IMPROVEMENTS IN THE MANUFACTURE OF LIQUIDS FOR DECOLORIZING AND BLEACHING
Year: 1878

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF LIQUIDS FOR DECOLORIZING AND BLEACHING." A
communication from abroad by Thomas Simon de Dienheim-Brochocki, of
Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 12th June 1878.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN THE MANUFACTURE OF LIQUIDS FOR DECO-
LORIZING AND BLEACHING." [A communication from abroad by Thomas Simon de
Dienheim-Brochocki, of Paris, France.]
This Invention relates to the manufacture of chlorozone on a commercial scale,
and to the applications of the same for bleaching fibres, fabrics, paper pulp, and
other materials.
In bleaching with chlorine in the ordinary manner, the material to be treated is
brought into direct contact with the bleaching agent, whether it consists of dry
chlorine gas or an aqueous solution of hypochlorite of lime. In the first case, the
chlorine destroys the coloring matter by combining with its hydrogen, forming
hydrochloric acid (CI + H H CI) which as fast as it is formed, acts destructively
upon the ligneous matter, and the mass is not entirely bleached without being de-
stroyed to a great extent.
=
In the other case, the hypochlorous acid of the chloride of lime which is to act
by its oxygen and chlorine, however too intimately combined with its base to
have any great tendency to combine with the hydrogen of the coloring matter, and
it is only by the addition of acid which displaces it from its base that it is rendered
active (Ca O, CIO + Ca Cl) + A Ca O, A Ca Cl + CI O. The result is,―
1st. À loss in hypochlorous acid which escapes from the mass, owing to the
more or less energetic action of the decomposition of the hypochlorite.
=
2nd. An immediate injurious effect upon the fibre caused by the acid added.

page_text: 3rd. A more or less slow destructive action due to the lime which becomes
encrusted in the pores of the fibres in the form of insoluble salts incapable of being
entirely removed by washing.
The object of the present Invention is to avoid these disadvantages as well as
those attending the preparation of the coloride of lime bath itself. For this purpose
it is proposed to treat the material to be bleached with an aqueous solution herein
termed chlorozone, and which is composed chiefly of an alkaline chlorate or chlorite,
plus a proper excess of hypochlorous acid. This latter, in presence of the material
to be bleached, combines eagerly with the hydrogen of the coloring matter acting
on it immediately by its two elements, chlorine and nascent oxygen or ozone,
without the intervention of any acid.
The oxygen forms water with the hydrogen of the coloring matter, and the
chlorine forms hydrochloric acid, which, without acting on the fibre, combines with
the alkaline base of the solution, setting free a fresh portion of the oxygen which in
turn acts on the coloring matter. The desired object is thus attained, as, besides
avoiding the objections of the chloride of lime bath, this great advantage is obtained
that, with an equal quantity of chlorine and one-half less of base, the chlorozone bath
will take up three times as much hydrogen from the coloring matter as the chloride
of lime bath.

page_text: containing the alkaline solution, and consist simply of vats or other vessels hermetically
closed. Next in order to these is a small glass bottle E, also closed and filled to
three-fourths of its capacity with water colored with indigo blue; lastly, H is the
air pump; F is the bleeching vat provided with an agitator.
It will be evident that when it is desired to use a gaseous acid, carbonic acid gas
for example it would be supplied.
The vessels B, C, D, E, are, like a Woulfe's apparatus, placed in communication
with each other by pipes g, g, f, which rise from the top of each vessel, and dip
down nearly to the bottom of the next, and finally connected by a pipe / with
pump H, which draw air through the whole series of apparatus.
Suppose it is desired to form a bath of chlorozone containing 1000 litres of hypo-
chlorous acid or 2000 decolorizing units, and that the elements for its production
are chloride of lime and hydrochloric acid, the vessel A is charged with 80 kilo-
grammes of hydrochloric acid diluted with water to about 12° Beaumé; and vessel
B is charged with 20 kilogrammes of chloride of lime at 100 chlorometric degrees;
the vessels C, D, are charged with a solution of 3 kilogrammes of soda in 500 litres
of water (250 litres in each vessel); and lastly, the bottle E is filled with water
colored with indigo blue. The cock of vessel A is then opened, and the acid
allowed to flow out slowly, and the pump H set in motion rather slowly in
order to avoid pumping out the gas.
Instead of a pump an exhauster may be used, working with a jet of steam or
water like a Giffard injector; and vessel A may be replaced by an electric battery,
whose poles are placed in vessel B.
The draught of air has the advantage,―
1st. Of transforming the chlorine gas resulting from the more or less energetic
re-action of its oxygen in the vessel B into hypochlorous acid.
2nd. Of moderating the violence of this re-action.
3rd. Of preventing any leakage, as well as any possible explosion of the apparatus
by reducing the pressure of the gases to a minimum.
And, 4th. Of facilitating the complete decomposition of the chloride of lime by
the constant agitation and the extraction from the generator of the last traces of
the hypochlorous gas.
The hypochlorous acid in traversing the liquid contained in the vessels C, D,
saturates them in unequal proportion, C receiving the maximum, and D the
minimum degree of saturation. The base held in solution in the former is trans-
formed into chlorate, and that in the second into hypochlorite of soda. If the blue
liquor in E be quickly decolorised it shows that gas is being drawn out with the
air, and that the exhaust should be moderated. When saturation is complete.
that is to say, when the whole of the acid has run out from vessel A, the exhaust is
stopped, after which the contents of the apparatus C, D, are discharged through
cocks i, j, and india-rubber pipes k, l, into vat F containing the materials to be
bleached.
The chemical action of this bath upon the coloring matter is very rapid, being
almost instantaneous, but never injurious, as it is principally due to the action of
nascent oxygen, as is shown by the following re-action (the water used for the
solution being understood):
[ (Na O, Cl 05 + 3 Cl 0)
(Na O, Cl 05 + Na O, CIO
+ Na O, CI O
+ Na O, Cl O + -
(2 Na Cl
(2 Na Cl
(3 Na Cl
+ (Na O, CI O + Na Cl)] + X. H =
+ Na Cl + 3 HO + 3 HCI) + X
6 HO3 CIO) + X
9 HO+3 H Cl) + X
11 HO 3 HCI) + X
+
-
6 H
6 H =
12 H
14 H
The stirrer in vat F should be at once set in motion, as the contact of air and the
movement of the materials greatly assist the bleaching. After this bleaching has

page_text: same pipes k, l, as were used for empting them, the cocks on the respective com-
municating pipes q, g, f, being suitably regulated for the purpose. Thus, if the
materials to be bleached require to be acted on repeatedly, each time for a short
period, rather than by the more energetic action of a single passage through the
bath of chlorozone, this may be readily done by this system of successive decantation
and saturation of the bleeching liquid.
In some cases it would even be advantageous to saturate the alkaline liquor in
presence of the material to be bleached, for which purpose the vat C would be
arranged to receive the material. In this case the agitation of the air replaces the
action of the stirrer. The vat D would in all cases receive the gas escaping from
the vat C.
The advantages of the Invention may be summed up as follows:--
1st. The objections to the chloride of lime bleaching bath are avoided.
2nd. The acids added to strengthen the re-action of the bath to the detriment of
the fibre and loss of Hyprochlorous acid are dispensed with.
3rd. The direct contact of the material to be bleached with the lime, which is
deposited in the fibres in the form of insoluble salts, cannot be removed by washing,
and in time destroys the fibre, is avoided.
4th. The bleaching action is most rapid and never destructive, and thus both
time and raw material are saved, as well as expense.
5th. All intermittent washings with water and acids between the several
successive immersions in the bleaching bath are dispensed with, one single bath of
chlorozone of suitable strength being capable of bleaching any vegetable matter
without a repetition of the treatment, whereby an economy in labour, machinery,
apparatus, acids, water, and fuel is effected.
6th. The residue of the bleaching bath is utilized, whereas that of a chloride of
lime bath is useless.
Manufacture of Concentrated Chlorozone. If instead of the weak solution a
concentrated alkaline solution be placed in vessels C, D, and then saturated as before
described, taking into account that in this case proportions equal to the equivalents
of the hypochlorous acid and of that of the base with which it is to combine are
necessary, a certain excess of the latter being even allowable, a pure alkaline hypo-
chlorite should, according to theory, be obtained Na 0+ Cl 0 = Na O, CI 0, which
is a very unstable salt; but owing, however, to a continuous re-action under the
influence of a constant air current in conjunction with that of the current of hypo-
chlorous acid itself, the final product of the operation is a triple salt, and, according
to circumstances, conforms to one of the following formulæ :-
(1) 3 Na + 3 CI O
(2) 5 Na 0+ 5 Cl O
=
=
both having a decolorizing power
Na O, CI O3 + Na O, CI O + Na Cl.
Na O, Cl 05 + 2 Na O, CI O + 2 Na Cl.
equal to that of the pure hypochlorite, but being
of much greater stability and neutrality than the latter. Their action on the
coloring matter has double the power of a common hypochlorite obtained by a
current of chlorine, and not by a current of hypochlorous acid,-
6 Na O+ 6 CI O = 2 (Na O, Cl³ + Na O, CI O + Na Cl) + X H
12 HO + X 12 H.
= 6 Na Cl +
6 Na O + 6 Cl =
3 (Na O, CI O + Na Cl) + X H = 6 Na Cl + 6 HO + X-6 H
It should be observed that during the saturation of the alkaline liquor by the
hypochlorous acid the more the liquor is concentrated for the purpose of obtaining
a more complete saturation the more it should be cooled, for which purpose the
vessels B, C, D, should be placed in a suitable refrigerating apparatus, by which the
(1) 3 Na + 3 Cl O
(2) 5 Na 0+ 5 C1 O
=
Na O, CI 0³ + Na O, CI O + Na Cl.
=
Na O, CI 0³ + 2 Na O, CI O + 2 Na Cl.
both having a decolorizing power
equal to that of the pure hypochlorite, but being
of much greater stability and neutrality than the latter. Their action on the
coloring matter has double the power of a common hypochlorite obtained by a
current of chlorine, and not by a current of hypochlorous acid,―
6 Na O+ 6 CO
=
2 (Na O, Cls + Na O, C O + Na Cl) + X H = 6 Na Cl +
12 HOX - 12 H.
-
6 Na O + 6 Cl =
3 (Na O, CI O + Na Cl) + X H = 6 Na Cl + 6 HO+X-6 H
It should be observed that during the saturation of the alkaline liquor by the
hypochlorous acid the more the liquor is concentrated for the purpose of obtaining
a more complete saturation the more it should be cooled, for which purpose the
vessels B, C, D, should be placed in a suitable refrigerating apparatus, by which the
temperature of the liquor is not allowed to exceed + 25° C.
It should also be observed that if for each equivalent of hypochlorite to be
decomposed two equivalents of pure hydrochloric acid be introduced into generator B
chlorine gas will be evolved instead of hypochlorous acid,-
100 CLO + Ca C + 2 CL = 2 C C+
L D A

page_text: The same phenomenon would take place if the action of the air current were
suspended. It is thus indispensable in order to produce hypochlorous acid to
operate only in conjunction with the air current, and to employ a single equivalent
of acid diluted with water; or one equivalent of hypochlorite, or three equivalents
of hydrochloric acid to one equivalent of chlorate.
(Ca O, C O + Ca CI) + A = 2 Ca O, A + CI O.
(M 0, C1 0³) + 3 H CI
= M CI 3. HO + 3 CI O.
The operation is very rapid, simple, and regular. It is performed cold, thus
avoiding all risk of bursting retorts, or of decomposing the product itself, which is
almost inevitable in the case of its concentration. When the concentration is
brought to 120° the product is readily crystallizable at a low temperature.
It is possible to suspend the production of hypochlorous acid at any moment, and
thus arrest the operation when in full swing without danger of causing any waste
of gas by simply closing cock 6 of vessel A, whereupon the flow of acid ceasing
the production of hypochlorous gas in generator B is arrested.
Owing to its superior qualities and the peculiar advantages attending its manu-
facture, the cost of the chlorozone is much less than that of the product obtained
by the processes now employed for the manufacture of alkaline hypochlorites.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
12th December 1878.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN THE MANUFACTURE OF LIQUIDS FOR DECO
LORIZING AND BLEACHING." A communication from abroad by Thomas Simon de
Dienheim-Brochocki, of Paris, France.
This Invention relates to the manufacture of chlorozone on a commercial scale,
and to the applications of the same for bleaching fibres, fabrics, paper pulp, and
other materials.
In bleaching with chlorine in the ordinary manner the material to be treated is
brought into direct contact with the bleaching agent, whether it consists of dry
chlorine gas, or of an aqueous solution of hypochlorite of lime. The former is only
applicable for bleaching paper pulp, and in that case the chlorine destroys the
coloring matter by combining with its hydrogen, forming hydrochloric acid,
Cl + H =
H CI, which as fast as it is formed acts destructively upon the ligneous
matter, and the mass cannot be entirely bleached without being destroyed to a
great extent.

page_text: In the other case the hypochlorous acid of the chloride of lime, which is to act by
its oxygen and chlorine, is however too intimately combined with its base to have
any great tendency to combine with the hydrogen of the coloring matter, and it is
only by the addition of acid, which displaces it from its base, that it is rendered
active. The result is,-
1st. A loss in hypochlorous acid which escapes from the mass owing to the
more or less energetic action of the decomposition of the hypochlorite.
2nd. An immediate injurious effect upon the fibre caused by the acid added.
3rd. A more or less slow destructive action due to the lime, which becomes
encrusted in the pores of the fibres in the form of insoluble salts incapable of being
entirely removed by washing.
As regards the alkaline hypochlorites, known in commerce under the name of
bleaching liquid or Labarraque's fluid, they, although preferable to chloride of lime,
are also attended in bleaching with objections which render their employment
difficult. Whether weak or concentrated relatively to their richness in decolorizing
power, they are always very alkaline, and consequently too corrosive, and bleach
with difficulty without the aid of an acid to stimulate the re-action and neutralise
the excess of alkali. The concentrated product being only obtained by a tedious,
objectionable, and troublesome process, its cost is necessarily very high.
The following are the two methods known and used in commerce for the manu-
facture of these hypochlorites :-
:-
1st. Saturation of an alkaline lye (carbonate or oxide) by a current of gaseous
chlorine obtained with peroxide of manganese, according to any known re-action.
2nd. Double decomposition of the solution of chloride of lime and of an alkaline
carbonate.
In the first case the operation of manufacture requires 24 hours. The base should
be considerably in excess in the solution, otherwise decomposition will certainly
take place. It is difficult to give the product marking 25° to 30° B., a richness in
chlorine exceeding 25 to 30 chlorometric degrees, which leaves about one-third of
base in excess. Beyond this limit the absorption of chlorine becomes difficult, the
heating of the material, notwithstanding refrigeration, is unavoidable, and its more
or less rapid decomposition ensues. The product moreover is most unstable, and
loses very rapidly the greater portion of its decolorizing power; it is dear, very
caustic, and difficultly conveyable during the summer season.
In the second case, neither the chloride of lime nor the alkaline carbonate being
soluble, except to a limited extent at a cool temperature necessary however in this
case, the product obtained by their double decomposition is still poorer in deco-
lorizing principles than the product obtained by the method above referred to. The
operation itself, though simple in principle, becomes long and tedious on account of
the many washings of the precipitate. After a high degree of concentration it yields
a product marking 25 chlorometric degrees, and very impure, as it contains in its
solution a considerable quantity of chloride of calcium, which in the bleaching
operation is found again in the fibres in the form of carbonate or sulphate of lime,
according to the mode of treatment adopted. Here again, as in the preceding case,
the product is too alkaline, most unstable, and too costly.
Different results at a much cheaper rate may be obtained in bleaching with
chlorozone produced by a simple, rational, and inexpensive operation. The chlorozone
may be acid or alkaline, liquid or solid. It is in either case obtained in the cold by
saturating a caustic alkaline lye by a current of hypochlorous acid in conjunction
with a current of air.
It is well known that by decomposing a hypochlorite or chlorate by an acid or
an electric current, free hypochlorous acid or chlorine is evolved, according to cir-
cumstances.—

page_text: It is also known that the oxygen of the air in the nascent state combines with
chlorine gas, and forms hypochlorous acid, and that water of the ordinary tempera-
ture dissolves two hundred times its volume thereof.
It is also known that a current of hypochlorous acid passing in excess through
the alkaline solution (oxide, carbonate, or chloride) converts these salts into
chlorate.
Starting from these premises, if, on the one hand, hypochlorous acid be produced
by the decomposition of a hypochlorite or chlorate by means of an acid in conjunc-
tion with a current of air, and if on the other hand an alkaline solution, such as of
soda, for example, be saturated with this gas, it is evident that the product obtained
will be the chlorozone in question, which is acid or alkaline, according to the pro-
portion of the equivalents of the base in solution, and of the hypochlorous acid by
which it is saturated. According to theory the result of this re-action should be a
pure alkaline hypochlorite, which is a very unstable salt, but owing however to a
continuous action, under the influence of a constant current of air, the final product
of the operation is a triple salt, and according to circumstances conforms to one of
the following formulæ :-
Acid chlorozne :-Na 0+X HO + (200
(199X) CIO.
X) CIO Na O, CIO³ + X H O +
Alkaline liquid dº:-(4 Na O + X HO) × 4 CIO = (Na O, ClO3 + 2 Na O, CIO
× Na Cl) + X H O.
Both may have a very high decolorizing power.
It evident that if the current
of air drawn in during the manufacture be shut off, and if the quantity of decom-
posing acid be halved, chlorine gas will be evolved and not hypochlorous acid.
The final product will then be a common hypochlorite.
Example: (MO, CIO + M CI) + 2 A 2 MO, A 2 Cl
=
2 Cl 2 Na O =
Na O, CIO+Na Cl.
The alkaline chlorozone, marking 40° B. and 100 to 120 chlorometric degrees,
becomes easily crystallizable at a low temperature, but the crystals obtained are
melted easily by the least heat. Its employment is on that account impracticable. The
contrary is the case if the chlorozone be solidified by the absorption of its excess of
water by means of a hygrometric alkaline salt. In this case neither the too low
temperature nor the maximum chlorometric richness of the chlorozone are exigible.
Dried carbonate of soda, for example, added to the chlorozone in proportions varied
according to the density of the liquid at a temperature of +6° to + 8° C. forms a
compact mass capable of being moulded or granulated, and which is the harder, as
the temperature of the operation was lower. It only softens at a persistent heat
at 20° C. Hardened anew by lowering the temperature, it resists ambient heat
better and losses none of its decolorizing qualities if it is kept protected from air,
light, and humidity. The liquid alkaline chlorozone marking 30° B. and 50 chloro-
metric degrees, is very stable, and may be kept several months; it is therefore
easily conveyable.
For equal quantities of base and chlorine the decolorizing power of chlorozone is
double that of an alkaline bypochlorite of commerce obtained, as before mentioned,
by a current of chlorine,
H) H.
Example:-Chlorozone: 4 Na 0+ 4 CIO = (Na O, CIO³ + 2 Na O, CIO + Na
CI) + X H (4 Na Cl + 8 H O) + (X
Hypochlorite-4 Na O + 4 CI
=
+4 HO)+(X - 4) H.
=
1
2 (Na O, CIO + Na Cl) + X H = (4 Na Cl
Its use is valuable for dyers and bleachers of linen, ns besides its decolorizing
power it possesses, owing to its alkaline base, saponifying qualities. As regards
acid chlorozone, it should be used immediately after being made, so that it is
necessary that it should be manufactured on the spot. It is chiefly intended for
bleaching raw vegetable matters, such as paper pulp, cotton, flax, hemp, and other
fibres. Compared with chloride of lime, it should be observed that chlorozone, with

page_text: an equal quantity of chlorine and three-fourths less base will take up three times
as much hydrogen from the coloring matter as the chloride of lime.
Example, Chloride of lime: 4 Ca O + 4 Cl = 2 (Ca O, CIO + Ca Cl) + X H =
(Ca Cl 4 HO + (X - 4) H.
=
=
Acid chlorozone: Na 0+ 4 C10 = (Na O, CI 05 + 3 ClO) + X H Na Cl +
9 HO3 H CI) + (X
12) H.
In this latter formula the water used for the solution is understood as well as the
action of the air introduced, furnishing oxygen to the chlorozone.
In the first case there is 4 H, and in the second case 12 H taken from the
coloring matter, as shown by the following re-action :-
(NaO, CIO +3CIO, HO) + XH = (NaO, C105 + 6HO + 3H CI) + (X - 6) H =
(Na Cl + 9HO + 3CIO) + (X - 6) H = (Na Cl + 12HO + 3H Cl) + (X - 12) H.
The apparatus employed in the manufacture of chlorozone is most simple, inex-
pensive, and requires but little room; it consists,-
1st. Of a hypochlorous acid gas generator, a closed vessel of about 150 litres
capacity.
2nd. Of two saturators, also closed, of about 200 litres capacity.
3rd. Of an air pump or exhauster working by a jet of steam or current of
water.
The whole of these apparatus are connected together by a system of tubes, fixed
and arranged as hereafter described.
The accompanying Drawing represents by way of example only the apparatus
which is employed in preparing the bath, the decomposing agent being a liquid
acid.
A is the receiver to contain the acid, provided with a graduated gauge a for indi-
cating the quantity of liquid in the receiver, and also that which has passed out, and
a cock 6 for regulating the flow. B is a receiver for the hypochlorite or chlorate to
be decomposed by the acid supplied from the vessel A, and introduced at the centre
of B in a fine stream through a pipe c, which also gives admission to air. The
mouth 0, 0, of the vessel, through which it is charged, is hermetically sealed, and
the vessel is provided with a cock d for emptying it; this vessel is the generator of
the hypochlorous acid. The next two apparatus C, D, are saturators containing the
alkaline solution, and consist simply of vats or other vessels hermetically closed.
Next in order to these is a small glass bottle E, also closed, and filled to three-
fourths of its capacity with water colored with indigo blue. Lastly, H is the air
pump; F is the bleaching vat, provided with an agitator.
It will be evident that when it is desired to use a gasecus acid, carbonic acid gas,
for example, it would be supplied in the usual way.
The vessels B, C, D, E, are, like a Woulfe apparatus, placed in communication
with each other by pipes q, g, f, which rise from the top of each vessel and dip down
nearly to the bottom of the next, and are finally connected by a pipe / with pump
H, which draws air through the whole series of apparatus.
Suppose it is desired to form a bath of chlorozone containing 2,000 litres of
hypochlorous acid, and that the elements for its production are chloride of lime,
and commercial sulphuric acid, the vessel A is charged with 20 kilogrammes of this
acid diluted with water to about 12° B., and vessel B is charged with 20 kilo-
grammes of dry chloride of lime to 20 to 30 litres of water; the vessels C, D, are
charged with a solution of 3 kilogrammes of soda in 500 litres of water (250 litres
of the solution in each vessel); and, lastly, the bottle E is filled with water colored
with indigo blue. The cock 6 of vessel A is then opened, and the acid allowed to
flow out slowly, and the pump H set in motion rather slowly in order to avoid
pumping out the gas.
Instead of a pump an exhauster might be used, working with a jet of steam or
water, like a Giffard injector; and vessel A may be replaced by an electric battery
whose poles are placed in vessel B.

page_text: The draught of air through the generator and saturators has the advantage,-
1st. Of assisting the production of hypochlorous acid in the generator by a portion
of its oxygen, which goes to produce this re-action.
2nd. Of moderating the chemical re-action in the generator.
3rd. Of preventing any leakage of gas as well as any possible explosion of the
apparatus by reducing the pressure of the gases to a minimum.
And 4th. Of facilitating the completion of the re-action by which the hypo-
chlorous acid gas is produced in the generator, and the extraction from the generator
of the last traces of the said gas.
The bypochlorous acid in traversing the liquids contained in the vessels C, D,
saturates them in unequal proportions, C receiving the maximum and D the mini-
mum degree of saturation. The base held in solution in the former is transferred
into chlorate, and that in the second into hypochlorite of soda. The excess of hypo-
chlorous acid gas will only be absorbed by the water of the solution in the first
saturator. The operation lasts about one hour. If the blue liquor in E be quickly
decolorized, it shows that gas is being drawn out with the air, and that the exhaust
should be moderated. When saturation is complete, that is to say, when the whole
of the acid has run out from vessel A, the exhaust is stopped, after which the cou-
tents of the apparatus C, D, are discharged through cocks i, j, and india-rubber pipes
k, l, into vat F, containing the materials to be bleached, which have previously been
suitably scoured and washed with acids and water.
The chemical action of this bath upon the coloring matter is very rapid, being
almost instantaneous, but never injurious, as it is principally due to the action of
nascent oxygen, as is shown by the following re-action (the water used for the
solution being understood).
[(Na O, CI 05 + 3 C10
+
(Na O, CI 05 +
(Na Cl
Na Cl
+
Na O, ClO +
+ Na O, CIO +
Na O, CIO +
HO) + (Na O, CIO
5 HO + 3 HCl)
(2 Na Cl
+
8 HO + 3 CIO)
11 HO + 3 HCl)
13 HO+3 HCI)
+
+ HO)] + XH
+(X6) H-
(X - 6) H =
+(X
=
+(X
-
12) H =
14) H
The stirrer in vat F should be at once set in motion, as the contact of air and
the movement of the materials greatly assist the bleaching. After this bleaching
has been effected the residues of the bleaching vat may be advantageously employed
for preparing the lye, or may be recovered and saturated afresh with hypochlorous
acid. The vessels C, D, may by the suction of the pump be charged through the
same pipes k, l, as were used for emptying them, the cocks on the respective com-
municating pipes q, g, f, being suitably regulated for the purpose. Thus, if the
materials to be bleached require to be acted on repeatedly each time for a short
period, rather than by the more energetic action of a single passage through the
bath of chlorozone, this may be readily done by this system of successive decantation
and saturation of the bleaching liquid..
In some cases it would even be advantageous to saturate the alkaline liquor in
presence of the material to be bleached, for which purpose the vat C would be
arranged to receive the material; in this case the agitation of the air replaces the
action of the stirrer. The vat D would, in all cases, receive the gas escaping from
the vat C; it is obvious that after the action of the chlorozone the bleached
materials should be carefully washed. The bleaching action of ozone is accompanied
also by a peculiar phenomenon, viz., that the ligneous matter is strengthened,
i. e., the resistance of its fibres in the same way as in grass bleaching. The cost of
chlorozone per 100 kilos. of material to be bleached does not exceed that of chloride
of lime now used for bleaching an equal quantity of material, and the advantages
of the former over the latter are as follows:-
1st. The long and objectionable preparation of the chloride of lime bleaching
bath is avoided.
2nd. The acids added to strengthen the re-action of the bath to the detriment of
the fibre and the loss of hypochlorous acid are dispensed with.
3rd. The direct contact of the material to be bleached with the lime (which is

page_text: deposited in the fibres in the form of insoluble salts cannot be removed by washing,
and in time destroys the fibre) is avoided.
4th. The bleaching action is most rapid and never destructive, and is accom-
panied by the saponifying action due to the soluble alkaline base, and thus both
time and raw material are saved as well as expense.
5th. All intermittent washings with water and acids between the several
successive immersions in the bleaching bath are dispensed with, one single bath of
chlorozone of suitable strength being capable of bleaching any vegetable matter
without a repitition of the treatment, whereby an economy in labor, acids, water,
machinery, apparatus, and fuel is effected.
6th. The residue of the bleaching bath is utilised, whereas that of a chloride of
lime bath is useless.
Besides the above advantages the substitution product, which is always the
result of bleaching with chloride of lime, and which injures the purity of the white
obtained, is almost entirely absent when the chlorozone is properly employed. This
is readily explained, since the substitution product results from the combination of
chlorine with some principles of the coloring matter, whereas chlorozone bleaches
only by the direct action of the ozone, which is its chief component, while the
chlorine, which is present in a much smaller proportion, combines with the
alkaline base of the solution and forms soluble salts, which may be eliminated by
washing.
By the process of this Invention a common alkaline bypochlorite, such as that
known as eau de javelle or bleaching liquid, may also be obtained, but much more
economically, as the operation takes two hours only, instead of from 18 to 24 hours, as
in the ordinary processes. Moreover, a greater chlorometric richness is obtained and
the cost of fuel is saved, as the operation is performed in the cold. The product
obtained is more stable and does not contain any alkali in excess, nor any trace of
chloride of calcium, and the cost of production is much less.
Having described the nature of the Invention, and the manner of performing the
same, I declare that what I claim as the Invention to be protected by the herein-
before in part recited Letters Patent is,―
1st. The manufacture of a new acid or alkaline product herein called chlorozone,
i. e., an oxygenated and chlorous decolorizing agent having for a base a soluble
alkali or alkaline earth, and obtained by the process herein-before described, which
consists in saturating an alkaline solution by a more or less considerable current of
hypochlorous acid gas (produced by the decomposition in the cold of hypochlorites
or of chlorates by an acid) and a current of air, essentially as herein described.
2nd. The manufacture by the same process of a coinmon alkaline hypochlorite,
more or less concentrated, with or without the use of a current of air.
3rd. The employment or application in bleaching generally of chlorozone, whether
in an acid or alkaline condition, and at any alkalimetric or chlorometric strength,
and whether liquid or solid.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Twelfth day of December, in the year of our Lord One
thousand eight hundred and seventy-eight.
A. M. CLARK. (L.S.)