Improvements in the Manufacture of Sesquioxide of Chromium direct from Chrome Ore.
Year: 1898

page_text: Date of Application, 30th Sept., 1898.
Complete Specification Left, 29th June, 1899-Accepted, 29th July, 1899
Improvements in the Manufacture of Sesquioxide of Chromium
direct from Chrome Ore.
We, RALPH WALDO EMERSON MACIVOR, 57, Gracechurch Street, London,
Professor of Chemistry, and THOMAS FRANKLIN SPENCER, 23, Melbourne Grove,
East Dulwich, Engineer, do hereby declare the nature of this invention to be
as follows:-
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water-
The chrome iron ore in a pulverized or ground state is kept at a red heat in
an enclosed apparatus or furnace through which a current of hydrogen or
gasis kept passing until the oxide of iron in the ore is reduced to the metallic
state. This point being reached, this furnace is allowed to cool, and the roasted
ore is transferred to a vat care being taken to keep it out of contact with the air
in order to prevent re-oxidation of the iron. In the vat it is digested in dilute
sulphuric or hydrochloric acid which dissolves out the metallic iron and also
the magnesia and some of the other constituents of the ore leaving the sesqui-
oxide of chromium as a sediment. This sediment is washed, collected and dried
in the usual way.
Dated this 29th day of September 1898.
R. W. E. MACIVOR,
THOMAS F. SPENCER.
Improvements in the Manufacture of Sesquioxide of Chromium
direct from Chrome Ore.
We, RALPH WALDO EMERSON MACIVOR, 57, Gracechurch Street, London,
Professor of Chemistry, and THомAS FRANKLIN SPENCER, formerly of 23, Mel-
bourne Grove, East Dulwich, now of 4, Bonfield Road, Lewisham, S.E., Engineer,
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:-
The main operation in this process is the reduction of the oxide of iron in the
chrome ore to the condition of metallic iron by the use of hydrogen or water-gas.
This operation is carried out in a furnace which in preference is rotating so as to
expose each particle of ore to the action of the hydrogen or water-gas. The ore
may, however, be kept in agitation by apparatus inside the furnace, if desired,
with the furnace stationary or rotating. The ore must be finely ground before
being put into the furnace, which may be more properly termed the reducing
chamber. Ordinary ore should be reduced to from 60 to 80 mesh.

page_text: The rotating reducing chamber should be kept at a bright red heat, not under
700° C. during the process of reducing the ore; the metallic iron produced by
roasting chrome ore at a dull red heat being more prone to re-oxidation when
brought in contact with ordinary air. It is also preferable that the hydrogen
or water-gas passed into the reducing chamber during the operation should be
heated to at least 700° C. The duration of the operation is from two to four
hours. To prevent accidents the reducing chamber should be filled with hydrogen
or water-gas before it is heated, 'and 'the 'roasted ore should be allowed to cool
down to 100° C. before being exposed to the air; in other words, the charge must
cool down in an atmosphere of hydrogen or water-gas.
The charge from the furnace or reducing chamber should, as soon as possible,
be passed into vats containing sulphuric, hydrochloric, or other suitable acid of
sufficient strength to extract the metallic iron from the sludge of impure chromic
sesquioxide. The liquor containing the iron and other impurities is then re-
moved. The residue is thoroughly washed in hot acid and dried. The result
is chromic sequioxide of a high grade in a fine powder.
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:
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The production of chromic sesquioxide direct from chrome.ore by the action
of hydrogen or water-gas upon the finely powdered ore in a heated reducing
chamber substantially as described.
Dated this 29th day of June 1899.
R. W. EMERSON MACIVOR,
THOMAS F. SPENCER,
Applicants.