Process of Converting Insoluble Phosphoric Acid Contained in Mineral and Petrified Phosphates into Available Phosphoric Acid.
Year: 1888

page_text: COMPLETE SPECIFICATION.
Process of Converting Insoluble Phosphoric Acid Contained in
Mineral and Petrified Phosphates into Available Phosphoric
Acid.
We, CHARLES GLASER of the City of Baltimore and State of Maryland, United
States of America, Gentleman and CHARLES F. W. DAMBMANN of Baltimore aforesaid
Gentleman 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 :-
Hitherto it has not been practicable to convert the phosphates of lime existing in
mineral phosphates (such for example as South Carolina Rock) into available phosphoric
acid; by direct application of phosphoric acid to such phosphates; but by the method
herein described, such mineral phosphates may be treated and converted into a
compound containing from 25 to 40 per cent. of available phosphoric acid, at the same
time avoiding the formation of any considerable quantity of sulphate of lime or other
similar compound.
To enable others skilled in the art to practice our process the following is the
method which we adopt. We take the hard rock or mineral phosphate and divide it
finely, by grinding or otherwise; it should be well ground; experiment has shown
that such mineral ground to pass through a mesh of from 50 to 100 to the inch, will
answer practically the purpose; when ground, we add directly phosphoric acid
containing about 40 per cent. in volume of phosphoric anhydride and the product is a
mineral phosphate, containing a high amount of available phosphoric acid. This
process may be followed without the application of artificial heat.
A good way is to take the mineral, and after grinding, divide into two parts, extract
the phosphoric acid from one portion by any of the known methods, for use in treating
the other; when extracted, concentrate to about 50° of Beaume and apply to the other
portion. We are aware that with animal bone and other phosphates of animal origin
it has been practicable to convert the bone phosphate of lime contained in such
phosphates into available phosphoric acid by direct application of phosphoric acid but
so far as we know, all efforts in this direction with the harder and denser mineral
and petrified phosphates have failed.

page_text: The proportion of the phosphoric acid to the ground mineral phosphate will vary
according to the character of phosphate used, from 100 of mineral phosphate to 50 of
phosphoric acid in those minerals most easily converted, up to 130 of phosphoric
acid in those which are hardest to treat.
We obtain by this process a mineral phosphate rich in available phosphoric acid 5
which may be readily used for fertilizers or any purpose to which it is applicable.
What we claim is :
The above described method of converting, the insoluble phosphoric acid contained
in mineral and petrified phosphates into available phosphoric acid by first finely
dividing the mineral, and then applying directly phosphoric acid substantially as I
described.
Dated this 18th day of September 1888.
CHAS. GLASER.
CHARLES F. W. DAMBMANN.
By Mc Kenna & Co.,
Test,
ARTHUR STEWART.
BENJ. PRICE.
Agents.