IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES, COPROLITES, AND OTHER INSOLUBLE PHOSPHATES IN THE PREPARATION OF SOLUBLE PHOSPHATE OR PHOSPHORIC ACID
Year: 1880

page_text: LETTERS PATENT to Balthasar Wilhelm Gerland, of Accrington, in the County
of Lancaster, Doctor of Philosophy, for an Invention of "IMPROVEMENTS IN
THE TREATMENT OF PHOSPHORITES, COPROLITES, AND OTHER INSOLUBLE
PHOSPHATES IN THE PREPARATION OF SOLUBLE PHOSPHATE OR PHOSPHORIC
ACID." A communication from abroad by Heinrich Albert, of Biebrich-on-
the-Rhine, in the Empire of Germany.
PROVISIONAL SPECIFICATION left by the said Balthasar Wilhelm Gorland
at the Office of the Commissioners of Patents on the 22nd May 1880.
BALTHASAR WILHELM GERLAND, of Accrington, in the County of Lancaster,
Doctor of Philosophy. "IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES,
THE PREPARATION
COPROLITES, AND OTHER INSOLUBLE PHOSPHATES IN
SOLUBLE PHOSPHATE OR PHOSPHORIC ACID." A communication from abroad by
Heinrich Albert, of Biebrich-on-the-Rhine, in the Empire of Germany.
OF
In the ordinary manufacture of soluble phosphate or phosphoric acid the insoluble
phosphate is treated with dilute acid, sulphuric acid being usually, employed for
the purpose.
The crude phosphate is crushed or commuted before treatment with.
the acid, the decomposition being only complete in the cases of the finer particles,
and to obtain a complete decomposition of the whole of the phosphate would.
require such a fine comminution as would render the process too costly. To obtain.
a more complete decomposition at a suitably small cost is the object of the said
Invention. To this end the insoluble phosphate is crushed or ground in the.
presence of the acid, whereby a more complete decomposition is obtained with
comparative rapidity. The crude phosphate is by preference crushed, and is then
mixed with a suitable proportion of dilute acid, which partially dissolves or
decomposes the phosphate. The mixture is then passed through a pair of stones or.
is subjected to the action of the edge runners, or is otherwise ground by suitable
apparatus, whereby the decomposition of the phosphate is completed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Balthasar Wilhelm Gerland in the Great Seal Patent Office on
the 19th November 1880.
BALTHASAR WILHELM GERLAND, of Accrington, in the County of Lancaster,
Doctor of Philosophy.
"IMPROVEMENTS IN THE TREATMENT OF PHOSPHORITES,
COPROLITES, AND OTHER INSOLUBLE PHOSPHATES IN THE PREPARATION OF
SOLUBLE PHOSPHATE OR PHOSPHORIC ACID." (A. communication from abroad by
Heinrich Albert, of Biebrich-on-the-Rhine, in the Empire of Germany.)
In the ordinary manufacture of soluble phosphate or phosphoric acid the insoluble
phosphate is treated with dilute acid, sulphuric acid being usually employed for
the purpose.
The crude phosphate is crushed or comminuted before treatment
with the acid, the decomposition being only complete in the cases of the finer
particles, and to obtain a complete decomposition of the whole of the phosphate
would require such a fine comminution as would render the process too costly. To
obtain a more complete decomposition at a suitably small cost is the object of the
said Invention. To this end the insoluble phosphate is crushed or ground in the
presence of the acid, whereby a more complete decomposition is obtained with
comparative economy.
In the preparation of a solution of phosphoric acid I mix the ground insoluble
phosphate of lime with water, or with the wash water of residues of former
operations, and whilst the powder is kept in suspension I add an acid such, for
example, as sulphuric acid, sufficient in quantity to liberate the phosphoric acid.
The mixture is kept agitated for some time, say, for about one hour or more, after
which it is subjected to the action of horizontal grinding stones or edge runners, or
of any suitable grinding apparatus which will crush or triturate the small solid lumps,
whereby the process is practically completed. The solution is now separated from
the insoluble part, which may be conveniently effected by means of a filter press
and by displacement by water. The strong solution thus separated is essentially a
solution of phosphoric acid, and can be further treated according to the purposes for
which it is destined. The wash waters may be advantageously collected separately,
and be used for a fresh mixture of insoluble phosphate with acid. The density of
such wash waters may vary, say, from 1·03 to 105, and after mixing these with a
similar quantity of insoluble phosphate and sulphuric acid and passing the whole
through the grinding apparatus, the density of the solution will have risen to
about 1.08 to 1.1, the solution containing about 10 per cent. of phosphoric acid.
An advantage of this method consists in the more perfect extraction of phosphoric
acid from the insoluble phosphate, as the following example will illustrate :-A
phosphorite containing 21 per cent. of phosphoric acid (anhydrous) when mixed in
a ground state with an equivalent quantity of sulphuric acid and water will yield
a solution containing only 18 per cent. of phosphoric acid, but after grinding the
mixture the solution will contain from 20 to 20 per cent. of phosphoric acid out
of the total 21 per cent. contained in the said phosphorite, so that only from
1 to 1 per cent. of phosphoric acid of the weight of the phosphorite is left with the
insoluble residue. All mineral phosphates can be worked economically according
to this method, as the expenses are more than covered by the increased weight of
phosphoric acid.
In order to prepare commercial superphosphate I mix the ground insoluble
phosphate with the required quantity of sulphuric acid previously diluted with
more or less water, and after letting it stand some time I pass the mixture through
a suitable grinding apparatus. The strength of the sulphuric acid used in this
process, and the time the mixture is allowed to stand previous to passing through
the mill, depends upon the nature of the phosphate and the temperature the

page_text: mixture attains, and has to be ascertained by experiment.
The mixture should
not be permitted to harden before being passed through, the mill. Instead of
sulphuric acid I may use other acids for mixing with the insoluble phosphate,
particularly when a superphosphate of high degree is desired, in which case I mix
a concentrated solution of phosphoric acid with the insoluble phosphate and after
some time grind the mixture in the manner before described.
In conclusion I would have it to be understood that I claim,-
First. The grinding or trituration of a mixture of insoluble phosphate with a
diluted acid, as for example, with dilute sulphuric acid, for the purpose of preparing
a solution of phosphoric acid.
Secondly. The grinding or trituration of a mixture of insoluble phosphate with
a suitable acid, such as sulphuric acid or phosphoric acid, more or less diluted with
water, for the purpose of preparing commercial superphosphate, substantially in
the manner herein before set forth.
In witness whereof, I, the said Balthasar Wilhelm Gerland, have hereunto
set my hand and seal, this 16th day of November, in the year of our Lord
One thousand eight hundred and eighty.
BALTHASAR WILHELM GERLAND. (L.S.)