IMPROVEMENTS IN THE MANUFACTURE OP ALUTM
Year: 1853

page_text: LETTERS PATENT to James Thomson Wilson, of Falkirk, North-
Britain for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OP ALUTM"
Sealed the 4th April 1854, and dated the 5th October 1853.
PROVISIONAL SPECIFICATION left by the said James Thomson
Wilson at the Office of the Commissioners of Patents, with his
Petition, on the 5th October 1853.
I, JAMES THOMSON WILSON, of Falkirk, N.B., do hereby declare the
nature of my Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
ALUM" to be as follows:-
This Invention relates to the manufacture of alum when shale and
sulphuric acid are employed, and consists in the employment of chloride
of potassium, or of ammonia and ammoniacal liquor. I would state
that the use of chloride of potassium and of ammonia is not new
generally in the manufacture of alum, and the peculiarity of the Inven-
tion consists in the use of such materials in cases where sulphuric
acid is employed to extract the alumina.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Thomson Wilson in the Great Seal
Patent Office on the 5th April 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JAMES THOMSON WILSON, of Falkirk, N.B., send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of October, in the year of
our Lord One thousand eight hundred and fifty-three, in the seven-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Thomson Wilson, Her special
licence that I, the said James Thomson Wilson, my executors, ad-
ministrators, and assigns, or such others as I, the said James Thomson
Wilson, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF ALUM," upon the condition
(amongst others) that I, the said James Thomson Wilson, by an instru-
ment in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Thomson Wilson, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof (that is to say):
My said Invention consists in the use of muriate of potash or
muriate of ammonia in conjunction with ammoniacal liquor in the
manufacture of alum from shale by means of sulphuric acid.
I would observe, that muriate of potash has been long used in the
manufacture of alum when made from the common alum schist, as at
Whitby and Hurlet, and has been found advantageous, both in con-

page_text: sequence of being the cheapest form of potash salt, and also from
decomposing the sulphates of iron present in the liquors, and rendering
their sulphuric acid available in the formation of the alum.
In manufacturing alum from clay, however, this salt of potash has
been found unsuitable, as the iron present is inconsiderable in quantity,
and if used it would cause a decomposition of the sulphate of alumina
itself. It has been found necessary therefore to decompose it and
convert it into sulphate of potash before using.
In the manufacture of alum from common shale by sulphuric acid a
good deal of iron exists in solution in the liquors, rendering it a desir-
able matter to use muriates for the same reason as in the alum made
from schist, but the existence also of a large amount of free sulphuric
acid has hitherto prevented their being employed, as this free acid
disengages the muriatic acid or chlorine in the liquors, and rapidly
destroys the leaden vessels used in the manufacture.
I have found, however, that when this manufacture is carried on
according to my process as described in the Specification of my Patent
for England for "Improvements in the Manufacture of Alum," of date
December the Seventh, One thousand eight hundred and fifty, in which
I use distilled ammoniacal liquor to neutralize the free acid in the
liquors, and combine with the sulphate of alumina to form alum, that
I can use a certain portion of muriate of potash or of ammonia with
very considerable advantage, both in saving the acid in union with the
iron, and also in preventing a deposit of busic sulphate of alumina.
In order to carry out the Invention all that is necessary is to modify
my process as described in said Specification as follows, viz:-Instead
of adding as much ammoniacal liquor as is there described, that is to
say, as much as is required to convert the whole sulphate of alumina
into alum, I add only about three fourths of that quantity, and for the
remaining one fourth of alkali necessary I add muriate of potash, or, if
the price admit, muriate of ammonia, either in the solid state or in
solution, as may be convenient. The exact quantities of muriates and
ammonia liquor respectively, however, which should be used in each
case will depend on the shale used and the consequent quantity of iron
present. What is necessary to be attended to in carrying out the

page_text: process is, first, that the quantity of acid used shall bear such a pro-
portion to the alumina which the shale yields that the excess of free
acid shall not be more than can be neutralized by the ammoniacal
liquor added; and, second, that the muriates used should be as nearly
as possible what is required to decompose the sulphates of iron present;
what these may be in each case will be found by testing the liquors,
as is well understood.
What I claim is, the use of muriate of potash or muriate of
ammonia in connection with ammoniacal liquor (distilled or otherwise)
in the manufacture of alum from shale by means of sulphuric acid.
In witness whereof, I, the said James Thomson Wilson, have
hereunto set my hand and seal, this Thirty-first day of March,
in the year of our Lord One thousand eight hundred and fifty-
four.
Witness,
GEO. FAIRBAIRN,
of Camelon, Falkirk.
JAMES T. WILSON. (L.B.)