Improvements in the Reduction of Zinc Blende and other Ores, and Recovery of the Lead with other Metals therefrom.
Year: 1897

page_text: Improvements in the Reduction of Zinc Blende and other Ores, and
Recovery of the Lead with other Metals therefrom.
HENRY ROBERT ANGEL, 7 St. Helen's Place, London, E.C., Ship Owner, do hereby
declare the nature of this invention to be as follows:-
With Sulphate of Soda mix one half its weight in Small Coals, and place into any
suitable furnace heated by Gas or other inflammable Matter, but Gas to be
preferred.
Allow this charge to burn into a flame for a short time, until the Sulphate of Soda,
becomes a "Calcined" Sulphate of Soda in a red hot granulated Condition.
Then add red hot Zinc Blend or other ores that have have been previously
roasted, in proportion to about double the weight of the Soda employed.
Rabble these charges well together, under moderate heat and the ores under
treatment will be speedily reduced, and the Lead, with other, and precious metals
will be precipitated and easily recovered.
Unroasted ores may be treated in the same manner by adding a little Carbonate
of Soda to the charge, but the results from the treatment of these ores are not by
any means so good as that from roasted ores.
Dated this 14th day of January 1897
Improvements in the Reduction of Zinc Blende and other Ores, and
Recovery of the Lead with other Metals therefrom.
I, HENRY ROBERT ANGEL, of 7 St. Helen's Place, London, E.C., Ship Owner, 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
According to this invention zinc blende ores or other sulphide ores containing
lead, are mixed and heated with sulphate of soda, (or it might be bi-sulphate of soda,
sulphate of potass, or the like,) and carbonaceous matter, preferably small coal,
Preferably the process is carried out as follows:-the ore is thoroughly calcined,
and 4 to 6 parts by weight are then intimately mixed with 2 parts of sulphate of
soda, and I part of small coal, the materials being first reduced to a granular
condition. The mixture is then fused in an open hearth gas furnace, care being
taken that the flame does not come into contact with the charge, and the lead
containing the greater part of the silver and gold is tapped out, the volatile
metals, such as zinc, being collected in chambers.

page_text: The remainder of the gold and silver are recovered by adding galena to the molten
slag.
Or the whole charge may be drawn from the furnace and cooled the metals
being separated from the slag by ordinary methods.
In place of mixing all three ingredients together before heating them, the sulphate
of soda and the coal may first be heated and rabbled together, until they burn into
a flame and assume a red hot granular condition whereupon the calcined ore, which
has been separately heated, is added and the mixture rabbled under a moderate
heat.
By this means the process can be carried on at a lower temperature, but more
labour is required.
It is not essential that the ore should be thoroughly calcined, uncalcined, or
imperfectly calcined ore may be employed, but in this case sufficient oxide of
zinc about equal to the amount of sulphur remaining in the ore (say th of the
weight of the ore) should be added to carry off the sulphur. This oxide of zinc may
be used over and over again as it is deposited in that form in the furnace flue.
With well roasted ore the process is facilitated by adding about 5% of lime to it.
Having now particularly described and ascertained the anture of my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. The process of extracting lead with other metals from its ores, consisting in
_mixing and heating the ore with sulphate of soda or the like and carbonaceous
matter.
2. The process of extracting lead with other metals from its ores consisting in
mixing and heating sulphate of soda or the like with carbonaceous matter and mixing
and heating the mixture with the ore.
3. The addition of oxide of zinc to the ore in the processes referred to in
Claims 1 and 2.