close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2131045

код для вставки
Sept. 27, 1938.
v
'
I
K. c. D, HICKMAN ET AL
L
“
SILVER
2,131,045
RECOVERY
Filed April 9, 1937
WASTE
couecnoubr WASTE m
LARGE snnuow PIT
gut-R WASTE
r_-cnusrlc 0!? sum 48!!
‘ FLOCCULATION IN W00
'
cLEAPwPERNAmMT
AGENT
GALLON TZNKS
'
*SLUDGE
' LIQUOR Dmmznm
sswm
REDUCTION OF,
swnee vow/ms ‘
SLUDGE
DLI U
Ac’
Q 0R
1
‘
REDUCTION OF
SI. UDGE VOLUME
*SLURR Y
CENTRIFUGING
“CA K E
DRYING & PULVEPIZING
$0114 ASH FUSION
SLAGS T0 BROMINE
SILVER T0 _
& IODINE RECOVER!
ELECTRO REFINING.
(21211, mm
BY
2,131,045
Patented Sept. 27, '1938
UNITED STATES PATENT oFFicE
' 2,131,045
SILVER- RECOVERY
Kenneth C. D. Hickman, John R. Turner, and
Walter J- Weyerts, Rochester, N. Y., assignors
Company, Rochester,
Eastman K
. to
N. Y., a corporation of New Jersey
Application April 9, 1937, Serial No. 135,952
11 Claims.‘ (c1. 75-83)
liquids obtained from photographic processes.
,
This invention relates to processes for the pro
Another object is vto provide a process for the re- ,
duction and recovery of metals from sources
which contain only small or minute amounts of
covery of silver contained'in wash solutions pro
duced in photographic processes. A still further
metals or metal-containing components, and
5 more particularly to processes for the recovery
of silver from solutions containing only small
amounts of silver or silver containing compo
nents,
,
‘
Various materials such as waste‘solutions, ores
A‘! and the like contain small amounts of a precious
metal such as silver. For example, there are vari
ous waste solutions containing silver produced in
photographic processes such as the solutions ob
tained by washing scrap ?lm and the like. These
15 solutions contain only a very small or‘minute
amount of precious metal; hence, standard met
allurgical processes for precious metal production
are unsatisfactory when applied to the treatment
of solutions containing such small quantities. It
20 is therefore apparent thatthe treatment of such
sources of materials involves not only the tech
nical problems of developing processes which
will successfully operate on small ‘quantities, but
that there is also the problem of developing proc
25 esses which are economically feasible. Certain
processes, while capable of recovering metals
object is to provide a process for the recovery of 5
valuable components contained in scrap ?lm and
other waste obtained in the production of photo
graphic materials. Another object is to provide
a recovery process in which the agents employed
may be produced or regenerated. Still another 10
object is to provide a ‘silver recovery process which
is simple and economic. A still further object is
'to provide a process for the recovery of silver
from waste photographic materials in which the
silver produced is of high-grade quality. Still 15
other objects will appear hereinafter.
These objects are accomplished by our inven
tion which includes the steps of adjusting the
composition of the waste metal-containing mate
rials, depositing the desired metal as a sludge, 20
reducing the sludge volume without material loss
of metal, and recovery of the desired metal.
For a more complete understanding of our in
vention, reference is made to the attached draw
ing, forming a part of the present application. .25
This drawing is in the nature of a ?ow sheet
graphically illustrating the series of steps em
ployed in carrying out one embodiment of our.
operation because their costs of operation are invention. Reference to the attached drawing
. more than the value of the materials recovered.
may be had in a consideration of the following 30
30 It has been proposed by certain British investi- ‘ example which is set forth to illustrate the pre
gators and others to precipitate'silver, but the ferred embodiment of our process. It is to be
resultant precipitate contained only a small understood that the values to be set forth in this
amount of‘ silver and a large bulk of other in
example are primarily for the purposes of illus—
g'redients. '
trating our preferred embodiment and are not 35
35
We have found a method of recovering metal to be construed as limiting our invention. I
from sources in which the metals or metal-con
Solutions from which silver was to be recovered
taining components are present in small amounts, were collected in a large pit or container. These
which process not only effectively permits the solutions were obtained from waste water ob
recovery of the metals but is relatively simple tained in photographic processing, washing ?lm 40
present in minute quantities, fail in practical
4° and economic in operation.
'
‘
invention has as one object to provide a
process'for producing or recovering metals from
various sources of materials, containing only small
or minute quantities of the metal. Another ob
Cit ject is to provide a process for treating solutions
containing small amounts of metals in which the
metal recovery is substantially complete. A still
scrap and various other sources. The solution
contained about 11 troy ounces of silver per
thousand gallons‘ of ‘liquid.
In addition, there
were various other components such as gelatin,
bromides, iodides and the like. This waste silver
liquid was treated with alkali such as soda ash,
in order to bring the pH value somewhere in the
range 6.4 to 7.8 and preferably of about 6.9 to
' further object is to provide a process of recover
ing metals present only in small amounts which, about ‘7.2. If desired, calcium chloride and the 50
‘5'9 is simple and economic in operation. A still fur- ‘ like may be added to the solution for converting
ther object is to provide a process for the re
silver to silver halides.
,
After the waste solutions have been brought
covery of small amounts of metals in which there
are no material losses of the agent employed,
to the correct pH and otherwise improved, de
Still another object is to provide a process par
positing agent, preferably a metallic sulphate is I
55 ' ticularly adapted for recovering silver present in
il
2
2,131,045
added thereto in ‘order to produce a ?oc which
carries down a sludge containing the silver com
ponent of the solution.
may be allowed to
settle for a period-of time and the clear super
- natant liquid . above
the silver sludge may be
discharged to the sewer. The silver sludge is
generally comprised of agent, gelatin and other
materials initially contained in the waste solu
tion. 'I‘he'sludge volume is‘so large and the sil
ver content so small, at this point, it may not
be the equivalent of a low grade ore.
We have found that if the newly deposited
silver containing sludge is treated with various
‘is
acids, not only is the sludge volume materially
reduced but in some instances solutions which
ceeded in obtaining the precious metal under
recovery, in a condition where economical fusion
steps may be applied thereto. In addition, we
have provided for the use of chemical materials
which are relatively cheap and readily available.
on the market.
,
Our process is susceptible of some modi?cation.
- While we prefer to use sulphate agents‘such as
aluminum sulphate, copper sulphate or the like, ,
such agents may be supplemented, supplanted or
otherwise modi?ed by other depositing or ?occu
' lating agents. - Some such agents are the hydrox
ides and ferric chloride. The sludge volume may
be altered by theme of other agents such as by
hydrochloric ornitric acid, ‘or various mixtures.
for example.‘ ’- The precipitation of sludge is pref 15
We prefer to employ about 5 cc. of 96% sulphuric ‘erably
carried ‘out on several supplies of waste
acid per gallon of sludge. However, varying
solutionbeforethe
sludge is transferred to treat
amounts from 1% or 2% up to. 15% or 120%. of
20 the 96% sulphuric or equivalent sulphuric, if of mentfor reducing sludge volume. The sludge
volume reduction may be carried out with heat 24B
a different concentration than 96%, may be uti
ing,~
desired. centrifuging, drying or pulver
lized depending on the sludge volume and other ' izingifmay
be more or less employed or steps ac
such factors.
‘~
complishing a similar result‘ substituted. There
This acid treatment may be carried out in one fore, we do not wish to be restricted in our in
25 or more steps; preferably two or three steps is
vention excepting insofar as is necessitated by
to be preferred, such as for example, in accord
the prior art and the appended claims.
ance with the attached ?ow sheet. We have
What we claim and desire to secure by Letters
found that the newly deposited sludge may be Patent
of the United States is:
, easily treated. By newly ‘deposited or‘ precipi
1. The ‘process of recovering precious metal 30 tated, we refer to a sludge, which is from a few
from materials containing the metal in small
hours to a few days old, as contrasted to sludge quantities, which comprises obtaining solutions $19
that has been permitted to remain untreated for containing small quantities of precious metals,
3-4 days or more. If acids such as nitric and
hydrochloric are employed, even older sludge may treating said solutions with sulphate agent which
causes the deposition of a sludge containing the
may have uses are produced as a by-product.
35
be treated.
.
The fraction resulting from the acid treatment
' and comprising sludge which has had its volume
reduced contains a materially high percentage
of silver. This material may be separated from
metals, subjecting thesludge to treatment with
sulphuric acid, whereby the sludge volume is re
duced, and treating the sludge to recover metal
therefrom
.
2. A process for the recovery of precious metals
slurry by centrifuging, settling or other similar
treatment and the cake thus obtained, dried, pul_ » ‘from solutions containing only small amounts of
verized and otherwise prepared for reduction to the metals, which comprises adjusting the pH of
silver. by fusion. The pulverized cake is then fed said solutions to between 6.44.8, adding ?occu
lating agent to the solution whereby metal-con
into any conventional fusion apparatus such as taining sludge is produced, treating the metal
45 crucibles, electric or gas fired furnaceslor other
containing sludge with sulphuric acid for reduc-'
‘at
similar equipment employed in metallurgical
. processes.
To these silver materials there is
added a small amount of silica in order to iiux'
any ?occulating or precipitating agents which
80 may have been carried through with the silver,
a small amount of sodium nitrate to prevent sul
phiding of the silver, and a substantial amount
. of soda ash. The fusion step is then carried out
in a manner similar to procedure known in met
tion of ‘sludge volume, and recovering precious
metal from the sludge fraction remaining.
‘ 3.‘A process for the recovery of silver from
waste photographic
'
solutions, which
comprises‘
subjecting. the solutions to treatment with agent
which produces a sludge containing silver, sub
jecting the sludge to treatment with sulphuric
acid, whereby the sludge volume is reduced, and
recovering silver from the sludge fraction re
5% allurgy and a high-grade silver metal is obtained ‘ maining from the sulphuric acid treatment.
therefrom.
'
‘
.
4. A process for the recovery of silver from
' This molten silver may be cast-into anodes and materials containing only a small amount
further re?ned electrolytically or the silver may thereof, which comprises ‘obtaining a solution
be otherwise employed or processed. The slags containing only a small amount‘ of metals, sub
of ‘the type above mentioned may take up valu
jecting the solution to a precipitating treatment
able components such as bromine and iodine. with an agent, ‘whereby a sludge deposit con
, These elements may alsmbe recovered in any
_ desired way from the slags.
/ From a consideration of the preceding exam
ple, it may be seen that we have provided .a sim
ple, efficient, and economic process for the recov
ery of precious metals such as silver from sources
which contain the metal in small quantities. By
means of our acid treatment we are able to re
70 duce the sludge volume to a utilizable quantity
for the removal of metal therefrom. This is par
is
ticularly important inasmuch as the process ini
tially involves the treatment ofmaterials con
taining only very small amounts. of recoverable
metal.
By our novel procedure we have suc
taining silver is obtained, subjecting the newly
deposited sludge to treatment with acid, whereby
the sludge volume is reduced, and further treat
ing the sludge fraction remaining to recover
silver therefrom.
‘
‘ 5. A process for the recovery of silver from
wash solutions obtained in photographic proc
esses, which comprises'adjusting the pH value
of said solutions to between about 6.9 to 7.2, de
positing silver containing materials from the
solutions by means of an aluminum ?oc agent,
subjecting the, newly deposited materials to an
acid treatment whereby the sludge volume is
reduced, and subjecting materials remaining
3
2,131,045
agent which produces a sludge containing silver,
subjecting the sludge to treatment with sulphuric
of silver therefromi
_
‘acid, whereby the sludge volume is reduced, re
6. A process for the recovery of silver from covering silver from the sludge fraction remain
wash solutions obtained in photographic proc
ing from the sulphuric acid treatment, and sub
esses, which comprises adjusting the pH value jecting the recovered silver to electrolysis.
of said solutions, depositing silver from the solu
10. A process for the recovery of silver from
tions by means of a ?oc precipitant whereby a
solutions obtained in photographic proc
silver-containing sludge is produced, subjecting wash
esses, which comprises adjusting the pH value
the sludge to an acid treatment whereby the of said solutions to between about 6.9-7.2 by the
sludge volume is reduced, and subjecting the ‘ addition of an alkali thereto, depositing silver
from the acid treatment to fusion for recovery
ll)
sludge fraction remaining to fusion in the pres
ence of a soda ash, silica, and nitre slag for the
recovery of silver.
‘
.
7. A process for the recovery of silver from
solutions containing only a small -,quantity
thereof, which comprises subjecting said solu
7 tions to treatment with an
agent' which causes
from the solutions by means of an aluminum
?oc agent whereby a'silver-containing sludge is
produced, subjecting the sludge within 36 hours of
deposition‘ to an acid treatment to reduce the 15
sludge volume, and subjecting the sludge frac
tion remaining therefrom to fusion in the pres
the deposition of a silver-containing sludge; sub- , ence of a soda ashslag for
jecting the sludge to treatment for reducing the
volume thereof, treating the sludge remaining to
therefrom.
the recovery of silver’
_
11. A process for the recovery of silver from 20
containing only a small quantity
separate acid slurry, caklng and drying the sludge, - solutions
thereof, which comprises subjecting said solu
and subjecting the sludge to treatment for recov
ering silver therefrom.
'
8. A process for the recovery of silver from
solutions containing only small amounts of the
25 metal, which comprises adjusting the pH of said
solutions to between about 6.9-7.2, adding a sul
phate to the solution which produces a metal
containing sludge, treating the metal sludge with
sulphuric acid to reduce the sludge volume, and
recoveringsllver from the sludge fraction re
maining from the acid treatment.
'
9. A process for the recovery of‘ silver from
waste photographic solutions, which comprisw
subjecting solutions to treatment with sulphate
tions to treatment with an agent which causes
the deposition of a silver-containing sludge, sub
jecting the sludge within about 24 hours after
deposition to acid treatment for reducing the vol
ume thereof, treating the sludge remaining to
separate acid slurry, caking and drying the
sludge, subjecting the sludge to a fusion reduc
tion treatment to produce bar silver, and subject 30
ing the bar silver to electrolysis.
‘
KENNETH C. D. HICEVIAN.
JOHN R. TURNER.
WAL'I'ER J. W'EYERTS.
35
Документ
Категория
Без категории
Просмотров
0
Размер файла
482 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа