The Eureka sentinel. [volume] (Eureka, Nev.) 1902-current, 1920-05-08

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ted plants for treating ores by this
process. Competent metallurgists be-
lieve that II will be a very short time
until a commercially successful ex-
traction of lead, copper, silver, and
gold values from oxidized ore will be
made possible by this method.
The volatilization method consists
! OF heating the ore to a temperature
high enough to drive the gold, silver,
lead, and copper from the charge in
the form of fumes, and then to pre-
cipitate the metals from these fumes.
This necessitates converting the met
ais into chlorites at the time the ore
Is heated. This is done by mixing
the ore charge with salt or some 9TH
er chloridizing agent at the time II is
placed In the stack, or furnace. The
fumes are collected by precipitating
them from the furnace gases BY
means of electrical precipitators; by
collecting them in bag houses; or by
any other effective contrivance.
Volatilization of ores was proposed
years ago. and many patents have
been taken out, covering different
methods. In recent times renewed
investigation of these methods by
both State and Federal bureaus and
institutions, and by unattached chem
lists and metallurgists, has brought a
vast amount of Information on this
subject to the surface, out of which
there will be undoubtedly be devel-
oped several methods rehabilitation
treatment that will be OF great COM
mercial value.
EUREKA ENGINEER MAKES
IMPORTANT EXPERIMENTS
II. r. Laying, who is now In charge
of the Holly and Bullwhacker mines
in Eureka, has been for a long time
engaged In experiments on volatiliz-
ing ores, and in an article in the
Mining and Scientific Press" states
the results of some of these expert
ments. Extracts from this article
follow:
"The revival of interest in chlori-
died volatilization processes will re-
suit In successful application of one
or other of them. The failures re-
sulting from attempts to conduct var
ious methods on a commercial scale
were In my opinion due to lack of
sufficient knowledge of the then un-
known chemical reactions and of GER
tain peculiar effects of heat.
During the early years of the Eu-
ropean war l had the opportunity of
observing the attempts made with
three different shaft-furnace plants
to treat antimony ores by volatiliza-
tion, all of which failed. My obser-
vations of these attempts caused me
to believe that the process could be
best carried on in furnace of the
revolving-kiln type. / tried treating
the ore in a small furnace and got
such good results that a furnace "a
#. long by 3S in. diameter on the
feed and fiue end and SO in. diameter
on the fire and discharge end was in
stalled. The early work with this
furnace did not result in better than
sos extractions. l found that the
low heat at. or toward, the flue end
caused the antimony tri-oxide fume
to be oxidized to the non-volatile
tetra-oxide. which precipitated in the
furnace and mixed with the molten
stibnite to form an almost non-vol-
atile oxy-sulphide. This stuck to
the wall of the furnace and balled
the charge so much that 1t was nec-
essary to shut the furnace down for
cleaning purposes at intervals of a
few days. l then made changes that
caused the fiue end to be hotter,
thereby causing the ore to be heated
more quickly, procedure that re-
suited in doubling the capacity Of the
furnace and yielding higher extrac-
tions, which were eventually brought
to over 90%, and, furthermore al
most completely eliminated the cause
OF the costly shut-downs for cleaning
purposes.
THE operation of the antimony
plant had shown me that the more
rapidly the ore could be heated to a
point sufficiently high to prevent
harmful reactions from occurring
and cause good rates of volatilization,
the better the resulting extraction.
During the past two years | have
many tests on a number Of
ores with chloridising methods and
find that in chloridizing volatilization
also 1t is necessary to heat the ore
quickly in order to prevent harmful
reactions. These would probably in
yolve the formation of non-volatile or
nearly non-volatile compounds like
of lead, oxides of cop
per, or alkaline zincates, or alkaline
lead silicates; also the formation of
fused compounds, like, for example,
sodium sulphate, which coat the min
erals in the ore and hinder the prop
or reactions. or prevent volatilization
Of the metal compound so encased.
Slow heating not only causes low ex-
fractions, due to these harmful re-
but also decreases the capaci- |
ty of the furnace, and therefore en-
tails an excessive consumption of
fuel. 1t may also prevent the deyel- |
opment of beneficial reactions.
"It is probably due. mainly, to the
serious effect of slow heating, especi-
ally when sodium chloride is used,
that most OF the large-scale attempts
made with chloridizing
processes have been un-
srcnasaful
These tests prove the necessity
taIl