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Page: of 428
322 She Hining wl Scientific Bresa.
Gomuninicntions,
In Tals DEPARTMENT we luvite the FREE DIscUSssION of
i d alone belng r
all
proper —corr for
the ideas and theories they advance. i
[Written for the Mining and Sclentific Press.]
New Process for Reducing Silver and Copper
from thsir Ores and Solutions.*
_BY DR. LANSZWEERT. * e
Berzelius (tom. 4, page 144, second edition)
has proposed to prepare certain proto-solts of
copper hy the salts of silver. “ It is probable,” .
he says, “that, tha best way to prepare the
oxy-salts of copper is to decompose the chiorida of copper by nentrn) salts of silver.” Tbe
simultaneons solubility of several proto and
bi-salts of copper; also of different salts of
silver in ammonia; the existence and the stability of some’proto-salts of copper in an excess of ammonia; aud the reduction of most
" of the salts of silver by these same proto-salts
of copper, always in tbe presence of ammonin,
are facts worth our attention.
Tbe reciprocal action of the solntions of
proto-salts of copper and silver, saturated with
ammonia, leads us to the interesting fact that
the salts of copper have a value for the extractidn and refining of silver. When a bi-salt of
copper is dissolved ina large excess of ammonia nnd this liquid, of n more or less intense
hlue color, is tbrown on metallic copper, freed
from the air, we observe that nll the hi-salts’
really soluble in ammonia, nitrate, sulphate,
phosphate, ncetate, oxalate, tartrate, chloride,
ete. dissolves a certain quantity of copper ;
producing proto-salts, difficult to isolate, uotwithstauding thot they monifest, sometimes,
their presence, by a complete discoloration of
tbe solution. But when tbe discoloration is
not complete, the existence of proto-salt can
olways be sbown hy dropping the ainmouial
copper solution in an aqueous solution of tbe
acid of the copper salt.
Thus in reducing the ammonio-sulphate
of copper by metallic cnpper, and pouring this
solution in diluted sulphuric acid a precipitate
nenrly white nppears, which colors immediately dark yellow, then red, and as final result of
this reaction, we find that metallic copper and
sulphate of tbe bioxyde is formed. The copper thus precipitated is amorpbous and of an
extreme tenuity, possessing the ‘red color of
pure copper, which it loses by exposure to the
air; hut by friction again takes its. metallic luster. This reaction is obtained by most of the
neids. Tbe nitrate, phosphate, oxalate, sul
_ phate, tsrtrate, experimented with, all givs less
or.more rapidly metallic copper. The chloride
and acetate are distinguished from the above
by prodacings fixed proto-salt. When the acetute of tbe bi-oxyde of ammonial copper,reduced
by a more or less continued contact. on metallic
copper is poured into concentrated acetic acid,
a white precipitate is ohtnined inthe form of
small clustered prisms, whicb retain their form
long enongh to be examined, altbough they are . ,
rapidly disintegrated by contact with the atmosphere. With tbebi-chloride of copper, obtdined and in the same conditions, n white
proto-chloride is ‘precipitated, of a more fixed
character, i
Proto-chloride of eopper fs not only produced by the reaction of the ammonio bi-chloride of copper, hut also more abundantly when
nmmonia is replaced by ehlorhydric ueid or chioride of sodium, : :
Twenty-five centimetres cubes of no colorless
solution of proto-chloride of copper, ohtained
by the acticn of metallie copper iu o solution
of bi-cbloride of copper in concentrated chlor
hydrie acid, hes given, hy the ordinary modes
of analysis 2.63 grms of hi-oxyde of copper, or
9.33 grms of nietallie copper per litre. ‘This
solubility of proto.chlohride of copper is only
obtained by a large excess of chlorhydric acid,
as.a litre of the same solution contains 235.8
germs of chlorine.
_Ten centimentres cubes of a solution of protoebloride of copper, obtnincd on metallic copPer, in a solutiun of bi-chloride of copper with
chloride of sodium bas given a quantity of bi¢ *Oollated from the “ Moniteur Scientifgue.”
Mest
oxide of copper corresponding to 135.4 grms
of metallic copper, by litre of solution.
V'he quantity of proto-chloride of copper obtained by ammonio bi-chloride of copper
through metallic copper, varies very much and
necording to the strength of the ammonia used.
By ammonia at 18 deg. Cartier, a liquor was
' obtained giving 92.8 of metnl in the state of
proto-chloride. With ammonia of 21 deg. the
quantity of copper,#s proto-chloride, was as
bigh as 139.8; ammonia at I8 deg., diluted
witb its volume of water, did not furnish over
74.4. of copper per litre of solution. The weight
of the proto-salt in solution can he considerable, even when the solution is still of a deep
blne. be coloring power of tbe bi-ammoniuted salts of copper is very great ; as it can be
shown tbat the difference between the quantity
of copper as proto-salt and the amount of metallic copper was only a fraction of a gramme
)in the solution stil! colored.
It results from the ahove facts tbat bi-bichlotide of copper, to which is added ammonia of
21 deg. constitutes the proper menstrnum to
coucentrate proto-salts of copper. For this
reason, and the stability of the solution, it has
always received the preference in the reduction
of the salts of silver. If it is desired to obtain pure proto-chloride of copper, a solution
of proto-chloride of copper iu chlorhydric acid
should be preferred, which precipitates by the
addition of water, a white chrystalized proto.
chloride.
We will now examine the reaction of the
salts of silver dissolved in an excess of ammonia. In pouring u solution of ammonia
proto-chloride of copper into a solution of ammonio uitrate of silver a precipitate of absolutely pure metallic silver is immediately obtained, aud ths fullowing particulars are observed :
The precipitated silver isin au omorphous
state and in such minute division that the diameter of ench atom does not exceed 0.0025 of
a millimeter. Silver obtained by galvanic action or through metals, is commonly brilliant
nnd ehrystalized. The amorphous silver is of
tarnish gray ; sometimes white ; hutin all enses
of the most vivid metallic luster, when hurnished ; and through its finely divided state, it
is easily applied to various substances, such as
wood, stone, leather or other tissues.
As silver thus obtained is pure nnd divided,
its application in various industries might be
made useful. To show the advantages to be
derived from this reaction, such as extracting,
purifying or gilding silver; or to obtain a niore
correct analysis of the compounds of eopper, it
should he borne in mind tliat the renction takes
place hetween the acting principles in the proportion of their chemical equivalents.
Thus by the weight of the precipitated silver
the correct quantity of oxyde of copper is determined, no matter whether the proto-salt is
pure or mixed with bi-salt. We have thus a
new nnd perfectly correct method hy which to
analyze a mixture of proto and hi-salt of copper, and thus are nble to nvoid all the uncertainties which have hitherto attended the nssaying of copper ores.
The following cases, where correct analyses
are difficult to he obtained, will show tbs value
of the ahove process: __
When bi-carbonate of soda is made to react
on proto-cbloride of copper (avoiding tbe cou
taet of the atmosphere) a red powder is obtained, ensy to dry, and which is not a carbonate as is generally supposed ; buta protoxyde
of copper which oftentimes precipitates other
substances. The nmount of copper contained
in this compound gives, by the ordinary method,
83.42 per cent. of metal To determine, by
the new process, in what state tbe copper combined iu this compound existed, 0.561 germs
were treated with a Solution of ammonio chlotide of silver. The weight of the precipitated
silver obtained was 0.800 grms—n number corresponding to 0.235 grmsa of copper, which,
multiplying by 2 gives 0.470 or 83.6 per cent. of
metallic copper—unearly eorresponding witb
83.42, found by the previous method. All the
metal is thus in this compound in the state of
proto-oxyde.
To obtain correct results some precautions
should be observed which practice very soon
leaches. ‘hus when the compound to be analyzed is clirystalized it should be reduced to
on impalpable powder before being placed in
the matrass in which the reaction is to take
place, aud which must be at least of n capacity
of 200 centimetres enbes. When placed in
tbe matrass it should first be covered with
water, on which should he carefully poured ainmouin, taking care thnt°the latter does not
comre in contaet with the substance to be treated; tben by the aid of a long pipette, which
reaches to ths bottom of the matrass, the ommomated silver solution should be placed io
direct contact with the pulverized substance.
Care should also be taken that the matrass is
full, then closed and shaken. If these precautions ure neglected, the oxygen of the air will
intervene and diminish the weight of the preCipitated silver. It should furthermore be observed that cyanide of silver ennnot be reduced
by proto-salts of copper; and that the presenca
-protochloride of copper, at its maxium of conof the sulpbocyanides, iodides, and hypo-snlphites nlso prevent the reaction and nore exceptions to this process. 7,
The study of copper compounds is accompanied with difficutties against which chemists
have long contended ; but which are completely obviated by ths use of this Gew metbod of
analysis.
In proof of ths correctness of the foregoing,
it will be found that if the copper compound is
used in proper proportion to the amount of:
silver contsined io solution, all tbe silver will
be precipitated from its solution. For example, take the following experiments:
First.—1.115 grins of pure silver dissolved in
nitric acid, and saturated with ammonia. ‘T'o
this add a solution of proto-chloride of copper,
also saturnted with ammonia, and‘wasb dry and
weigh the precipitate, whicb will give 1.114
grms or 99.91 per cent. of metallic silver.
Second.—0.588 grms of silver treated the
same os above, gave 0.5855 grms of silver or
99.57 per eent of silver, 2
Third.—0.9827 ol the same metal, treated the
same way, and precipitated by the ammonio
chloride of copper, gave 0.983 grms or 100.03
of silver in place of 100.
This process gives the silver in such an ensy
state to collect and weigh that the analysis of
silver compuunds, by this metbod will be found
much simpler and more quickly cffected.
To determine the solubility of chloride of
silver in various liquids, pure ummonia of different degrees of strength are employed ; also
ammonia to which was added an aqueous solution of chloride of ammonium, potassium, ete.;
besides solutions of the chloride of silver, in
other chtorides, without the nddition of ammonia. For the precipitation of the silver in the
metallic state proto-chloride of copper, stronsly ammoniated, was used, and the numbers in
the following table give the quantity of metallie silver ohtained from a litre of solution :
Solvents of. Am't of Metallle Silver
Chloride of Silver. per litre of Solution.
Ammonia 18° Cartier...... 51.6 grms.
Ammonia 18° do with its volume of water.....: oe sims 23.8 grms
Ammonia 22° Cartier...... 58.0 grms
Ammonia 26° Cartier... «+.. .49.6 grins.
Ammonia 18° Cartier diluted withits volume ol suturated solution
of chloride of sodium.... 20.8 grnis.
Ammonia 18° Cartier diluted with
its volume of a saturated solution of chloride of potassium. .20.4 grms.
Ammonia 18° Cartier diluted witb.
its volume of cliloride of nmmonium...... ° +..22.4 pris.
Saturated solution of chloride of
SOUIUM, eevee eee ian..
Saturated solution of chloride of
potassium
Saturated solution of chloride of
ommonium 1.2 grms,
Chloride of silver is insoluble in chloride ol
calcium or zinc. ‘The above numbers have
been obtained hy using the curdy chloride of
silver; the difference in using fused chloride is
very little, admitting ths solubility of the
former chloride as 49.6 that of the lused would
be 48.4; in this latter state it takes a longer
time to dissolve. ‘The above table shows that
58 grms ol chloride of silver nre easily dis.
solved in ammonia of 22°, which is usually the
commercial strength of this article. Jt seems
plansible, thercfore, that silver ores converted
into chlorides could he more easily and cbeaply reduced than by the use of mercury. ‘The
residue of silver of the laborntories and assay
offices are so promptly reduced by tbis process
that no other will eventually be resorted to.
A litre of amnionia, saturated with chloride
of silver, would be precipitated by 230
centeinetres cubes of ammouio solution of
1.2 grms.
0.5 gris.
centration. The precipitant sbould always be
maintaioed in excess ; and, therefore, it shows
that the same quantity of copper would be
used indefinitely for this purpose. ‘The chloride of copper obtained should be reduced by
zioc, which is easily done in the ammonsiated
solution, nnd thug metallic copper obtained,
necessary to the formation of the protochloride,
Furthermore, ammonia could be reproduced
by lime, and brought to the proper degree of
strength. It seenis useless to dwelf upon tbe
simplicity of this novel process as npplied to
the refining of silver.
Wuy will the emblems of America outlive
those of England, France, Ireland or Scotland ?
Because the Rose will lade, the Lily will droop,
the Shamrock wither, and the Thisile die; but
the Svars ure ETERNAT.
To pREAM gloiously, you must act gloriously
while awake ; and to bring angels down to converse with you in your sleep, you must labor in
the cause of virtue duting the day,
Oxe of our exchanges says: “Dr. Joseph
forms a fitting frame to this grund picture.
‘Worcester, author of a dictionary, and inventor of
Worcestershire sauce, is dead.” Such is fame.
“Have you seen my black-faced antelope 7?’
inquired Mr. Lowcope, who has a colleetion of;
animals, of his friend. “No, I hav’nt. Who)
did your black-faced aunt elope with ?”
[Wrliten for tho Mining and Scientific Press.]
Letter from Placer County.
THE BANKER MINE.
Enrrors Press:—The Banker mine is
time of a truly remarkable lead, of whicb
send yon here a brief description, which .
think will prove interesting to your nu
merous readers, The above-named mine i
situated in the county of Placer, four and a balf”
miles from. Lincoln, in an ‘nortbeastern diree
tion. The locality was' formerly called WI
ky Diggings, but its present owner, going it
pace with nor more civilized times, which hava
brought into desnetnde such names as Hangs
town, Murderer’s Bar, Jockass Gulch, etc., hng .
named this place Valley View ; and a very aps
propriate™name it is, since from here one ca n
see at a glance the greatest part of that former
inland sea, called the Sacramento Valley.
The whole Coast Range, intercepted only hy.
the Marysville Buttes, is plainly visible, and
In tbe origin it was called the Baker Copper
mine, and incorporated ; three years ago it was
opened under the efficient superintendence of
J. CG. Croshy, Esq., and it wns whilst huntiog for
copper that n streak of gold-bearing rock was
found alongside the copper ore, at a depth of
about sixty feet from the surface. The mine
came then under the notice of A. Harpending
Esq., who thought there was somethijlg there
and he nequired tbe title to nearly ull tbe
ground hy purchase.
The ground claimed extends a thonsand) § f
feet in length, and comprises all that is nppnr‘
ently valuable. Che length of the mine is f
much easicr to define than its width, and Jom) §»
tempted to say that it is as wide as it is long.
But I think I can affirm, without fear of being
taxed with exaggeration, that the pay rock extends on a width of two hundred and filty i
feet. First, let mesay what conetitutes pay
rock in this instancs. .
This mine has n doubls and very distinct
character ; there isa gold mine and a copper
mine in the same ground ; tha top or outcrop,
to a depth of over seventy feet, is a true copper
gossan or decomposed iron hat, such as is
found over most ull the mines of Cornwall and
Devonshire, which yield copper pyrites or yellow copper ore. ‘The same class of rock is found
in the surface of the copper mines of Copperopolis, such as the Union, Keystone, Calaverns,
and especially the Webster mine, three miles
south of Copperopolis; also, at the Newton,
nnd Dotie, ond Randall mines in Amador
county ;-also soma of the Campo-Seco mines.
The ouly difference is, thot where there is in
the above-named mines n few feet in width of
this goesan, it has assumed here colossal proportions botb in deptb ond width. ’Phe only
mine in ths Stats which hears much resemblance to this is the Hughes mine in Gopher
District, Calaveras county. In this instance, I
eannot do better than quote the very lunguags
used by Prof. Whitney in his work on ths
‘Noted Mines of the World;” it applies so
closely to the Banker mine that it secms to
hove been written os a description of tbs
same : , :
Among the first things to he noticed is the
deoomposed state of the upper portion of the
veins, giving rise to what the miners call “ goasan,” which usually forms the back of the productive copper lodes. This suhstance is, all
over the world, locked npon as o favornhle
indication of valuahle ores at some depth below.
It iso mixture of quarizose matter, more or
less mixed with oxide of iron, and usually contnins traces of other met:la in thé shape of ’
oxides, cnrbonates and sulphurets, as would 9)
naturally be expected, since it is in oll eases
the result of the decomposition of copper and .
‘iron psrites, and other sulphureted .ores which
formed tbe origiual vein. The sulphuret of
copper is oxidized into a sulphate, which is
soluble in water, and is carried away in the
streams and by the rains, wmle the iron ramainsas an insoluble hydrated oxids. If thers was
gold or oxide of tin in the veinstone, it remains
in its orivinal form, and is generally coucentrated togetber.
The vein rons northwest and sontheast; the
incline is nenrly northeast nt ac angle of about
seventy degrees, so faras known. The mine has )
been opened in the start by menns of two
shafts, ons’ of which was sunk at tbe southern .
mm wdt
y te ow UD ety 4 cies j