Improvements in the Manufacture, Treatment, or Purification and Production of Salts or Compounds of Alumina.
Year: 1895

page_text: Date of Application, 21st Jan., 1895
Complete Suec fication Left 21st Aug.
1895-Accepted. 5th Oct., 1895
Date of Application, 21st Jan., 1895
Complete Spec fication Left 21st Aug. 1895-Accepted. 5th Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture, Treatment, or Purification and
Production of Salts or Compounds of Alumina.
I, JACQUES LOUIS KESSLER of 21 Boulevard Poissonniere Paris in the
Republic of France Chemical Engineer do hereby declare the nature of this
invention to be as follows:-
Attempts which have been hitherto made for avoiding coloration due to the
presence of iron in the salts or compounds of alumina by means of phosphoric acid
have not proved satisfactory as this body or its combinations do not in the methods
hitherto used remove the reddish colour of the acid compounds of alumina (for
example the sulphate) which colour depreciates the value thereof and is due to the
contained oxide of colloidal iron. When the base is precipitated by an excess of a
stronger base such as lime potash or soda, the latter takes up phosphoric acid and
sets free the peroxide of iron which reappears with its objectionable colour.
This invention relates to certain means as hereinafter described whereby the
desired decoloration and the desired whiteness of the salts of alumina are obtained
by the elimination of the peroxide of colloidal iron either by reducing in solution
the iron to the minimum of oxidation by deoxidizing its peroxide using for the
purpose any well known or suitable means such as sulphuretted hydrogen zinc, or
the like, or by adding to the solution sulphurous acid or a sulphite or by leaving
therein a small quantity of acid.
In respect of the aluminous precipitates; the quantity of the phosphoric com-
pound is proportioned so as to contain about a quantity by weight of phosphoric
acid equal to the peroxide of iron contained in the salt or capable of being formed
therein by oxidation of the salt of protoxide of iron. When the aluminous solution
is precipitated by a more powerful base than the alumina too large a quantity of
the said base should not be added so that the liquor may remain either slightly acid
or almost neutral, or a basic compound should be employed for effecting the
precipitation, sufficiently powerful to precipitate the alumina but incapable (even
when added in excess) of separating the iron from its phosphoric combination.
Suitable precipitants of this class are. precipitated magnesia, or its carbonate,
carbonate and bisulphite of lime, and the alkaline, or magnesium bicarbonates.
The phosphoric compound employed according to this invention may be of any
origin or source and it may be introduced directly into the salts or compounds of
alumina or indirectly for instance into paper or cardboard making materials or the
like where compounds of alumina are employed.
If the phosphoric compound be phosphate of alumina I may add phosphato-
aluminate products from the treatment of natural phosphates of alumina either to
the salts of alumina or to waste or by products (for example those of paper sizers)
in which ferruginous alumina is present.
The following phosphoric combinations or compounds may be used. The ortho-
meta- or pyro-phosphoric acids or their soluble or insoluble combinations, natural
phosphate of lime, precipitated or dissolved, calcined bones, natural or precipitated,
phosphate of alumina, phosphate of baryta, magnesia, and ammoniacal magnesium
phosphate.
The soluble phosphates can be simply added to the solution or to the aluminous
salts. Whilst with those which are insoluble they can be added to the solution

page_text: either hot or cold and the precipitate which may be formed be separated by any
known or suitable means or it may be left in the product.
Dated 21st January 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, Agents.
Improvements in the Manufacture, Treatment, or Purification and
Production of Salts or Compounds of Alumina.
I, JACQUES LOUIS KESSLER, of Clermont Ferrand, late of 21 Boulevard
Poissonniere, Paris, in the Republic of France, Chemical 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:-
Attempts which have been hitherto made for avoiding coloration due to the
presence of iron in the salts or compounds of alumina by means of phosphoric acid
have not proved satisfactory as this body or its combinations do not in the methods
hitherto used remove the reddish colour of the said compounds of alumina (for
example the sulphate) which colour depreciates the value thereof and is due to the
contained oxide of colloidal iron. When the base is precipitated by an excess of
a stronger base such as lime, potash or soda, the latter takes up phosphoric acid
and sets free the peroxide of iron which reappears with its objectionable colour.
This invention relates to certain means as hereinafter described whereby the
desired decoloration and the desired whiteness of the salts of alumina are obtained
by the elimination of the peroxide of colloidal iron either by reducing in solution
the iron to the minimum of oxidation, by deoxidizing its peroxide using for the
purpose any well known or suitable means such as sulphuretted hydrogen, zinc or
the like or by adding to the solution sulphurous acid or a sulphite or by leaving
therein a small quantity of acid.
a
In respect of the aluminous precipitates, the quantity of the phosphoric
compound is proportioned so as to contain about a quantity by weight of phosphoric
acid equal to the peroxide of iron contained in the salt or capable of being formed
therein by oxidation of the salt of protoxide of iron. When the aluminous
solution is precipitated by a more powerful base than the alumina too large
quantity of the said base should not be added so that the liquor may remain either
slightly acid or almost neutral or a basic compound should be employed for effecting
the precipitation sufficiently powerful to precipitate the alumina but incapable
(even when added in excess) of separating the iron from its phosphoric
combination. Suitable precipitants of this class are precipitated magnesia,
or its carbonate, carbonate and bisulphite of lime, and the alkaline or magnesium
bicarbonates.
The phosphoric compound employed according to this invention may be of any
origin or source and it may be introduced directly into the salts or compounds of
alumina or indirectly for instance into paper or cardboard making materials or the
like where compounds of alumina are employed.
If the phosphoric compound be phosphate of alumina I may add phosphate-
aluminate products from the treatment of natural phosphates of alumina either to
the salts of alumina or to waste or by products (for example those of paper sizes)
in which ferruginous alumina is present.
The following phosphoric combinations or compounds may be used. The
ortho-meta- or pyro-phosphoric acids or their soluble or insoluble combinations,
natural phosphate of lime, precipitated or dissolved, calcined bones natural or

page_text: precipitated, phosphate of alumina, phosphate of baryta, magnesia and ammoniacal
magnesium phosphate.
The soluble phosphates can be simply added to the solution or to the aluminous
salts. Whilst with those which are insoluble they can be added to the solution
either hot or cold and the precipitate which may be formed be separated by any
known or suitable means or it may be left in the product.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
(1.) The manufacture, treatment or purification and production of salts or
compounds of alumina, substantially as hereinbefore described.
(2.) In the manufacture, treatment or purification of salts or compounds of
alumina, eliminating the peroxide of colloidal iron by reducing in solution the iron
to the minimum of oxidation by deoxidizing its peroxide by any suitable and well-
known means such as sulphuretted hydrogen.
(3.) In the manufacture, treatment or purification of salts or compounds of
alumina, eliminating the peroxide of colloidal iron by adding to the solution
sulphurous acid or a sulphite or by leaving therein a small quantity of acid.
Lot dan of August 1005
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.