IMPROVEMENTS IN TREATING CERTAIN ORES AND REGULUSES, AND IN OBTAINING PRODUCTS THEREFROM.
Year: 1879

page_text: LETTERS PATENT to William Henderson, of Irvine, Ayrshire, North Britain,
Manufacturing Chemist, for the Invention of "IMPROVEMENTS IN TREATING
CERTAIN ORES AND REGULUSES, AND IN OBTAINING PRODUCTS THEREFROM.'
"
Sealed the 30th April 1880, and dated the 3rd November 1879.
PROVISIONAL SPECIFICATION left by the said William Henderson at
the Office of the Commissioners of Patents on the 3rd November 1879.
WILLIAM HENDERSON, of Irvine, Ayrshire, North Britain, Manufacturing
Chemist. "IMPROVEMENTS IN TREATING CERTAIN ORES AND REGULUSES, AND IN
OBTAINING PRODUCTS THEREFROM."
These improvements relate to the ores of copper, silver, cobalt, nickel, and zinc,
or mixtures of these ores, and, to the reguluses of the first four, zinc being seldom
found in any regulus, and consists of an improved method of obtaining these metals
in solution as sulphates. To effect this I proceed as follows:-If the ores contain
a notable proportion of magnesia, lime, almumina, or other earthy matter, and
silica, I convert them into a copper regulus of not more than 50% copper by
smelting in the usual way as is well understood by copper smelters.
If nickel or cobalt, or both, are present a sufficient amount of arsenical pyrites
should be added previous to smelting to prevent these metals passing into the slag.
When the ores do not contain much alumina, or alkaline earths, or silica, this
smelting operation may be dispensed with. The ores or regulus are now calcined
in the usual way to drive off the sulphur and arsenic and leave the metals as near
as practicable in the state of oxides.
The calcined or burnt ores and regulus are now mixed preferably with a variable
proportion (according to the amount of metals to be converted into soluble
sulphates) of bisulphate of soda, or what is technically known in commerce as
nitre-cake. This should be previously crushed to a coarse powder and then
intimately mixed with the oxidised ore or regulus, and crushed to pass through
a sieve of about the fifth or sixth of an inch clear mesh. The mixed ores and

page_text: bisulphate are now transferred to a calcining furnace and subjected to a low red heat
with repeated stirrings and turnings over. In a short time it will be found that
the copper, silver, cobalt, nickel, zinc, and some other metals of rarer occurence are
converted into soluble sulphates. The calcination is continued until this has been
effected. The charge is then withdrawn and lixiviated and the metals precipitated
from their solutions in the usual way. If silver is present it will be necessary to
use water free from chlorine or chlorides.
·
The sulphate of soda may be recovered from the residual solutions by evaporation
and crystallization.
Burnt cupreous pyrites may be treated in the same way without previous calci-
nation if well burnt.
Bisulphate of potash and other bisulphates may be substituted for the bisulphate
of soda, wholly or in part, but I prefer the soda-salt by reason of its cheapness and
low chemical equivalent carrying a larger proportion of available sulphuric acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henderson in the Great Seal Patent Office on the 3rd
May 1880.
WILLIAM HENDERSON, of Irvine, Ayrshire, North Britain, Manufacturing
Chemist. "IMPROVEMENTS IN TREATING CERTAIN ORES AND REGULUSES, AND IN
OBTAINING PRODUCTS THEREFROM."
These improvements relate to the ores of copper, silver, cobalt, nickel, and zinc,
or mixtures of these ores, and to the reguluses of the first four, zinc being seldom
found in any regulus, and consists of an improved method of obtaining these metals
in solution as sulphates..
To effect this I proceed as follows:-If the ores contain a notable proportion of
magnesia, lime, alumina, or other earthy matter, and silica, I convert them into a
copper regulus of not more than 50° copper by smelting in the usual way as is
well understood by copper
smelters.
°
If nickel or cobalt, or both, are present a sufficient amount of arsenical pyrites
should be added previous to smelting to prevent these metals passing into the slag.
When the ores do not contain much alumina or alkaline earths or silica this
smelting operation may be dispensed with.
The ores or regulus are now calcined in the usual way to drive off the sulphur
and arsenic and leave the metals as near as practicable in the state of oxides.
The calcined or burnt ores and regulus are now mixed with a variable proportion
of bisulphate of soda, the proportion being varied according to the amount of
metals to be converted into soluble sulphates. In some cases instead of bisulphate
of soda, which is technically known in commerce as "nitre cake," analogous bisul-
phates of other alkalies may be used.
The bisulphate should be previously crushed to a coarse powder and then
intimately mixed with the oxidised ore or regulus, and crushed to pass through a
seive of about the fifth or sixth of an inch clear mesh.
The mixed ores and bisulphate are now transferred to a calcining furnace and
subjected to a low red heat with repeated stirrings and turnings over.
I have found it in practice preferable to use such a heat as will decompose
the sulphate of iron which is formed at the commencement of the process, and to
maintain this heat till it is found that all the metals which one desires to have in
solution are soluble. For instance, with rich copper reguluses containing small per
centages of nickel, cobalt, and silver, or one or more of these, it is not desirable to
have any of the copper in solution. This can be accomplished by adding to the
crushed ore not more than 2 per cent. of bisulphate of soda in excess of what is
necessary to convert these metals into sulphates. No doubt sulphates of iron and
copper will in the first place be formed, but as the charge gains in heat the sulphate
of iron will be decomposed, and finally such a heat must be used as will decompose
the sulphate of copper, when the silver and other valuable sulphates will alone
remain soluble.
The charge is then withdrawn and lixiviated, and the metals precipated from
their solutions in the usual way. If silver is present it will be necessary to use
water free from chlorine or chlorides.
The calcined copper regulus can be smelted for copper in the usual or any other
manner, and will produce copper of very high quality.
0
In treating burnt cupreous pyrites or other calcined ores containing no lime,
magnesia, alumina, or other earthy matter, and only a small quantity of silica, and
where the per centage of copper is small, not exceeding 6° copper and 3 to 5 oz.
of silver, I proceed as follows:-The nitre cake should first be broken by a stone
breaker closely set, and then passed through a flour mill and there ground about
as fine as oatmeal; when thus prepared it is taken to the mill where the burnt ore
is crushed to pass through a slightly finer sieve than is used for my salt process,
now so universally in use. By that process a clear mesh of '/, of an inch is after
long experience generally adopted.

page_text: I find however that by this new process, where a much smaller quantity of reagent
is needed, finer grinding is necessary, and as far as my experience goes I prefer a clear
mesh of th of an inch, and in the case of reguluses which are to yield only a
small proportion of soluable matter the mesh should be reduced to 1/10
I take into account that these ineshes are always wearing larger, and I give the
sizes which, in my opinion, are the best to start with when working the two classes
of materials indicated.
It is of very great importance that when dealing with such poor ores and such
small quantities of reagents that the mixture should be very intimate before passing
into the furnace. Hence I recommend that the bisulphate of soda or nitre cake
should be reduced to a coarse flour and added in small and often repeated quantities
to the burnt ore as it is thrown into the mill or crusher, and a thorough mixture is
thus secured.
In calcining this mixture either close or open furnaces can be used, and the
quicker the charge is brought to a full red heat the better.
There is no fear of loss of copper by volatilization, and in a remarkably short
space of time the copper is entirely soluable in water. The sulphate of silver is very
sparingly soluble in water, which requires to be acidulated with pure sulphurio
acid to remove it afterwards. It is of course of the greatest importance where
silver is to be extracted from ores or reguluses that no chlorides can reach the
mixture from floors, mills, furnaces, or water used in lixiviating, and that old
tanks used in my first or salt process be lined with new sheet lead; with these
precautions it is possible to extract the whole of the copper, silver, cobalt, and
nickel from an ore containing all four metals.
The oxide of iron residue obtained will be found to be very valuable as a
pigment. It is not of the character of purple ore, or what is termed "blue billy,"
but is of a fine brilliant red color, and when ground forms a new and valuable
pigment.
The silver from these sulphate solutions can be readily plated down on copper
sheets and the copper also in the metallic state, and the pure sulphate of soda
utilized.
This process must be varied according to the analysis of the ores and the metals
therein contained. The elements of zinc and sulphur not properly elimininated in
the first stage of burning or calcining will vary the proportions of reagent to get rid
of their adverse influence early in the process, but this can be done by a judicious
management of the heat and a slight increase of the reagent.
Bisulphate of potash and other bisulphates may be substituted for the bisulphate
of soda, wholly or in part, but I prefer the soda salt by reason of its cheapness
and low chemical equivalent carrying a larger proportion of available sulphuric acid.
Having now described the nature of my Invention and the best means now in
my possession for carrying into effect all its objects, I claim,-
First. The improved process of treating metallic ores and materials wherein I use
the bisulphate of soda or of potash or analogous bisulphates in the manner and for
the purposes substantially as herein described.
Secondly. The manufacture from the residue resulting from the use of my
improved process of the new and valuable pigment, substantially as herein
described.
Thirdly. The recovery of the reagent used in a more valuable form, in the
manner herein described.
In witness whereof, I, the said William Henderson, have hereunto set my
hand and seal, this Twenty second day of April, One thousand eight
hundred and eighty.
WM. HENDERSON. (L.S.)