IMPROVEMENTS IN THE TREATMENT OF CERTAIN RESIDUAL SALTS FORMED IN THE MANUFACTURE OF CAUSTIC ALKALIES to be as
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
We JOHN HEDLEY of 54 Upper Parliament Street Liverpool in the County of
Lancaster Manufacturing Chemist GEORGE PRYDE of 28 Brompton Avenue Sefton
Park Liverpool in the County of Lancaster Manufacturing Chemist and WALTER
HAVELOCK SWIM of Runcorn in the County of Chester, Chemist do hereby declare
the nature of our said Invention for "IMPROVEMENTS IN THE TREATMENT OF
CERTAIN RESIDUAL SALTS FORMED IN THE MANUFACTURE OF CAUSTIC ALKALIES
to be as follows:-
93
In the manufacture of caustic soda or caustic potash from the carbonate forined
by the Leblanc process, various impurities have to be contended with which are
introduced in the limestone, the fuel and the sulphate employed; also the chloride
and sulphate undecomposed in the previous process have to be crystallized out
sufficiently to bring the caustic to standard strength. These salts and impurities
are in large part eliminated in the process of concentrating by fishing out the
crystalline and other solid matters as they form. These fished salts contain large
quantities of caustic and carbonate but are so contaminated with iron and sulphur ;
as to be of little value.
Now this Invention consists in adding nitre natron or other oxidizing agent to
these salts, preferably when in solution, or in blowing air or oxygen through them
till thoroughly oxidized, and then evaporating to dryness and fusing. By this
fusing the silica, alumina and iron and other impurities being insoluble in the fused
salt subside and the clear hot liquid after standing to allow the impurities to
subside, is drawn off, cooled, broken up, ground and utilized for any desired
nurnosA.

page_text: We, JOHN HEDLEY, of 54 Upper Parliament Street, Liverpool in the County of
Lancaster, Manufacturing Chemist, GEORGE PRYDE, of 28 Brompton Avenue, Sefton
Park, Liverpool, in the County of Lancaster, Manufacturing Chemist, and WALTER
HAVELOCK SWIM, of Runcorn, in the County of Chester, Chemist, do hereby declare
the nature of our said Invention for "IMPROVEMENTS IN THE TREATMENT OF
CERTAIN RESIDUAL SALTS FORMED IN THE MANUFACTURE OF CAUSTIC ALKALIES"
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
In the manufacture of caustic soda or caustic potash from the carbonate formed
by the Le Blanc process, various impurities have to be contended with, which are
introduced in the limestone, the fuel and the sulphate employed, also the chloride
and sulphate undecomposed in the previous process, have to be crystallized out
sufficiently to bring the caustic to standard strength. These salts and impurities
are in large part eliminated in the process of concentrating by fishing out the
crystalline and other solid matters as they form. These fished salts contain large
quantities of caustic and carbonate, but are so contaminated with iron and sulphur
compounds as to be of little value.
Now this Invention consists in adding nitre, natron, or other oxydising agent, to
these salts, preferably when in solution; or in blowing air or oxygen through them,
till thoroughly oxydised, and then evaporating to dryness, and fusing.
By this fusing, the iron completely subsides as does also the silica and alumina
in great measure, and the clear hot liquid after standing to allow the impurities
to subside is drawn off, broken up, ground and utilized for any desired purpose.
No special apparatus is necessary for the treatment of these salts, the plant in
use at all caustic works being available for the purpose.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1st. The process of treating the crude salts, separated from caustic alkali solutions
during concentration, which consists in thoroughly oxydising the solution of these
salts, evaporating it to dryness, fusing, allowing the impurities to subside, drawing
off the liquid, cooling, breaking up, and grinding or pulverizing, substantially as
described.
2nd. The improvement in the treatment of the crude salts separated from
concentrating solutions of caustic alkalies, which consists in fully oxydizing the
said salts. by the addition of natron or other oxydizing body thereto, or by
thoroughly intimate contact with atmospheric air, whereby the salts are made to a
very large extent insoluble in fused caustic alkali
Dated this 2nd day of September 1884.