Americus times-recorder. [volume] (Americus, Ga.) 1891-current, 1906-02-23
INSTRUCTIVE LETTER OF
STATE CHEMIST.
Violent Reaction In the Mixer, Nature
of Acid Phosphate.
LETTER NO. 10.

EE Ell NO. 1U.
Violent Reaction In the Mixer, Nature
of Acid Phosphate.
We will now go back to the mixture
which we k4t in the iron mixer and
study it little further. AS we saw
the chemical energy of the action OF
the sulphuric acid upon the phosphate
meal was prodigious, steam and hot
stffiing gases are expelled from the
mixture, and finally the semi-liquid
mass is dumped into an iron car, run
out upon track, built far above
deep den or pit, the car is tilted and
the mass precipitated to the bottom
or the pit; this operation is repeated
many times, until the den or pit con.
talns hundreds of tons of acid phos.
phate. The mass lying in the pit
gradually becomes drier and drier.
owing to the escape of steam, and
also to the absorption of some of the
water in crystal form by the sulphate
OF lime or land-plaster which has been
formed. -,----~----
This water which escapes as steam,
and which is absorbed as crystal
water, came from the sulphuric acid
with which it was mixed The sui
phuric acid used in the manufacture
is usually what is known as (50) fifty
acid, or fifty degree Beaume acid, and
contains about fifty-five per cent OF
real sulphuric acid, the other forty.
five per cent being water. After the
seml-liquid mass has remained for
few days in the pile, it is dry enough
to be handled, and on digging into it
we find it to be of a porous honey
cOmbed structure, crumbling easily
between the fingers. If the acid phos-
phate is allowed to remain for a still
longer time, still more water dries out
from it, and it becomes hard and
lumpy, and requires to be broken up
In disintegratfng machine, before it
can be manipulated or sacked.
But no matter how dry it becomes,
it readily dissolves when placed in
water, the water at once acquiring an
acid taste. This acid taste is due, not
to the sulphuric acid from which it
was made, but to the mono-calcic
phosphate, or acid phosphate, or SUI
perphOsphate of lime, which was pro
du2e1 by the splitting up of the phos-
pha5e rock by the sulphuric acid This
phOsphOric acid is called the soluble
CT water soluble phosphoric acid. In
a we!l-made superphosphate there is
TO longer q particle of sulphuric acid
remaining rs such. It's powerful caus-
tic and corrosive properties have been
absolutely killed or neutralized by the
lime of the phosphate rock A won
derful transformation has been eff
fected. We started with powdered
phosphate rock and dilute sulphuric
acid; in the material which we have
produced from them there is neither
phosphate rock nor sulphuric acid,
but we have a mixture of a little free
phOsphOric acid, of mono-calcic pbo&
phate, of sulphate of lime or land
plaster, little water and little sand,
anu lew OllCf impurities, SuCn as
were found in the phosphate rock to
begin with.
The phosphOric acid, the mono
calcic phosphate, and the sulphate of
lime are now harmless, soluble in the
soil waters, and ready for appropria
tion as food by the rootlets of the
plant.
What InsoubIe Phosphoric Acid Is.
In practice the composition of the
material will vary somewhat from
what | have just described; for in
stance there will usually be present
a small percentage Of what is known
as ''insoIuble phosphoric acid" This
expression refers to little phosphate
rock which escaped the action of the
sulphuric acid, because it is safer to
use a little less sulphuric acid than is
required for all the phosphate rock
than 10 run the risk of getting too
much of this caustic and corrosive
liquid, and thus spoil the mixture
Thus, if on studying the analysis of
an acid phosphate or other fertilizer