Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The invention relates to a method for rendering waste
substances harmless, especially used oils and oily substances.
The increasing use of hydrophobic substances, such
as oils and oily substances, as well as macromolecular substances -
especially, has created new problems which arise mainly out of
the handling of these substances. Particularly the use of old
oil, heating oils, lubricating oils and diesel fuels often leads,
either intentionally or through negligence, and often due to
emergency situations, to dangerous contamination of the environ-
ment.
There are a number of methods for rendering harmlessoils or oily substances which, in a single phase or in multiple
phase systems, entail an endangerment of the environment. Thus,
for example, oil can be chemically reacted by being burned, for
example, or biologically degraded.
The combustion method used frequently in combating oil
damage results in considerable air pollution if the burning is
performed in the open rather than in expensive combustion apparatus. -
The use of adsorbents solves the present problem only
when the oil can be fixed with them in such a manner that it ischemically unaltered but no longer constitutes any danger to the
environment or is accessible to biological degradation. With the ;~
known adsorptive agents such as active charcoal, kieselguhr or
bentonite, waste oil, for example, can be adsorptively bound only
with difficulty. Large amounts of oil may cement the adsorptive
agent, especially in the case of high-viscosity oils, making
further processing difficult. It has furthermore been proposed
in various ways to treat porous mineral substances with hydro-
phobic substances for the purpose of improving their adsorptive
characteristics. In this manner hydrophobic waste substances can
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~ .
~' .
..
1 be preferentially bound, while the water is no longer primarily
absorbed. In such adsorptive agents, such as hydrophobized
pearlite, however, the absorptive capacity is greatly reduced,
since the mineral starting material is partially sealed by sur-
face treatment with hydrophobizing substances, so that the inner
cavities are no longer accessible.
It is particularly important that the substances which
are adsorptively bound by the known processes are so fixed on the
adsorptive agent that they no longer constitute any danger to the
10 environmentO
The invention is addressed to the problem of creating
a method which in a simple manner will make it possible to render
waste substances harmless, especially used oils and oily substances.
The subject of the invention is a method~for rendering
waste substance harmless, which is characterized in that an
alkaline earth oxide, which has been treated with surface active
substances,which delay the reaction with water, is added to the
waste substances, the alkaline earth oxide charged with the waste
substances is made to react with approximately stoichiometric
amounts of water to form the alkaline earth hydroxide, and the solid
thus obtained is dumped or a technical application is made of it
Whenever the term "waste substances" is used in the '`
framework of the present invention, it is to be understood in its
. .
broadest sRnse. Such wastes may be organic or inorganic wastes.
The applicability of the process of the invention is
largely independent of the physical state of the waste substances,
and is also possible, for example, when the mostly organic wastes
are in the form of solids which are still suspended in water at
low temperature, and do not become liquid until the temperature is ~ -
increased or until they are dissolved by a solvent. They may be
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- - : - .- - ~ : --. ~ , : . ... : . .:
1 not only one~ase systems and two-phase systems of water and an
organic fluid that is not miscible or is miscible only to a
limited exten~t with water, but also multiple-phase systems with
the inclusion of finely divided solids. The viscosity of the
phase containing the wastes is not of decisive importance for
the applicability of the method of the invention. -
The same applies to the chemical nature of the wastesO
They may be both monomeric compounds and polymers, polycondensates
and polyaddition compounds. These substances may be of natural
or synthetic origin. Examples of waste substances which occur
in practice also in the form of emulsions are: old oils, such
as used motor oils, cutting oils, drilling oils, vegetable and
animal fats, waxes and wax-like substances such as those produced
by the removal of wax from automobiles, tar oils, resins, bitumin-
ous substances and pitchesJ acid resins, synthetic resins, petro-
leum, petroleum fractions such as gasoline and kerosene, as well
.. . .
as machine oils, cylinder oils and lubricating oils, and also
aromatic compounds such as benzene and toluene.
The following are given as examples of multiphase
systems which are produced, sometimes in large quantities, as
a waste product in technical processes, and which can be rendered
harmless by the method of the invention:
Acid resinl~, drilling greases, drilling oils, cutting
oils, enamel emulsions, waste impregnating emulsions used in the
textile industry as well as resin emulsions in the paper industry,
synthetic resin emulsions such as are produced in the after-treat~
ment of metals, waste waters containing grease and oil discharged
from machines for washing ball bearings and friction bearings,
electroplating sludges, bleaching earths charged with oily comp- ~-
onents such as are produced, for example, in the decoloring of
.~
. . . . -
. ~ : . , : : . . . : -
1 dark mineral oils, fats and waxesO
Suitable for the performance of the process of the
invention are all alkaline earth oxides, ioeO, the oxides of
calcium, barium, strontium or magnesium. For the purposes of the -
invention, calcium oxide is preferred in the form of the commercial
quicklime, e.g., fine white lime, but coarse granules are usable
in many casesO The quicklime may contain up to 18 wt-% magnesium
oxide or other foreign componentsO As the percentage of magnesium
oxide increases the water slaking of the pretreated quicklime
charged with the organic substances is slower and takes place
with a lesser development of heat, which may be advantageous in
a number of applicationsO On account of the preferred use of
quicklime the following measures and advantages of the invention
will be described only with reference to calcium oxide, although
. .
they apply essentially also to t~e other name~ alkaline earth ; ~ -
oxides or their mixturesO ~-~
Quicklime reacts with water rapidly and exothermicallyO i: ;
It would therefore be slaked, i.e., transformed to calcium hydrox-
ide, in aqueous systems, without needing special preliminary
treatment, and the calcium hydroxide would adsorb the oily sub-
stances just as unsatisfactorily as directly added slaked limeO
: .:
Even hydrophobized calcium hydroxide has only a comparatively
. .
low capacity for the adsorption of oily substances. ~
:, :,
Now it has surprisingly been found that calcium oxide
behaves quite differently if, after preliminary treatment with
hydrophobizing agents, it is reacted in the presence of the waste -~
materials with water which either is already present in the system ~;
in the stoichiometric minimum amount necessary for the formation
of hydroxide or is added after the absorption of the liquid wastesO
.
What the reason for this is not entirely understood. Apparently
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1 the calcium oxide micelles loaded with the hydrophobizing agent
are protected against slaking with water, so that the formation
. . ..
of the hydroxide takes place only with a considerable delay whose
degree depends on the quantity and chemical nature of the hydro-
phobizing agent. ~n-cethe reaction with water of a calcium
oxide thus hydrophobized does not take place even after several
minutes and may be delayed for as much as an hour or more, we are
justified in speaking of a calcium oxide that does not react with
water. It is all the more surprising that it can react with water
again after it has come in contact with, for example, an organic
waste substance, such as oils, and has managed to become charged
therewith. It is assumed that the molecules of the hydrophobizing
agent first cover the surface of the calcium oxide micelles and
protect it against the attack of the water. Under the action of
the organic substances contained in the nonaqueous phase, the
molecules of the hydrophobizing agent become gradua~ly inactivated -
ioe., absorbed by the organic phase, so that water molecules can
get to the CaO lattice and, with a considerable increase in vol-
ume, form calcium hydroxide whose particles in statu nascendi
absorb the organic substances.
In the method o the invention, the surface can increase
to more than 20-fold during the formation of hydroxide in the
presence of an organic phase. In particular, the surface enlarge-
ment depends on the nature of the substance to be adsorbed and on
the surface-active substances used, which delay the reaction with
water ~nd with which the calcium oxide has been treated. The
surface-active substances are contained in the ~uicklime in amounts
of from OoOOl to 10% by weight, preferably OoOl to 5 wt-%o They
are particularly effective when they are very uniformly distributed - -
therein. This can be achieved by intimately grinding the quicklime,
' ~'
1 for example, in the presence of the surface active substancesor by impregnating it with them if they are liquids of low
viscosity, or by impregnating it with solutions of the surface
active substances. This can be done, for example, by injecting
them into a mixing drum in which the calcium oxide is being stirred.
- For the purposes of the invention, surface active sub-
stances in the widest sense are suitable. Apparently the only
important thing is that they have a special affinity for the ;
waste substance to be separated, especially in the case of an
aqueous multi-phase system, so that a preferred interaction with
the latter takes place before the reaction with water begins.
Fundamentally, anion-active and cation-active as well
as non-ionogenic surface active substances are usab~ë,. Chemically
these substances may be in the followi~g classes: fatty acids
such as stearic and palmitic acid, alkyl su~fates, alkyl aryl
sulfonates, alkyl sulfonates, sulfosuccinic acid esters, salts
of carboxylic acids, the true soaps, sulfosuccinamides, ether
sulfates,nonylphenylpolyglycol ethers, fatty alcohol polyglycol
ethers and their sulfation productsO But polyglycol ethers, ;
aliphatic amines, aminoxides, aliphatic alcohols and c~llulose
derivatives as well as polymeric compounds are usable.
The selectivity of the above-named adjuvants for the
organic substances to be separated may be adjusted very precisely
through the selection of the functional groups and of the chain
length of the molecule. This is especially important whenever
the substance to be adsorbed is inhomogeneous and contains sub-
stances of different origin, e.gO, emulsifiers, lubricant additives,
etc.. It is desirable in determining the appropriate adjuvant to
start with representatives of a homologous series. If one series
fails completely, another is tested. With the aid of simple lab-
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1 oratory tests a suitable representative will be found in known
homologous series, such as for example the series of the alkanes,
the aliphatic carboxylic acids or the aliphatic alcohols. The
precision with which the selective behavior of the adjuvant added
to the calcium oxide can be adjusted is surprising to the technical
man. For example, an emulsion that could not be separated by any
former means can be separated within seconds by using a fine lime
pretreated with n-octylamine, but the separation of the emulsion
fails when the homologous C12 amine is used.
The adjuvants may also be selected in such a manner as
to cancel the effect of certain types of emulsifier present in the
multi-phase system that is to be separatedO For example, anion-
active emulsifiers, such as soaps for example, can be rendered
harmless by cation-active additives, such as long-chain ammonium ;
salts for example, so that the separation of the emulsion takes
place substantially rap~dly. The same applies to the addition of
other adjuvants, such as hydrocarbons for example.
To render hydrophobic wastes harmless it is desirable
to use a calcium oxide treat~d with fatty acids or paraffin oilO
The calcium oxide treated with these or other hydrophobizing ag0nts
is not of itself especially hydrophobic, but it loads up--pr2ferent-
ially it seems-- with hydrophobic wastes when they occur in aqueous
multi-phase systems~ In the course of the gradually beginning
reaction of the calcium oxide charged with the organic wastes
with the water contained in the aqueous multi-phase system or added
in accordance with the stoichiometric requirements, to form calcium
hydroxide, the organic substances are adsorbed uniformly and extrem-
ely finely. The calcium hydroxide containing the hydrophobic ;
adjuvant and the wastes displays an unusually intensified hydro-
phobic behavior, so that it can be separated without difficulty
~ 7 ~ ;~
.. . - . ~ .. .. . .. , . - - . . ..
1 from any aqueous phase that might possibly remain. Furthermore,
the calcium hydroxide that forms remains virtually undissolved
even upon long contact with water
In view of the properties of the end product of the
process of the invention, those hydrophobizing agents are espec- -
ially selected which give the calcium hydroxide hydrophibic prop-
erties by themselves or in conjunction with the absorbed organic ;
substancesO Suitable for this purpose are, for example, fatty
acids, such as stearic and palmitic acid, but also fractions of
petrole~m, such as paraffin oil. The selection and amount of the
.............. .
hydrophobizing agent will depend decisiv~i*y{~on what is to be done
with the end product, i.e., the calcium hydroxide cantaining the
waste substances in adsorbed form. As a rule the desired action
is achieved by the addition of 0ol to 5 wt-%, especially 1 to 3
wt-%, of the hydrophobizing agent.
In order that the calcium oxide treated with hydro-
phobizing agents and in some cases other adjuvants may absorb
the wastes before it is reacted to alkaline earth hydroxide -
with the w~ter present in the system or added thereto, with the
2~ adsorptive binding o~ the organic substances, it suffices to mix
the treated quicklime with the waste substanceO If liquids are
involved, it is enough to stir the treated quicklime into them
or to imbibe lumps of quicklime with themO If the waste addition- ~'
ally contains solidsJ provision can be made for a thorough distrib-
ution of the treated calcium oxide in the system by means of suit-
~le mixers or kneaders
The amount of treated quicklime required in order-to
render the wastes harmless depends essentially on the desired state
of the end product or the possible use to which it may be puto In
the case of liquids it is sufficient to add so much treated calcium ;
- 8 - -
1 oxide that the calcium hydroxide containing the wastes adsorptively
bound is produced in the form of a dry powder on the basis of its
hydrophobic properties. In the majority of practical applications
the weight ratio of treated calcium oxide tothe waste substances
to be made harmless ranges from about 1:1 to 1:10O
Surprisingly it has been found that the~hydrophobic
calcium hydroxide resulting as the end product can be carbonized
with the included wastes with exceptional ease, which is evidently
due to the fine division of the calcium hydroxide formed in the
process of the inventionO After only a few days of storage in air,
it is no longer alkaline calcium hydroxide, but calcium carbonate.
Through the appropriate choice of the hydrophobizing agent, this
and the adsorbed organic waste substances which are also in finely
divided form, can be biologically degraded. In cases in which
biological decomposition of the waste is possible, adjuvants which
themselves are biodegradable are s~l-ected. These include, for
example, natural fatty acids, such as stearic and palmitic acid,
and alkanes such as paraffin oil. What has been said also applies
when the waste substance still contains a solid phase, and it is,
for example, crude oil which is both on and in the soil. In this
case it is expedient to use hydrophobized quicklime containing,
for example, 0.4 wt-% stearic acid and 0.2 wt-% paraffin Gil in
very finely divided formO This can then be blown onto the oil
layer according to its thickness; the oil that is on the ground
immediately sinks in, and the oil in the soil is brought in contact
with the treated quicklime mechanically, with a rotary tiller, for
exampleO If the soil~L~mo~sture is insufficient for the reaction, the
amount of water necessary for hydroxide formation is sprinkled on
and worked in, the distribution of the oil which is in the hydro~
phobized calcium oxide into the large surface area of the end product,
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. :. : . . .. . . :
l i.e., the calcium hydroxide, will then take place The charged
powdered adsorption agent can be tilled into the subsoil where
the oil is accessible to biodegradation on account of its extremely
~ - , . . .
fine division. The calcium hydroxide will be transformed in the
course of time into calcium carbonate.
If aqueous multi-phase systems with a highper-
centage of acid resins or emulsified used oils are
to be made fit for dumping, hydrophobized calcium oxide is added
preferably in such amounts that the end product will be a solid.
The dry, highly hydrophobic po~der that results, which is no longer
wettable with water, can be used in the form of a layer up to
several meters thick as a lining for dumps for oily materials.
That is, this very hydrophobic powder absorbs oil very greedily,
so that oil pol~ution can no longer get into the ground water. For
example, if calcium hydroxide and used oil are present in an end ~ -
product obtained by the present invention, in a weight ratio of
1 ~, additional oil and oily substances can nevertheless be adsorbed
in considerable amounts, namely upcto approximately double its '
weightO The hydrophobic end product is particularly well suited
20 for the above-named application if it contains non-biodegradable
adjuvants such as, for example, stear~lamine, or dimethylbenzyl-
stearyl ammonium chloridec It can also be used to special advantage
as a construction material in street and highway construction, esp-
ecially as a frostproofing layer.
Lastly, it is very important to transform waste substances
such as used lubricating and motor oils, even chemically in some
cases. The adsorption in accordance with the instant invention is
performed such that the heat of the reaction of the reactive, charged
quicklime with water is dammed up until a spontaneous coking process
30 begins. For this purpose the product charged with the waste and
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,. .
1 containing the necessary amount of water, but not yet fully
reacted to calcium hydroxide, is placed in a ditch and covered
with a thin layer of dirt. After a period of time the contents
of this "minidump" cokes without any appreciable formation of
smoke; this will take place in hours or days depending on the
quantity~ What remains is an ash which can be used for ~ertiliz-
ing purposesO
The process of the invent'on, however, is usable not only
for rendering liquid wastes harmless; sludges can also be rendered
harmless, such as those, for example, which are produced by electro-
plating processes, or which are produced in the form of charged
bleaching earths in the bleaching of dark mineral oils or fatty
oils. To this end the alkaline earth oxide to be used in accord-
ance with the invention is stirred into the waste sludge in a
ratio of about 1:1, and is then further processed in the manner -~
taught by the invention.
Oils floating on water, as well as whole lakes of waste
oils representing ~queous multi-phase systems due to the presence
of ground water or rainwater, may be rendered harmless by the
method of the invention~ It is expedient to select again for
this purpose hydrophobized quicklime which has been pretreated with
somewhat larger amounts of hydrophobizing adjuvants, namely 1 to 5
wt-%, for the purpose of checking the formation of hydroxide as
long and as effectively as possible. The quicklime thus treated
is so hydrophobic that it floats on water.
It absorbs the oil at different rates according to
the origin of the oil, and sinks when it is charged with oil
After a period of time--hours, for example, on open waters~e
the chemical reaction with the water begins. This results in
the formation of calcium hydroxide which acts as an adsorptive
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7 . ~
1 agent which in statu nascendi fixes the oil in very finely
divided formO If the adjuvants serving for the pretreatment of
the ~uicklime are appropriately selected, this end product is
biodegraded after a period of time.
In combatting oil on deep waters, suitable oxygen
carriers can be added to the treated calcium oxide, which promote ~ -
not only chemical but also biological degradation. These include,
for example, nitrates and sulfates. They are locked onto the
particles after the reaction and cannot be eluted by the water
on account of the hydrophob~c shell.
EXAMPLE 1
For the elimination of 190 kg of used motor oil, 190
kg of quicklime containing lwt-% stearic acid and 0.2 wt-% sodium
diisooctylsulfosuccinate is mixed in with ito Then the calcium
oxide is reacted with 80 1 of waterO After about 30 minutes a ~ '
powdery, dry solid is obtained, one kilogram of which can still
absorb approximately one half kilogram of additional used oil.
EXAMPLE 2
100 kg of an electroplating sludge containing approx-
imately 20 wt-% of inorganic and organic components plus 80%
water can no longer be broken down to separate a clean aqueou~
phase on account of its consistency. 150 kg of pretreated quick-
lime (1% fatty acid) is stirred into it. The water that is present
is completely eliminated by the formation of hydroxide and by
evaporation due to the heat of reactionO A highly hydrophobic
powder forms which contains the components of the electroplating
sludge 90 fixed that the dumped product is no longer wetted by
surface or ground waterO
EXAMPLE 3
500 kg of a pasty emulsion containing 240 kg of various
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~(~4~1Z ~
1 organic substances is mixed by stirring with 500 kg of a fine
white lime pretreated with 5 wt-% of a mixture of stearic and
palmitic acid. After the reaction a dry3 dumpable powder is formed.
EXAMPIE 4
10 kg of an acid resin industrial byproduct is placed
in a kneader in which sulfuric acid present in the resin is first
neutralized with untreated quicklime. Then 4 kg of water and 10 kg
of fine white lime are added, the latter having been treated with
2 wt-% of a mixture of stearic and palmitic acid and 0O5 wt-% of
succinateO During the kneading only the resin is at first absorbed -
by the hydrophobized calcium oxide. The reaction with water does
not take place until after about 20 minutes of additional mechanical
treatmentO A dumpable powder results
EXAMPLE 5
100 kg of diesel oil is to be removed from a sea beach.
Aperoximately 100 kg of fine white lime plus 1 wt-% of a mixture
of stearic and palmitic acid and 0.5 wt-% paraffin oil is distrib-
uted over the beach by means of a spreader truck with a proportion-
ing apparatusO Then the ground is worked over with a rotary tiller
to such a depth that all of the diesel oil that has seeped into
the soil comes in contact with the pretreated fine white lime.
After 80 liters of water have been sprayed on the ground i5 tilled
again~ The end product that ~orms can be left in the ground since
it contains the diesel oil in very finely divided form, ioeO, in
easily decomposable form.
EX~MPLE 6
. .
One cubic meter of an emulsion from a special dump is ~ ~ -
treated in a tank equipped with a propeller type agitator with
600 g of a pretreated calcium oxide containing 5% of a nonylphenyl
polyglycol ether. Then the propeller agitator is operated for
- 13 -
l about l minute. The emulsion precipitates and in about 10
seconds a botb~m sludge has formed, the supernatant liquid
consisting of clear water. The purified aqueous phase is decanted -
and theremainder plus the sludge is filtered on a belt filterO
After the chemical reaction of the sludge the hydrophobic components ~ -
from the oily phase of the emulsion are so fixed on the adsorptive
agent that the end product can be dumped as a dry powderO
EXAMPLE 7
One cubic meter of a synthetic resin dispersion contain- ;
ing ap~ oximately 7% synthetic resin is stirred energetically with
l kg of pretreated calcium oxide (2~ paraffin oil) for several ;~
minutæ~SO The synthetic resin immediately precipitates and sinks ~-
on the adsorptive agent to the bottomO Filtration with a belt
filter yeilds a clarified aqueous phase and, after the chemical
reaction of the sludge, a dry powderO ~;
EXAMPLE 8
Two kg of an adsorptive agent consisting of ~uicklime
with 2 wt-% paraffin oil is stirred into 100 liters of an aqueous
neutral emulsion containing 2 kg of drilling oil. After a fewS-
minutes complete clarification tak0s place; the bottom sludge isremoved by filtration. The pH of the aqueous m0dium is at first 11,
but by brief gassing with air it is easily reduced.
EXAMPLE 9
! An aqueous emulsion from a machine shop (2 kg oil in 100 1
of water) is stirred with 2 kg of quicklime containing 6 wt-%
nonylphenoltetraglycol etherO Within 2 minutes complete clar-
ification of the emulsion takes placeO The solid end product is
removed by filtration
EXAMPLE 10
For the separation of a synthetic resin dispersion con-
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:' . -
1 taining 400 g of an epoxy resin per liter, the adsorber ~electedis a mixture or calcium oxide and magnesium oxide (10% MgO) con-
taining 1 wt-% paraffin oil and 1 wt-% nonylphenol tetraglycol
ether, 50 g of this adsorber is stirred into 1 liter of th~ ; -
synthetic resin dispersion. After 5 minutes clarification of the ~; ~
dispersion takes placeO The precipitated solid is removed by ~-
filtration.
EXAMPLE 11
'
Approximately 50 tons of crude oil which is lying on
arable land and some of which had seeped into the soil are rendered
harmless in the following manner: approximately 50 tons of pow-
dered calcium oxide containing 0O5 wt-% of a mixture of stearic
acid and palmitic acid plus 0.2 wt-% of paraffin oil very finely
distributed therein are deposited with a blower from a hopper truck
onto the surface of the crude oil (approximately 15 cm thick).
After about 30 minutes the free oil is absorbed by the treated
calcium oxide. This results in a thin slurry of treated oxide
and oil. Then the soil is worked with a rotary tiller to such
a depth that all of the percolated oil comes in contact with the
calcium oxide. In spite of the presence of moisture in the soil,
no reaction with the ground water takes place until all of the oil
has~been adsorbed in the mechanical working by the calcium oxideO
In the chemical reaction a dry and hydrophobic powder is formed
of the oil slurry in the soil. The end product, which was part-
ially on the surface of the ground and partially in the soil,
is buried with a bulldozer at a depth of about 50 cm under the
previously bulldozed subsoil, where tne oil, no longer recogniz-
able as a phase is accessible to biological decomposition after
the carbonization of the calcium hydroxide, due to its being ~ ;~
so very finely divided.
- 15 -
t^X`r~MPlE 12 1
From a pond whose surface is covered with an oil slick
about 10 cm thick, oil and water are pumped into a conical con~
tainer with a capacity of about 5 m e~uipped with a stirrer. -
At the bottom of the cone with the container has an outlet valve
In addition, a second outlet valve is installed on the con~ iner
such that, after the liquid above it has been drained, a volume
of 600 liters of liquid will remain. After the water-oil mixture
is pumped in ~e oil floats on the surface of the water in the
tankO Excess -water is let out of the tank through the side valve
and the pumping action is repeated until approxim tely 1600 liters *
of oil have collected in the tank (measured by a level mark
Underneath the oil the re~uired amount o~ 600 liters of water will
thus be present. By means of a screw conveyor 1600 liters of
powdered, pretreated (with 1 wt-% of a fatty acid mixture of C
to C18 acid) calcium oxide are added, and the stirrer is started
up. The calcium oxide at first rapidly mixes with the oil and is ~-
not wetted by the waterO Not until after 10 minutes of stirring
is the water also absorbed by the suspensionO A thin slurry formsO
This slurry is immediately released through the bottom valve into
a reaction vessel i~ the resultant product is to be further pro-
cessedJ or, if the end product is to be dumped, it is immediately
delivered to the floor of the dumpO Here the chemical reaction
takes place after a period of time (about 1/2 to one hour) and a
dry, hydrophobic powder forms in whichthe oily phase is no longer
recognizable.
.', .:~: ' ':
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