The Manning times. [volume] (Manning, Clarendon County, S.C.) 1884-current, 1920-12-22
new DISCOVERY May CHANGE
WORLD FERTILIZER INDUSTRY
Bureau of Soils Announce 1t Has Sol
we'd Problem of Worldwide In.
terest--Process Worked Out on
Approximately Commercial Basis
at Arlington, Va.

at Arlington, Va.
What may prove to be revolutionary
development in the fertilizer industry
of the world has been reached by the
Bureau of Soils, United States De-
partment Of Agriculture, which has
just solved the problem of extracting
phosphotic acid from phosphate rock
by heating mixtures of this min raj,
sand, and coke to a smelling tempera-
ture in n fuel-fed furnace. The new
process has been worked out on an
approximately commercial basis at
the departments experimental plant
at Arlington, Va.
Comes Largely from Florida
The phosphate used for fertilizer in
the United. States comes largely from
the deposits of rock in Florida. There
are also large deposits in Tennessee
and a number Of beds in South Caro-
| lima, where the rock was first exploit
cd for this purpose. The established
method for producing soluble phos-
phate has consisted in treating the
rock with sulphuric acid. In practice,
a quantity of sulphuric acid equal to
the quantity of rock is used, and the
resulting product, which is known as
acid phosphate, contains only one-half
the percentage of phosphoric acid con-
tanned in the rock from which it was
derived. Commercial acid phosphate,
for instance, made from a 32 per cent
rock contains only 16 per cent of phos-
phoric acid. The elaborate washing
and screening process now used in
preparing phosphate rock for treat
ment with sulphuric acid often results
in the loss of two-thirds of the rock,
and it was with view to saving this
immense waste of phosphate that the
new process was evolved.
The United States Department of
Agriculture has been experimenting
for some time along the lines of free
ing the phosphoric acid by means of a
high degree of heat. It was the first
to adapt the Cottrel precipitator to
the collection of phosphoric acid, the
apparatus having been previously de-
vised by DR.. Cottrell to abate, the
smoke nuisance and TO recover sui
phuric acid from smelling operations.
The first work was done in an electric
furnace which was though to be re-
quired to generate the high degree of
heat necessary, about 1000 c.. or g.
900 r. At this temperature mixtures
of phosphate rock, sand, and coke were
reduced to molten Stag which was
tapped off at intervals, the phosphoric
acid escaping in the form of fumes
which were afterwards collected in q
liquid or solid form.
1t soon became evident that this
process would be prohibitively expen-
sive with an electric furnace, except
in localities where electric power could
be obtained at yer ylow cost, about
$25 per horsepower year ,and the de-
partment therefore turned it's atten-
tion to the possibilities of using crude
oil, the cheapest fuel obtainable in the
vicinity of the large phosphate-rock
deposits of Florida. The efforts have
recently met with success, and figures
kept on the experimental runs at Ar
lington indicate that phosphoric acid
can be extracted more cheaply in an
oil-burning furnace than by the old
sulphuric- acid process.
One problem which department
scientists have worked out is that of
keeping the fuel in direct contact with
the rock material until the reaction is
well started. For this purpose, and
for convenience in handling, the ma.
tcrial is briqueted with coke and sand
BriquetinE keeps the coke fuel with
in the mass and retains it until the
reaction is we'll started. Sand or sill
ca is necessary to bring about the
chemical reactions and this sand is
largely present as an impurity in the
Florida phosphate deposits, together
with clayey ingredient which acts as
an excellent binder in making the
briquettes Thus the very impurities
which make rock Objectionable under
the old process are turned into an as
set.
!, The practical value of the new de-
vclopment is indicated by the fact that
in the experimental runs at Arlington
the department chemists were able to
recover Cd Del' cent nhocnbor;o oo;d