Improvements in Obtaining Pigments.
Year: 1892

page_text: Date of Application, 1st Feb., 1892
Complete Specification Left, 29th Oct., 1892-Accepted, 3rd Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Pigments.
I, DAVID SWAN, of 5, Kelvinside Gardens, Glasgow, in the County of Lanark,
North Britain, Chemist, do hereby declare the nature of this invention to be as
follows that is to say :-
My said invention relates to processes for obtaining pigments from protochloride
of iron as described in my Patent Specification No. 2310 of 1886, and my object is
to improve the color of those varieties of the said pigments in the production of
which calcination is employed.
My present invention consists in combining or mixing an oxide or suitable salt
of zinc with the materials prior to calcination. I prefer to mix chloride of zinc
with protochloride of iron in solution, or to take a solution containing both salts
and which is sometimes obtainable as a used or residuary liquor in galvanizing or
similar processes. If the iron liquor contains free hydrochloric acid I add to it
metallic zinc or any suitable alloy or compound of zinc. I next mix with the
solution carbonate of lime or other carbonate of an alkaline earth and I subject
the mixture to agitation and aeration. The carbonate of lime or other carth is
by preference added in a powdered condition, oxides, hydrates or carbonates of the
metals are formed and precipitated, and chloride of calcium remains in solution.
The precipitates are separated, washed, and dried, and then subjected to
calcination.
Instead of mixing the iron and zinc salts in solution, the oxide, hydrate, or
carbonate of iron may be precipitated separately, and a suitable compound of zinc
may then be intimately mixed therewith, the mixture being afterwards subjected to
calcination.
Dated this Thirtieth day of January 1892.
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Obtaining Pigments.
I, DAVID SWAN, of Kelvinside Gardens, Glasgow, in the County of Lanark,
North Britain, Chemist, 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, that is to say:-
My said invention relates to processes for obtaining pigments from protochloride
of iron as described in my Patent Specification No. 2310 of 1886, and my object
is to improve the color of those varieties of the said pigments in the production of
which calcination is employed.
My present invention consists in combining or mixing an oxide or suitable salt
of zinc with the materials prior to calcination. I prefer to mix chloride of zinc
with protochloride of iron in solution, or to take a solution containing both salts
and which is sometimes obtainable as a used or residuary liquor in galvanizing or
similar processes. If the iron liquor contains free hydrochloric acid, I add to it
metallic zinc or any suitable alloy or compound of zinc. The proportion of zinc
or compound or salt of zinc to be added may be varied, I have however obtained
satisfactory results by adding one part of zinc chloride to every hundred parts of
protochloride of iron. I next mix with the solution carbonate of lime or other
carbonate of an alkaline earth and I subject the mixture to agitation and aeration,
as described in the earlier Specification hereinbefore referred to.

page_text: The carbonate of lime or other earth is by preference added in a powdered
condition, oxides, hydrates or carbonates of the metals are formed and precipitated
and calcium chloride or other-chloride remains in solution. The precipitates are
separated, washed, and dried, and then subjected to calcination.
Instead of mixing the iron and zinc salts in solution the oxide, hydrate, or
carbonate of iron may be precipitated separately, and a suitable compound of zinc
may then be intimately mixed therewith the mixture being alterwards subjected to
calcination.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The obtaining of pigments by calcining a mixture of compounds of iron and of
zinc the said compounds being themselves obtained in the manner hereinbefore
described or referred to.
Dated this Twenty-eighth day of October 1892.
EDMUND HUNT,
Applicant's Agent.