IMPROVEMENTS IN THE TREATMENT OF SPENT OXIDES OF IRON AND OTHER SUBSTANCES CONTAINING SULPHUR SUCH AS IMPURE SULPHUR PRECIPITATE AND IMPURE MELTED SULPHUR TO OBTAIN SULPHUR AND ALSO ARSENICAL COMPOUNDS WHEN THE LATTER ARE PRESENT to be as follows:
Year: 1885

page_text: I JOHN ROBINSON of Grove House Farnworth in Widnes, in the County of
Lancaster, Chemist do hereby declare the nature of the said invention for
"IMPROVEMENTS IN THE TREATMENT OF SPENT OXIDES OF IRON AND OTHER
SUBSTANCES CONTAINING SULPHUR SUCH AS IMPURE SULPHUR PRECIPITATE AND
IMPURE MELTED SULPHUR TO OBTAIN SULPHUR AND ALSO ARSENICAL COMPOUNDS
WHEN THE LATTER ARE PRESENT to be as follows:-
"
My invention has for its object the obtaining of pure sulphur from (1) spent
oxides of iron (2) impure sulphur precipitate, (3) dirty melted sulphur and (4) the
product known as "black sulphur" obtained in the process of melting sulphur and
other like compounds containing sulphur. It further consists in obtaining arsenical
compounds when these happen to be present in the substances above named.
In carrying my invention into practice I prefer to proceed in manner following:
I take the substances above mentioned and place them in a suitable vessel prefer-
ably closed, and with air or other pressure added, and subject them to lixiviation
and digestion or either of them with or without the aid of heat with a solution of
an alkaline sulphide or polysulphide or both of them or solution of a sulphide or
polysulphide or both of them of an alkaline earth produced by any suitable means
but I prefer to use the solution consisting of calcium sulphide and polysulphide and
calcium sulphite and Hyposulphite obtained by the lixiviation of soda waste which
solution is commonly known as "yellow liquor." When the process of lixiviation
and digestion has been continued for a sufficient period I run off the solution into
suitable settling tanks from which it may be taken and the sulphur contained
in solution therein be separated by either concentration and crystallization or
concentration and deposition or by precipitation by the addition of Hydrochloric
acid or other suitable precipitant either with or without the assistance of steam or
other pressure.
In case I find on examination of the materials operated on that
the whole of the sulphur has not been extracted I first allow the liquor to settle for

page_text: some time in the vessel and run off into the settling tanks only the clearer liquor,
leaving the more solid portion behind, and I subject such remaining portion to
lixiviation and digestion or either of them as before with a fresh portion of the said
solution of an alkaline sulphide or polysulphide, and I repeat these operations as
often as I find necessary for the complete solution of the sulphur contained in the
original substance. I prefer to add the solution obtained by the above lixiviation
and digestion or either of them to a solution which contains sulphites or hyposul-
phites (or both of them) previous to precipitation in order to prevent the formation
of sulphuretted Hydrogen and consequent loss of sulphur.
When the substance to be treated contains arsenical compounds and it may be
other soluble impurities I prefer to first lixiviate and digest with a small quantity
of the alkaline sulphide or polysulphide and oxide or solution of a sulphide or
polysulphide of an alkaline earth and in order to first dissolve out the arsenical
compounds or other soluble impurities and from the solution which I thus obtain
I prefer to extract the sulphur by fractional precipitation or deposition or crystal-
lization employing for the purpose as a precipitant hydrochloric acid or other
precipitant the process of precipitation being suspended when the liquid is almost
neutral and after filtering out the precipitated sulphur. I precipitate the arsenical
compounds contained in the solution by further addition of the precipitant. After
I have dissolved out the whole of the major portion of the arsenical compounds or
other soluble impurities I proceed to lixiviate and digest as before described for the
extraction of sulphur.
When treating substances which contain no free sulphur I first subject them to
the action of suitable reagents and so set free the sulphur which may then be
extracted by lixiviation and digestion, or either of them, as above described.
J. T. KING,
Agent for the Applicant.

page_text: Improvements in the Treatment of Spent Oxides of Iron
and other Substances Containing Sulphur, such as Impure
Sulphur Precinitate and Imnure Melted Sulnhur to Obtain
I, JOHN ROBINSON of Grove House Farnworth in Widnes in the County of
Lancaster Chemist do hereby declare the nature of this invention for and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention has for its object the obtaining of pure sulphur from (1) spent.
oxides of iron (2) impure sulphur precipitate (3) dirty metal sulphur (4) the
product known as "black sulphur" obtained in the process of melting sulphur and
other like compounds containing sulphur It further consists in obtaining arsenical
compounds when these happen to be present in the substances above named.
In carrying out my invention I proceed according to one of the following
methods or a combination of them according as the material upon which I propose
to operate contains 1st Sulphur and other substances but is free from arsenical
compounds 2nd Sulphur and arsenical compounds and it may be other substances
3rd Sulphur in combination with other substances and it may be sulphur in
combination mixed with free sulphur.
First When the material upon which I am operating, and from which I wish to
extract the sulphur consists of sulphur and other substances but is free from
arsenical compounds I proceed as follows.
I place the material, from which I desire to extract the sulphur, after having if
need be broken up the lumps and rendered the mass fine by means of a mill or of
crushers or of hammers suitably arranged on the top of the soda waste contained in
the oxidizing vats or heaps in use in Monds or other process for the recovery of
sulphur from soda waste or I place it under the soda waste in such oxidizing vats
or heaps or I place it in such vats or heaps in layers alternate with layers of soda
waste or I mix the material from which I wish to extract the sulphur, intimately
with soda waste, and place the mixture in such oxidizing vats or heaps in such
manner in any of these cases that it shall be immersed in the liquor with which
soda waste is usually lixiviated upon every occasion on which the soda waste shall
he subjected to lixiviation The liquor usually used being a solution of sulphides
and polysulphides with sulphites and hyposulphites of calcium with such other
compounds of the alkalies and alkaline earths as are extracted by the solvent
action of water on soda waste and such liquor is often known as "waste water
"yellow liquor "waste liquor" or "sulphur liquor" and by the lixiviation of the
materials contained as described in the oxidizing vats or heaps, I dissolve out the
sulphur therein contained by means of the aforesaid solution or yellow liquor.
"
"

page_text: Or I place the material, from which I desire to extract the sulphur, after having
if need be, broken up the lumps and rendered the mass fine, by means of a mill or
of crushers or of hammers suitably arranged in a shoot or well or tank or vat, or
in a series of shoots wells tanks vats or a combination of these either on the bottom
of such or on shelves or sieves or within partitions so placed in such shoot or
vessel that the liquor used for the lixiviation of such material may pass over or
through or around such material so placed and I cause "yellow liquor" or other
solution of the sulphides and polysulphides (or either of them) of the alkalies or of
the alkaline earths (or a mixture of both) to pass over or through or around the
material under operation placed in the vessel aforesaid and so I extract the sulphur
contained in the material operated on and obtain a solution which contains a
larger proportion of sulphur or of polysulphides than did the solution used for
lixiviation before such lixiviation.
And I sometimes so arrange the shoots, wells, tanks vats or other vessels, that by
a suitable arrangement of flues pipes or passages under or around or within them
I can apply heat to such vessels and so heat the contents and I sometimes pass
steam through such pipes or passages as a more convenient method of applying
heat than allowing the products of combustion from a fire or heated air to pass
through the passages or pipes or I heat the liquor used for lixiviating previous to
its introduction into the vessels or shoot aforesaid or I cause the liquor which
results from the aforesaid lixiviation in the shoot or vessel to pass into a well or
vat containing soda waste partially oxidized or I sometimes cause the liquor
running from the vat or well containing soda waste to pass into the vessel
containing the material from which I desire to extract the sulphur.
Sometimes I so attach or fix an agitator that I can stir up or agitate the
material either before or after or during the process of lixiviation.
Under another modification I introduce the materials containing sulphur which
I wish to extract into a tank well or digester or other vessel provided with a
charging hole and door (or more than one hole and door if convenient) to make up
same such door being capable of being made secure by means of bolts levers
wedges bars or a combination of any or all of them and provided also with a pipe
at the bottom or so fixed as to reach near to the bottom of such tank or other
vessel for the purpose of withdrawing or discharging the contents and provided
also with another pipe or tap so fixed in such vessel as to allow of a portion only
of the contents of such vessel being withdrawn The said digester or vessel is
preferably provided with a pressure guage or other means of indicating the
pressure within such vessel and with a pipe or other means for introducing the
yellow liquor" or solution used for lixiviating or digestion In such tank or
vessel as described I subject the material to lixiviation or digestion (or both of
them) with the "yellow liquor" or other solution before named.
"
Sometimes during the time of lixiviation or digestion I subject the contents of
such tank or vessel to a pressure (as may be found most convenient from 5 lbs on
the square inch up to 80 lbs on the square inch produced either by means of
a steam jet as in Kortings blower or other form of steam blower or of a force pump
employing for the purpose a portion of the solution to be used for lixiviation or by
means of an air compressing or other blowing engine or fan or by subjecting the
tank or vessel and its contents to heat so as to expand both the liquor and air
contained in the tank or vessel I find it preferable to subject the contents of the
tank or vessel to a pressure during the process of lixiviation or digestion as by this
means to a great extent the formation of sulphide of Hydrogen in the tank or
vessel is prevented.
Sometimes I find it convenient to provide and fix an agitator within the tank or
vessel so as to allow me to thoroughly agitate and mix the contents of the tank or
vessel and sometimes I place the materials on shelves or sieves suitably placed
within aforesaid tank or vessel in order to allow of a better lixiviation of the
materials operated on.

page_text: When during the process of lixiviation or digestion by any of the means
described I find on examination of the liquor in the tank or vessel that it has
dissolved as much sulphur as I wish or when on examination of the solid materials
upon which I am operating I find that the whole or as much as I wish of the
sulphur has been dissolved I cause the contents to be run off partly or wholly into
suitable settling tanks or wells or into drainers of filters or sieves so as to obtain a
clear or nearly clear solution If I find on examining the materials operated on
that the whole of the sulphur has not been dissolved or extracted I repeat the
lixiviation or digestion with a fresh portion of "yellow liquor or other such
solution in the tank or vessel and I repeat the process described till I find I have
extracted the whole of the sulphur or so much as I deem worth extracting.
For the precipitation of the sulphur I take the clear or nearly clear solution
obtained by any of the foregoing methods, and treat it with Hydrochloric acid,
sulphuric acid or other such like or convenient precipitant in any suitable vessel
but owing to the gas or sulphide of Hydrogen which is sometimes evolved during
this process I prefer to use for this purpose the "decomposer" usually employed in
Monds' process or that employed in Shaffner and Helbigs process for the recovery
of sulphur from alkali waste.
I prefer however to first mix the solution obtained in the processes of lixiviation
or digestion mentioned with another solution containing a larger proportion of the
oxygen compounds of sulphur such as sulphites and hyposulphitis of the alkalies
or alkaline earths, which solution is often known as over blown sulpbur liquor,"
in order to prevent the formation of gaseous sulphur compounds during the
process of precipitation.
"
Sometimes I take the liquor obtained in the processes of lixiviation or digestion
before mentioned, and cause a current of atmospheric air or steam, or a mixture of
both to pass into or through it in order to partially oxidize or transform the
sulphides and polysulphides therein contained into other compounds which on the
addition of a precipitant, such as Hydroshloric acid, will not give off noxious
gaseous sulphur compounds.
I find it most convenient to construct the apparatus previously mentioned, of
iron, stone or wood but obviously any materials may be used which are uninjured
by the action of hot solutions of sulphides of the alkalies or of the alkaline earths.
For the digester described I much prefer a cast iron tank or vessel.
Second: In treating materials which consist of sulphur and arsenical compounds
and it may be other substances, I eliminate the arsenical compounds before
proceeding to dissolve or recover the sulphur, and in this case I use any of the
apparatus before mentioned for the treatment of the materials apart from the
oxidizing vats or heaps, or I use a combination of such before mentioned apparatus
as follows-
I lixiviate or digest the materials, prepared as described, by crushing if need be
with only a small proportion of the "yellow liquor" or solution of the sulphides
and polysulphides (or either of them) of the alkalies or of the alkaline earths, and
after I have subjected the materials to digestion or lixiviation and found by
examination of the resulting liquor that I have dissolved therein as much of the
arsenical compounds as it is capable of containing, or as I deem requisite I allow
the contents of the digester or other vessel or vessels used to settle in the digester
or vessel and then I run off the upper portion of the liquor as far as it is possible to
do without taking away any of the solid materials and again introduce a further
quantity of the yellow liquor or other solution used and again subject the contents
of the vessel to lixiviation or digestion, and I repeat this operation until I find on
examination of a portion of the solid material that I have extracted the whole or a
considerable portion of the arsenical compounds.
I then run out the whole contents of the vessel into settling tanks, drainers or
filters and afterwards proceed to melt the solid material in any accustomed manner
as for instance in the sulphur melter used by Shaffner & Hilbig in their process for

page_text: the melting of sulphur precipitate. Or I run off only the clearer liquor from the
digester leaving the solid portion behind and by closing up the outlets of the
digester and introducing steam at a pressure of from 50 lbs to 80 lbs on the square
inch. I proceed to melt the solid portion in the digester, but for this purpose
I provide a suitable steam inlet pipe with a coil or worm pipe at the bottom and
also a suitable sulphur outlet or discharge pipe reaching to near the bottom of the
vessel or digester.
By the means above described I am enabled to obtain a good melted sulphur
from an impure precipitated sulphur.
Sometimes after having extracted the arsenical compounds by lixiviation or
digestion as before described I prefer to treat the solid portion remaining in the
manner previously described in the first part of this specification, for the treatment
of material which consists of sulphur and other substances, but is free from
arsenical compounds, or I do not eliminate the arsenical compounds till I precipitate
the sulphur from solution-In these cases I employ any of the methods described
in the first part of this specification for the dissolving of the sulphur in "yellow
liquor" or other solution and when I am adding the precipitant (as before stated)
for example Hydrochloric Acid I am very careful not to add a sufficient amount to
cause the precipitation of the whole of the sulphur contained in solution, and
which might be precipitated by the addition of a sufficient quantity of the
precipitant and when on examining the liquor to which I have added the
precipitant I find that a further addition of the precipitant would cause a
precipitation of arsenical compounds I arrest the addition of the precipitant and
run out the contents of the "decomposer" into the usual settling tanks, filters or
drainers and catch the liquor which drains away and afterwards add in a suitable
decomposer a further quantity of the precipitant and thus obtain a precipitate
containing a high per centage of arsenical compounds separate from the precipitate
of sulphur obtained in the first instance-This arsenical precipitate I run into
drainers, and treat in the usual manner.
For the purpose of catching the precipitate of sulphur which is obtained by the
first addition of the precipitant as described I prefer to use covered drainers which
are provided with a spout, pipe, shoot or funnel so fixed as to carry off any noxious
gaseous sulphur compounds away from the men who are working at the process
either by connecting such flue, pipe or shoot with the flues and thence within such
pipe or shoot and thus causing a current of air to traverse the pipe and so carry
away any noxious gas; or I connect aforesaid filters or drainers with a suitable
condensing or absorbing tower, and thus condense or absorb any noxious sulphur
gas which might be produced.
Third When the substance from which I wish to extract the sulphur contains
sulphur in combination with other substances as in the case of spent oxides of iron
I cause a current of air or steam or a mixture of both to pass through such material
and such air or steam may be heated or superheated respectively if need be by any
suitable means-For the above purpose I place the materials such a spent oxides
of iron on shelves or sieves or in cylinders or boxes, or I operate upon it in the
purifiers and afterwards I subject it to any of the before mentioned processes for
the extraction of the sulphur by lixiviation or digestion-After dissolving out the
sulphur the oxides of iron may readily be made suitable for use in the purifiers
again.
In case I wish to dissolve the sulphur from spent oxides of iron in the purifiers
I attach to them the necessary pipes as described in the first part of this Specifica-
tion in reference to the "digester."
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. The recovery or obtaining of sulphur from the substances hereinbefore
imentioned by treating such substances with a solution of an alkaline sulphide or

page_text: polysulphide or both, or with a solution of a sulphide or polysulphide (or both) of
an alkaline earth.
Second. The elimination and subsequent recovery of arsenical compounds, and
other soluble impurities from the sulphurous substances berein mentioned by first
treating the said substances with a small proportion of the above mentioned
solutions.
Third. The separation of arsenical compounds from solutions containing sulphur
in the state of sulphides or polysulphides or other compounds such as sulphur
liquor by the process of fractional precipitation as herein described.
J. T. KING,
Per J. Richinan,,
Agent for the Applicant.
Dated this 15th day of October 1889.
J. T. KING,
Per J. Richinan,,
Agent for the Applicant.