magnesia. I have also used sulphate of ammonia but it has
given less satisfactory results and is more difficult to manipulate. I keep on adding
the salt so long as dextrone continues to separate from the liquor, the dextrone
being removed from time to time as it is formed. The quantity of salt to be used
varies according to concentration of the liquors, the kind employed and also
according to the particular sulphite liquor to be treated; but taking as an example
a sulphite. liquor which has been obtained by boiling wood under pressure with a
solution of bisulphite of magnesia or sulphurous acid and magnesia and which has
been subsequently evaporated as bereinbefore described to a specific gravity of
about 63° Twaddel at 85° centigrade the liquor having first been made alkaline or
not as may be convenient and an acid added as above described,-to 300 parts by
weight of the heated liquor I add about 100 parts of sulphate of magnesia and I
continue the heating, stirring the liquor until all the salt is dissolved.
dextrone rises to the top and forms a soft crust which is removed and the process
is continued as long as more dextrone is separated. The removed dextrone is
placed in a vessel in which it is kept warm for some time or is gently heated, when
some of the liquor will separate therefrom; the dextrone should be removed with
care so that as little liquor as possible may adhere to it. The dextrone when cold
forms a stiff mass which may be dissolved so as to be used in a liquid form, or it
may be dried, preferably at a low temperature, and reduced to a powder so as to be
used like powdered dextrine.
The
If a more purified product is desired the dextrone obtained as above is dissolved
in water and again separated by means of a salt as above described, and this
operation can be repeated as often as may be thought necessary.
The dextrone obtained as above described if mixed with a solution of gelatine or
glue forms a very concentrated material of the nature of that called gela-lignosine
in the Specification of Cross and Bevan's Letters Patent No. 1548 of 1883, and
which when dissolved in a suitable solvent such as sulphite of soda is used for
mordanting or sizing textile fabrics or sizing paper.
The solution left after the separation of the dextrone as above explained can also
be employed for the manufacture of a material of the nature of gela-lignosine by
adding a solution of gelatine or glue to the liquor and allowing it to precipitate,
more and more gelatine or glue being added until no more precipitate is formed.
The product or gela-lignosine thus obtained becomes a dense mass on cooling, but
it is desirable to remove as much as possible of the liquor adhering to it and this
can be effected by pressing or kneading or by washing when in a disintegrated
state in a limited amount of water or in a weak solution of a suitable salt such as a
bisulphite or alum solution which will not dissolve the gela-lignosine.
•
The still remaining liquor is left to cool when the salt which has been employed
will partly crystallize; the liquor is then drawn off and can be further evaporated
and again left to crystallize and this operation can be repeated as long as any salt
can be obtained by crystallization and this can be facilitated by cooling down to a
low temperature.
Sometimes I make a material suitable for sizing by dissolving glue or gelatine in
the sulphite liquor which bas been made alkaline as above described and which
may first be more or less concentrated but in this case no acid should be added
before the glue or gelatine. The glue or gelatine can be dissolved direct in the
liquor, but it is generally more convenient to first soak the glue in cold water, then
dissolve it by gentle heat and then mix it with the sulphite liquor which has been
previously warmed. The proportion of glue or gelatine will depend upon the
purpose for which the size is required, but when light color is of consideration only
as much liquor should be used as is necessary to precipitate the glue or gelatine
when mixed with alum solution in excess because the larger the amount of liquor

page_text: the darker will be the color it will give to the material that is sized; a larger
amount of liquor however gives a greater amount of precipitate and a product
having better sizing properties. Speaking generally, suitable proportions are
10 parts by weight of gelatine dissolved in 30 parts of water and then mixed with
40 parts of liquor evaporated to about 63° Twaddel at about 85° centigrade; or
if color is of consideration then only about 30 parts of liquor.
This size contains a large amount of a soluble form of gela-lignosine like that of
Cross and Bevan herein before referred to and it can therefore be used for many of
the purposes for which in their Specification they recommend their gela-lignosine
in a soluble form and more particularly for paper sizing when the color is of no
consideration because this impure product will discolor more than the ordinary
gela-lignosine after it has been dissolved. As is the case with gela-lignosine, when
a suitable acid or salt, preferably alum or sulphate of alumina, is added to the
solution gela-lignosine is precipitated, so it is with this size, and this size can be
used with advantage for the preparation of gela-lignosine.
Dated this 24th day of October 1893.
J. C. MEWBURN,
55 and 56, Chancery Lane, London, Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Obtaining Useful Products from the Liquors.
Resulting from the Manufacture of Cellulose or Fibres by the
Sulphite Process.
I, CARL DANIEL EKMAN of 57 Old Broad Street in the City of London,
Chemical Engineer, 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 : —
The object of this invention is to obtain useful products from the liquors (herein-
after called the sulphite liquor) resulting from the manufacture of cellulose or fibres
from wood or other fibrous plants by boiling under pressure with a sulphite solution
or a solution containing the sulphurous acid and a base such as potash, soda,
magnesia or lime.
The first part of my invention when carried out to its fullest extent is a process
or method of treatment which consists in first making the sulphite liquor alkaline
by means of a suitable base, then concentrating it, then adding to it a small quantity
of a suitable acid or alum, sulphate of alumina or bisulphate of soda to improve its
color, then adding a suitable soluble salt to separate from the liquor a product
resembling or having properties similar to those of dextrine, and then after the
removal of the said dextrine-like product adding gelatine or glue to the liquor to
obtain a product suitable for sizing and mordanting and at the same time to separate
or recover the salts that were used for separating the dextrine-like product.
It is, however, not an essential point of this part of my invention that the process
or method of treatment hereinbefore described should be carried out in its entirety,
because useful products in a commercial and marketable form are obtained by
carrying out only some of the stages or steps hereinbefore given, and the invention
therefore includes processes or methods of treatment which comprise only some of
said steps or stages. For example, it is not essential to render the sulphite liquor
alkaline or to add an acid thereto before adding to it a soluble salt as hereinbefore
described in order to obtain a dextrine-like product, but nevertheless I find that the
obtaining of this dextrine-like product is much better effected and the product is
of a better quality when the sulphite liquor has previously had an acid added to it
as described, while the liquor need not be made alkaline if lead vessels are
employed. Further, the addition of gelatine or glue to the liquor after the

page_text: dextrine-like product has been separated and removed may be dispensed with if for
any reason it may be preferred not to obtain the product suitable for sizing and
mordanting or to recover the salts that were employed for separating the
dextrine-like product.
Having stated what are the nature and main features of this part of my invention
I will now describe how it can be carried into effect.
In carrying out the invention, after the sulphite liquor has been clarified by
settling or filtration I concentrate it by evaporation to a suitable thickness which
will vary according to the purpose for which it is to be used, say for example, a
specific gravity of about 63° Twaddel at a temperature of 85° centigrade. The
evaporation should be effected in such manner that the liquor is not burnt or over-
heated; a convenient way of obtaining the required heat is to employ a steam coil
or steam jacket, the liquor being placed in a pan or vessel which should be of a
material which will resist the action of the liquor. When a steam coil is used for
heating the liquor either the said coil should be made of lead or other material
which will resist the action of the acid in the liquor or if it is desired to use
evaporating pans of iron or other materials which will be affected by the acids in
the liquor, the liquor should be made slightly alkaline by mixing with it a suitable
base such as potash, soda and magnesia. These can be used in the state of caustics
or carbonates but if magnesia is employed, well burnt magnesite in fine powder
answers well when intimately mixed with the liquor while hot. Sufficient of the
base should be added to cause the liquor to produce an alkaline reaction on red
litmus paper. After the liquor has been concentrated I preferably add a small
quantity of a suitable acid to improve the color. Or when a base is not added to
the liquor as before described before evaporation the acid can with advantage also
be added before concentration. Sulphuric or hydrochloric acid is suitable for the
purpose and the proportion used can be varied as desired, it being understool that
the greater the amount of acid used up to a certain point the lighter will be the
color of the liquor, but there should be no free sulphuric or hydrochloric acid in the
liquor. Oxalic acid gives a good color but it has the disadvantage of forming
insoluble compounds with magnesia and lime; these can however be removed by
settling and decantation if the liquor is not concentrated to very thick state, or
water can be added to it and the liquor be again evaporated to the desired degree
of concentration. Or I can use alum, sulphate of alumina or bisulphate of soda
instead of an acid in order to improve the color of the liquor.
The product obtained as above described is hygroscopic. I employ this product
for the manufacture of further products and more particularly of a product
resembling or having properties similar to those of dextrine, and therefore like
dextrine readily soluble in cold water. For the sake of convenience 1 will herein-
after call this product "dextrone." In order to manufacture or obtain this dextrone
I separate it from the organic substance which gives the liquor the hygroscopic
property already mentioned. For this purpose I add to the liquor when hot,
(preferably after treatment as hereinbefore described although I can use the liquor
in its original state but by preference more or less concentrated) one or more of
certain soluble salts such as sulphates of potash, soda or magnesia, and chlorides of
potash and soda. I have obtained the most satisfactory results and best colors with
the sulphates mentioned, and of these I prefer sulphate of magnesia. It is
generally better both as regards the quality of the products obtained and the
carrying out of the process to add alum or sulphate of alumina to one of the salts
mentioned. I have also used sulphate of ammonia, but it has given less satisfactory
results and is more difficult to manipulate. I keep on adding the salt or salts (they
can be used alone or mixed) so long as dextrone continues to separate from the
liquor and rise to the surface. The dextrone may be removed from time to time as
it is formed, or when enough salt has been added the liquor may be allowed to
remain in a hot state, when the dextrone will go to the top and the liquor can be
drawn off from the bottom of the vessel. The quantity of salt to be used varies
according to the concentration of the liquors, the kind employed, and also according

page_text: to the particular sulphite liquor to be treated, but taking as an example a sulphite
liquor which has been obtained by boiling wood under pressure with a solution of
bisulphite of magnesia or sulphurous acid and magnesia, and which has subsequently
been evaporated as hereinbefore described to a specific gravity of about 63° Twaddel
at 85° centigrade, the liquor having first been made alkaline or not as may be
convenient and an acid added as above described,-to 300 parts by weight of the
heated liquor I add about 100 parts of sulphate of magnesia, and I continue the
heating, stirring the liquor until all the salt is dissolved. The dextrone rises to
the top and forms a soft crust which may be removed and the process may be
continued as long as more dextrone is separated, or if left hot the liquor can be
drawn off from the bottom as before described. The dextrone should be removed
with care so that as little liquor as possible may adhere to it. The dextrone when
cold forms a stiff mass which may be dissolved so as to be used in a liquid form, or
it may be dried, preferably at a low temperature, and reduced to a powder so as to
be used like powdered dextrine.
If a more purified product is desired the dextrone obtained as above is dissolved
in water and again separated by means of a salt as above described, and this operation
can be repeated as often as may be thought necessary.
"
The dextrone obtained as above described if mixed with a solution of gelatine or
glue forms a very concentrated material of the nature of that called "gela-lignosine
in the Specification of Cross and Bevan's Patent No. 1548 of 1883 and which when
dissolved by means of a suitable solvent, as a solution of sulphite of soda in water,
can be used for mordanting or sizing textile fabrics or sizing paper.
The solution left after the separation of the dextrone from the sulphite liquor
as above explained can be employed for the manufacture of a material of the
nature of gela-lignosine by adding a solution of gelatine or glue and allowing it to
separate, more and more gelatine or glue being added until no more product is
formed. The product or gela-lignosine is of better color and separates more
easily if alum or sulphate of alumina has been added either before separating the
dextrone or afterwards. The gela-lignosine thus obtained becomes a dense mass
on cooling, but it is desirable to remove as much as possible of the liquor adhering
to it and this can be effected by pressing or kneading or by washing when in a
disintegrated state in a liquid which will not dissolve the gela-lignosine, such as a
weak solution of a suitable salt as a bisulphite or alum solution or in a limited
amount of water if alum has been added before. The gela-lignosine thus obtained
after having been properly dissolved is suitable for sizing and mordanting.
The still remaining liquor is left to cool, when the salt which has been employed
will partly crystallize; the liquor is then drawn off and can be further evaporated
and again left to crystallize, and this operation can be repeated as long as any salt
can be obtained by crystallization.
According to another part of my invention I make a material suitable for sizing
by dissolving glue or gelatine in the sulphite liquor which has been made alkaline
as above described and which may first be more or less concentrated, but in this
case no acid should be added before the glue or gelatine. The glue or gelatine can
be dissolved direct in the liquor but it is generally more convenient to first soak
the glue in cold water, then dissolve it by gentle heat, and then mix it with the
sulphite liquor which has been previously warmed. The proportion of glue or
gelatine will depend upon the purpose for which the size is required, but when
light-color is of consideration only as much liquor should be used as is necessary to
precipitate the glue or gelatine when mixed with alum solution in excess, because
the larger the amount of liquor the darker will be the color that it will give to the
material that is sized; a larger amount of liquor, however, gives a greater amount
of precipitate, and a product having better sizing properties. Speaking generally,
suitable proportions are 10 parts by weight of gelatine dissolved in 30 parts by
weight of water and then mixed with 40 parts by weight of liquor evaporated to
a specific gravity of about 63° Twaddel at 85° centigrade, or if color is of
consideration then only 30 parts of liquor.

page_text: This size contains a large amount of a soluble form of gela-lignosine like that
of Bevan and Cross herein before referred to, and it can therefore be used for many
of the purposes for which in their Specification they recommend their gela-lignosine
in a soluble form, and more particularly for paper sizing, when the color is of no
consideration, because this impure product will discolor more than the ordinary
gela-lignosine after it has been dissolved. As is the case with gela-lignosine when
a suitable acid or salt, preferably alum or sulphate of alumina is added to the
solution, gela-lignosine is precipitated, so it is with this size, and this size can be
used with advantage for the preparation of gela-lignosine.
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 method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in first making the liquor
alkaline, then concentrating it, then adding thereto a color-improving agent, then
adding thereto a soluble salt to separate from the liquor a dextrine-like product,
and then, after removal of this product, adding gelatine or glue to the liquor to
obtain a further useful product, substantially as and for the purposes hereinbefore
described.
2. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in first making the liquor
alkaline, then concentrating it, then adding thereto a color-improving agent, and
then adding thereto a soluble salt to separate from the liquor a dextrine-like
product, substantially as and for the purpose hereinbefore described.
3. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in first making the liquor
alkaline, then concentrating it and then adding thereto a soluble salt to separate
from the liquor a dextrine-like product substantially as and for the purpose
hereinbefore described.
4. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in adding to the liquor a
color-improving agent and then adding thereto a soluble salt to separate from the
liquor a dextrine-like product, substantially as and for the purpose hereinbefore
described.
5. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in adding to the liquor a
soluble salt to separate therefrom a dextrine-like product, and then after removal
of this product adding gelatine or glue to the liquor to obtain a further useful
product, substantially as and for the purposes hereinbefore described.
6. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in adding to the liquor
a soluble salt to separate therefrom a dextrine-like product, as hereinbefore
described.
7. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in first making the liquor
alkaline, then concentrating it, then adding thereto a soluble salt to separate from
the liquor a dextrine-like product, and then, after removal of this product, adding
gelatine or glue to the liquor to obtain a further useful product substantially as and
for the purpose hereinbefore described.
8. The method of treating the liquor resulting from the manufacture of cellulose
or fibres by the sulphite process, which method consists in first concentrating the
liquor, then adding a color-improving agent, then adding thereto a soluble salt to
separate from the liquor a dextrine-like product, and then after removal of this
product adding gelatine or glue to the liquor to obtain a further useful product
substantially and for the purposes herein before described.
9. The method of treating the liquor resulting from the manufacture of cellulose

page_text: or fibres by the sulphite process, which method consists in first making the liquor
alkaline (with or without more or less previous concentration) and then dissolving
glue or gelatine therein, whereby a product is obtained suitable for use as size,.
substantially as hereinbefore described.
Dated this 24th day of July 1894.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Patent Agents.