IMPROVEMENTS IN THE MANUFACTURE Or ARSENIC
Year: 1866

page_text: LETTERS PATENT to Brereton Todd, of 4, Victoria Terrace, Newcastle-
on-Tyne, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE Or
ARSENIC."
Sealed the 9th July 1866, and dated the 13th January 1866.
PROVISIONAL SPECIFICATION left by the said Brereton Todd at the
Office of the Commissioners of Patents, with his Petition, on the 13th
January 1866.
I, BRERETON TODD, of 4, Victoria Terrace, Newcastle-on-Tyne, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF ABSENIC," to be as follows:-
Hitherto the separation of arsenic from minerals, and the revolatilizing of
arsenious acid in the manufacture of arsenic, has been effected in a furnace
heated by the combustion of coal or coke in a grate or fire-place attached to
the furnace, during which operation a quantity of grit or dust from the fuel,
with sometimes a large portion of free carbon, is carried over by the draught
into the condensers and condensed with the arsenious acid to the injury of the
whiteness and quality of the arsenic.
The improvements consist in roasting the arsenical ore and revolatilizing the
arsenious acid in a furnace heated by the combustion of a combustible gas
generated from coal or coke in a furnace. kiln, or retort so situate that any
grit or dust may be separated or deposited, and the free carbon consumed or
Price S.1

page_text: washed out before entering the condensers with the arsenious acid. The gas
from the tops of the iron blast furnaces may be used if near at hand. The
furnace used for the process may be either like those now in use for the manu-
facture of arsenic or like those now in use for the roasting or calcining of ore,
the shape and size of the furnace may however be varied. The gas may enter
the furnace and be ignited either where the present grate or fire-place is
situate or in one or several places by the sides of the furnace used.
The method of generating the combustible gas used in the process forms
no part of the Invention, which refers only to the application of it in the
manufacture of arsenic. I prefer to use carbonic oxide gas sufficiently pure
to allow of combustion, this gas being the cheapest to obtain.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Brereton Todd in the Great Seal Patent Office on
13th July 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BRERETON
TODD, of 4, Victoria Terrace, Newcastle-on-Tyne, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of January, in the year of our Lord
One thousand eight hundred and sixty-six. in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Brereton Todd, Her special licence that I, the said Brereton Todd,
my executors, administrators, and assigns, or such others as I, the said Brereton
Todd, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed: should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANU
FACTURE OF ARSENIC," upon the condition (amongst others) that I, the said
Brereton Todd, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Brereton Todd, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-

page_text: formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
Hitherto the separation of arsenic from minerals and the revolatilizing of
arsenious acid in the manufacture of arsenic has been effected in a furnace
heated by the combustion of coal or coke in a grate or fire-place attached to
the furnace, during which operation a quantity of grit or dust from the fuel,
with sometimes a large portion of free carbon, is carried over by the draught
into the condensers and condensed with the arsenious acid to the injury of the
whiteness and quality of the arsenic.
The improvements consist in roasting the arsenical ore and revolatilizing the
arsenious acid in a furnace heated by the combustion of a combustible gas
generated from coal or coke in a furnace, kiln, or retort so situate that any
grit or dust may be separated or deposited, and the free carbon consumed or
washed out before entering the condensers with the arsenious acid. The gas
from the tops of the iron blast furnaces may be used if near at hand. The
furnace used for the process may be either like those now in use for the
manufacture of arsenic or like those now in use for the roasting or calcining
of ore, the shape and size of the furnace may however be varied.
The gas
may enter the furnace and be ignited either where the present grate or fire-
place is situate or in one or several places by the sides of the furnace used.
The method of generating the combustible gas used in the process forms no
part of the Invention, which refers only to the application of it in the manu-
facture of arsenic. I prefer to use carbonic oxide gas sufliciently pure to allow
of combustion, this gas being the cheapest to obtain.
Having thus stated the nature of my Invention, I will proceed to describe
more fully the manner of performing the same.
I roast the arsenical ore or substances containing arsenic or revolatilize
the arsenious acid in the general way in a furnace or furnaces such as are in
general use in connection with condensers; for such purposes I prefer them
from 30 to 50 feet in length but instead of heating such furnace or furnaces
by the combustion of coal or coke in a fire-place attached to the furnace, I
heat it by a clear flame obtained by the admission and combustion of carbonic
oxide gas and atmospheric air. The form of furnace I prefer to employ is
shown in the Drawing hereunto annexed. The gas is introduced into the
furnace through a pipe or pipes at the end or sides of the furnace, I prefer it
in a single jet at the end where the fire-place is generally situated; the amount
of gas admitted into the furnace is regulated by a valve, and sufficient air is
admitted to ensure the perfect combustion of the carbonic oxide and the
oxidating of the arsenic and sulphur; should the furnace used have a fire-grate

page_text: à shovelful or so of ignited coke or charcoal may be placed on the fire-bars
in front of the pipe that admits the gas from the generator in order to ignite
the same, in any case it is advisable to have it carburetted; hydrogen gas may
be used for the same purpose and in the same way as carbonic oxide gas, as
arsenic volatilized from minerals or other substances by the heat of the flame
from the combustion of either of these gases with a free admission of air is
obtained by one process in the state of arsenious acid or arsenic of commerce.
Any well-known plans may be employed for separating dust and grit from the
gases, as for instance, the gas either before or after combustion may be passed
through a tower filled with coke through which water is allowed to fall. Should
the substance treated contain sulphur as well as arsenic the sulphurous acid
evolved will be drawn by the draught through the condenser (in which the
arsenious acid is condensed) together with the carbonic acid gas produced
from the combustion of the carbonic oxide, and can be conducted into a lead.
chamber and converted into sulphuric acid by the well-known means. Should
the sulphurous acid contain arsenious acid I wash the latter out by causing it
to pass through a condenser through which water or water saturated with
sulphurous acid is falling, before conducting it to the lead chamber.
In order to manufacture the arsenious acid into lump arsenic I employ the
well-known ways now in general use, and use the same sort of pans and kettles,
but instead of having a fire-place between each two pans, or a fire-place under
each to heat them by the combustion of coal, I do away with the fire-places
and put a flue about 12 inches deep and the width of the pans in their place,
under as many pans as are required, and heat the bottoms of the pans by
allowing a stream of gas in a state of combustion to pass through the flue,
regulating the heat by the quantity of gas admitted for combustion.
In witness whereof, I, the said Brereton Todd, have hereunto set my
hand and seal, this Tenth day of July, in the year of our Lord
One thousand eight hundred and sixty-six.
BRERETON TODD. (L.S.)

page_text: R. The hearth of Ore furnace 29 foot long on which
the are to be nasted, is placed:
HH The pipe Urough which the carbonic acide gas
from yourator and unters furnace on
pa
the fire place G.
K'd valve for regulating the quantity of Gus
PPP. Doors for tuming and charging the ora
C.C. Flue through which the anious and, aplau
acid, and carbonic acid, gue passes to andar.
DD ban palas covaring openings into the arched
chamber E, which are inmored when the refuse