Improvements in the Preparation of Bleaching Agents.
Year: 1889

page_text: Date of Application, 8th Apr., 1889
Complete Specification Left. 8th Jan., 1890-Accepted. 15th Feb.. 1890
PROVISIONAL SPECIFICATION.
Improvements in the Preparation of Bleaching Agents.
I DESMOND GERALD FITZ-GERALD of 6 Akerman Road Brixton, in the County of
Surrey, Electrician, do hereby declare the nature of this invention to be as follows:-
My invention relates to a former patent (No. 5542, dated 21 April 1886) granted
to me for the regeneration of Chromic Acid from exhausted solutions of this oxidant.
Now the objects of my present invention are: 1st, to utilize chromic acid, as
regenerated by the process described and claimed in the specification of the above
patent, for the production of Chlorine by the most economical and effective means;
2ly, to produce, by means of the liberated chlorine, alkaline or earthy hypochlorites of
any degree of strength suitable for bleaching vegetable fibres, tissues &c.; and, thirdly,
to generate oxygen by continuing the electrolytic process whereby chromic acid is
regenerated, with a view to bring this electrolytic oxygen into admixture with the
chlorine obtained by the agency of chromic acid, and to employ this mixture, or its
products, in the operation of bleaching.
In carrying out my invention, I preferably mix sulphuric acid with the chromic
acid (the solution of which may contain alkaline sulphate and other impurities) in the
proportion of 3 atoms of the former to 2 of the latter. To this mixture I add
hydrochloric acid in the proportion of 6 atoms. Chlorine is generated by the reaction
expressed as follows:-
= 2 H, Cr O, + 3 H, SO, + 20.
This oxygen may be brought into admixture with the chlorine liberated as above.
The mixture of the gases in the proportion indicated (two atoms of oxygen to six of
chlorine) or in other suitable proportions, may, in presence of moisture and, preferably,
of an alkali or alkaline earth in contact with the fibre, be utilized for bleaching
purposes.
Or the chlorine generated may be passed into an alkaline solution, or, preferably,
into water holding in suspension magnesia, (calcined magnesite) so as to produce an
alkaline or earthy hypochlorite of any requisite degree of strength.
T
1 14
1000

page_text: COMPLETE SPECIFICATION.
Improvements in the Preparation of Bleaching Agents,
I DESMOND GERALD FITZ-GERALD of 6 Akerman Road Brixton in the County
of Surrey Electrician do hereby declare the nature of this Invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :—
My Invention relates to a former Patent (No. 5542 dated 21st April 1886) granted
to me for the regeneration of Chromic Acid from exhausted solutions of this Oxidant.
Now the objects of my present Invention are firstly to utilize chromic acid as
regenerated by the process described and claimed in the Specification of the aforesaid
Patent for the production of chlorine by very economical and effective means.
Secondly to produce by means of the liberated chlorine, alkaline or earthy
hypochlorites of any degree of strength suitable for bleaching vegetable fibres tissues
and the like and thirdly to generate oxygen by continuing the electrolytic process
whereby chromic acid is regenerated with a view to bring this electrolytic oxygen
into admixture with the chlorine obtained by the agency of chromic acid and to
employ this mixture or its products in the operation of bleaching.
In carrying out my invention I mix sulphuric acid with the chromic acid (the
solution of which may contain alkaline sulphate and other impurities) in the pro-
portion of 3 atoms of the former to 2 of the latter. To this mixture contained in a
stoneware retort or other equivalent vessel I add hydrochloric acid in the proportion
of 6 atoms. When the mixture is heated Chlorine is generated by the reaction
expressed as follows:-
Now the electrolytic regeneration of Chromic Acid from the Chromium Sulphate
bus obtained may be said to take place according to the following equation :-
chromium into chromic acid Oxygen will be evolved thus:-
Cr, 3 SO, +10 H₂ O
1
10 H = 2 H, Cr O₁ + 3 H, SO + 20.
This electrolytic Oxygen may be brought into admixture with the chlorine liberated
as above. The mixture of the gases in the proportion indicatod (two atoms of Oxygen
to six of Chlorine) or in other suitable proportions may in presence of moisture and
preferably of an alkali or alkaline earth in contact with the fibre be utilized for
bleaching purposes. As the electrolytic Oxygen contains Ozone it adds materially to
the bleaching effect of the Chlorine.
Or the Chlorine generated may be passed into an alkaline solution or preferably
into water holding in suspension magnesia (calcined magnesite) so as to produce an
Alkaline or earthy hypochlorite of any requisite degree of strength.
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed I declare that what I
claim is
First. The production of Chlorine from a mixture of Chromic Acid, Sulphuric
Acid and Hydrochloric Acid in the proportions named this Chlorine being used as a
bleaching agent either directly by causing it to act upon the material to be bleached
in presence of moisture and of an Alkali or Alkaline earth or indirectly by the
production of a solution of Alkaline or earthy hypochlorite as described.
157

page_text: Second. The production substantially as described of a mixture of electrolytic
Oxygen and of gaseous Chlorine for the purpose of bleaching in presence of moisture
vegetable fibre or material impregnated with an Alkali or Alkaline earth.
Dated this 8th day of January 1800
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.