IMPROVED PROCESS IN THE MANUFACTURE OF BI-CHROMATE OF POTASH
Year: 1882

page_text: LETTERS PATENT to Friedrich Carl Glaser of Berlin in the Kingdom of Prussia
and Empire of Germany Engineer and Patent Solicitor for an Invention of
IMPROVED PROCESS IN THE MANUFACTURE OF BI-CHROMATE OF POTASH
A communication to him by Peter Römer in the City of Elberfeld, Empire
of Germany.
PROVISIONAL SPECIFICATION left by the said Friedrich Carl Glaser at the
Office of the Commissioners of Patents on the 12th December. 1882.
FRIEDRICH CARL GLASER of Berlin in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Solicitor "IMPROVED PROCESS IN THE MANUFAC-
TURE OF BI-CHROMATE OF POTASH. [A communication to him by Peter Römer in
the City of Elberfeld, Empire of Germany.]
In the existing process for the manufacture of bichromate of potash, only
potassium salts have been used. The present invention relates to an improvement
in this process whereby there are employed in part sodium salts in place of the
expensive potassium salts, both for the melting and the lixiviating processes, so that
the quantity of the expensive potassium salts is reduced to one half. The special
process employed for this purpose is as follows:-
Finely ground chromium ore is mixed in suitable proportions with lime, potash
and carbonate of soda, and is oxidised in a reverberatory furnace until there is no
more chromium ore present.
11

page_text: and of potash, and which are brought to a strength of from 30° to 40° Beaumé by
evaporation.
In acidulating the cooled lyes with sulphuric or hydrochloric acids, according to
the formula
K. Na, Cr, O + H₂SO. = K, Cr, O, + Na SO₁ + H₂O
bichromate of potash will be separated while the sulphate of soda will remain in
solution.
By re-crystallising, the bi-chromate of potash will be purified.
From the liquor containing the sulphate of soda the latter is obtained by
evaporation either as anhydrous salt, if treated hot, or as hydrate in the cold.
Potash and soda can be replaced in the above process by any soluble potash and
soda compounds
The process can also be varied by melting the ore together with carbonate of
soda and lime, and adding the potash when lixiviating, or the converse.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Friedrich Carl Glaser in the Great Seal Patent Office on the
1st June 1883.
FRIEDRICH CARL GLASER of Berlin in the Kingdom of Germany, Engineer and
Patent Solicitor "IMPROVED PROCESS IN THE MANUFACTURE OF BI-CHROMATE
OF POTASH A communication to me by Peter Römer in the City of Elberfeld,
Empire of Germany.
"
In the existing process for the manufacture of bi-chromate of potash, only
potassium salts have been used. The present invention relates to an improvement
in this process whereby there are employed in part sodium salts in place of the
expensive potassium salts, both for the melting and the lixiviating processes, so that
the quantity of the expensive potassium salts is reduced to one half. The special
process employed for this purpose is as follows.
Finely ground chromium ore is mixed in suitable proportions with lime, potash,
and carbonate of soda, and is oxidised in a reverberatory furnace until there is no
more chromium ore present.
Suitable proportions for the mixture are as follows:-
100 parts by weights of ore
150 parts by weight of lime
40 parts by weight of potash
30 parts by weight of carbonate of soda.
but, these may be varied according to the percentage of chromium oxide in the ore.
By lixiviation of the melt, in which is added if necessary some soluble potassium
salt, lyes are obtained which contain both chromates of soda and of potash, and
which are brought to a strength of from 30° to 40° Beaumé by evaporation. In
acidulating the cooled lyes with sulphuric or hydrochloric acids according to the
formula K, Na, Cr, O, + H, SO₁ = K, Cг, O₁ + Na So. + H, O bichromate of
potash will be separated while the sulphate of soda will remain in solution.
By re-crystallising, the bi-chromate of potash will be purified.
From the liquor containing the sulphate of soda, the latter is obtained by
evaporation, either as anhydrous salt, if treated hot, or as hydrate in the cold.
Potash and soda can be replaced in the above process by any soluble potash and
soda compounds.
Having thus described the nature of this invention and in what manner the
saine is to be performed as communicated to me by my correspondent, I claim.
The production of bi-chromate of potash by the decomposition of a lye containing
equivalent quantities of chromates of potash and of soda by means of a quantity of
sulphuric acid equivalent to that of the chromate of soda.
In Witness whereof, I the said Friedrich Carl Glaser have hereunto set my
hand and seal this twentyeighth day of May in the year of our Lord, One
thousand, eight hundred and eighty-three.
BUTEDDIATY
AT LAK
מזמזות
RICH
ΠΑΤΡΟ
AT LAKO
CUADER
("SUT)