Improvements in the Treatment and Reduction of Sulphide Ores Containing Zinc or otherwise.
Year: 1897

page_text: Date of Application, 13th Apr., 1897
Complete Specification Left, 13th Jan., 1898-Accepted, 2nd Apr., 1898
Improvements in the Treatment and Reduction of Sulphide Ores
Containing Zinc or otherwise.
HENRY ROBERT ANGEL, 7, St. Helens Place, London, E.C., Shipowner, do hereby
declare the nature of this invention to be as follows:-
It consists in mixing with raw, or partially roasted, sulphide ores sulphate of soda,
or bisulphate of soda, or a mixture of these chemicals, or sulphate of potash, with
coals or other carbonacious matter but coals preferred and zinc oxide.
Mix these ingredients well together in suitable proportions, and in fine granulated
conditions and then place into any suitable furnace or other reducing apparatus heated
by coals or coke or gas or gas with air or other inflaminable matter-Rabble well, so
that the carbon in the charge burns freely, and the ores under treatment will be
speedily reduced. If the ores are well roasted before treatment the oxide of zinc must
be omitted and caustic lime or sulphate of lime introduced when the ores under
treatment will be quickly reduced.
Improvements in the Treatment and Reduction of Sulphide Ores
Containing Zinc or otherwise.
HENRY ROBERT ANGEL, 7, St. Helens Place, London, E.C., Shipowner, 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:-
To one ton of finely ground ore, that has been partially roasted, add of a ton (or
more) of sulphate of soda, or bisulphate of soda or sulphate of potash, and of a
ton (or more) of coals or other carbonacious matter, or ½ of a ton (or more) of sulphate
of soda, or the like, calcined with carbon may be used, and zinc oxide. The quantity
required is about equal to the amount of sulphur left in the ore.
Mix these ingredients well together in finely divided conditions, and, I then prefer
to, place the charge into a V shaped furnace heated by gas or other inflammable matter,
and under sharp heat (with rabbling preferred). The whole of the lead and nearly all
the precious metals can be recovered in one operation. But if moderate heat only is
employed, the greater part of the metals can be recovered in the first operation and
the balance can be obtained by "concentration (jigging preferred) and in this case a
large proportion of the soda employed can be recovered as caustic, which can be sold
for commercial purposes, or can be used for smelting.

page_text: .
With ores that have been well roasted the same proportion of flux must be used,
and under sharp heat, the whole of the lead and precious metals can be recovered in
one operation.
Raw ores can be successfully treated by the same process, but it requires a second
operation to recover all the precious metals, and this is done by adding galena to the
slag which takes up the silver and both are recovered in metallic form, after the zine
has been burnt out and recovered as an oxide. In all cases the zinc contained in the
ore is recovered as an oxide along with the zinc oxide used in the process. In the
treatment of all ores when caustic soda is not required, as a bye product, lime can be
used to great advantage, and it can be used with zinc oxide, or without zinc oxide, in
quantities varying from about 5% to 20% according to the class of ore under
treatment.
In a properly constructed furnace fitted with chambers for catching the zine, nearly
all the metals contained in the ore can be recovered in one operation.
The calcined sulphate of soda (or the like) can be sent to any part of the world
free from risk, and without losing any of its reducing qualities.
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 -
1. The use of sulphate of soda, or the like mixed with coals or other carbonacious
matter also the use of calcined sulphate of soda (or the like), both to be used as a flux
for the reduction of sulphide ores containing zinc and for other ores, in the manner and
proportions as herein described preferred.
2. The use of zinc oxide and lime to improve the process in the manner and
proportions as herein described preferred.