Improvements in the Manufacture of Red Oxide from the Waste Liquors from Galvanizing Works, Tin Plate Works, Wet Copper Process, or other Residual Liquors containing Iron in the Form of Chloride.
Year: 1897

page_text: Date of Application, 27th Apr., 1897
Complete Onanifnationa
1000
Date of Application, 27th Apr., 1897
1000
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Complete Specification Left, 24th Jan, 1898- Accepted, 12th Mar., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Red Oxide from the Waste
Liquors from Galvanizing Works, Tin Plate Works, Wet Copper
Process, or other Residual Liquors containing Iron in the Form of
Chloride.
I, THOMAS TOWARD SILL, of Weston, Runcorn, in the County of Chester,
Manager of Chemical Works, do hereby declare the nature of this invention to be
as follows:
:—
This invention relates to the manufacture of red oxide from the waste liquors
of galvanising works, tin plate works, wet copper process or other residual liquors
containing iron in the form of chloride. The object is to produce a red oxide,
applicable for use in making paints, which in regard to colour will be as good
or superior to what has hitherto been produced.
In carrying the invention into effect, the spout liquor or pickle, which always
contains a large quantity of free hydrochloric acid is put into vats and treated
with scrap iron to neutralise the free acid, and increase the yield of oxide, from
the same bulk of liquor to be treated. The liquor is allowed to settle, and the iron
precipitated from the clear liquid by milk of lime or other known means as
ferrous hydrate.
In precipitating the iron from the liquor with lime or other known precipitant,
care must be taken to keep the iron in excess, or a satisfactory colour will not be
obtained. The ferrous hydrate is then washed quite free from soluble impurities,
and dried at a low temperature on an open drying bed with full exposure to the
air.
When all the moisture is expelled, the ferrous-hydrate will be converted into
ferric-hydrate. Care should be taken that the drying is not done too quickly
or the oxidation is liable to be not complete. The drying bed can either be
heated by waste heat, direct firing, or exhaust steam. As an alternative the
ferrous-hydrate can be oxidized to ferric-hydrate as stated above, and then washed
till free from soluble salts in the same way as the ferrous-hydrate. The ferric-
hydrate well washed obtained by either of the above methods, is then furnaced in
either a reverberatory or muffle furnace till the required tint is obtained.
By the present invention I am able to obtain an increased yield from a given
quantity of liquor, and also by my process I effect complete oxidation and drying
of the ferrous-hydrate into ferric-oxide before charging into the furnace for cal-
cination. Furthermore an important feature of the invention is the keeping of the
iron in excess in the liquors during the process of precipitation, also the washing
of the ferrous or ferric hydrate either partially or completely before furnacing.
Dated this 26th day of April 1897.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Red Oxide from the Waste
Liquors from Galvanizing Works, Tin Plate Works, Wet Copper
Process, or other Residual Liquors containing Iron in the Form of
Chloride.
I, THOMAS TOWARD SILL, formerly of Weston, Runcorn, in the County of
Chester, but now of Flint, North Wales, Manager of Chemical Works, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
4
This invention relates to the manufacture of red oxide from the waste liquors
of galvanizing works, tin plate works, wet copper process or other residual liquors
containing iron in the form of chloride. The object is to produce a red oxide
applicable for use in making paints, which in regard to colour will be as good
or superior to what has hitherto been produced. The waste liquors of the galvaniz-
ing works usually contain besides iron in the form of chloride a certain quantity
of free hydrochloric acid. This crude liquor is put into cisterns and scrap iron is
added to neutralise the free acid and incidentally to increase the amount of
yield of oxide from a given quantity of liquor. When the liquor has--become
saturated with iron it is taken and the iron precipitated as ferrous hydrate by 1
milk of lime carbonate of soda or other suitable known precipitant. In pre-
cipitating the iron great care should be used to leave a little iron in the solution
and avoid all excess of the precipitant or a satisfactory colour will not be obtained.
The best amount of iron to leave in the liquor is from 50 to 150 grains per cubia
foot, but larger or smaller quantities can be left as a lighter or a darker tint is
required in the finished oxide. The precipitated ferrous hydrate is now washed to
remove the chloride of calcium or sodium of other soluble salts. It is then
filtered and oxidized or the precipitant can be filtered without washing and then
oxidized. The method of oxidation consists in heating the filtered hydrate with
full exposure to air or oxygen on a drying bed made of iron plates, firebrick, or
other material till all the moisture has been expelled when the ferrous hydrate
will be converted into ferric hydrate. Only a moderate heat should be used, as
if otherwise some of the hydrate may escape through oxidation. The material
is now washed till quite free from chloride of calcium and other salts and roasted.
or baked in either a muffle or reverberatory furnace till the required tint is g
obtained.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
The improvements in the manufacture of red oxide from the waste liquors from 3
galvanizing works, tin plate works wet copper process and like liquors containing "
iron in the form of chloride, which consists, in,
(a) Precipitating the same with milk of lime or other suitable material in
such manner that there shall always be an excess of iron.
(b) Oxidising by driving off the moisture with full exposure to air and at a 4
comparatively low heat.
Washing hydrate free from soluble salts before farmacing.
L
SHING
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DALLO
ΔΙΟΤΑΙ
fur macing.
Dated this 22nd day of January 1898.
'
W. P. THOMPSON & Co.,
Patent Agents, of Liverpool, Manchester, Birmingham and London.