Improvements in the Manufacture of Sugar.
Year: 1894

page_text: Date of Application, 2nd Jan., 1894-Accepted, 3rd Feb., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by P. H. VANDER WEYDE and ORAZIO LUGO,
both of the City of New York, United States of America.]
Improvements in the Manufacture of Sugar.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
The invention consists in defecating and decoloring impure sugar solutions by
treating the same with nascent oxyhydrates of aluminum generated by the action
of an electric current passing through the solutions.
The sugar solution, preferably heated to about 200° F., is contained in a rather
shallow tank provided with electrodes of aluminum metal, or with anodes of
aluminum metal and cathodes of carbon or other material which will not react by
secondary action. The electrodes are connected in the usual way to the poles of
an electric generator, preferably a constant current dynamo machine, capable of
generating the required current. The E.M.F. of the current need not be more
than four or five volts and the quantity is proportional to the surface of the
electrodes in contact with the solution. When the electric current passes through
the sugar solution the positive electrodes or anodes of aluminum metal will be
actively attacked by the oxygen liberated on their surfaces, producing nascent
oxyhydrates of aluminum, while at the surfaces of the negative electrodes hydrogen
gas will be evolved, and any positive metal, such as iron, contained in the sugar
solution will be deposited on the negative electrodes. The result of this operation
is that noxious albuminoidal substances will be coagulated and rendered insoluble.
The liquor is then passed through filtering bags, and then through bone-black, and
afterwards is boiled down and crystallized in the usual way. The electrolytically
treated liquor being freed from much of the iron, gums and colouring matters, the
action of the bone-black will be more perfect, enabling a much larger quantity of
liquor to be treated by a given quantity of bone-black, and the bone-black will be
much more easily washed and more quickly revivified. The electrolysed liquor is
sterilized, preventing danger of fermentation, and will crystallize in a shorter time
and give better crystals, and the sugar being "free" will purge well and easily in
the centrifugal machine. The length of time the solution should remain under the
electrolytic action depends upon the kind of solution used and the quality of the
sugar desired-usually from five to ten minutes will suffice. The process is
applicable to the treatment of sugar solutions of all kinds, such as expressed juice
of sugar cane and beet-root, sweet water, glucose, molasses syrup and solutions
made by remelting sugar or made from refuse. It can be used with advantage
both at the plantation and the refinery.
If it is desired to avoid the use of bone-black it may be done by the addition or
presence in the electrolytic bath of salts of phosphorus and especially those of the
alkaline earths.
The oxyhydrates of aluminum produced by the electrolytic action are insoluble
in the sugar solution and act mechanically upon certain of the impurities present
and remain insoluble in them, but a part of the oxyhydrates of aluminum combine
with other impurities in the sugar solution and form soluble compounds.
phosphate in the bath combines with the soluble aluminum compounds and forms a
double salt, which is insoluble. The heat of the bath facilitates the aggregation
The

page_text: and coagulation of the insoluble compounds and brings them together, leaving the
liquor clear and decolored and capable of being easily filtered off, and the resulting
liquor, free from such insoluble substances, can be made into white sugar by
evaporation, without the necessity of treatment with bone-black. I prefer to use
the acid phosphate of lime produced by treating bone-ash, bone-black or spent
bone-black with sulphuric acid. The phosphate may be added to the bath of sugar
solution in either a liquid or solid condition, but the liquid is preferable as being
more convenient and effective. One part of phosphate with one thousand parts of
sugar solution makes an effective solution, but the proportions may be varied. In
ordinary practice a constant stream of sugar solution will be flowing into and out
of the electrolytic tank, and a constant and proportional addition of the phosphate
will be made.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated by my
foreign correspondents, I declare that what I claim is :-
1. The herein described improvement in the manufacture of sugar, which
consists in treating saccharine solutions with nascent oxyhydrates of aluminum
generated by an electric current.
2. The herein described improvement in the manufacture of sugar, which consists
in producing oxyhydrates of aluminum in a bath of sugar solution by the action of
an electric current, rendering the soluble oxyhydrates insoluble by a salt of
phosphorus, and separating the insoluble compounds from the sugar solution.
Dated this 2nd day of January 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.