IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND OTHER SALTS OF ALUMINA
Year: 1882

page_text: LETTERS PATENT to Peter Spence and Francis Mudie Spence both of
Manchester in the County of Lancaster, Mauufacturing Chemists, for an
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ALUM AND OTHER
SALTS OF ALUMINA."
on the
PROVISIONAL SPECIFICATION left by the said Peter Spence and Francis
Mudie Spence at the Office of the Commissioners of Patents
⚫ 11th August 1882.
PETER SPENCE and FRANCIS MUDIE SPENCE, both of Manchester in the County
of Lancaster, Manufacturing Chemists IMPROVEMENTS IN THE MANUFACTURE
"
OF ALUM AND OTHER SALTS OF ALUMINA."
Our invention consists in producing alum and other salts of alumina with but a
very minute proportion of iron and of coloured organic impurity by digesting their
solutions with an oxide of manganese.
In carrying out our invention we add to the aluminous solution which it is
proposed to treat a small percentage of an oxide of manganese and then mix and
digest. If the liquid under treatment be for example a solution of the sulphates
of alumina and iron, obtained by digesting sulphuric acid upon bauxite we add the
oxide of manganese to the hot liquor before the sediment has been settled out from
it and then boil and settle. The settlings after having been washed in the usual
way may be thrown away. The clear liquor will now be found to practically free
from iron, its coloured organic matter will have disappeared and it will have
become a very pure solution of sulphate of alumina. It may now either in the
liquid condition, or after being reduced by evaporation to the solid form, be utilized
for the various purposes for which pure sulphate of alumina is employed. If the
crude solution of sulphates of alumina and iron is intended to be manufactured
into alum of extreme purity an alkaline sulphate is added to it, and to the alum
solution thus forined is then added the oxide of manganese and the whole is then
boiled and settled, and the clear liquor is drawn off and if necessary evaporated till
it is of sufficient strength, after which it may be crystallized by cooling in any of
the usual nodes.
The alum thus produced is of an exceedingly high degree of purity and is
suitable for mordanting alizarin and other cloth dyes of the most delicate shades, or
for other purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Spence and Fraucis Mudie Spence in the Great Seal Patent
Office on the 10th February 1883.
PETER SPENCE and FRANCIS MUDIE SPENCE both of Manchester in the County
of Lancaster Manufacturing Chemists " IMPROVEMENTS IN THE MANUFACTURE
OF ALUM AND OTHER SALTS OF ALUMINA "
Our Invention consists in producing alum and other salts of alumina with but a
very minute proportion of iron and of coloured, organic impurity by digesting or
acting upon their solutions with an oxide of manganese-In carrying out our said
invention we take for example a solution of sulphate of alumina made by digesting
sulphuric acid upon bauxite or any suitable aluminous mineral which solution will
usually contain varying quantities of sulphate of iron and coloured organic
impurities The above solution we prefer to be nearly free from uncombined
sulphuric acid-We add to the above named solution peroxide of manganese in the
proportion of six parts by weight of dry peroxide of manganese to every one
hundred parts by weight of dry sulphate of alumina cake contained in such solution,
such peroxide of manganese we form artificially in a mode similar to the production
of "Weldon Mud" in the chloride of lime inanufacture and it should be fully
oxydized by modes well known and when added to the solution we occasionally or
continuously stir the mixture for from one to two hours and then allow it to
settle-If the solution is of the specific gravity of about 1.35 or 70 degrees of
Twaddles hydrometer then it must be kept hot but if as low as 1.25 specific
gravity or 50 degrees of Twaddles hydrometer it may be allowed to cool After
settling from ten to twelve hours the manganese peroxide will have subsided and
carried down the iron and also destroyed the colour of the organic impurities―
The clear solution is now removed from the sediment and if intended for sulphate
of alumina cake is boiled up to a specific gravity of about 1-6 or 120 degrees of
Twaddles bydrometer and then run into lead coolers to solidify but if intended
for the manufacture of alum it is boiled up to the strength found most convenient
for crystallisation such strength being from 70 to 80 degrees or thereabouts of
Twaddles hydrometer and sulphate of ammonia or sulphate of potash being added
as is well known alum can then be crystallised from it and in either case practically
the whole of the iron and coloured organic impurities in the solution having been
removed by the action of the peroxide of manganese the alum and sulphate of
alumina will be found of a very high degree of purity-The peroxide of manganese
when washed free from the solution before referred to may either be thrown away
or if found desirable it can be dissolved and converted into Weldon Mud "as is
well known-We have stated in our Provisional Specification that the solution
intended for alum may be purified after the addition of the alkaline sulphate but
we find it more convenient to purify it before the addition of such alkaline
sulphate as in the production of sulphate of alumina cake as herein before described-
We would have it understood that we do not confine ourselves to the above
specified quantities nor to the precise mode specified for the application of our
Invention nor do we confine ourselves to the use of the aforesaid "Weldon Mud"
Having thus described and ascertained the nature of our said Invention and the
manner in which the same is to be performed we desire it to be understood that we
claim as secured to us under the above in part recited Letters Patent
The use of manganese combined with oxygen as peroxide whether produced

page_text: from lower oxides by oxydization or from manganic acid or permanganic acid or
their salts by deoxydization for the purpose of purifying solutions of sulphate or
other salts of alumina
In witness whereof we the said Peter Spence and Francis Mudie Spence have
hereunto set our hands and seals this eighth day of February in the year
of our Lord one thousand eight hundred and eighty three.
PETER SPENCE
(L.S.)
FRANCIS MUDIE SPENCE (L.S.)