The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1903-12-10


tL.a country OF acia phosphate Of
Rae The materials necessary for
i4-!s manuiacturs are sulphuIic acid
ard phosphate rock. The plant re-
CURED for the manufacture of sui,
phnric aci1 is costly one, and the
process s somewhat complicated.
Either birthstone from Sicily, or
pyrites, which is a compound of sui
phur and iron, some of which is i'm
ported from Spain and some produced
from mines in this country, are the
raw materials used in the manufac-
ture.
The birthstone or pyrites are burned
In specially constructed burners, and
the sulphurous gases which result from
the burning are caused to mix with
nitrous gases produced from nitrate Of
soda, and drawn into great towers
made of lead and packed with fiints;
thence they are drawn into immense
leaden chambers or rooms, usually
three in row connected together. In
these chambers the sulphurous and .
trous gases are mixed with steam, and
condensed into sulphuric acid, which
rails In rain on the floors of the lead
en- chambers. 1t is necessary to con-
struct these chambers of lead, because
almost any other material would be
destroyed and eaten out by the action
OF this corrosive acid.
The phosphate rock is hauled to the
factory, usually a building located
alongside the sulphuric acid chambers,
1t is there thrown into crushers which
break 1t into small pieces; thence cor
veyed to the grinding machinery,
either steel mills or buhrstones,
; where it is pulyerized into a fine meal
or flour. You would naturally ask
at this point, why not use this fine
phosphate meal directly on the soil,
without mixing it with the caustic
corrosive sulphuric acid? 1t is sim
ply because this meal is Of rocky
nature and only dissolves with diff
Guilty in the soil waters, and we have
seen plants require their food to be
easily soluble in water, so that the
roots suck it in. The phosphate rock
meal, no matter how finely ground,
dissolves only to Q very limited ex-
tent in water, and it is necessary to SO
treat it as to liberate the rock-bound
phosphoric acid; and render it solu-
bic in water. Hence the necessity,
for the sulphuric acid.
The phosphate meal (say it is from
South Carolina rock, and contains 20
per cent of phosphoric acid, combined
with lime to form 81 per cent of bone
phosphate of lime) Is first weighed,
and we will take say 1000 pounds of
it, and dump it into a circular cast-iron
mixer. into which has already been
introduced 1000 pounds of sulphurlc
acid of the proper strength.
The acid and meal are now thor
oughly mixed togethed by machinery
in the iron pan. The mixture be-
comes very hot, the strong sulphuric
acid attacks the lime combined with
the phosphoric acid of the phosphate
meal with amazing axf- {y.falsl efyF-
gy and appropriates to itself the great
er part of the lime in The form of sui
pHdCe OF lime, gypsum Ut ldnu-plaSLeI6
and liberates the same moment the
phosphoric acid, which is only allowed
to retain its hold on small part of
the lime, with which 1t was first com
bined
This smaller portion of lime and
the phosphoric acid with which 1t is
combined is what the chemists call
ACKNOWLEDGEMENTS, or superphos
plate of lime. 1t is also known as
the acid phosphate of lime. This
acid phosphate of lime, or superphos
plate, is soluble in water; we have,
therefore, accomplished what we set
out cIas,,s< rendered the phosphoric
aci ssrws6S This dicovery was made
by WsV; EAShemist Liebig, who thus
put t.gG:4 NO .World in his debt, lay
ing tsnRe WaS1Ons Of the great fer.
tilizer % MsioE. and rendering an in
estimabz sss9B modern agriculture
p3EzkfN M. McCANDLESS,
4A Stats Chemist