IMPROVEMENTS IN TREATING SPENT OXIDE OF IRON OBTAINED IN THIE PREPARATION OF GAS TO PRODUCE COLORING MATTERS AND OTHER PRODUCTS
Year: 1876

page_text: LETTERS PATENT to Friedrich Wilhelm Bernhard Mohr, of 3, Love Lane,
Eastcheap, in the City of London, Doctor of Philosophy, for the Invention of
"IMPROVEMENTS IN TREATING SPENT OXIDE OF IRON OBTAINED IN THIE
PREPARATION OF GAS TO PRODUCE COLORING MATTERS AND OTHER PRODUCTS."
Sealed the 7th November 1876, and dated the 20th May 1870.
PROVISIONAL SPECIFICATION left by the said Friedrich Wilhelm Bernhard
Mohr at the Office of the Commissioners of Patents on the 20th May 1870.
FRIEDRICH WILHELM BERNHARD MOHR, of 3, Love Lane, Eastcheap, in the City
of London, Doctor of Philosophy. "IMPROVEMENTS IN TREATING SPENT OXIDE OF
IRON OBTAINED IN THE PREPARATION OF GAS TO PRODUCE COLORING MATTERS AND
OTHER PRODUCTS."
This Invention has for its object improvements in treating spent oxide of
iron obtained in the preparation of gas to produce coloring matters and other
products.
I carefully wash with water the spent oxide obtained from gasworks in order to
remove all soluble ammoniacal compounds, and digest the mass with a solution of
caustic soda or with lime water. To the clear liquor I then add muriatic acid and
heat slightly, and pour off the liquor from the sulphur that is deposited. To the
liquor thus obtained I add a salt of protoxide of iron and a small quantity of a
solution of chloride of lime, I thus obtain a beautiful Prussian blue.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Friedrich Wilhelm Bernhard Mohr in the Great Seal Patent Office on tho
20th November 1876.
FRIEDRICH WILHELM BERNHARD MOHR, of 3, Love Lane, Eastchcap, in the City
of London, Doctor of Philosophy. "IMPROVEMENTS IN TREATING SPENT OXIDE OF
JRON OBTAINED IN THE PREPARATION OF GAS TO PRODUCE COLORING MATTERS
AND OTHER PRODUCTS."
This Invention has for its object improvements in treating spent oxide of
iron obtained in the purification of gas to produce coloring matters and other
products

page_text: I carefully wash with water the spent oxide obtained from gasworks in order to
remove all soluble ammoniacal compounds, and digest the mass with a solution of
caustic soda or with lime water. To the clear liquor I then add muriatic acid and
heat slightly, and pour off the liquor from the sulphur that is deposited. To the
liquor thus obtained I add a salt of protoxyde of iron and a small quantity of a
solution of chloride of lime, I thus obtain a beautiful Prussian blue.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the manner in which I prefer to
operate.
I submit the before mentioned spent oxide of iron to the action of hot water in
order to separate the soluble salts or compounds of ammonia, which may be further
distilled with lime and collected in acid in the known manner. Secondly. I employ
a livigating process and by the aid of water eliminate the sawdust or such like
material usually mixed with the coal gas purifying agent. Third. I submit the
residual spent oxide of iron to the action of a solution of a caustic alkali. I use by
preference a saturated solution of caustic soda, and for every 100 parts of spent
oxide I employ from 3 to 10 parts of caustic soda (Na OHO), according as the spent
oxide contains or will yield less or more Prussian blue. Fourth. I separate the
solution thus obtained from the insoluble residue, and then neutralize and slightly
acidify it with hydrochloric acid or other mineral acid in order that a portion of
the sulphur contained therein may be liberated and be precipitated. The sulphur
may be let to deposit by time or it may be hastened by introducing into the
liquor a little alumina or other indifferent insoluble substances. Fifth. After the
sulphur has been deposited I precipitate the products capable of producing colors
or coloring matters by means of a salt of peroxide or protoxide of iron, either alone
or in conjunction with an oxidising agent, such, for example, as chloride of lime or
atmospheric air.
Having thus described the nature of my said Invention and the manner of
performing the same, I would have it understood that I claim-
First. The treatment of spent oxide of iron obtained in the purification of gas by
dissolving out the products capable of producing colors or coloring inatters which it
contains, then precipitating and separating the sulphur from such solution and
afterwards precipitating the products producing colors or coloring matters, sub-
stantially as described.
Second. The treatment of spent oxide of iron obtained in the purification of gas
producing coloring matters and other products therefrom, substantially in the
manner described.
In witness whereof, I, the said Friedrich Wilhelin Bernhard Mohr, have here-
unto set my hand aud seal, this 15th day of November, in the year of our
Lord One thousand eight hundred and seventy-six.
F. W. B. MOHR. (L.S.)