Year: 1886

page_text: Date of Application, 15th May, 1886.
Complete Left, 14th Feb., 1887.
Complete Accepted, 15th May, 1887.
I, Dr. REINHARD WEISS, of Charlottenburg, in the German Empire, Chemist, do
hereby declare the nature of this invention to be as follows:-
The aqueous solution of aluminium hypo-chlorite has long been used for bleaching
purposes under the name of Wilson's bleaching liquor, and has been valued as
considerably accelerating the bleaching process, and being less injurious to the fibre
than chloride of lime. Hitherto this solution of aluminium-hypochlorite has always
been produced by adding to a solution of aluminium sulphate an aqueous extract of
chloride of lime, by which process calcium-sulphate is precipitated and aluminium-
hypochlorite enters into solution.
This manufacture of bleaching liquor is very expensive owing to the use of two very
expensive raw materials, namely, chloride of lime and aluminium sulphate.
I have found that similar but still more energetic bleaching compounds of alumina
are produced by the direct action of chlorine on aluminates, especially sodium-
calcium and magnesium-aluminates, thus completely avoiding chloride of lime.
These bleaching compounds of alumina may be produced in the shape of a solution,
as well as in a solid shape. In the first case chlorine is conducted into a suitably
diluted solution of sodium-aluminate; or into water containing calcium-aluminate or
magnesium-aluminate, or both, in suspension. In the second case the chlorine is
caused to act on the solid aluminates, whereby the bleaching compound is obtained as
a solid mass, similar to chloride of lime.
The chlorine is allowed to act on the dissolved, suspended, or solid, aluminates as
long as an energetic absorption of the same is perceptible, and taking all precautions
usually observed in the manufacture of liquid and solid bleaching lime, (avoidance of
an excessive rise of temperature, and so forth). As soon as chlorine escapes from the
apparatus in large quantity, the transformation is complete, and the compound has
reached its maximum contents of active chlorine.
If the action of chlorine be continued, decomposition ensues, oxygen being liberated
and the total quantity of chlorine increases, while the quantity or proportion of active

page_text: chlorine decreases. This separation of oxygen manifests itself by a very energetic
development of gas and the production of froth if the alluminates used aro dissolved
or suspended in water.
According to my researches the reaction between chlorine and aluminate may be
represented by the following equation:
a) Sodium-aluminato (Al, O. 3 Na, 0) 3 [Al₂ (OH). 6 Na OH] + 30 Cl
(OCI) 3 9 Na OCl) + Al, Cl + 9 Na Cl + 15 H₂O.
2 (Al₂
(OH)3.
b) Calcium-aluminate (Al, O₂. 3 Ca O) 3 [Al, (O H¸. 3 Ca (O H),] + 24 Cl
2 (Al, (OH)
(OUI), 3 Ca OGI
он
+ Al, Cl + 3 Ca Cl₂ + 12 H₂O.
6
2
-
=
Quite analogous to equation b is the transformation of magnesium-aluminate.
The real constitution of the new bleaching compound is probably as difficult to
ascertain as the real nature of "chloride of lime."
The compounds of alumina produced by my process have a very rapid bleaching
action by giving off ozonized oxygen. Spun or woven fabrics, paper pulp and similar
materials may be bleached by it in a few days without being spread out, and the acid
baths, which in bleaching with chloride of lime follow the use of chloride of lime, are
dispensed with.
Dated this 15th dox of Mov 1986

page_text: COMPLETE SPECIFICATION.
Process for the Production of Alumina Compounds Applicable
for Bleaching.
I, REINHARD WEISS, of Oranienburg near Berlin in the Kingdom of Prussia and
German Empire do hereby declare the nature of this Invention and in what manner
the same is to be performed to be particularly described in and by the following
statement
The aqueous solution of hypochlorite of alumina has long since been used extensively
for bleaching purposes under the name of Wilson's bleaching liquid' and it has been
preferred on the grounds that it accelerates the bleaching process and that it
deteriorates the fibres of the tissue much less than chloride of lime. Up to the
present time this solution of hypochlorite of alumina has been prepared by mixing a
solution of sulphate of alumina with an aqueous extract of chlorido of lime, whereby
sulphate of lime is set free and precipitates and hypochlorite of alumina passes into
solution. This method of preparing the bleaching liquid is rather expensive becauso
of the use of chloride of lime and sulphate of alumina.
Experiments have proved that similar but still more energetic bleaching compounds
of alumina are produced by the direct action of chlorine on aluminates and especially
on aluminates of sodium of calcium, and of magnesium, whereby the use of chloride of
lime is entirely obviated. These bleaching alumina compounds may be prepared either
in the form of a solution or in a solid form. In the first case the chlorine is passed or
introduced into an appropriately diluted solution of aluminate of sodium or into water
in which aluminate of calcium or of magnesium or both is or are suspended. In the
second case the chlorine is made to act upon the solid aluminate, whereby the bleaching
compound is obtained in a form similar to that of chloride of lime.
As
The chlorine is allowed to act upon the aluminate, either when it is in solution,
suspended or solid as long as a perceptible absorption of it takes place and all
precautions, which are to be observed in the preparation of liquid of solid bleaching
lime, such as avoiding too high a temperature, &c., are also to be observed here.
soon as chlorine escapes in large quantities from the apparatus, the compound is
saturated with effective chlorine. A continued action of chlorine would now produco
decomposition by delivering an excess of oxygen; the total amount of chlorine would
increase, but the amount of effective chlorine would decrease.
When the aluminates are in solution or supended in water, the delivery of the
oxygen would take place with a vivid formation of gas and froth.
According to the experiments of the inventor, the action of the chlorine on an
aluminate seems to be as follows
--
8
a) with aluminate of sodium (Al, Na, O₁) 3 [Al, Na¸ O¸ + 6 H₂O] + 30 Cl
2 [Al² (OCI)3] + 9 Na OCI + Al² Cl³ + 9 Na Cl + 15 H³O.
=

page_text: The action of chlorine on aluminate of Magnesium is similar to that on aluminate of
Calcium. The real constitution of the bleaching compounds is just as difficult to
determine as that of chloride of lime. An aluminate of potassium, of barium, or of
zinc may also be treated as above.
The alumina compounds prepared in the manner hereinbefore described act as very
rapid bleachers in consequence of the delivery of ozonized oxygen so that, as
experiments on a large scale have proved, lace, tissues, paperpulp, and the like, may
be bleached thoroughly white in a few days without being spread out.
The use of acid baths following the chlorine baths when chloride of lime is employed
are also dispensid with. It is further of great importance that these alumina
compounds deteriorate the fibres much less than chloride of lime.
Having thus particularly described and ascertained the nature of my said Invention
and in what manner the same is to be performed, I declare that what I claim is:
The process for the preparation of bleaching alumina compounds by the direct action
of chlorine on aluminate of potassium, sodium, Calcium, Barium, Magnesium or Zinc,
either in the solid form, or dissolved or suspended in water, substantially as herein
described.
HUGHES, ELI & HUGHES,
76, Chancery Lane, London, W.C.,
Agents for the Applicant.