Process for Obtaining Salts of Thorium. Zirconium, and like Metals from their Ores or. from Waste Residues of Hoods used for Incandescent Gas Lighting.
Year: 1889

page_text: Date of Application, 19th Oct., 1889
Complete Specification Left, 19th July, 1890-Accepted, 23rd Aug., 1890.
PROVISIONAL SPECIFICATION.
[Communicated from abroad by WILLIAM, MACKEAN, Analytical Chemist, of Hôtel
Richepanse, Paris, France.]
Process for Obtaining Salts of Thorium. Zirconium, and like Metals
from their Ores or. from Waste Residues of Hoods used for
Incandescent Gas Lighting.
1, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, do hereby declare the
nature of this invention to be as follows:-
This invention relates to a process for obtaining salts of thorium and zirconium
and like metals from their ores or from waste residue of hoods used for incandescent
gas lighting in a state of purity suitable for incandescent gas lighting and such like
purposes.
For obtaining salts of thorium from the ore the mineral is finely ground and
treated with hydrochloric acid and then dried. The mass is again treated with
hydrochloric acid, heated diluted with water and the silica is allowed to settle. The
clear liquid is then poured off and the residue is again treated with hydrochloric acid
several times, the liquid in each case being added to that first poured off, the whole
forming a chloride solution. This solution is if necessary, rendered somewhat less
acid by adding an alkali, leaving however acid in excoss, and an alkaline sulphide,
such as sodium sulphide is added, causing evolution of sulphuretted hydrogen and
the precipitated sulphides are allowed to settle. Instead of the alkaline sulphide,
sulphuretted hydrogen may be employed. The liquid is syphoned off and reserved
for treatment, as hereafter described.
For obtaining salts of zirconium, the mineral is finely ground and fused with
about four times its weight of sodium or potassium hydrate or with strontia or
baryta. After fusion the mass is ground into a coarse powder and digested with
water containing half its volume of acid. The acid employed depending on the
alkali used for fusion, if soda or potash is used hydrochloric acid preferred, but
if strontia or baryta sulphuric acid is preferred. To the solution containing the
zirconium and other matters either as chlorides or as sulphates a small quantity of
an alkaline sulphide is added such as sodium sulphide the sulphides are allowed to
settle, and the clear liquid is syphoned off. If sulphuric acid has been used an excess.
of caustic soda or other alkali is added whereby the zirconia and other oxides are
precipitated. These are then well washed to free them from the soluble sulphates
and are transferred to cloth filters to drain, after which they are dissolved in hydro-
chloric acid and treated in the following manner :
The chlorides of zirconium and thorium are diluted to any convenient strength
such as (30 to 80 Twaddell) and heated or if a large excess of acid is present, it is
slightly reduced by alkali. A small quantity of byposulphite of soda is then added,
whereby any iron present is reduced to the ferrous state afterwards an excess of the
hyposulphite is added causing precipitation of the thorium or zirconium as hypo-
sulphite. The precipitate is allowed to settle, the clear liquid is syphoned off and
the precipitate is well washed with hot water containing about one per cent. of
hydrochloric acid. The washed precipitate is then transferred to a cloth filter and
allowed to drain. After this the hyposulphite precipitate is dissolved in hydro-
chloric acid and the clear liquid is separated from the precipitated sulphur.
This precipitation of hyposulphite is repeated as often as is necessary.
hyposulphite is afterwards well drained and dissolved in hydrochloric acid as before
described and boiled till all the sulphurous acid is expelled.
The pure
After its separation from the precipitated sulphur, the clear liquid is diluted, and

page_text: the hydrate precipitated, preferably by ammonia, is well washed with distilled water
to free it from ammoniacal salts. After this it is dissolved in an acid to obtain the
required salt.
Other earths which are not precipitated as sulphites or byposulphites are recovered
from the first liquors of the hyposulphite precipitation by adding ammonium oxalate
& treating the oxalates for the separation of the earths which they contain.
The waste or residue of hoods used for incandescence containing oxides of thorium
zirconium, lanthanum and cerium are first subjected to a magnet to remove metallic
iron and are afterwards sifted and calcined if necessary.
They are then treated in the same manner as the zircon mineral after fusion that
is to say with sulphuric or nitrosulphuric acid. Excess of acid is evaporated off the
residue is ground into a coarse powder which is dissolved in cold water, & the clear
liquid is treated with sodium sulphide, caustic soda or its equivalent to obtain the
chlorides.
The mixed chlorides obtained as above described are then treated with hyposulphite
of soda to separate the zirconia or thoria or both as the case may be & treated as
before described.
If the hyposulphite contain both zirconium and thorium & it is desired to
separate them this can be done in the chloride solution after dissolving the hypo-
sulphite, by adding to the solution of mixed chlorides an excess of ammonium oxalate
or oxalic acid and heating.
The thorium is precipitated as oxalate while the zirconium compound remains in
solution. The zirconium compound is recovered by precipitating as hyposulphite,
while the thorium compound is treated with ammonia to convert it into the hydrate
or dissolved in sulphuric acid and treated as before described.
To the filtrate from the hyposulphite precipitation for the recovery of the
lanthanum and cerium ammonium oxalate is added causing precipitation of the
oxalates of the metals. The oxalates are then well washed dried & ignited by which
means the oxides are obtained. To separate the lanthanum and cerium oxides dilute
nitric acid is added, the mixture is heated and allowed to stand whereupon the cerium
oxide separates out.
Dated this 19th day of October 1889.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Process for Obtaining Salts of Thorium, Zirconium, and like Metals
from their Ores or from Waste Residues of Hoods used for
Incandescent Gas Lighting.
I, OLIVER IMRAY of 28 Southampton Buildings in the County of London,
Fellow of the Institute of Patent Agents 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 :-
This Invention relates to a process for obtaining salts of thorium and zirconium and
like metals from their ores or from waste residue of hoods used for incandescent gas
lighting in a state of purity suitable for incandescent gas lighting and such like
purposes.
For obtaining salts of thorium from the ore, the mineral is finely ground and
treated with hydrochloric acid and then dried. The mass is again treated with hydro-
chloric acid, heated, diluted with water and the silica is allowed to settle. The clear
liquid is then poured off and the residue is again treated with hydrochloric acid
several times, the liquid in each case being added to that first poured off, the whole
forming a chloride solution. This solution is, if necessary, rendered somewhat less
acid by adding an alkali, leaving however acid in excess; and an alkaline sulphide
such as sodium sulphide, 'is added causing evolution of sulphuretted hydrogen and the

page_text: precipitated sulphides are allowed to settle. Instead of the alkaline sulphide,
sulphuretted hycogen may be employed. The liquid is syphoned off and reserved
for treatment as hereafter described.
For obtaining salts of zirconium, the mineral is finely ground and fused with about
four times its weight of sodium or potassium hydrate or with strentia or baryta.
After fusion, the mass is ground into a coarse powder and digested with water
containing half its volume of acid. The acid employed depends on the alkali used for
fusion, if soda or potash is used, hydrochloric acid is preferred, but if strontia or
baryta, sulphuric acid is preferred. To the solution containing the zirconium and
other matters, either as chlorides or as sulphates, a small quantity of an alkaline
sulphide is added such as sodium sulphide, the sulphides are allowed to settle and
the clear liquid is syphoned off. If sulphuric acid has been used, an excess of caustic
soda or other all ali is added, whereby the zirconia and other oxides are precipitated.
These are then well washed to free them from the soluble sulphates, and are trans-
ferred to cloth filters to drain, after which they are dissolved in hydrochloric acid
and treated in the following manner.
The chlorides of zirconium and thorium are diluted to any convenient strength
such as (3° to 8° Twaddell) and heated, or, if a large excess of acid is present, it is
slightly reduced by alkali. A small quantity of hyposulphite of soda is then added,
whereby any iron present is reduced to the ferrous state; afterwards an excess of
the hyposulphite is added causing precipitation of the thorium or zirconium as
hyposulphite.
The precipitate is allowed to settle, the clear liquid is syphoned off and the
precipitate is well washed with hot water containing about one per cent. of hydro-
chloric acid. The washed precipitate is then transferred to a cloth filter and allowed
to drain. After this the hyposulphite precipitate is dissolved in hydrochloric acid
and the clear liquid is separated from the precipitated sulphur.
This precipitation of hyposulphite is repeated as often as is necessary. The pure
byposulphite is afterwards well drained and dissolved in hydrochloric acid as before
described and boiled till all the sulphurous acid is expelled.
After its separation from the precipitated sulphur the clear liquid is diluted and
the hydrate, precipitated, preferably by ammonia, is well washed with distilled water
to free it from ammoniacal salts. After this it is dissolved in an acid to obtain the
required salt.
Other earths which are not precipitated as sulphites or byposulphites are recovered
from the first liquors of the hyposulphite precipitation by adding ammonium oxalate,
and treating the oxalates for the separation of the earths which they contain.
The waste or residue of hoods used for incandescence, containing oxides of thorium,
zirconium, lanthanum and cerium, are first subjected to a magnet to remove metallic
iron and are afterwards sifted and calcined if necessary.
They are then treated in the same manner as the zircon mineral after fusion, that
is to say, with sulphuric or nitrosulphuric acid. Excess of acid is evaporated off, the
residue is ground into a coarse powder which is dissolved in cold water, and the clear
liquid is treated with sodium sulphide, caustic soda, or its equivalent to obtain the
hydro-oxides which are dissolved in hydrochloric acid to obtain the chlorides.
The mixed chlorides obtained as above described are then treated with hyposulphite
of soda to separate the zirconia or thoria or both, as the case may be, and treated as
before described.
If the hyposulphite contain both zirconium and thorium and it is desired to
separate them, this can be done in the chloride solution after dissolving the hypo-
sulphite by adding to the solution of mixed chlorides an excess of ammonium oxalate
or oxalic acid and heating.
The thorium is precipitated as oxalate while the zirconium compound remains in
solution. The zirconium compound is recovered by precipitating as hyposulphite,
while the thorium compound is treated with ammonia to convert it into the hydrate
or dissolved in sulphuric acid and treated as before described.
To the filtrate from the hyposulphite precipitation for the recovery of the lanthanum

page_text: and cerium, ammonium oxalate is added causing precipitation of the oxalates of the
metals. The oxalates are then well washed dried and ignited by which means the
oxides are obtained. To separate the lanthanum and cerium oxides, dilute nitric acid
is added, the mixture is heated and allowed to stand, whereupon the cerium oxide
separates out.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described process for obtaining salts of thorium from its ores by
treating with hydrochloric acid, separating impurities, precipitating as hyposulphite
and dissolving the same in acid.
2. The herein described process for obtaining salts of zirconium from its ores, by
fusing with an alkaline hydrate, dissolving in acid, separating impurities, precipitating
as byposulphite, and dissolving the same in acid.
3. The herein described process for obtaining, from waste residues of incandesence.
hoods, the salts, of the metals contained therein by dissolving in acid, separating
impurities precipitating as hydro-oxides, dissolving in, hydrochloric acid to obtain,
the chlorides and treating these for separation of the different metals in the mapper
described.
Dated this 10th T... 1000
ABEL & IMRAY.
Agents for the Applicant.