San Marcos free press. [volume] (San Marcos, Tex.) 1877-1892, 1882-03-09
South Carolina Phosphates.

Among the advantages possessed b,
South Carolina phosphates are:
l. The most OF the phosphate bed
have convenient points of shipmen
for whole cargoes, or the rock may b,
forwarded from Charleston, Port Royal
or Savannah, at lower rate, in ballast
under cotton. Some of these ports
have sufficient water for ships of two
thousand tons burthen, while the rest
are generally situated on streams navi.
gable for schooners and other ligh,
draft vessels. A few miners use the
railroads crossing the phosphate belt
for the transportation of their product
to deep water.
2. The proximity of the beds to the
field OF greatest consumption on this
continent, viz: The Southern States,
which annually consume about two
hundred and fifty thousand tons of
commercial fertilizers. AS competition
reduces the profit on the manufactured
articles, it will be found necessary to
manipulate the crude rock here, thus
avoiding the expense of two freights
on the phosphate.
B. Commercial phosphate manures
consist very generally of superphos-
pilates Il. e., ground phosphates treated
with sulphuric acid, containing from
ten to thirteen per cent. soluble phos-
phosphoric acid, to which may be add
ed ammoniacal matter aud potash salts.
For the manufacture of such articles
the South Carolina phosphate rock ex-
GELS, and for the following reasons: 1t
is cheap. 1t is remarkably free from
gangue rock and other impurities. 1t
is readily ground to that impalpable
fneness which is indispensable for its
complete decomposition by sulphuric
acid. 1t contains little furide of cal
cium, and consequently yields on its
treatment with acid less noxious fumes
than is the case with apatitic phos-
pilates. The superphosphate made
from it dries readily, and is light in
color and weight. 1t may be easily
made to contain the amount of soluble
phosphoric acid required in commerce,
and this ingredient is subject to less
reversion than takes place in most OF
it's competitors.
4. Its physical structure and chemi.
cal composition favor its resolution
without the intervention of sulphurie
acid by the natural solvents of the
soil; and consequently the assimilation
of its constituents by plants takes place
more rapidly and efectually than oc
ours with most other mineral phos
pilates.
A very considerable part of the Caro-
lima phosphate is excavated by dredg
ing boats from deeper waters, where i
lies bare on the bottom, or sometimes
covered with several feet Of sand an(
mud. These powerful machines worl
best in about whelve feet of water bu
have been employed in double tina
depth. Their strength is adequate tt
tear up the thickest and hardest phos
phate beds Under favorable circum
stances, they can daily raise one hun
dred tons of rock. The clipper" O
the dredging machine empties its loa(
of rock, mari, mud and sand on a graf
ing, or into preliminary conica
"washer," where it is subjected to I
heavy steam of water, which carries OF
the greater part of the mud and sand
thereby enabling the operatives to de
tect any pieces of mari, sandstone O.
oyster shells that may be mixed will
the rock. These are picked out ant
cast aside. The partially cheaned rocl
then falls, or is cast by the machinery
into "crusher," and thence into tn
second washer" where the fragment
are thoroughly cleansed from remain
ing impurities. A few days continu
Gus drying, by means of hot air, driver
from an oven by a fan, through ever.
part, is sufficient to expel all the moist
IRE from the originally saturated rock