FERTILIZER.
FERTILIZER -- BLOOD -- RECEIVING TANK -- COOKING -- PRESSING --
PURITY -- STORING -- QUICK HANDLING -- TANKAGE -- QUOTATIONS AND
VALUE -- GREASE -- INFLUENCE OF STICK -- DIGESTER TANKAGE -- SLIME --
DRYERS -- DRYING -- EXPENSE FOR DRYING -- COMMERCIAL FERTILIZER --
STATE REGULATIONS -- MIXING MATERIALS -- CONVERSION FACTORS.
=Fertilizer.=--In this department we discuss the manipulation of the
products after leaving the tanking process in the case of tankage, and
of blood, beginning with its release from the animal.
=Blood.=--The sources of the collection of blood are from animals
slaughtered, viz: cattle, sheep, calves and pigs. In nearly every
instance this is collected at a given point near the sticking rails and
transferred to the fertilizer department for processing.
It is rather difficult to pump blood, although it can be readily
done with a ball valve pump, or a centrifugal pump. The latter is
satisfactory if foreign substances can be kept out, and if the
reservoir can be situated high enough so that the blood can gravitate
to the suction of the pump. Mechanical agitation is a benefit in
the receivers. A very satisfactory way to handle blood is by means
of a blow tank. This is a tight, heavily constructed cylinder with
an admittance valve on the inlet pipe, and a closing valve on the
discharge pipe; the latter preferably a quick opening valve. A means
for admitting air or steam to the blood is arranged. To operate, the
valve on the inlet line as well as the outlet valve is closed, and air
or steam pressure is built up as required for the lift. The outlet
valve is then quickly opened when the contents of the tank is virtually
“shot” to the receiving tanks.
=Receiving Tank.=--This is preferably a closed type of tank with an air
vent to allow displacement of air when blowing blood. It is preferably
situated above the cook tank with an admittance valve between them so
that blood can be lowered to the cooking tank at will.
=Cooking.=--Blood should be “_baked_,” not boiled. By this is meant,
the steam should be admitted slowly and the heat dispersed through the
mass rather than boiled violently, by admitting high pressure steam.
The blood, by this method, seems to coagulate in larger grains, and,
in pressing, a larger proportion is retained in the cloths, while the
serum or white water draining away is of a lighter color, with the net
result that the yield of blood is better.
=Pressing.=--The pressing is performed in the same manner as described
for tankage, except that the material is handled dry. The waters from
cooking, as well as from pressing, are saved for evaporation as tank
water. Blood when pressed properly is “caked.” It should be broken up
before being passed to the dryers.
=Purity.=--Means should be provided and arrangements made to keep
all raw or fluid blood free from water and manure. Frequently cattle
that are hay or grass fed, have a draining from the stomach via the
mouth when hung, and comparatively large quantities of undigested food
are spilled. This should be collected before the animal is stuck and
prevented from mixing with the blood.
=Storing.=--After drying, blood should be cooled and stored in piles on
the floor in dry rooms to be put in bags at the time of shipment. It
is usually unnecessary to grind or screen it. It should be dried to 8%
moisture.
=Quick Handling.=--Blood is so highly susceptible to decay that it
should be handled quickly and with as little contact with air as
possible.
=Tankage.=--This name embodies the dried material from the residue in
the tanks after cooking in digesters, and pressing. It is classified
into several grades. Digester tankage, is usually sold for stock
foods. No. 1 tankage of commerce, has a high nitrogen content and low
percentage of bone, it is usually produced from beef tanks; No. 2
tankage is low in nitrogen or ammonia, as it is known to the lay-mind,
and high in bone. The usual comparative analysis is:
Blood No. 1 No. 2
Bone Phosphate ... 10% 28%
Ammonia 16-17% 10-12% 6-8%
=Quotations and Values.=--Tankage and blood is usually sold on its
value per unit of ammonia. That is to say, if blood be quoted at
$3.00 per unit of ammonia and analyzes sixteen per cent, it sells for
$48.00 per ton. Tankage may contain eleven per cent ammonia and twelve
per cent bone phosphate, quoted at $2.75 per unit, and 10c per unit
respectively, which would make the relative market $31.45 per ton.
By reference to market quotations it will be noted usually that the
lower the ammonia content, the lower the price per unit of ammonia,
consequently it behooves the maker to produce all the No. 1 tankage
possible, and this is accomplished by cooking bone as raw bone and
separately--in preference to tanking it.
=Grease.=--Grease in fertilizers or dried tankage is a positive
detriment. It is useless and valueless, consequently the point to be
striven for is to lower the percentage of grease to the minimum. The
best methods known are described under tanking. Some packers doing
business on a large scale have “degreasing” plants where the grease
is extracted by naphtha process, but, this is a highly specialized
department and not desirable in a small plant. By careful attention the
grease can be lowered to eight per cent on dry basis analysis.
=Influence of Stick.=--The use of stick in tankage drying adds greatly
to the average ammonia content. Dried stick separately analyzed yields
15¹⁄₂ per cent ammonia, greatly increasing the value of the product in
which it is used.
=Digester Tankage.=--This is a general name for the product sold to pig
feeders for providing a nitrogenous element in their feeding. State
Agricultural Departments and packers have been conducting campaigns
for years introducing this as a feed. It is usually a No. 1 tankage
made from freshly killed material and promptly dried. It is supposed to
contain a stated protein content, which is really a multiple or unit
based upon its nitrogen content, 5.137 being the factor. Stick is used
in the digester tankage and with benefit provided it is kept sweet.
In hog producing localities practically the entire output of tankage
can be disposed of to the farmer for stock food purposes.
=Slime.=--The slime scraped from intestines in the casing department
has a high ammonia value and should be collected and cooked in a manner
similar to the method used in cooking blood.
=Drying.=--This operation consists of extracting the moisture from the
tankage by means of air which is used as a vehicle to carry away the
moisture. Various devices are employed for performing this function,
such as barometric condensers, siphon tees, pipe condensers, and fan
with air wash tower. There is some objection to all of these types, and
each operator usually has some home-made device based upon experience.
The fan is the more logical; it sweeps a large volume of air through
the dryer by withdrawing it and passing it to the wash tower. The air
carries away the moisture. To dry cheaply have a positive circulation
of air through the dryer by keeping the inlet open, the fan attached to
the air outlet connection. Single or multiple of dryers can be arranged
on one fan.
=Dryers.=--The principal apparatus in the fertilizer department is the
dryer. Of these there are several types.
_Direct Fire Dryers._--In direct fire dryers, the tankage and flame
produced by the use of oil, coke or coal, are introduced and passed
through a cylindrical rotating machine similar to a cement dryer. The
dried tankage is discharged at the opposite end from the feed, and the
gases and moisture pass through a water spray and chimney to the air.
It is practically impossible to operate a dryer of this type without
producing an offensive odor in the surrounding territory and they are
also considered hazardous from a fire standpoint.
_Smith Type._--This type of dryer is shown in the illustration (Fig.
75) and is of the steam jacketed type. The barrel is stationary with
a revolving shaft and extended arms carrying the tankage upward which
falls back through the air.
_Ord Type._--This dryer is also illustrated, Fig. 76, and is of the
same type, except that the shaft is placed vertical and the revolving
arms at right angle to the shaft device which accomplishes the same
result.
[Illustration: FIG. 75.--ILLUSTRATING THE SMITH TYPE OF DRYER.]
[Illustration: FIG. 76.--SHOWING THE ORD TYPE OF DRYER.]
=Expense for Drying.=--In a charge type of machine where batches are
placed in the machine and unit lots dried, the expense for drying
seems to be per short ton, about as follows: Labor, $1.25 to $2.00;
Dryer repairs, $0.75 to $1.25; Steam, variable. The item of steam is
quite a large factor. In a well handled equipment, properly insulated,
about ³⁄₄ of a pound of moisture can be extracted per pound of steam
condensed in the jacket, when drying tankage, and ⁶⁄₁₀ of a pound
when drying blood. The latter requires about twice as long to dry as
tankage; in other words, the output per hour of dryer operation is
about one-half.
=Commercial Fertilizer.=--Commercial Fertilizer is the name generally
applied to prepared or diluted mixtures thought to be best adapted
for use on ground or for some special crop. The standard tankage as
produced contains an ammonia content of from eight to twelve per
cent and may be short in other ingredients such as potash and acid
phosphate, which are mineral substances, usually converted to a form
readily soluble, or in condition to be assimilated. Also the ammonia
content is reduced to a moderation, the dilution being accomplished by
the use of a filler, such as pulverized dried peaty soil, which has
the advantage of carrying a certain quantity of humus or selected sand
which serves a drill nicely.
=State Regulations.=--Most states have found it desirable to protect
the purchaser by insisting that an analysis of the fertilizer be
supplied with each shipment, indicating the content, the state then
making sporadic analyses to see that it generally qualifies to the
stated contents.
=Mixing Materials.=--The mixing materials used are:
Dried Tankage.
Dried Blood.
Bone Meal.
Steam Bone.
Acid phosphates, which is phosphate rock treated with sulphuric
acid--a more or less complicated process--and which product is usually
purchased by small works.
Muriate of potash, a substance known as kainit usually produced from
mines in Germany, although some potash is being produced from sea weed
in America.
=Conversion Factors.=--The following table will be found handy for
changing the bone quantity into another term, as for example, wishing
to know the per cent of nitrogen if ammonia be expressed:
CONVERSION FACTORS
Multiply by
A B A to B B to A
Nitrogen Ammonia 1.2158 .8225
Nitrogen Nitrate of Soda 6.0678 .1648
Nitrogen Nitrate of Potash 7.2170 .1386
Nitrogen Protein 6.2500 .1600
Ammonia Nitrate of Soda 4.9906 .2004
Ammonia Nitrate of Potash 5.9358 .1685
Ammonia Protein 5.1404 .1945
Ammonia Sulphate of Ammonia 3.8791 .2578
Nitrate of Soda Nitrate of Potash 1.1894 .8408
Actual Potash Muriate of Potash 1.5830 .6317
Actual Potash Sulfate of Potash 1.8500 .5405
Actual Potash Nitrate of Potash 2.1467 .4658
Actual Potash Carbonate of Potash 1.4671 .6816
Muriate of Potash Sulphate of Potash 1.1687 .8557
Muriate of Potash Carbonate of Potash .9268 1.0790
Phosphoric Acid Bone Phos. of Lime 2.1850 .4577
Carbonic Acid Carbonate of Lime 2.2748 .4396