IMPROVED MODES OF TREATING METALLIC ORES AND MATERIALS, AND OBTAINING METALLIO AND CHEMICAL PRODUCTS THEREFROM, AND FOR UTILIZING SOME OF THE WASTE PRODUCTS FROM SMELTING WORKS, CHEMICAL WORKS, TIN PLATE WORKS, GALVANIZING WORKS, AND PAPER MILLS, AND FOR IMPROVEMENTS IN FURNACES AND APPARATUS IN CARRYING OUT THE SAME
Year: 1869

page_text: LETTERS PATENT to Charles Crockford, of Holywell, in the County
of Flint, Manufacturing Chemist, for the Invention of "IMPROVED
MODES OF TREATING METALLIC ORES AND MATERIALS, AND OBTAINING
METALLIO AND CHEMICAL PRODUCTS THEREFROM, AND FOR UTILIZING SOME OF
THE WASTE PRODUCTS FROM SMELTING WORKS, CHEMICAL WORKS, TIN PLATE
WORKS, GALVANIZING WORKS, AND PAPER MILLS, AND FOR IMPROVEMENTS IN
FURNACES AND APPARATUS IN CARRYING OUT THE SAME."
Sealed the 3rd May 1870, and dated the 5th November 1869.
PROVISIONAL SPECIFICATION left by the said Charles Crockford at
the Office of the Commissioners of Patents, with his Petition, on
the 5th November 1869.
I, CHARLES CROCKFORD, of Holywell, in the County of Flint, Manu-
facturing Chemist, do hereby declare the nature of the said Invention
för "IMPROVED MODES OF TREATING METALLIC ORES AND MATERIALS, AND
OBTAINING METALLIC AND CHEMICAL PRODUCTS THEREFROM, FOR UTILIZING
BOME OF THE WASTE PRODUCTS FROM SMELTING WORKS, CHEMICAL WORKS, TIN
27

page_text: PLATE WORKS, GALVANIZING WORKS, AND PAPER MILLS, AND FOR IMPROVEMENTS
IN FURNACES, AND APPARATUS IN CARRYING OUT THE SAME," to be as follows:-
I obtain chloride of lead by treating the sulphate of lead with chloride
of sodium or magnesium, or by treating galena with hydrochloric acid,
collecting and utilizing the sulphuretted hydrogen gas generated, or by
heating galena with chloride of sodium or magnesium; I then reduce
the chloride of lead to the metallic state by heating it with zinc or iron.
Any silver contained in the ore or material accompanies the lead through-
out the operation, but I may dissolve out the silver when it exists in a
state of sulphate, and so separate it from the lead; or I dissolve the
chloride of lead in a strong solution of chloride of calcium, strontium,
potassium, barium, magnesium, or manganese, and I precipitate the
lead with any known reagent; or I precipitate it by means of a galvanic
battery in a metallic state, and I collect and utilize the chlorine gas
given off in the process. When the solution contains silver I may pre-
cipitate that metal with copper before precipitating the lead. I reduce
galena to the metallic state by passing over it a current of hydrogen gas
at a red heat, and I collect and utilize the sulphuretted hydrogen gas
generated in the operation. I condense the fumes and gases from
furnaces in which lead or other metals are smelted by drawing them off
from the flues of such furnaces by means of a fan or other appliance,
and forcing them into a chamber, to leave which they must pass through
a certain filtering medium, such as canvas, small coke, or perforated
metal; the fumes will be deposited on the surface of the filtering
medium and the gates will escape through the interstices thereof; these
gases may be afterwards collected and utilized. In conducting the
fumes and gases into the chamber I prefer to force them downwards
and to oppose to them a considerable quantity of the filtering medium
in their descent, and thus the greater part of the fumes will be deposited
at the bottom of the chamber, and only a small portion will be carried
up with the ascending gates. I keep the filtering medium clear for the
passage of the gases by washing or brushing off the deposited fumes
continuously or intermittently. I use sulphate of baryta in the chambers
called regenerators in the "Siemens' gas furnace" when it is applied to
smelting the ores of lead. In constructing fans to be used in flues or
exposed to heat I make them with a long shaft on one side with the
two bearings on it, and so I am able to keep the bearings outside the flue.
In treating minerals or materials containing lead, silver, zinc, copper,

page_text: iron, or other metals I proceed as follows:-I reduce all the metals to
the state of sulphates, either by roasting the ore when it contains
sulphur and utilizing the sulphur in the manufacture of sulphuric acid
and then dissolving the roasted ore in sulphuric acid, or by roasting the
ore at a very low heat and thereby converting the metals into sulphates.
I then wash out the soluble sulphates, and having first precipitated the
copper with any known reagent I precipitate the iron with the carbonate
of magnesia or caustic magnesia, and having separated the precipitate
from the liquor by pressure I then add more carbonate of magnesia or
caustic magnesia to precipitate the zinc, and again seperating the
precipitate from the liquor I boil down and crystallize the latter, and
thus obtain sulphate of magnesia. The sulphates of lead and silver
left in the undissolved residue I treat as before described. Instead of
precipitating the iron and copper with magnesia I may precipitate the
iron with carbonate of zinc and afterwards precipitate the zinc with
ammonia vapour distilled from gas liquor, and so obtain sulphate of
ammonia. Or the roasted mineral or other material may be dissolved in
hydrochloric acid, and the iron precipitated by carbonate of zinc, after
which the zinc may be precipitated by ammonia vapour distilled from gas
liquor, and thereby the muriate of ammonia will be obtained. I take
the waste liquor of tin plate works or of galvanizing works, consisting of
sulphate or chloride of iron, and I add sufficient ammonia vapour from
the distillation of gas to precipitate all the iron, and I thus obtain
sulphate or muriate of ammonia and oxide of iron. I take the refuse of
galvanizing works, known as flux skimmings, and add sufficient hydro-
chloric acid to convert all the zinc contained in the material into
chloride of zinc, I then precipitate the zinc with ammonia vapour (from
the distillation of gas liquor), and thus I obtain oxide of zinc and
muriate of ammonia. I take the liquor from paper mills resulting from
the boiling of esparto grass or like material or of wood which has boiled
in caustic soda, and having evapourated it to dryness I submit it to
distillation in retorts, and thereby I condense and obtain valuable
products; I then wash from the residue in the retort a quantity of black
material answering all the purposes of lampblack and the solution of
carbonate of soda; I then reduce it to the state of caustic soda by
boiling it with quicklime. Instead of distilling the material in retorts
after evaporating it to dryness I submit it to slight calcination in an
open furnace and then collect the black material as before described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Crockford in the Great Seal Patent Office
on the 4th May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
CROCKFORD, of Holywell, in the County of Flint, Manufacturing
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of November, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Crockford, Her special
licence that 1, the said Charles Crockford, my executors, adminis-
trators, and assigns, or such others as I, the said Charles Crockford,
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 "IMPROVED MODES
OF TREATING METALLIC ORES AND MATERIALS, AND OBTAINING METALLIC AND
CHEMICAL PRODUCTS THEREFROM, AND FOR UTILIZING SOME OF THE WASTE PRODUCTS
FROM SMELTING WORKS, CHEMICAL WORKS, TIN PLATE WORKS, GALVANIZING
WORKS, AND PAPER MILLS, AND FOR IMPROVEMENTS IN FURNACES AND APPARATUS
IN CARRYING OUT THE SAME," upon the condition (amongst others) that I,
the said Charles Crockford, 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 Charles Crockford, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement:-
The first part of my Invention consists in the mode of treating the
pres of lead or materials containing lead, and I proceed as follows:-

page_text: When the ore or materials contain sulphide or oxide or carbonate of
lead or metallic lead I treat it with hydrochloric acid, using sufficient
to convert the whole of the lead into chloride of lead; and in the case
of sulphide of lead 1 perform the operation in a close vessel, either
with or without the application of heat, and I collect and utilize the
sulphuretted hydrogen generated during the process. If the material
contains sulphate of lead I add a sufficient quantity of chloride of
sodium or magnesium to convert the lead into chloride of lead, and in
whatever state the lead may be in any of the materials which I may
operate upon 1 first convert it into chloride of lead. I then dissolve out
the chloride of lead with a strong solution (hot or cold) of chloride of
calcium, strontium, potassium, barium, magnesium, or manganese, and
I precipitate the lead from this solution by any known reagent, or I
precipitate it by galvanic action, in which case I collect and utilize the
chlorine given off during the process. When the mineral or material
contains silver this metal may be precipitated from the solution before
the lead by means of metallic lead or copper. In the case of the
sulphate of lead, instead of first converting it into chloride of lead I
prefer at once to treat it with the strong solution of earthy chloride,
which converts it and dissolves it at the same time.
The second part of my Invention consists in treating materials or
minerals containing lead, silver, zinc, copper, iron, or other metals, or
any of them; the process which I am now going to describe being more
particularly applicable to the treatment of the mineral known as blue-
stone, which is obtained from the island of Anglesey.
I proceed as follows:-I first calcine the mineral and collect and utilize
the sulphur driven off in the manufacture of sulphuric acid, or I calcine
it at a very low heat so as to convert the greater part of the metals into
sulphates. I complete the conversion of the metals into sulphates by
the addition of sulphuric acid. I then wash out the soluble sulphates
with water, and first precipitate the copper by any known reagent. I
then precipitate the iron, if there be any in the solution, with caustic
magnesia, and having separated the precipitate from the liquor I then
precipitate the zinc by the addition of more caustic magnesia, and
liquor I boil down the
having again separated the precipitate from the
latter and crystallize it as sulphate of magnesia. I dry and calcine the
precipitated oxide of zinc, and it may then be used for spelter making.

page_text: Instead of precipitating the zinc from the solution I prefer in some cases
to boil the sulphate of zinc to dryness, and I mix the carbonate or
caustic magnesia with it. I submit the mixture to the action of heat
in a reverberatory or other furnace, by which the interchange is effected,
and I afterwards wash out the sulphate of magnesia. The undissolved
residue of the mineral or material containing sulphate of lead and silver
I treat in the manner described in the first part of my present Specifi-
cation. Instead of precipitating the zinc with carbonate of magnesia or
caustic magnesia, I prefer in some cases to precipitate it with ammonia
distilled from gas liquor, in which case I produce oxide of zinc
intermixed with sulphide of zinc and also sulphate of ammonia.
instead of dissolving the bluestone or like material in sulphuric acid
and converting the metals into sulphates, I prefer sometimes to dis-
solve the roasted mineral or material in hydrochloric acid and precipitate
the zinc with ammonia from gas liquor, thus producing oxide and
sulphide of zinc and hydrochlorate of ammonia.
Or
The third part of my Invention consists in treating the waste liquors
from tin plate works and iron galvanizing works, consisting of sulphate
and chloride of iron, and these I treat with ammonia from the gas
liquor and produce oxide and sulphide of iron and sulphate or hydro-
chlorate of ammonia.
The fourth part of my Invention consists in treating the material
known as flux skimmings produced in the process of galvanizing or
coating iron with zinc. For this purpose I add a sufficient quantity of
hydrochloric or sulphuric acid to the flux skimmings to dissolve all the
zinc, and I then precipitate the zinc with the ammoniacal gas arising
from the distillation of gas liquor, by which means I obtain oxide and
sulphide of zinc and hydrochlorate or sulphate of ammonia. Sometimes
I pass through the solution towards the end of the operation a stream
of sulphuretted hydrogen for the purpose of rendering the precipitation
quite complete.
"
The fifth part of my Invention consists in treating the liquor from
paper mills, resulting from boiling esparto grass," wood, or other
material in caustic soda. I first evaporate the liquor to dryness, and
I then submit the dry product to distillation at a red heat, whereby
I am able to collect the volatile resinous and other matters, and I

page_text: afterwards extract the carbonate of soda left in the furnace or retort in
which the distillation has been effected by lixiviation, and at the same
time I am able to extract a quantity of black, similar to "lamp-
black."
The 6th part of my Invention consists in condensing and collecting
fumes from smelting works. I draw off the mixed fumes and gases from
the flues of furnaces wherein lead or other metal is smelted, and force
them by means of a fan or other similar means into and through a
quantity of filtering material, such as canvas, cotton, or fine coke, which
material I may renew from time to time when it becomes clogged, and
I prefer before passing the fumes and gases through the said material
to cool them by passing them thro' showers of water or otherwise, and
I am thus able to use materials which would otherwise be destroyed by
the heat.
Having now described the nature of my said Invention, I declare
that what I claim is,-
First. The conversion of lead contained in any material into chloride,
and dissolving it out by means of the solutions of earthy chlorides, and
the precipitation of it by galvanic action with the utilization of the
generated chlorine, in manner herein described and set forth.
Secondly. I claim the precipitation of the oxide of zinc from solution
or by means of heat with the carbonate of magnesia or caustic mangnesia
or ammonia, and also the mode of treating the bluestone obtained from
the island of Anglesey, all as herein described and set forth.
Thirdly. I claim the precipitation of the iron from the salts of iron
produced at tin plate works and galvanizing works by means of
ammonia, whereby the acid forming the salt of iron is recovered in the
ammoniacal salt, and the iron is also recovered as oxide and sulphide, as
herein described.
Fourthly. I claim the mode of treating flux skimmings by dissolving
them in hydrochloric or sulphuric acid and precipitating the zinc with
ammonia, as herein set forth.
Cifall.. Talaim the made on mathad bonain doannibad of tunations the

page_text: Sixthly. I claim the mode or method herein described for effecting
the condensation of the fumes from smelting furnaces.
In witness whereof, I, the said Charles Crockford, have hereunto
set my hand and seal, this Second day of May One thousand
eight hundred and seventy.
CHARLES CROCKFORD. (L.S.)