IMPROVEMENTS IN THE PROCESS OF ALUMING OR CURING HIDES OR SKINS
Year: 1884

page_text: or Skin8.
"
I, BERTRAM HUNT, of Buslingthorp Tannery, Leeds, in the County of York,
Analytical Chemist, do hereby declare the nature of my said invention for
IMPROVEMENTS IN THE PROCESS OF ALUMING OR CURING HIDES OR SKINS" to be
as follows, that is to say :-
My said Invention has for its object to improve the process in leather dressing
known as the aluming or curing of hides or skins so that whilst the hides or skins
are rendered less liable to be affected by atmospheric humidity, there is more
alumina or other metallic oxide taken up by them and fixed so as to resist washing
out, than when the ordinary process is used.
In carrying out my Invention instead of using a mixture of alum and common
salt I employ a basic solution of alum, or of aluminic sulphate, or of aluminic
chloride. I prepare the basic solution by gradually adding a solution of sodic or
potassic carbonate, to a solution of the salt of aluminium, or by dissolving freshly
precipitated hydrate of aluminium in such solution.
The basic solution is to be used in the same way as the ordinary alum and salt
solution.
In a similar way when other metallic compounds are used for curing the hides
or skins instead of a compound of aluminium, my Invention is to be applied by
using a basic solution of the metallic compound employed, such for example as a
basic solution of chloride or sulphate of iron (ferrous or ferric) or of chloride or
sulphate of chromium.
EDMUND HUNT,
Applicant's Agent.

page_text: Improvements in the Process of Aluming or Curing Hides
or Skins.
I, BERTRAM HUNT, of Buslingthorp Tannery, Leeds, in the County of York,
Analytical Chemist, do hereby declare the nature of my said invention for
"IMPROVEMENTS IN THE PROCESS OF ALUMING OR CURING HIDES OR SKINS," and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement, that is to say :-
My said Invention has for its object to improve the process in leather dressing
known as the aluming or curing of hides or skins, so that whilst the hides or skins
are rendered less liable to be affected by atmospheric humidity, there is more
alumina or other metallic oxide taken up by them and fixed so as to resist washing
out, than when the ordinary process is used.
In carrying out my Invention, instead of using a mixture of alum and common
salt, 1 employ a basic solution of alum, or of aluminic sulphate, or of aluminic
chloride. I prepare the basic solution by gradually adding a solution of sodic or
potassic carbonate to a solution of the salt of aluminium, or by dissolving freshly
precipitated hydrate of aluminium in such solution.
For curing calf kid, for example, I make a solution of 40 pounds aluminic
sulphate in 8 or 9 gallons of water, and add gradually to it 20 pounds soda crystals
dissolved by steam, the solution being agitated during the addition, and a clear
solution of basic aluminic sulphate being thereby formed. An equivalent weight
of soda ash or bicarbonate may be used instead of the soda crystals. With the
basic solution about one third of its volume of water is mixed; and the mixture
having been heated to about the same temperature as in the ordinary process, the
usual flour, egg yolk, and other ingredients are added, and the skins are worked in
the liquor or emulsion in the usual way. The working should be continued a little
longer as the basic sulphate does not penetrate quite as quickly as when a large
quantity of salt is present, as in the ordinary process. The skins are stoved and
finished in the ordinary way.
For glove leather I prefer to employ a liquor to which a smaller proportion of
carbonate of soda has been added, say 10 to 15 pounds in a solution containing
40 pounds aluminic sulphate. The curing operation is conducted as in the ordinary
process in which alum and salt is used.
In some cases it is advantageous to use a little salt along with the basic aluminic
sulphate.
When aluminic chloride is employed about 18 pounds of it may be used instead
of the 40 pounds of aluminic sulphate.
In a similar way, in what is known as mineral tanning, whẹn other metallic
compounds are used for curing the hides or skins instead of a compound of
aluminium, my Invention is to be applied by using a basic solution of the metallic
compound employed, such for example as a basic solution of chloride or sulphate
of iron or of chloride or sulphate of chromium.

page_text: In using an iron compound, for example, I make 10 gallons of strong liquor by
dissolving 10 pounds of ferric chloride and gradually adding 5 to 6 pounds of soda
ash or an equivalent quantity of soda crystals or bicarbonate. Or instead of
adding soda to the ferric chloride solution, I form the basic solution by dissolving
in it freshly precipitated ferric hydrate to saturation. This liquor can be put into
pits in which the hides or skins may be worked in the ordinary way; or it may be
put along with the hides or skins into what is known as a tumbler or tanning
drum. In practice the hides or skins should go first into old liquor for a day or
two, next into fresher liquor, and finally into the strong liquor. The iron remaining
in the spent liquor can be recovered by precipitating it with lime or soda ash as
hydrate, which can be used as herein before mentioned for forming the basic
solution. The hides or skins may be subsequently treated in the ordinary way.
Mixtures of any two or more of the basic solutions herein before referred to may
be used in carrying out my Invention.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim is
The employment in the process of aluming or curing hides or skins, of a basic
solution of alum, or of aluminic sulphate, or of aluminic chloride, or of ferric
chloride, or of ferric sulphate, or of chromic chloride or of chromic sulphate or of
a mixture of two or more of these substances substantially in the manner herein-
before described.
EDMUND HUNT,
Applicant's Agent.