AN IMPROVED PROCESS AND APPARATUS FOR CALCINING SULPHATE OF IRON OR OTHER COMPOUNDS OF IRON OXIDE AND SULPHURIC ACID, OR THE LIKE, FOR THE MANUFACTURE OF PIGMENTS, AND THE UTILIZATION OF THE SULPHUROUS ACID IN SUCH COMPOUNDS
Year: 1878

page_text: LETTERS PATENT to Charles Leech and Thomas Neal, of the Firm of Leech
and Neal, of Derby, in the County of Derby, Manufacturers, for the Invention
of "AN IMPROVED PROCESS AND APPARATUS FOR CALCINING SULPHATE OF
IRON OR OTHER COMPOUNDS OF IRON OXIDE AND SULPHURIC ACID, OR THE
LIKE, FOR THE MANUFACTURE OF PIGMENTS, AND THE UTILIZATION OF THE
SULPHUROUS ACID IN SUCH COMPOUNDS."
PROVISIONAL SPECIFICATION left by the said Charles Leech and Thomas
Neal at the Office of the Commissioners of Patents on the 1st April 1878.
CHARLES LEECH and THOMAS NEAL, of the Firm of Leech and Neal, of Derby,
in the County of Derby, Manufacturers. "AN IMPROVED PROCESS AND APPARATUS
FOR CALCINING SULPHATE OF IRON OR OTHER COMPOUNDS OF IRON OXIDE AND
SULPHURIC ACID, OR THE LIKE, FOR THE MANUFACTURE OF PIGMENTS, AND THE
UTILIZATION OF THE SULPHUROUS ACID IN SUCH COMPOUNDS."
This Invention relates to a novel process or mode of calcining sulphate of iron
(green copperas), precipitated yellow ochre, pyrites, or other combinations of iron
oxide and sulphuric acid, to produce from the oxide of iron pigment of various
shades of colour, and at the same time to arrest the sulphurous acid fumes and convert
the same into either sulphuric acid and sulphite or sulphate of iron.
The said Invention also relates to apparatus for carrying this improved process
into effect.
In practising our Invention we use a kilu, in shape similar to an ordinary brick
kiln heated by fires from the outside, the number of the fires being regulated by the
diameter of the kiln. We fill this kiln with shallow fire-clay or other pans con-
taining the sulphates of iron and other materials. On the roof of this kiln we place
a small chamber with which is connected two iron pipes. Each pipe has in it a
throttle valve; one pipe is conducted into a chimney and the other into a chamber

page_text: lined with lead or other suitable material. The size of this chamber must be
regulated by the size and number of kilns used; the said chamber is also connected
by an iron pipe with a column built of fire-brick or other suitable material, and
filled to within about three feet of the bottom with light scrap iron. This column
is connected with the said chimney by an iron pipe, and on the top of the said
column is placed a water cistern or reservoir with a double bottom, perforated to
permit a regular flow of water.
The mode of operation is as follows, that is to say:-The kiln or kilns being
filled, or charged and closed, and the fires lighted, the valve of the pipe leading to
the chimney is opened, while the valve of the pipo leading to the lead-lined chamber
is closed; the heat is then slowly raised until it is sufficiently high to decompose the
sulphuric acid contained in the material being calcined. At this stage of the process
the said pipe leading from the kiln to the said chamber is opened, while the pipo
leading from the kiln to the chimney is closed, when the sulphurous acid and other
vapours pass into the said chamber, the bottom of which is covered to a depth of a
few inches with water to absorb the sulphuric acid passing over, while the sulphurous
acid fumes are conducted by the pipe provided for this purpose into the lower part
of the column filled with light scrap iron, through which water is constantly per-
colating from the reservoir, and passing upwards through the moistened scrap iron;
these fumes are arrested and converted, in conjunction with the oxide of the iron,
into sulphite of iron by the action of the water which is carried down into the
reservoir at the bottom of the said column; the various other fumes meanwhile pass
upwards, and are carried by the aforesaid iron pipe into the chimney. This chimney
must be sufficiently high to create the required draught; where there is not a
sufficient height of chimney we propose to employ a small chamber in connection
with the aforesaid column and the chimney, and to provide the latter with a fan or
other exhauster.
When the decomposition of the sulphuric acid is completed, should the material
being calcined require greater or longer heat, the valve in the pipe leading from the
kiln to the chimney should be opened, and that in the pipe leading to the chamber
closed.
The iron liquor in the reservoir at the bottom of the said column can be pumped
up several times into the other reservoir; and finally, by the application of a further
quantity of scrap iron and by evaporation can be converted into sulphate of iron,
and may be used again in the manner herein-before described to produce pigments
of oxide of iron, sulphuric acid, and sulphate of iron.
The liquor in the aforesaid chamber when sufficiently charged with sulphuric
acid may either be concentrated in the usual manner or be converted, by the addition
of scrap iron and by evaporation; into sulphate of iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Leech and Thomas Neal in the, Great Seal Patent Office on
the 1st October 1878.
CHARLES LEECH and THOMAS NEAL, of the Firm of Leech and Neal, of Derby,
in the County of Derby, Manufacturers. "AN IMPROVED PROCESS AND APPARATUS
FOR CALCINING SULPHATE OF IRON OR OTHER COMPOUNDS OF IRON OXIDE AND
SULPHURIC ACID, OR THE LIKE, FOR THE MANUFACTURE OF PIGMENTS, AND THE
UTILIZATION OF THE SULPHUROUS ACID IN SUCH COMPOUNDS."
This Invention relates to a novel process or mode of calcining sulphate of iron
(green copperas), precipitated yellow ochre, pyrites, or other combinations of iron
oxide and sulphuric acid, to produce from the iron oxide pigments of various
shades of colour, and at the same time to arrest the sulphuric and sulphurous acid
fumes and convert the same into either sulphuric acid, or sulphite or sulphate of
iron.
The said Invention also relates to apparatus for carrying this improved process
into effect.
In practising our Invention we use the apparatus shewn in the accompanying
Drawing, in which Figure 1 is a plan or top view; Figure 2 is a side elevation; and
Figure 3, an end elevation.
Like letters indicate the same parts in all the Figures.
This apparatus comprises a kiln a, in shape similar to an ordinary brick-kiln,
heated by fires from the outside, the number of the fires being regulated by the
diameter of the kiln. We fill this kiln with shallow fire-clay or other pans con-
taining the sulphate of iron and other materials. On the roof of this kiln a we
place a small chamber a', with which are connected two iron pipes b, d. Each pipo
has in it a throttle valve or damper b', '. One pipe b is conducted into a chimney c,
and the other pipe d into a chamber e lined with lead or other suitable material.
The size of this chamber e must be regulated by the size and number of kilns used.
The said chamber is also connected by an iron pipe f with a column g built of fire-
brick or other suitable material and filled to within about 3 feet of the bottom with
light scrap iron. This column is connected with the said chimney c by an iron pipe h,
and on the top of the said column is placed a water cistern or reservoir i with a
double bottom, perforated to permit a regular flow of water.
The mode of operation is as follows, that is to say-The kiln or kilns a
being filled, or charged and closed, and the fires lighted, the valve or
damper of the pipe b leading to the chimney c is opened, while the valve or
damper of the pipe d leading to the glazed or lead-lined chamber e is
closed; the heat of the kiln is then slowly raised until it is sufficiently high
to decompose the sulphuric acid contained in the material being calcined. At
this stage of the process the pipe leading from the kiln a to the chamber e is opened,
while the pipe leading from the said kiln to the chimney c is closed; the sulphuric
and sulphurous acid and other vapours then pass into the said chamber, the bottom
of which is covered to a depth of a few inches with water to absorb the sulphuric
acid passing over, while the sulphurous acid fumes are conducted by the pipe f pro-
vided for this purpose into the lower part or space of the column g; through this
column water is constantly percolating from the reservoir i, and passing upwards
through the moistened scrap iron the fumes are arrested and converted, in con-
junction with the oxide of iron and the water into sulphite of iron, which by the
action of the water is carried down into the reservoir j at the bottom of the said
う
column; the various other fumes meanwhile pass upwards, and are carried by the
aforesaid iron pipe into the chimney c. This chimney must be sufficiently high to
create the required draught; where there is not a sufficient height of chimney we
propose to employ a small chamber in connection with the aforesaid column and
the chimney, and to provide the latter with a fan or other exhaust.
When the decomposition of the sulphuric acid is completed, should the material

page_text: being calcined require greater or longer heat the valve or damper in the pipe b
lending from the kiln a to the chimney c should be opened, and the valve or damper
in the pipe & leading to the chamber e should be closed.
The iron liquor in the reservoir j at the bottom of the said column can be pumped
up several times into the reservoir, and finally, by the application of a further
quantity of scrap iron, together with the sulphuric acid from the chamber e and by
evaporation, it can be converted into sulphate of iron, and may be used again in
the manner herein-before described to produce pigments of iron oxide, sulphuric
acid, and sulphate of iron, or it can be used as an iron liquor for dyeing purposes, or
for the manufacture of Prussian blue.
The liquor in the aforesaid chamber when sufficiently charged with sulphuric acid
may be concentrated in the usual manner, or may be converted by the addition of
scrap iron and by evaporation into sulphate of iron.
Having thus fully described the said Invention and the manner of performing the
same, we wish it understood that we claim,-
First. The improved process of manufacture, consisting in the treatment for
sulphate of iron or other compound of iron oxide and sulphuric acid or the like for
the manufacture of pigments, sulphuric acid, or sulphate or sulphite of iron, in the
manner above sot forth.
Second. The improved apparatus, comprising the kiln or kilns provided at the top
with a small chamber, the large lead-lined or glazed chamber, the column partly
filled with scrap iron, the reservoirs at the top and bottom of the said column, and
the chimney, constructed and arranged in connection with each other by suitable
pipes provided with regulating valves or dampers, as shewn and operating as and
for the purposes specified.
In witness whereof, we, the said Charles Leech and Thomas Neal, have here-
unto set our hands and seals, this Twenty-sixth day of September, in the