IMPROVEMENTS IN PREPARING MATERIALS USEFUL IN THE PURIFYING OF GAS FROM SULPHURETTED HYDROGEN
Year: 1863

page_text: LETTERS PATENT to Richard Laming, Priory Road, Kilburn, West
Hampstead, Middlesex, for the Invention of "IMPROVEMENTS IN PREPARING
MATERIALS USEFUL IN THE PURIFYING OF GAS FROM SULPHURETTED HYDROGEN,
33
Sealed the 20th May 1864, and dated the 26th November 1863.
PROVISIONAL SPECIFICATION left by the said Richard Laming at the
Office of the Commissioners of Patents, with his Petition, on the 26th
November 1863.
I, RICHARD LAMING, Priory Road, Kilburn, West Hampstead, Middlesex,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PREPARING MATERIALS USEFUL IN THE PURIFYING OF GAS FROM SULPHURETTED
HYDROGEN, CARBONIC ACID, AND AMMONIA, AND IN MAKING AMMONIACAL COMPOUNDS,"
to be as follows:-
This Invention consists, firstly, in exposing metallic iron to the action of
ammoniacal liquor or washings of gas or other liquor or watery vapour highly
charged with sulphuretted hydrogen or carbonic acid to convert it into sulphide
or carbonate of iron, and then oxidizing the ferruginous matter to render it fit
for purifying gas from sulphuretted hydrogen. The ammoniacal liquors and
washings of gas are thus made conveniently available for previously purifying
the gas from great part of its sulphuretted hydrogen, carbonic acid, and
ammonia.

page_text: Secondly, in further decomposing gas or ammoniacal liquor which has thus
been converted into a comparatively pure solution of carbonate of ammonia,
and in preference after being subsequently distilled by sulphate or muriate
of manganese to obtain carbonate of manganese and sulphate or muriate of
ammonia.
Thirdly, in decomposing carbonate of manganese by sulphuric or hydro-
chloric acid, to liberate carbonic acid for combination with ammonia, to make
a carbonate of ammonia while forming sulphate or muriate of manganese
useful for making the other ammoniacal salts above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Laming in the Great Seal Patent Office on the
25th May 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
LAMING, Priory Road, Kilburn, West Hampstead, Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of November, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Richard Laming, Her special licence that I, the said Richard Laming,
my executors, administrators, and assigns, or such others as I, the said
Richard Laming, 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
PREPARING MATERIALS USEFUL IN THE PURIFYING OF GAS FROM SULPHURETTED
HYDROGEN, CARBONIC ACID, AND AMMONIA, AND IN MAKING AMMONIACAL COM-
POUNDS," upon the condition (amongst others) that I, the said Richard
Laming, 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.

page_text: NOW KNOW YE, that I, the said Richard Laming, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
The use of hydrated peroxide of iron for purifying gas from sulphuretted
hydrogen is well known, and it is of superior efficacy generally when it is
formed by precipitation and recently made. I make the hydrated peroxide
from waste metallic iron, cast or wrought, old or new, by certain processes by
which it is passed through the intermediate condition of a carbonate of iron in
solution, or of black sulphide of iron, or of both these conditions. I apply my
processes to the metal in the form of turnings, cuttings of sheet, fragments of
hoop iron, borings, and other scraps which cannot expose too much surface;
but the pieces should never be so minute as to lie together in a mass not freely
pervious to fluids and gases. I proceed as follows:-On the floor of a water-
tight tank, which may be of brickwork, about a yard deep, and any convenient
number of yards in area, I place one or more cast-iron pipes pierced with
numerous small holes for the emission of gases, which I connect by an
ascending branch with the delivery pipe of an air-pumping machine that
communicates through its suction pipe with some source of carbonic acid gas,
mixed or not with sulphuretted hydrogen; as, for example, a flue conducting
gaseous products of combustion from a furnace to a chimney shaft, I put into
the tank a loosely packed mass of scrap iron exposing great surface, and then,
having filled it up with water, I set the air-pumping machine in action, causing
it to force carbonic acid gas upwards through the mass of water and iron.
Carbonic acid gas thereupon dissolves in the water, and that solution dissolves
iron. If sulphuretted hydrogen be present it causes the formation of some
black sulphide of iron. If atmospheric oxygen be among the products of
combustion, it acts upon the carbonate of iron, and also upon the sulphide of
iron, converting them both into hydrated peroxide. In order to effect those
changes as rapidly as possible I pump into the tank more atmospheric oxygen
than accompanies the products of combustion, by leaving more or less open an
air cock placed on the suction pipe of the air-pumping machine. The exact
regulation of that air cock is not of greatest importance, and must be
determined approximately by experience, as it varies with the construction and
state of repair of the furnaces and flues. The heated gases should arrive at the
tank through a long pipe or other condenser to ensure their refrigeration, and
the total quantity of gaseous matters agitating the solution of carbonic acid
should be great enough to keep the oxide and the sulphide of iron in
suspension. The decomposition of carbonate of iron by the oxygen of the air

page_text: and by sulphuretted hydrogen sets free in the water some carbonic acid, which
helps to maintain its solvent power, the same carbonic acid being competent to
dissolve many successive portions of iron. A time arrives when it is desirable
to collect the solid compounds of iron which have been formed in the tank,
which I do in the following manner :-While the fluid in the tank is being
agitated by the passing gases I let it run off into a lower reservoir, and there
leave it until the sediment has precipitated; the supernatant fluid being then
drawn off, I place the sediment upon a bed of sand or other drainer, and
eventually leave it open to the air to become dry, and the iron thoroughly
peroxidized. The tank may then be recharged with the same or fresh water,
more iron added, if necessary, and the process for the solution and the
precipitation of the iron and the collection of the oxide repeated. When
sulphuretted hydrogen has accompanied the carbonic acid into the water
containing the iron, the resulting bydrated peroxide is always mixed with some
proportion of solid sulphur, but when required it may be obtained free from
that substance by purifying the carbonic acid on its way to the tank by passing
it through hydrated peroxide of iron contained in a close vessel, as is practised
with coal gas, or by collecting it from the combustion of carbonaceous
materials free from sulphur, or other sources which supply it pure, as when
eliminated by the action of diluted sulphuric or muriatic acid on chalk or on
impure solutions of carbonate of ammonia.
The use of solutions of ammonia not fully saturated with acids for removing
from coal gas, in washers or scrubbers, the whole or great part of its sul-
phurated hydrogen and carbonic acid, is to some extent publicly known. By
the following process I bring the ammoniacal liquors furnished by the
condensers and washing vessels or scrubbers of gasworks into a state of less
perfect saturation, thereby better adapting them for the purifying of gas as
well as for certain other purposes. Into a tank of any convenient material,
form, and dimensions, I introduce a freely pervious mass of iron turnings or
other small scrap iron, and then nearly fill up the tank with the ammonical
liquor to be operated upon. By means of a pumping machine I force
atmospheric air through perforated distributing pipes laid upon the floor of the
tank; the surface of the metal which is almost immediately made by the
sulphuretted hydrogen of the liquor into black sulphide of iron, speedily
changes into an oxide of iron by combining with the oxygen of some of the
passing air; that oxide, by attracting more sulphurated hydrogen, passes into
the condition of black sulphide, which again is made by the atmospheric
oxygen into oxide; and thus incessantly the iron continues to alternate
between the two conditions of sulphide and oxide until all the sulphuretted

page_text: hydrogen in the liquor has disappeared.
When that is the case I leave the
contents of the tank at rest for some metallic compounds which will have
become detached from the surface of the metal to subside, when I draw off
the desulphurated liquor and supply the tank with fresh liquor, with which
to renew the operation; and this I repeat as many times as the process will
continue to go on satisfactorily. Finally, I throw out all the solid contents of
the tank, and when they have become dry in the air I sift them, or otherwise
mechanically separate the mixed oxide and sulphur from the residue of
metallic iron.
According to my experience, it is better to modify this process in the
following manner :-Instead of using metallic iron to be converted into the
oxide which is to undergo alternate decomposition and recomposition during
the desulphuration of the ammoniacal liquor, I introduce the metallic reagent
in the state of hydrated peroxide in the first instance, in the proportion of about
five parts by weight to one hundred parts of the ammoniacal liquor. I cause
the air to give up a larger proportion of its oxygen by passing it through
several charged vessels in succession arranged on the principle of a Woolfe's
apparatus, each vessel being fitted with an agitator moved by steam power,
and all on such different levels that the liquor may be discharged from each
into the next in succession in a direction opposite to the course of the air; by
keeping the agitators always in motion the metallic material is made to pass
with the liquor from one vessel to another downward from the highest in the
series where it is introduced, every charge being let down one stage whenever
a finished charge is drawn off from the series by the exit pipe of the lowest
vessel; after deposition in a separate vessel the sediment of each charge
withdrawn may be restored to the highest of the vessels, to be used as oxide
with fresh liquor until it has become inconveniently charged with sulphur,
when it may be set aside as a useful material to be burned for the making of
sulphuric acid in any of the furnaces known to be suitable for burning for the
same purpose the ordinary oxide of iron material which has been used for the
purification of coal gas. Although artificial hydrated peroxides of iron are to
be preferred for the desulphuration of ammoniacal liquors by this Invention,
they may have substituted for them with some measure of success oxides of
iron from any other source if they be finely levigated; or the metallic base
may be introduced in the form of black sulphide of iron, or even of a neutral
salt of iron, which under the circumstances would immediately produce a black
sulphide.
The arrangement of means for artificially making hydrated peroxide of iron
by the conjoint influences of metallic iron, solution of carbonic acid, and

page_text: atmospheric oxygen, may be diversified with results more or less satisfactory;
and various arrangements may also be adopted for desulphurating the
ammonical liquors of gasworks by the alternate sulphuration and oxidation of
iron under the simultaneous influences of atmospheric oxygen and their own
sulphuretted hydrogen. But in each of the two cases the means I have
pointed out I consider to be the best respectively. During the process I
have described for desulphurating ammoniacal liquors, their specific gravity
becomes sensibly increased, corresponding to a formation in them of sulphuric
acid and ammonia by a combination of the elements of atmospheric air with
those of sulphuretted hydrogen; and this is observable notwithstanding some
ammonia and sulphuretted hydrogen are carried away from the liquors by the
residue of the air blown through them, and which may be arrested by passing
the gaseous matters into a final bath of hydrated peroxide of iron in water.
When the intention is more to produce oxide than desulphurated liquor, I
sometimes wholly or nearly altogether dispense with the action of atmospheric
oxygen while forming the black sulphide of iron. This I can best do by using.
cast iron reduced to very fine powder, adding it to any given quantity of the
ammoniacal liquor with a constant mechanical mixing, in such proportion as
will just suffice to take from the liquor all its sulphuretted hydrogen; after
settling I remove the desulphurated liquor and expose the black sulphide of
iron to the atmosphere to become peroxidized.
The ammoniacal liquors of gasworks, after they have been divested of their
sulphuretted hydrogen, either by the means herein-before described or others,
are solutions chiefly of carbonate of ammonia combined with matters of
disagreeable odour, from which the salt cannot be separated by boiling, as the.
carbonate as well as the odours are volatile and rise together in the vapour.
I fix the carbonic acid and the ammonia of the carbonate of ammonia
separately, and deodorize them while in a fixed condition, preparatory to their
recombination. I mix the deodorized gas liquor with as much muriate or
sulphate of manganese in solution as will effect their reciprocal decomposition
into insoluble carbonate of manganese and solution of muriate or sulphate of
ammonia. I separate the two compounds and subject each to a boiling heat
until it no longer exhibits any objectionable odour; I next decompose the salt
of ammonia by means of lime, and submit the product to distillation to obtain
a pure ammonia in a fluid or gaseous form by processes that are well known.
At the same time I let in upon the carbonate of manganese contained in a
close vessel enough diluted muriatic or sulphuric acid to set free its carbonic
acid, which I conduct into the vessel containing the free ammonia, and with
which it enters into chemical combination, forming a pure carbonate of

page_text: ammonia in solution or in the solid state, as the case may be. The acid
which served to set the carbonic acid free from the manganese constitutes
with it a neutral salt in solution, with which the process may be commenced
anew.
Sometimes instead of proceeding to purify the separated ammonia and the
carbonic acid preparatory to their recombination as above said, I set aside the
carbonate of manganese for other uses, and evaporate and crytallize the
solution of ammoniacal, muriate, or sulphate, in any ordinary manner; when
that is the case and I desire to have the crystals free from colour, I begin by
submitting the desulphurated liquor to distillation, and I use the distillate
either condensed and diluted with water, or in the state of vapour received
into a dilute solution of the salt of manganese, which should be maintained at
a low temperature; when the decomposition is complete I separate the solid
and the fluid products, and evaporate and crystallize the solution of the
ammoniacal salt. This process may be modified by substituting other bases
for manganese, as, for example, lime; and when lime is made use of and its
carbonate in the form of chalk can be cheaply obtained, the native carbonate
may always be substituted for the precipitated carbonate, and the trouble of
deodorizing the latter thereby avoided. When muriate or sulphate of lime is
cheaply available I use it as a source of acid for making with the desul-
phurated ammonical liquors muriate or sulphate of ammonia; for this
purpose I stir into the liquors or their fluid distillate as much of the salt of
lime, either in solution or in fine powder, as contains a quantity of acid
chemically equivalent to the ammonia which is present in the condition of
carbonate of ammonia, taking care that there is always sufficient water in the
mixture to allow of the ready deposition of the precipitated carbonate of lime
after a few hours agitation. The supernatant solution of ammoniacal muriate
or sulphate being drawn off from the sediment, and the latter washed and placed
on a filter, I add the filtrate to the stronger solution, perfect its saturation, if
need be, by a sufficient quantity of muriatic or sulphuric acid, and then I
evaporate the whole in the usual manner to obtain crystals. Or having
deodorized the solution by heat I decompose its ammoniacal salt by lime, and
by distillation and other known means obtain its pure ammonia, either in the
form of gas or in solution, or solidified by carbonic acid. The ammoniacal
liquors of gasworks in their undesulphurated condition have in times past
been treated with sulphate and muriate of lime for making the corresponding
salts of ammonia; the present Invention improves upon those practices by first
removing the sulphuretted hydrogen, thereby greatly diminishing the tendency
of the precipitate to remain suspended in the ammoniacal solutions.

page_text: Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim in respect thereof,―
Firstly, preparing hydrated peroxide of iron by exposing metallic iron in
small pieces to the action of carbonic acid artificially dissolved in water,
whether accompanied by sulphuretted hydrogen or not, and precipitating by
the agency of atmospheric oxygen.
Secondly, preparing hydrated peroxide of iron by forcing atmospheric air
into a solution of iron in water impregnated with carbonic acid, whether
accompanied by sulphuretted bydrogen or not.
Thirdly, preparing hydrated peroxide of iron by combining the sulphuretted
hydrogen in the ammoniacal liquors of gasworks with metallic iron in small
pieces, and exposing the resulting black sulphide of iron to the air to become
oxidized.
Fourthly, desulphurating the ammoniacal liquors of gasworks by the action
of metallic iron in small pieces, with or without the simultaneous influence of
atmospheric air.
Fifthly, desulphurating and enriching the ammonical liquors of gasworks
by forcing into them, while containing metallic iron in small pieces, or black
sulphide of iron, or oxide of iron, a current of atmospheric air.
Sixthly, the process I have described for obtaining in a state of inodorous
combination the ammonia which consists in the desulphurated ammonical
liquors of gasworks and carbonic acid.
Seventhly, the use of the desulphurated ammonical liquors of gasworks for
decomposing sulphate and muriate of lime into solutions of sulphate and muriate
of ammonia, either for the manufacture of ammoniacal salts, or to be deodorized
by heat, decompozed by lime, and distilled as sources of free ammonia.
In witness whereof, I, the said Richard Laming, have hereunto set my
hand and seal, this Twenty-fourth day of May, in the year of our Lord
One thousand eight hundred and sixty-four.
Witness,
HENRY HATHAWAY,
864, Old Kent Road.
RICHARD LAMING. (L.S.)