Improvements relating to the Extraction of Aluminium Hydrate or Aluminium Salts from Aluminium Silicates or Clay.
Year: 1891

page_text: Date of Application, 7th Aug., 1891
Complete Specification Left, 7th May, 1892-Accepted, 18th June,
1892
PROVISIONAL SPECIFICATION.
Improvements relating to the Extraction of Aluminium Hydrate or
Aluminium Salts from Aluminium Silicates or Clay.
I, Dr. ENNO MEYER, of 165, Garten Strasse, Berlin, N., in the Empire of
Germany, Chemist, do hereby declare the nature of this invention to be as
follows:-
:-
As is well known it is either quite impossible or extremely difficult to extract
alumina from clay by means of acid. Even a preliminary heating does not render
the clay much more suitable for the extraction of alumina or aluminium salts.
Now the object of the present invention is to so transform the clay that it can
be easily and advantageously employed for producing aluinina or aluminium salts
on a large scale.
Numerous trials have demonstrated that when clay is gently heated with alkaline
or earthy alkaline chlorides or with aluminium chloride it is changed in such a
manner that the alumina can be readily dissolved or extracted by weak (mineral or
organic) acids.
Accordingly the process constituting the subject of my invention may be carried
out in the following manner, that is to say, a mixture of clay and chlorides of the
alkaline or alkaline earth metals, for instance common salt, calcium chloride and
the like, is subjected to a gentle red heat. Equal proportions have been found
suitable, but similar results may be obtained with other quantitative proportions.
For the purpose of recovering the chloride, the mass is lixiviated with water and
then treated with diluted acid (mineral or organic acid, such as hydrochloric acid,
sulphuric acid, acetic acid). After filtering the solution from the residue containing
silicic acid, aluminium hydrate, if such to be obtained, is precipitated in the well-
known manner from the filtrate containing the aluminium salt.
When aluminium chloride is employed, very small quantities of the same suffice
for the required purpose. For instance when the finely ground mass is saturated
with about 0.1 to 1 per cent. of a solution of aluminium chloride, dried and then
subjected to heat, the decomposition is more rapid and complete than when other
chlorides are used. It is evident that in this case the washing and lixiviation for
the purpose of recovering the chlorides are dispensed with, for the heated mass
contains no longer any aluminium chloride or only very small traces of the same,
as aluminium chloride becomes volatile upon subjecting it only to a gentle heat.
In this manner all the salts of aluminium or the aluminium hydrate can be
directly obtained in the pure state.
Dated this 7th day of August 1891
HASELTINE, LAKE & Co..
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to the Extraction of Aluminium Hydrate or
Aluminium Salts from Aluminium Silicates or Clay.
I, Dr. ENNO MEYER of 165 Garten Strasse, Berlin, N., in the Empire of
Germany, Chemist, 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 :-
As is well known it is either quite impossible or extremely difficult to extract

page_text: alumina from clay by means of acid. Even a preliminary heating does not render
the clay much more suitable for the extraction of alumina or aluminium salts.
The object of the present invention is to so transform the clay that it can
be easily and advantageously employed for producing alumina or aluminium salts
on a large scale.
By means of numerous trials it has been ascertained that when clay is gently
heated with alkaline or earthy alkaline chlorides or with aluminium chloride it is
changed in such a manner that the alumina can be readily dissolved or extracted
by weak (mineral or organic) acids.
Accordingly the process constituting the subject of my invention may be carried
out in the following manner that is to say, a mixture of clay and chlorides of the
alkaline or alkaline earth metals, for instance common salt, calcium chloride and
the like, is subjected to a gentle red heat. Equal proportions have been found
suitable, but similar results may be obtained with other quantitative proportions.
For the purpose of recovering the chloride, the mass is lixiviated with water and
then treated with diluted acid (mineral or organic acid, such as hydrochloric acid,
sulphuric acid or acetic acid). After filtering the solution from the residue
containing silicic acid, aluminium hydrate if such is to be obtained is precipitated
in the well known manner from the filtrate containing the aluminium salt.
When aluminium chloride is employed, very small quantities of the same suffice
for the required purpose. For instance when the finely ground mass is saturated
with about 0.1 to 1 per cent. of a solution of aluminium chloride, dried and then
subjected to heat, the decomposition is more rapid and complete than when other
chlorides are used. It is evident that in this case the washing and lixiviation for
the purpose of recovering the chlorides are dispensed with, for the heated mass no
longer contains any aluminium chloride or only very small traces of the same, as
aluminium chloride becomes volatile upon subjecting it to only a gentle heat.
In this manner all the salts of aluminium or the aluminium hydrate can be
directly obtained in the pure state.
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 :-
The extraction of aluminium salts or aluminium hydrate from aluminium silicates
or clay by heating the latter materials with alkaline or earthy alkaline chlorides or
aluminium chloride and then treating with acid and if desired precipitating aluminium
hydrate from the solution formed, if such is to be obtained.
Dated this 7th day of May 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.