IMPROVEMENTS IN THE MANUFACTURE OF SUPERPHOSPHATE OF LIME
Year: 1870

page_text: LETTERS PATENT to Campbell Morfit, Consulting Chemist, of the
City of Baltimore, in the State of Maryland and United States of
America, but now residing at Sudbrook Park, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
SUPERPHOSPHATE OF LIME."
Sealed the 2nd December 1870, and dated the 20th August 1870.
COMPLETE SPECIFICATION filed by the said Campbell Morfit at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 20th August 1870, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CAMPBELL
MORFIT, Consulting Chemist, of the City of Baltimore, in the State of
Maryland, and United States of America, but now residing at Sudbrook
Park, in the County of Surrey, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF SUPERPHOSPHATE OF LIME," and have petitioned Her
:

page_text: Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and have made solemn Declara-
tion that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Campbell Morfit, do hereby declare
that the following Complete Specification, under my hand and seal, fully
describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement
thereof, that is to say :-
My Invention consists in the chemical treatment of animal or
mineral phosphates of lime without regard to the amount of carbonate
of lime which they may contain for their conversion into bi-phosphate of
lime, either pure or associated with sulphate of lime and ammonium or
potassium chlorides.
To carry out my Invention practically a vat of wood or stone fitted
with a stirrer is to be provided and charged with commercial hydro-
chloric acid of specific gravity, 1·170, to the extent of two pounds for
every per cent. of carbonate of lime which the crude phosphate may
contain. Assuming that South Carolina phosphate or coprolites are to
be operated upon, and that they contain respectively twelve per cent. of
carbonate of lime and fifty-five per cent. of tri-phosphate of lime or
thereabouts, then for every ton of either one of those raw materials
there will be required five hundredweight of hydrochloric acid of specific
gravity, 1170. The crude phosphate must be in fine powder, and allowed
to fall into the acid very gradually from a hopper during constant
stirring. As the mass thickens it is to be diluted with hot or cold water
from time to time. When all the crude mineral has been added and
stirred into a complete mixture the whole is to be left at repose for eight
or ten hours. At the end of that period all or nearly all of the carbonate
of lime will have been decomposed and dissolved into chloride of
calcium. This solution of chloride of calcium is now to be allowed to
drain off into a separate vat, after which the solid residue is to be
washed with several relays of water, and the wash waters mixed with
the previous strong liquor. The united liquors in the separate vat are
to be treated apart, as will be explained directly.
To the solid residue in the first vat brown oil of vitriol of specific
gravity, 1·700, is to be added in a very thin stream. Every per cent. of
bone or tri-phosphate of lime will require, say, 0.80 of brown oil of

page_text: vitriol. In round numbers each ton of crude phosphate of lime will
need nine to nine and a half hundredweight of this acid. After about
eighteen hours, during which interval the mass is to be roused by stirring
for ten to fifteen minutes every hour, the whole of the phosphate of
lime will have become converted into bi-phosphate and sulphate of
lime.
The action of the hydrochloric acid preliminary to that of the sul-
phuric acid and its dilute state keep down the proportion of fluoride of
calcium and oxides and phosphates of aluminium and iron which other-
wise might be dissolved. Moreover the use of hydrochloric acid in this
manner gives the advantage of introducing subsequently chloride of
ammonium or potassium, by chemical interaction, into the fertilizer,
thus increasing the potency and profit of the latter, and correcting at
the same time all tendency to humidity which the presence of chloride
of calcium would promote.
If only an ordinary commercial superphosphate of high strength is
required then the sand and other insoluble matters of the crude
phosphate material may be allowed to remain in the fertilizer, and the
whole dried for market.
But should it be required to make pure bi-phosphate of lime free from
sulphate and carbonate of lime, sand, and other insoluble matters, the
mass after being freed from the chloride of calcium liquor, and treated
with brown oil of vitriol, as above, is to be thinned with warm water,
well stirred, and then put into draining boxes. Here the contained
liquor holding in solution bi-phosphate of lime with traces of sulphate is
allowed to drain off, after which fresh relays of water are to be poured
on several times until all the bi-phosphate of lime has been displaced
from the nearly insoluble sulphate of lime. The first liquor passing
through together with the subsequent wash waters are to be united and
evaporated in a properly constructed pan or kiln to as great a density
as possible. At this stage sufficient of finely powdered mineral phosphate
of lime to dry the whole is to be added, and when the well-stirred mass
has become cool it is to be dashed into a fine powder by a Howel or
other mill.

page_text: after it may have been dried in air currents or a moderately heated
apartment.
To economize the hydrochloric acid employed in the preliminary
treatment of the crude phosphate the liquor and wash waters which were
reserved in a separate vat are now to be treated with a dense aqueous
solution of either sulphate of ammonia or sulphate of potassa during
constant stirring until a precipitate ceases to be produced. The chloride
of calcium formed from the carbonate of lime is thus converted into
chloride of ammonium or chloride of potassium, while sulphate of lime
results simultaneously, there being a double exchange of bases between
the two salts in this reaction.
The choice of the ammonia or potassa sulphate must depend upon the
application for which the fertilizer may be intended. The two salts may
be even employed together for the same product in half portions con-
secutively, so as to produce a mixture of ammonium and potassium
chlorides when a compound fertilizer is required.
Crude ammoniacal liquor or “pearl ash” may be substituted for the
sulphates, and in manner as just explained, but in such cases the lime
salt produced would be carbonate instead of sulphate.
The alkaline liquor or rather solution of the ammonium or potassium
chlorides is to be drawn off from the precipitated sulphate or carbonate
of lime, as the case may be, evaporated to dryness, and mixed with
the bi-phosphate of lime, as previously dried, or sent into market
separately.
Having thus described the nature of my said Invention, and the mode
in which I carry the same into effect, I would have it understood that
what I claim is,-
"
66
The joint use of hydrochloric acid, sulphuric acid, sulphate of
ammonia, or crude ammoniacal liquor and sulphate or carbonate of
potassa in the treatment of bones, bone ash, bone black, phosphorite,
"Navaza guano,"
apatite, cooperite, or
Sombrero guano," South
Carolina phosphate, coprolites, and the mineral phosphates of lime
generally, for the economical production of bi-phosphate of lime in a
concentrated form either with or without the association of amonia or

page_text: potassa salts, after the manner and by the means as herein substantially
set forth and described.
In witness whereof, I, the said Campbell Morfit, have hereunto
set my hand and scal, this Twentieth day of August, in the year
of our Lord One thousand eight hundred and seventy.
CAMPBELL MORFIT. (L.S.)