IMPROVEMENTS IN CONVERTING BASIC PHOSPHATES OF LIME INTO SOLUBLE ACID PHOSPHATES OF LIME, AND IN OBTAINING AND UTILIZING SULPHITE OF LIME
Year: 1868

page_text: LETTERS PATENT to Michael Henry, of 68, Fleet Street, in the City
of London, Patent Agent, for the Invention of "IMPROVEMENTS IN
CONVERTING BASIC PHOSPHATES OF LIME INTO SOLUBLE ACID PHOSPHATES
OF LIME, AND IN OBTAINING AND UTILIZING SULPHITE OF LIME."-A
communication from abroad by Ernest Deligny, of 17, Boulevart
Saint Martin, Paris, France.
Sealed the 1st December 1868, and dated the 5th June 1868.
PROVISIONAL SPECIFICATION left by the said Michael Henry at
the Office of the Commissioners of Patents, with his Petition, on
the 5th June 1868.
I, MICHAEL HENRY, of 68, Fleet Street, in the City of London,
Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CONVERTING BASIC PHOSPHATES OF LIME INTO SOLUBLE
ACID PHOSPHATES OF LIME, AND IN OBTAINING AND UTILIZING SULPHITE OF
LIME," communicated to me from abroad by Ernest Deligny, of 17,
Boulevart Saint Martin, Paris, France, to be as follows:--
The usual mode of rendering basic phosphates of lime soluble and

page_text: assimilable consists in treating them with sulphuric acid, which is an
objectionable method, whereas according to this Invention sulphurous
acid is employed and caused to act on the basic phosphates of lime
for the purpose of producing soluble acid phosphates and sulphite
of lime. The basic phosphate of lime to be converted is treated with
water saturated with sulphurous acid, the saturations with sulphurous
acid gas are repeated again and again, and the saturated liquid is
passed over or through the basic phosphate, or the basic phosphate
is treated therewith until a sufficiently concentrated solution is obtained.
The sulphurous acid being in excess produces soluble bi-sulphité of
lime which is decomposed by heat, whereby one equivalent of sul-
phurous acid is volatilized and sulphite of lime is precipitated and
separated from the acid phosphate which remains held in solution.
The solution is then evaporated and acid phosphate of lime will be
obtained leaving sulphite of lime as a residuum; this sulphite can be
readily converted into sulphate of lime, and it is also available for
bleaching and for fumigating purposes and for producing sulphurous
acid especially by utilizing the great residue of hydrochloric acid
which is left in the manufacture of sulphate of soda from sea salt.
It may also be utilized for producing sulphite of soda and insoluble
sulphate of lime by causing it to react on sulphate of soda.
I do not confine myself to any particular apparatus, but the following
are suitable:-1st. Ovens for burning the sulphur in form of pyrites
or other form. 2nd. Refrigerating chambers for cooling the sulphurous
acid gas, the heat given off being utilized for heating the saturated
solutions and precipitating the sulphite of lime. 3rd. Towers for
condensing the sulphurous acid gas by water or solutions below the
point of saturation; these towers are filled with lumps of basic
phosphate or inert resisting material, the liquid being showered in
at top and falling into lead or other vats. 4th. Dissolving and
filtering vats for acting on basic pulverulent or powered phosphates.
The apparatus should have air-tight or hydraulic joints to prevent
leakage. The draft for promoting combustion and causing the gas
to circulate may be produced by an exhauster such as used in gas
works. The nodules of phosphate need not be crushed as they dissolve
continuously when sprinkled.
Sulphite of lime may also be produced by using sulphurous acid
with carbonate instead of phosphate of lime, such sulphite being

page_text: caused to react on sulphate of soda to obtain the sulphite of soda
and sulphate of lime in the manner above described with reference
to sulphite of lime formed from phosphates.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Michael Henry in the Great Seal Patent Office
on the 5th December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MIOHAEL
HENRY, of 68, Fleet Street, in the City of London, Patent Agent, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of June, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Michael Henry, Her special licence
that I, the said Michael Henry, my executors, administrators, and
assigns, or such others as I, the said Michael Henry, 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
CONVERTING BASIC PHOSPHATES OF LIME INTO SOLUBLE ACID PHOSPHATES OF
LIME, AND IN OBTAINING AND UTILIZING SULPHITE OF LIME," communicated
to me from abroad by Ernest Deligny, of 17, Boulevart Saint Martin,
Paris, France, upon the condition (amongst others) that I, the said
Michael Henry, 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 Michael Henry, do hereby declare

page_text: be performed, to be particularly described and ascertained in and by the
following statement thereof, as communicated to me, that is to say :-
The usual mode of rendering basic phosphates of lime soluble and
assimilable consists in treating them with sulphuric acid, but this is an
objectionable method, whereas according to this Invention sulphurous acid
is employed, and is caused to act on the basic phosphates of lime for the
purpose of producing soluble acid phosphates and sulphite of lime. The
basic phosphate of lime to be converted is treated with water saturated
with sulphurous acid. These saturations with sulphurous acid gas are re-
peated again and again, and the saturated liquid is passed over or through
the basic phosphate, or the basic phosphate is treated therewith until
a sufficiently concentrated solution is obtained. The sulphurous acid
being in excess produces soluble bi-sulphite of lime, which is decomposed
by heat, whereby one equivalent of sulphurous acid is volatilized and
sulphite of lime is precipitated and separated from the acid phosphate
which remains held in solution. The solution is then evaporated, and
acid phosphate of lime will be obtained, leaving sulphite of lime as a
residuary product or residuum. This sulphite of lime can be readily
converted into a sulphate. It is also available for bleaching and for
fumigating purposes, and for producing or reproducing sulphurous acid,
especially by utilizing the great residue of hydrochloric acid which is
left in the manufacture of sulphate of soda from sea salt. It may
also be utilized for producing sulphite of soda and insoluble sulphate of
lime by causing it to react on sulphate of soda.
I do not confine myself to any particular apparatus for performing
the Invention as this apparatus may be of ordinary construction and
arrangement, but the following are suitable for carrying the Invention
into practical effect:-1st. Ovens for burning the sulphur in form of
pyrites or other form. 2nd. Refrigerating chambers for cooling down the
sulphurous acid gas; the heat given off by the gas may be utilized for
heating the saturated solutions and precipitating the sulphite of lime.
3rd. Towers for condensing the sulphurous acid gas either by means of
water or of solutions below the point of saturation. These towers are
filled according to the available materials either with large lumps of
basic phosphate or inert resisting materials, the liquids being showered
in at top, and falling into lead or other vats. 4th. Dissolving and filtering
vats in which takes place the action on the basic pulverulent or

page_text: powdered phosphates. The apparatus should have air-tight or hydraulic
joints to prevent waste of sulphurous acid by leakage. The draft for
promoting combustion and causing the gas to circulate may be produced
by an ordinary exhauster such as is used gas works. The nodules
of phosphate need not be crushed, as they will dissolve continuously
when sprinkled.
Sulphite of lime may also be produced by using sulphurous acid
with carbonate of lime instead of phosphate of lime, such sulphite of
lime being caused to react on sulphate of soda to obtain the sulphite of
soda and sulphate of lime in the manner above described with reference
to sulphite of lime formed from phosphates.
The following statement more fully explains the nature of the
Invention, and the mode in which it is carried into practical effect:-
The known process hitherto employed for rendering basic phosphates
of lime soluble and assimilable consists, as before stated, in treating these
phosphates with sulphuric acid, whereby they are converted into soluble
acid phosphates, and into nearly insoluble sulphates of lime; and it
may be stated that according as to whether a completely soluble
phosphate or a pulverulent or powdery product is to be obtained as a
final product the quantity of sulphuric acid to be used must approxi-
mate to the degree of saturation to a greater or less extent. Hydro-
chloric acid has sometimes been hitherto used for the purpose, but its
employment is not advisable, because when used it gives rise to two
equally soluble products, acid phosphate of lime and chloride of calcium.
These products cannot be separated, and the chloride of calcium exerts
a prejudicial action on vegetation. The compound produced by com-
bining these two salts is of no available industrial application. When
sulphuric acid is employed a soluble phosphate or mixture of phosphate
and sulphate of lime is obtained; but this process, that is to say, the
use of sulphuric acid, is disadvantageous and troublesome, and when
large quantities of material have to be treated the production of the
quantity of sulphuric acid required would involve the use of very large
apparatus, and occasion expensive outlays.
Now according to the present Invention sulphurous acid is employed
which acts energetically on all basic phosphates of lime, and converts
them into soluble acid phosphate and into sulphite of lime, the latter
becoming insoluble as soon as the excess of sulphurous acid is with-
drawn from the solution.

page_text: Water at ordinary temperature only dissolves fifty times its volume of
sulphurous acid gas, say 0.144 of its weight; and a saline solution if
obtained from water saturated with sulphurous acid would be too weak,
and it would be expensive to extract a soluble salt by evaporation
.therefrom.
Now in carrying out this process this saline solution is collected and
saturated again and again with sulphurous acid gas, and then passed
over basic phosphate, which acts on it until a sufficiently concentrated
solution is obtained. It should be stated that sulphurous acid in excess
maintains the lime in a state of soluble bi-sulphite, and consequently
the liquids can be readily passed through the basic phosphate in a state
of atoms or a pulverulent condition. Next heat is employed to decompose
the bi-sulphite of lime, and this heat volatilizes an equivalent of
sulphurous acid, precipitates the sulphite of lime, and separates it from
the acid phosphate. When the liquid is evaporated either in the open
air or in warm temperatures or in heated boilers acid phosphate of lime
is obtained, this phosphate containing a very small proportion of sul-
phite, which is promptly converted into sulphate of lime, a product
very suitable for agricultural purposes. The sulphite of lime, which
forms an abundant residuum or residuary product of this manufacture,
is a product which may be utilized or rendered available for many
industrial and useful purposes. Among these may be specially mentioned:
-First, it may be used for bleaching. Secondly, it may be employed for
producing or reproducing sulphurous acid, especially in all localities
in which the manufacture of sulphate of soda with sea salt leaves a
large excess of residuary hydrochloric acid, and in this case the
treatment of the phosphates will only consume a small proportion of
sulphurous acid finally. Thirdly, sulphite of lime may be substituted
for sulphur used for fumigating vines and other plants. Fourthly, it
may be employed for producing sulphite of soda by causing it to
react on sulphate of soda, whereby sulphite of soda and insoluble sulphate
of lime are obtained.
Ordinary apparatus, as above explained, may be used for performing
the Invention, and the liquids are raised to the top of the condensing
towers by any ordinary means. Also, ordinary apparatus may be used
for concentrating the acid phosphate in solution. The dimensions of the
apparatus of course vary according to the nature of the sulphur and
pyrites, and the phosphates to be treated, and the dimensions of the

page_text: condensing towers and solution vats also vary according to the degree
of hardness or friableness of the substance. These towers not only
serve for condensing the gaseous sulphurous acid, but also as powerful
continuous solution apparatus.
However, it must be understood that no claim is herein made to
these arrangements of apparatus in respect of their construction, and
apart from their employment in carrying out the Invention.
The principal distinctive and essential feature of the Invention consists
in the employment of sulphurous acid for the purpose of acting upon
the basic phosphates of lime, and also in the series of operations above
described for obtaining concentrated solutions of acid phosphates, leaving
a residuary product of commercial and industrial utility.
It may be mentioned that the apparatus required for producing
sulphurous acid is much less expensive than that required for the
production of sulphuric acid; also that in the production of sulphurous
acid, whereof the equivalent of saturation is the same as that of
sulphuric acid, only one material is required, namely, sulphur or pyrites.
Hence by the employment or adoption of this Invention all the expences
involved in producing sulphuric acid, and especially the cost of nitrate
of soda and of steam, and the wear and tear of lead chambers, are
avoided and economized. Indeed the first and subsequent costs of
manufacture would be considerably reduced.
The product obtained according to this Invention will contain the
useful portion of the phosphates concentrated to the highest degree, and
it is consequently capable of being conveyed inexpensively to various
parts of the country as a liquid or solid manure.
In the ordinary process the nodules have to be crushed, but when
the sulphurous acid towers are used as above described these nodules
have only to be sprinkled, and they are acted on and dissolved in a
continuous manner.
The residuary sulphite of lime may be utilized in various ways; and
its employment in the manufacture of sulphite of soda is a new and
advantageous process, because it avoids the necessity of treatment with
carbonate of soda.
It may be mentioned that the Invention is applicable to basic phos-
phate of lime, whether of organic or of mineral origin. If there be
no phosphate of lime available sulphite of lime may be prepared by

page_text: sulphurous acid and carbonate of lime, and when thereafter the double
decomposition of sulphate of soda and sulphite of lime is effected sulphite
of soda is obtained, which is a very useful product in the manufacture
of sugar.
Having now described the nature of the Invention, and the mode
in which the same may be performed, I declare that I claim,―
First. The employment of sulphurous acid for the purpose of acting
on the basic phosphates of lime in order to produce soluble acid
phosphates and sulphite of lime.
Secondly. The method consisting of the series or combination of
operations herein-before described for producing acid soluble phosphates
of lime and sulphite of lime by means of sulphurous acid, as hercin-
before explained.
Thirdly. The application of sulphite of lime for bleaching fabrics and
materials, for fumigating plants, shrubs, and trees, for producing or
reproducing sulphurous acid, and for obtaining sulphite of soda and
insoluble sulphate of lime, as above described.
Fourthly. The mode of obtaining sulphite of lime by using sulphurous
acid and carbonate of lime, as above described.
In witness whereof, I, the said Michael Henry, have hereunto
set my hand and seal, this Fourth day of December, in the year
One thousand eight hundred and sixty-eight.
Witness,
E. EDMONDS.
M. HENRY. (L.S.)