IMPROVEMENTS IN THE MANUFACTURE AND REFINING OF SUGAR
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BIRKMYRE, of Fulbeck Cottage, Hampstead, Chemist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by.
Her Royal Letters Patent under the Great Seal of the United Kingdom
of Great Britain and Ireland, bearing date at Westminster, the Twelfth day
of December, One thousand eight hundred and forty-nine, in the thirteenth
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said William Birkmyre, my exors, adñiors, and assigns, Her
especial license, full power, sole privilege and authority, that I, the said
William Birkmyre, my exors, adiñiors, and assigns, or such others as I, the
said William Birkmyre, my exors, adññiors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the
years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed, in
the Islands of Guernsey, Jersey, Alderney, Sark, and Man, and in all Her
Majesty's Colonies and Plantations abroad, my Invention of "IMPROVEMENTS
IN THE MANUFACTURE AND REFINING OF SUGAR;" in which said Letters Patent
is contained a proviso that I, the said William Birkmyre, shall cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, by an instrument in writing under my band and
seal, to be inrolled in Her Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso,31, the said
William Birkmyre, do hereby declare that the nature of my Invention, and
the manner in which the same is to be performed, is described and ascertained
as follows (that is to say):-
-
Now the nature of my Invention is chiefly to render insoluble the coloring
matter of cane juice and syrups of raw sugar by precipitating in these liquids a
small quantity of alumina by lime, chalk, or limestone, either from sulphate of
alumine or from sulphate of alumina and silica or silex, this last-named com-
pound being the product of the action of sulphuric acid and heat upon china
or pipe-clays. The compound of sulphuric acid, alumina, and silex is obtained
by adding an equal weight of sulphuric acid if it be of the specific gravity,
1847, to dry china or pipe-clay, either of which consisting almost entirely of
alumina and silex, and thon heating the mixture to about seven hundred
degrees Fahrenheit, when every one hundred parts of the dry common china
clay of commerce become one hundred and seventy-five parts. In this way
the sulphuric acid and the alumina form a salt, which is, as near as possible, a
sulphate of alumina with free silex. And in some parts of this country the
above compound can be made for less than four pounds per ton; and while it
contains no soluble substance that is not precipitated by lime or chalk, it has
the further advantage of yielding double the quantity of alumina to be found
in the alum of commerce.
I proceed to state, according to my experience, the best mode of applying
to cane juice and syrups of raw sugar the sulphate of alumina, either by itself
or with silex. As my process is more especially applicable to the manufacture
of sugar, I shall begin with the clarifying and decolorizing of the cane juice:-To
every one hundred imperial gallons of unskimmed but concentrated cane juice,
previously treated either with or without lime (temper), of the density 1200, or
40° of Twaddell's hydrometer, and of the ordinary color, there ought to be added
by degrees twenty-five lbs. of a mixture consisting of fourteen lbs. ground
sulphate of alumina and silex, and eleven lbs. of ground chalk. Upon the
addition of these bodies there immediately ensues an effervescence from the
escape of carbonic acid, and simultaneously with it a precipitate of alumina
with the coloring matter. After boiling for a few minutes, the whole contents
of the pan ought then to be passed through bag filter, of the construction well
known in this country by the name of Schroder's filters. The purified juice
should now be concentrated either in the open or the vacuum pan; if the
former pan be used, the juice should be brought up to the temperature of two
hundred and thirty-nine degrees, and struck at once into cones of iron or
carthenware capable of holding about sixty lbs. of the juice. On standing

page_text: twenty-four hours they should be once liquored with strong syrup. By pro-
ceeding thus the sugar is obtained of a good color, and cured in much less time
than by the ordinary process of making Lisbon sugar in the Brazils or Cuba,
and the serious average loss of ten per cent. saccharine matter by drainage
and fermentation on shipboard from British colonies completely avoided. As
more than half of the coloring matter has been abstacted from the juice by
the alumina, while the filtration has withdrawn all the insoluble matter, a
sugar is produced which gives a clear solution, and is free of the sediment
which appears in dissolving ordinary Muscovadoes. The sediment in the bags
should be first washed with weak but hot juice, and then with hot water. The
washed sediment (consisting of alumina with coloring matter and other im-
purities of the cane juice, sulphate of line, and silex, with a small excess of
chalk,) may be used as a fertilizer, or converted by heat into a species of
charcoal fit for decolorizing cane juice or syrups. When the pure sulphate of
alumina is used, eleven lbs. of finely ground chalk should be thrown alternately
into the one hundred imperial gallons of concentrated cane juice, with nino
lbs. of sulphate of alumina, either in powder or solution. The sulphate of
alumina and chalk in the above proportion are equally as powerful as the
mixture of twenty-five lbs. of sulphate of alumina, silex, and chalk.
I now proceed to state the manner in which I would recommend the sul-
phate of alumina to be used in the refining of raw sugar-For every cwt. of
ordinary Muscovado sugar dissolved in the clarifiers (blow ups) there is to be
added, by degrees and alternately, two lbs. of finely ground chalk, and the
like quantity of sulphate of alumina, to the hot syrup of the usual strength,
27° of the saccharometer, or 47° Twaddell's hydrometer. As the sulphate
of alumina is very soluble in water, it may be more convenient in seme
instances to add it in solution; for this purpose it should be dissolved in an
adjoining vessel. Every gallon of the solution of specific gravity 1150, or 30°
Twaddell's hydrometer, contains almost exactly two lbs. sulphate of alumina.
The syrup should be brought to near the boiling point, and kept there for a few
minutes; and if steam be the heating agent of the clarifiers, the apparent boiling
point of 203° Fahrenheit produced by high-pressure steam will be quite high
enough. The steam is now to be turned off, and the whole contents allowed to
settle for a few minutes, after which they should be allowed to pass into bag
filters. The filtered liquor may now be passed into the charcoal cistern, or at once
evaporated in an open or vacuum pan, then crystallized, poured into moulds,
brushed off, and syruped in the usual way. When as much as possible of the
strong syrup has gone through the filters, they should be washed by passing
hot water through them, and the weak syrup pumped into the clarifier for
dissolving more sugar. In this way it is found that the alumina completely

page_text: dispenses with blood (spice), and at the same time abstracts from the sugar at
least one half of the coloring matter, and thereby dispensing with one half of
the animal charcoal. If no blood nor animal charcoal be used, the refined
sugar produced from raw sugar, and that from cane juice, in the mode just
described, retain an agreeable smell.
The process of manufacturing and refining sugar, which has been described,
may be varied by using lime alone, with sulphate of alumina, in the syrups; or
by using various proportions of lime with chalk or limestone.
Having thus described the nature of my Invention, and the best means I am
acquainted with for performing the same, I would have it understood that I do
not confine myself to the precise details herein described provided the peculiar
character of my Invention be retained. But what I claim is,-
Firstly, the decolorizing of cane juice and syrups of raw sugar by adding to
them a mixture of pounded chalk or limestone, and the substance (sulphate of
alumina and silex) derived from the action of sulphuric acid and heat upon
china or pipe-clays.
Secondly, I claim the decolorizing of cane juice and syrups. of raw sugar
by precipitating alumina in the cane juice and syrups from sulphate of alumina
by lime or ground chalk, or limestone, or by a mixture of lime with chalk or
limestone.
Lastly, I claim the use of the substance formed in the cane juice or syrups
of raw sugar by the action of lime, chalk, or limestone upon sulphate of
alumina and silex, or of lime, chalk, or limestone upon sulphate of alumina
without the silex.
In witness whereof, I, the said William Birkmyre, have hereunto set my
hand and seal, this Twelfth day of June, One thousand eight hundred