The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1918-12-05
LOW GRADE LEAD ORES
AND THEIR TREATMENT
.es,ILTs OF EXPERIMENTS CON.
QUOTED BY THE BUREAU
OF MINES.

Netallurgy of Lead" by Dorsey A
I.von and Oliver c. Ralston. has just
,aen issued by the bureau of mines
department of the interior.
This bulletin discusses the subjecV
cr the treatment of lead ores by other
than the ordinary metallurgical pro-
casses which are at the present time
anplied for the recovery Of the metal
values from such ores
AS is we'll known, one of the prin-
cinal functions of the bureau of mines
is wherever possible, to devise ways
and means of preventing waste of the
colntry's mineral resources in con-
nection with mining and metallurgi-
cal work. 1t is for this reason that
the work Of the bureaus station at
salt Lake City has been devoted
largely to the problem of extracting
the values from the large bodies of
ores which occur in Utah and the
adjoining states and which are too
low grade to permit of their being
treated by present day metallurgical
processes, without previous concen-
tration. AS a rule these low grade
ores can not be concentrated by or
binary gravity concentration pro-
cesses, or even by the flotation pro-
cess, due to their chemical and ply
steal nature. These ores may be
grouped as follows:
Class of Ores.
/. Argentferous and non -argentif-
erous lead carbonate ores.
2. Complex ores of lead and zinc,
containing other metals.
8. Shines from COMMENTATORS
treating lead sulphide ores.
Flotation has recently done much
toward the solution of the last men
toned problem.
As for the ores of class l, namely,
the argentiferous and non-argentifer-
Gus lead carbonate ores, the low grade
ores of this class are very difficult to
concentrate by gravity concentration
processes because the lead silver min
erals slime very readily causing ex-
cessive losses in the mill shines. When
the oxidized ores can be treated by
sulphidizing followed by flotation. the
problem of treating this class Of ores
becomes a comparatively simple one,
but when they contain elements that
make sulphidzing impossible, resort
must be had to some other method Of
treatment, and so the bureau has
made a study of the possibility of de-
vising hydrometallurgical or pyro-
metallurgical processes which it
would be commercially feasible to
apply to ores Of this class.
The work on hydrometallurgical
processes which the bureau has done
for the recovery of lead from oXidized
ores has been based upon the solu-
biity of lead chloride and lead sui
plate in neutral, saturated brine SOL
utions and the solubility of lead car
Donates and oxides in aciditied satu-
rated brine solutions. From these
solutions the lead may be precipitated
by means Of the electric current or by
Stacked lime. The product resulting
from the precipitation by electrolysis
is sponge lead, and that from the lime
precipitation is a complex lead hy-
droXde.
The bulletin gives the details Of the
experimental work which was carried
out along this line, discusses the
chemistry of brine teaching in general
and states the conclusions that were
drawn from a very extensive series OF
tests Of teaching and electrolysis. 1t
also discusses the subjects of chlor-
idizing roasting followed by brine
teaching, volatilization Of lead from
oxidzed ores, liberalization of oxl-
died lead ores containing gold and
silver and flotation of lead carbonate
ores and the possibility of applying
such methods commercially.
Conclusions.
The general conclusions of the au'
thors as regards the work which has
been done by the bureau on lead ores
are
l. It is possible to recover at
profit by the application Of hydro
metallurgical and other processes no
at present commonly used, depending
upon existing conditions, the meta
values contained in oxidized ant
complex lead sulphide ores.
g. Both neutral or acid satur
ated, brine solution will dissolve Leaf
sulphate or chloride.
3. When the solutions are pure
the lead may be precipitated Wit
lime, but when they are impure the
should be precipitated with the cleo
trio current
4. The metal values may be Cd
tanned from oxidized lead ores d
either one of the three followin
methods Sulphidizing followed d
flotation; the acid brine teaching
the raw ore; and volatilization of IN
lead with salt and heat.
5 When silver and gold are pres
ent in the ores, the best treatment
by chloridizing and volatilizing pal
OF the lead. followed by the leachin
OF the remainder from the calcines.