Improvements relating to the Decoloration and Purification of Liquids.
Year: 1898

page_text: Date of Application, 29th Mar., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improvements relating to the Decoloration and Purification of
Liquids.
I, PIERRE PESSÉ, of Rue de la Gare, Marcq-en-Baroeul, in the Republic of
France, Engineer, 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:
This invention relates to a process of decoloration and purification of liquids
by means of animal charcoal in a pulverulent state employed repeatedly without
previous revivification.
Hitherto animal charcoal serving to decolorize liquids has been employed either
in a more or less coarsely granulated condition, the liquid to be decolorized being
caused to pass over it, or in a pulverulent state often with the addition of blood or
albumen, the whole being subsequently separated by filtration. In other cases,
the animal charcoal in a granular state is crushed after undergoing revivification,
the powder thus obtained is employed as a decolorant and then separated by filtra-
tion; it is subsequently utilised as a manure or employed for other purposes.
The employment of the charcoal in a granular state necessitates keeping a very
considerable stock, in addition to which a large quantity of water is required for
washing purposes whilst the loss of the substances to be purified is large owing to
the fact that a considerable quantity of such substances remain in the washing
water and in the charcoal itself. Black in the state of powder (as hitherto em-
ployed) gives only a defective and relatively expensive purification, because it is
employed once only and in such a manner as to exert only a simple or single effect.
My improved process consists in decolorizing economically by means of powdered
animal charcoal, liquids such as the juices and syrup of the sugar and refining
industries, glucose syrup, molasses and the like, and in general all those liquids
upon which animal charcoal exerts any action.
The process itself is as follows:
The liquid to be decolorized, whether acid, alkaline or neutral, according to
circumstances, is mixed with powdered animal charcoal in variable proportions, at
a temperature which is determined for each different product and the mixture is
allowed to digest in a mixing apparatus of any suitable description which main-
tains the charcoal in constant suspension in the liquid. The time allowed for this
digestion varies with the result to be produced and the density and temperature
of the liquids. The mixture is then passed through a filter press or other
similar filter and afterwards through a second filter of any suitable
kind which is intended to retain the last traces of the charcoal in suspension in the
liquid. The cake contained in the filter press is slightly washed in water and
then dried by steam; it may be submitted to one such washing only or it may
even not be washed at all, according to circumstances. The filter is then dis-
mounted and the cake is employed in the following manner: I have ascertained
that this charcoal which has already been used, still possesses considerable purify-
ing and decolorizing power and this without any revivification. I take such
charcoal then, and utilise it directly for a treatment similar to that above described,

page_text: but with a liquid more impure and more coloured than that with which it was
originally employed.
In the sugar manufacturing or refining industries it may, for example, be
employed with the syrupy water obtained from the residues or drainings of the
boiled mass from the first operation, or from sugar refining operations and these
drainings or residues so purified serve for the manufacture of products suitable for
consumption and very white, such as granulated and muscavado or bastard sugars
and so forth, or it may be used direct in the first stage of the operations.
Generally speaking, however, it is preferable to employ it in a double or triple
action upon the original syrup, in the following manner.
The original syrup is first of all treated, in the manner above described, with the
cakes of charcoal arising from a preceding operation.
By means of this operation two results are obtained
1st. The syrup undergoes considerable decoloration.
2nd. It is freed from gums and organic matter which oppose decoloration.
The mixture is filtered through a filter press, and a syrup which is already highly
refined is obtained. Under these conditions the syrup is more readily decolorized;
it is mixed with either fresh or revivified charcoal passed through the filter press
and then through a second filter. The cake resulting from this operation (whether
washed or not) serves to purify syrup in its initial state; the cake coming from
syrup treated in its initial state is washed and then revivified.
If it is desired to carry out a three-fold process, the operation is performed a
third time, the charcoal passing through the syrups in inverse order so as to ensure
methodical action.
In this manner, with the same quantity of charcoal and the same outlay a degree
of purification which is more than twice as great as that which would be secured
by causing the charcoal to act once only, is obtained; because the first action,
whilst effecting decoloration itself, has likewise the result of causing the syrup to
be more susceptible to the action of the charcoal in the second operation.
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The employment of pulverised animal charcoal in a series of operations
without intermediate revivification, for the purification and the decoloration of
liquids; that is to say, when the charcoal has already served once, it may be
employed a second and even a third time for purifying and decolorizing liquids
more impure and more colored than that which it has already served to purify
and decolorize, and this without any intermediate revivifying process being
necessary.
2. The combinations of the double acting operation above described and
applicable to the syrups or juices of the sugar manufacturing and refining
industries.
Dated this 20th Joof 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.