IMPROVEMENTS IN THE MANUFACTURE OF BICHROMATE OF SODA
Year: 1884

page_text: We, EDMUND PEEL POTTER and WILLIAM HENRY HIGGIN both of Little Lever
near Bolton, in the county of Lancaster, do hereby declare the nature of our said
invention for "IMPROVEMENTS IN THE MANUFACTURE OF BICHROMATE OF SODA "
to be as follows:-
This invention relates to improvements in the processes for which we have
obtained Letters Patent No 587 of 1883 and No 3329 of 1883 and the following is
n description of the same.
We find it advantageous to and accordingly wash the salts thrown out from
the chrome liquor on concentration with hydrochloric acid in the cold, as this acid
completely removes all chromates from the sodium chloride and leaves the latter
behind, owing to the fact that sodium chloride is nearly insoluble in hydrochloric
acid. We apply this process as we find most convenient either for the extraction
of the chromates from the strong residual salts, or from the same salts after being
washed with prepared vat liquor, as described in our previous patents as above, in
either case we utilize the strongly acid liquor after washing the strong or partially
washed salts for bichromating further quantities of vat liquor.
DA
7001
EDMUND PEEL POTTER.
WILLIAM HENRY HIGGIN.

page_text: "
We EDMUND PEEL POTTER and WILLIAM HENRY HIGGIN, both of Little Lever
near Bolton, Lancashire do hereby declare the nature of our said invention for
and in what
"IMPROVEMENTS IN THE MANUFACTURE OF BICHROMATE OF SODA
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:―
This invention relates to improvements in the processes for which we have
obtained Letters Patent No 587 of 1883, and N° 3329 of 1883, and the following is
a description of the same.
We find it advantageous to and accordingly wash the salts thrown out from the
chrome liquor on concentration with hydrochloric acid in the cold, as this acid
completely removes all chromates from the sodium chloride and leaves the latter
behind owing to the fact that sodium chloride is nearly insoluble in hydrochloric
acid.
We apply this process as we find most convenient, either for the extraction of
-the-chromates from the strong-residual-salts, or-from the same salts-after-being
washed with prepared vat liquor as described in our previous patents, as above.
In each case we utilize the strongly acid liquor formed by washing the above salts
with hydrochloric acid for bichromating further quantities of vat liquor.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1st. The improvement in the manufacture of bichromate of soda, which consists
in extracting the residual bichromate from the foreign salts separated during tho
concentration of the crude bichromate liquor, by means of hydrochloric acid,
substantially as described.
2nd. The improvement in the manufacture of bichromate of soda, which consists
in washing the foreign salts separated from the crude bichromate solution by
concentration with the kind of acid that is employed for bichromating, and then
using the resulting strong acid liquor for bichromating a further batch of chromato
liquor instead of fresh acid, substantially as described.