Apparatus therefor.
Year: 1889

page_text: Apparatus therefor.
I, JAMES BALLANTYNE HANNAY, of Cove Castle, Loch Long, in the County of
Dumbarton, North Britain, Chemist, do hereby declare the nature of this Invention to
be as follows, that is to say :—
My said Invention has for its object to improve and cheapen the manufacture of a
white pigment from lead; and it comprises improved processes and apparatus
by means of which the white pigment is obtained in the form of an amorphous
sulphate of lead in a state of great fineness and purity.
In carrying out my Invention I take galena or other suitable lead ore containing
sulphur, adding sulphur or a suitable sulphide if there is not sufficient in the ore to
form a sulphate of all the lead; and I treat this ore in a special furnace which has
combined with it a combustion chamber or passage and a fiue leading to a wet fume
condenser.
The furnace is of a square or other convenient form in plan, and has a door at the
upper part of the front for feeding in fuel and ore; and doors are provided at the lower part
for removing ashes and unvolatilised residues. Provision is also made for admitting
air into the furnace either through tuyeres, through which it is forced by a fan or
blower, or through gratings or other apertures into which it is drawn by the action of
apparatus hereinafter referred to and by which the fumes and gases are drawn from
the furnace and passed through the condenser.
The furnace is filled up to about the level of the charging door with coke, and this
coke being ignited is, by regulating the air supply, worked so as to produce some
carbonic oxide whilst also evolving the necessary heat to act on the lead. The lead
ore is thinly spread over the top of the coke, fresh quantities being supplied as the
action proceeds. The furnace is closed at the top, and there is an aperture at the back,
which communicates with a chamber or passage constructed of refractory brick and
which constitutes a combustion or oxidising chamber. A mixture of fumes comprising
a considerable quantity of sulphate of lead together with sulphite and sulphide passes
along with carbonic oxide and other gases from the furnace into the combustion

page_text: chamber or passage; and the necessary additional air being admitted the combustion
and oxidation is made as complete as possible in such combustion chamber or passage.
The sulphate of lead, which is formed in a very fine amorphous condition is for the
most part carried by the current of gases outwards through the flue forming a con-
tinuation of the combustion chamber leading to the fume condenser. This condenser
is by preference of the improved kind described in the Specification of my Patent
No. 16290 of 1886; but any suitable wet fume condenser may be used. A portion
of the fumes is deposited in the flue leading to the condenser and is to be removed
periodically and treated as hereinafter described.
A little sulphuric acid is put into the water in the condenser to dissolve out any
iron or other metal or impurity present and soluble in dilute sulphuric acid. A fan
or other suitable blower may be used for drawing the fumes from the furnace and
passing them into the condenser; I however prefer to use for that purpose one or
more steam jets or steam injectors placed in or near the condenser, the steam whilst
inducing a current at the same time facilitating the admixture of the fumes with the
water.
After removal from the condenser the sulphate is well washed; and it is finally
dried, and made up for the market in a dry form; or it may be ground with oil or
other medium to form paint, or so-called enamel, for which latter purpose it is an
extremely suitable and advantageously applicable material.
If a suitable quantity of free sulphurous acid is present amongst the fumes entering
the condenser it will become converted by the action of the steam jets and water
into sulphuric acid and render it unnecessary to add that acid from another source.
The fumes deposited in the flue and which are to be periodically removed as herein-
before prescribed are to be well washed with very dilute sulphuric acid which will
dissolve impurities and leave a very pure sulphate of lead.
Dated this Twenty-third day of January 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Making a White Pigment of Lead and in
Apparatus therefor.
I, JAMES BALLANTYNE HANNAY, of Cove Castle, Loch Long, in the County of
Dumbarton, North Britain, Chemist, 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, that is to say :-
My said Invention has for its object to improve and cheapen the manufacture of a
white pigment from lead; and it comprises an improved combination of processes and
apparatus by means of which the white pigment is obtained in the form of an
amorphous sulphate of lead in a state of great fineness and purity.
In carrying out my Invention I take galena or other suitable lead ore containing
sulphur, adding sulphur or a suitable sulphide if there is not sufficient sulphur in the
ore to forin a sulphate of all the lead; and I treat this ore in a special furnace which
has combined with it a combustion chamber or passage and a Hue leading to a wet
fume condenser.
The apparatus I use is partly shown on an accompanying sheet of explanatory
drawings, Figure, 1, being a front elevation of the furnace, Figure, 2, a vertical
section of the furnace and a portion of the passages, and Figure, 3, a vertical section
of the continuation of the passages and also showing other parts.
The furnace, 5, is of a square (or other convenient) form in plan, and has a door, 6,
at the upper part of the front for feeding in fuel and ore; and doors, 7, are provided
at the lower part for removing ashes. Provision is made for admitting air into the
furnace by tuyeres, 8, supplied with compressed air by branch pipes, 9, from a main
pipe, 10, from a fan or blowing apparatus. Or air may be admitted through gratings
or other apertures into which it is drawn by the action of apparatus hereinafter
referred to, and by which the fumes and gases are drawn from the furnace and passed
through the condenser.
The furnace, 5, is filled up to about the level of the bottom of the charging door, 6,
with coke, and this coke being ignited, is by regulating the air supply, worked so as
to produce some carbonic oxide, whilst also evolving the necessary heat to act on the
lead. The lead ore is spread over the coke, fresh quantities of coke and ore being
supplied as the action proceeds. The furnace, 5, is closed at the top and there is an
aperture, 11, at the back which communicates with a chamber or passage, 12, con-
structed of or lined with refractory brick and which constitutes a combustion or
oxidising chamber. A mixture of lead fuines with carbonic oxide and other
gases passes from the furnace into the combustion chamber or passage, 12, and the
necessary additional air being supplied by branch pipes, 13, the combustion and
oxidation are made as complete as possible in the combustion chamber or passage, 12.
The sulphate of lead, which is formed in a very fine amorphous condition is for the
most part carried by the current of gases onwards through a flue, 14, forming a
continuation of the combustion chamber, 12, and which may communicate with the
combustion chambers of two or more volatilising furnaces.

page_text: The flue, 14, communicates with a depositing chamber or tower, 15, in which a large
portion of the sulphate of lead is deposited, and from this tower, 15, the remaining
fumes and gases pass into the fume condenser, 16. This fume condenser, 16, is by
preference of the improved kind described in the Specification of my Patent
No. 16290 of 1886 but any suitable wet fume condenser may be used. The portion
of the fumes deposited in the flue, 14, and tower, 15, is to be removed periodically and
treated as hereinafter described.
A little sulphuric acid is'put into the water in the condenser, 16, to dissolve out any
iron or other metal or impurity present and soluble in dilute sulphuric acid. For the
purpose of drawing the fumes from the furnace and passing them into the condenser, 1
employ one or more steam jets or steam injectors 17, placed at the inlet into the
condenser, 16, as shown, the steam whilst inducing a current at the same time
facilitating the admixture of the fumes with the water.
After removal from the condenser the lead sulphate is well washed, and it is finally
dried and made up for the market in a dry form; or it may be ground with oil or 1
other medium to form paint or so called enamel, for which latter purpose it is an
extremely suitable and advantageously applicable material.
.
Sometimes the fumes and gases carry with them to the condenser some sulphurous
acid which will become converted by the action of the steam jets and water into
sulphuric acid; and if in sufficient quantity will render it unnecessary to add that acid
from another source.
The fumes deposited in the flue, 14, and tower, 15, and which are to be periodically t
removed as herein before prescribed are to be well washed with very dilute sulphuric
acid which will dissolve impurities and leave a very pure sulphate of lead.
Having now particularly described and ascertained the nature of my said Inven- a
tion and in what manner the same is to be performed, I declare that what I
claim is
.
1 In a process for manufacturing sulphate of lead volatilising suitable lead ore
containing sulphur in a furnace simultaneously producing combustible gas, and then
burning the gas and oxidising the fumes substantially as hereinbefore described.
2-The
process for manufacturing sulphate of lead consisting of the following steps, i
first, volatilising suitable lead ore containing sulphur and at the same time producing
combustible gas mingled with the fumes, secondly, burning the gas and oxidising the
fumes with the requisite admission of air, thirdly, by means of a steam injector forcing
the gases and fumes into water or acidulated water in a fume condenser in which the
sulphate of lead is deposited, and finally washing and drying the sulphate of lead t
produced all substantially as herein before described.
3-The apparatus for manufacturing sulphate of lead in the manner referred to in
the preceding claim consisting of a furnace for volatilising suitable lead ore and
producing combustible gas, a combustion chamber with ain supply wherein the lead
fumes are oxidised, flues or passages in which a portion of the fumes is deposited,.
.steam injectors drawing the fumes and gases and forcing them into. a. condenser, and
a condenser receiving the fumes, substantially as herein before described and shown by
the drawings.