IMPROVEMENTS IN THE MANUFACTURE OF ALKALIES
Year: 1882

page_text: LETTERS PATENT to Edward William Parnell of Widnes in the County of
Lancaster Analytical Chemist and James Simpson of Liverpool in the same
County Alkali Manufacturer for an Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF ALKALIES
"
PROVISIONAL SPECIFICATION left by the said Edward William Parnell
and James Simpson at the Office of the Commissioners of Patents on the
4th October 1882.
EDWARD WILLIAM PARNELL of Widnes in the County of Lancaster. Analytical
Chemist and JAMES SIMPSON of Liverpool in the same County. Alkali Manufacturer.
"IMPROVEMENTS IN THE MANUFACTURE OF ALKALIES
"
In the manufacture of caustic soda from vat liquor made by the Le Blanc process
the undecomposed carbonate and sulphate of soda separate from the concentrated
caustic alkaline solution in the form known as "caustic salts." These salts usually
contain an excessive proportion of caustic alkali and also-among other impurities-
iron in various soluble combinations-the presence of which interferes with their
direct utilization for the manufacture of soda ash, Bi carbonate of soda and other
merchantable forms of alkali in which whiteness of color is desirable; while the
liquor adhering to the salts (in some cases amounting to as much as one third of
the mass) is to a great extent wasted and a large amount of fuel consumed when
the wet salts are used for making Black Ash.
The objects of our invention are First. To treat the salts in such a manner as
to free them from the liquor aforesaid, thereby rendering them more suitable for
the direct manufacture of Soda Ash, Bi Carbonate of soda or Black Ash. Secondly.
To remove the said liquor in such a way that it may be available for the direct
manufacture of caustic soda, and Thirdly. To provide a furnace suitable for the
conversion of the salts, after the liquor has been so removed, into merchantable
soda ash.
For this purpose we introduce the salts into a closed chamber having a perforated
surface connected with a drain pipe and we cause steam to pass through the mass

page_text: of salts and out through the perforations, thereby carrying the liquor with it, and
leaving the salts behind. The chamber should be fitted with a helical scraper or
contrivance for compressing the surface of the mass and preventing the steam from
forming channels. The filter press described in the specification to British Letters
Patent Number 2816 of the year 1882. is specially suited for this operation, but it
is manifest that other machines of different construction would also be available.
When the liquor has been removed by the steam it may be boiled down or
concentrated into merchantable caustic soda by the ordinary known methods, while
the residual salts which are exceedingly dry and of greatly improved color may
be used instead of salt cake for the Black Ash operation, or instead of Soda crystals
for the manufacture of Bi-Carbonate of soda, or they may be treated in the
ordinary method in a finishing furnace for the manufacture of soda ash. For
the latter purpose however we find it preferable to subject the salts after
treatment with steam as aforesaid to a gentle uniform heat for which purpose we
recommend a specially constructed heating bed or air furnace, so designed that the
flame of the fuel shall not come in contact with the salts and that the heat shall
not at any time be high enough to flux the soda or injure its color. A furnace
suitable for the manufacture of a very good quality of soda ash from salts after the
liquor has been removed we construct as follows:-A drying bed is surrounded at
the top and ends with flues through which heated air and products of combustion
are caused to pass say from a furnace at one end of the drying bed. One end of
the drying bed is in communication with the atmosphere through pipes or tubes
passing through the flue over the furnace, and the other end is in communication
through a suitable opening with the flue leading to the chimney.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward William Parnell and James Simpson in the Great Seal
Patent Office on the 4th April 1883.
EDWARD WILLIAM PARNELL of Widnes in the County of Lancaster, Analytical
Chemist and JAMES SIMPSON of Liverpool in the same County Alkali Manufacturer.
"IMPROVEMENTS IN THE MANUFACTURE OF ALKALIES "
In the manufacture of caustic soda from vat liquor made by the Le Blanc
process the undecomposed carbonate and sulphate of soda separate from the con-
centrated caustic alkaline solution in the form known as "caustic salts." These
salts usually contain an excessive proportion of caustic alkali and also among other
impurities iron in various soluble combinations, the presence of which interferes
with their direct utilization for the manufacture of Soda Ash. Bi-carbonate of soda
and other merchantable forms of alkali in which whiteness of color is desirable,
while the liquor adhering to the salts (in some cases amounting to as much as one
third of the mass) is to a great extent wasted and a large amount of fuel consumed
when the wet salts are used for making black ash.
The objects of our invention are First. To treat the salts in such a manner as to
free them from the liquor aforesaid, thereby rendering them more suitable for the
direct manufacture of Soda Ash, Bi carbonate of Soda or Black Ash. Secondly. To
remove the said liquor in such a way that it may be available for the direct
manufacture of caustic soda and Thirdly. To provide a furnace suitable for the
conversion of the salts after the liquor has been so removed-into merchantable
soda ash.
For this purpose we introduce the salts into a closed chamber having a perforated
surface connected with a drain pipe and we cause steam to pass through the mass
of salts and out through the perforations-thereby carrying the liquor with it-and
leaving the salts behind. The chamber should be fitted with a helical scraper or
contrivance for compressing the surface of the mass and preventing the steam
from forming channels. The filter press described in the specification to British
Letters Patent Number 2816 of the year 1882 is specially suited for this operation,
but it is manifest that other machines of different construction would also be
available.
When the liquor has been removed by the steam it may be boiled down or
concentrated into merchantable caustic soda by the ordinary known methods, while
the residual salts which are exceedingly dry and of greatly improved color may be
used, instead of salt cake for the Black Ash Operation, or instead of soda crystals
for the manufacture of Bi-carbonate of Soda, or they may be treated by the
ordinary method in a finishing furnace for the manufacture of Soda Ash. For the
latter purpose however we find it preferable to subject the salts after treatment
with steam as aforesaid to a gentle uniform heat for which purpose we
recommend a specially constructed heating bed or air furnace so designed that
the flame of the fuel shall not come in contact with the salts, and that the heat
shall not at any time be high enough to flux the soda or injure its color.

page_text: at the top and ends with the flues 6 through which heated air and products of
combustion from the furnace or fire place c reach the chimney d. e are pipes or
tubes passing through the flue b over the furnace or fire place c and opening
communication between the atmosphere and the drying bed. f is an opening
leading from the drying bed into the flue b near to the chimney. The drying bed
and furnace are built of bricks in the usual manner and the pipes or tubes f are
preferably of fire clay. The salts to be treated are placed on the bed a and air is
allowed to circulate through the pipes or tubes e over the bed a and through the
opening to the chimney d.
Having now described and particularized the nature of our said invention in
such manner that others will be enabled to carry our improvements into effect
We claim :-
First. The method herein described of treating caustic salts with steam while
subjecting them to mechanical pressure for the purposes set forth.
Second. The furnace herein described for the purpose of manufacturing soda ash
from caustic salts from which the liquor has been removed.
In Witness Whereof I the said James Simpson have hereunto set my hand
and seal this second day of April in the year of Our Lord, one thousand
eight hundred and eighty three.
JAMES SIMPSON (1.8)