recovering silver from photographic processing solutions
TRANSCRIPT
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Eastman Kodak Company, 1999
Kodaks health, safety,
and environmental
publications are available
to help you manage your
photographic processing
operations in a safe,
environmentally sound
and cost-effective
manner. This publication
is part of a series of
publications on silver
management designed
to help you optimize
silver recovery. It will
help you understand
available silver-recovery
EnvironmentI N F O R M A T I O N F R O M K O D A K
J-215 $12.00
techniques.
Recovering Silver from
Photographic Processing Solutions
Silver halide crystals are a majorcomponent of photographic film orpaper. The chemistry of silverhalide image capture and thesubsequent chemical changes thattake place during processing
represent the most efficient form ofhigh-quality image capture knowntoday. Although electronics arechanging the frontier of imagingscience, they will probably neverreplace all silver halide products,but will instead complement theimaging technology.
THE PHOTOGRAPHICPROCESS
As silver halide films and papersundergo the photographicprocessing steps, key changes takeplace in the form and location of thesilver. In color processes virtually100% of the silver comes out of thefilm or paper and remains in one orseveral of the processing solutions.With black and white processes thesilver is split between remaining in
the processed image and migratinginto a photographic processingsolution.
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Recovering Silver from Photographic Processing Solutions J-2152
Silver is recovered from thephotographic processing solutionsfor two reasonseconomic andregulatory (compliance). The tablebelow presents an overview of thethree most common types of silver
recovery.
The technique you choose and themethod you use depends on anumber of factors including: Whether you are recovering the
silver for economic reasons or tocomply with stringent dischargecodes
The volume of solution to betreated
Your budget
Comparison of Silver-Recovery Techniques
Electrolysis Metallic
Replacement Cartridges Precipitation
Recovery Efficiency > 90% > 95% > 99%
Advantages Can produce> 90% pure silver Initial costs are relativelyinexpensive; if used for
compliance; ongoing costs
can be high.
Consistent low silverconcentration. Easy to
monitor preformance.
Disadvantages Relatively high final silver
concentration; may require
secondary recovery
Difficult to know when to
replace; discharges iron;
limited by some sewer codes.
In some cases, not consistent.
Not available for all
processes
Applications All photographic processing
facilities except
very small facilities
All photographic
processing facilities
Very small and
large facilities
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The diagram below details thedifferences between terminalprimary silver recovery, terminalsecondary silver recovery, and in-line recirculation silver recovery.
Unit
#2 Silver
Recovery
Comparisons of Primary, Secondary, and In-Line Silver Recovery
Terminal Primary Silver Recovery(typically electrolysis)
Solution Source
(holding tank or processor)
#1 Silver
Recovery
Unit
Drain
Processor
Fixer
Tank
In-Line
Recirculation
Unit
Terminal
Silver Recovery
and Drain
In-Line Circulation Silver Recovery
Terminal Secondary Silver Recovery(optional, typically MRC)
The amount of silver found inoverflow photographic processingsolutions varies extensively fromsolution to solution. The table at theright shows some of shows theranges that are found in commonprocessing cycles.
Silver Concentrations in Various Overflow Solutions
Solution KODAK Process Silver Concentration
(mg/L)
Bleaches
(Washless Process) C-41 Minilab 5 200
Bleach-Fix RA-4, NR 6,000 10,000
RA-4, NT 3,000 4,000
Fixer Black-a nd -White 3,0 00 7,000
E-6, Tank 1 5,000 12,000
E-6, Tank 2 1,000 3,000
C-41 5,000 12,000
RA-4, separate
bleach and fixer 2,000 10,000
Low Flow Washes RA-4, Tank 1
Low Flow 1,000 3,000
Stabilizers
(Washless Process)
C-41/RA-4
Minilab 100 1,000
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Recovering Silver from Photographic Processing Solutions J-2154
Electrolytic silver recovery is, inmany cases, the most cost-effectiveand efficient way to remove silverfrom silver-rich photographic
processing solutions. However,silver concentrations out of theelectrolytic unit usually are in therange of 200 800 mg/L and sometype of secondary or tailingrecoverytechnique is necessary in order tomeet stringent regulatory dischargelimits. Trying to push mostelectrolytic equipment to treatsolutions lower than about200 mg/L: Is usually not energy or time
efficient
May generate noxiousby-products
Requires larger-than-normal cellsize (high cost)
You can treat almost all fixers,bleach-fixes, low flow washes, andcombinations by electrolysis.
ELECTROLYSIS
There are three basic types ofelectrolysis cells: Fixed cathode
Rotating cathode (or some well-
designed fluid pump throughcells)
In-line recirculation (either fixedor rotating cathode cells with theinstallation of special electroniccontrollers)
Fixed cathode units generally areused for low-iron solutions such asProcess C-41 or black-and-whitefixers. Rotating cathode cells arecommon for solutions that contain ahigh level of iron chelate such as
color paper bleach-fixes. The iron inthese solutions produces anelectrochemical reaction thatcompetes with the reduction ofsilver at the cathode; increased fluidmovement across the cathode isnecessary to produce a higherplating efficiency to offset thiscompetition and provide anadequate desilvering rate. Thedisadvantage of rotating cathodeunits is that they contain more parts,which adds to their cost and
maintenance.
TYPES OF UNITSIn-line electrolytic fixer
recirculation or closed-loop fixerrecirculation, is common in certainblack-and-white and Process C-41color applications. Either kind ofelectrolytic cell will work. The
solution is continually desilveredand returned to the processor tank.The fixer tank is maintained at amuch lower silver level thannormal (0.51.0 g/L versus asmuch as 6.0 g/L or higher). Theresult is a reduced amount of silverbeing carried into the wash tank inthe next processor section.Therefore, you dont need toconcerned with silver concentrationin the wash discharge. Thereplenishment rate of the fixer may
also be reduced by as much as 50%.A colorimetric silver test is an
excellent tool used to adjust andmonitor in-line electrolyticrecirculation equipment to ensureoptimum performance. Too muchsilver being removed by the unitmay result in solution sulfiding anddeposits on the film or paper; toolittle silver being removed defeatsthe purpose of the equipment.
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Recovering Silver from Photographic Processing Solutions J-215 5
Two of the major factors thatdetermine the correct electrolyticunit for a photographic processing
facility to use are the type ofsolution(s) being treated and thedaily volume requiring treatment. Ifyou are going to treat largequantities of bleach-fix, low-flowwash following bleach-fix tanks, orE-6 fixer, you should use a rotatingcathode unit or pump-throughunit specially designed for thisapplication. If you are going to treatonly low iron solutions such asblack-and-white or Process C-41fixers, you can use a simpler (andusually less expensive) fixedcathode unit. Always pay carefulattention to the manufacturersadvertised rate of silver removal.Although occasionally optimistic,these specifications represent thebest approximation of how muchsilver can be removed per unit timeand therefore are key in determiningthe size of cell necessary to meet afacilitys needs. The examples on theright provide a method of
calculation to size an electrolyticunit to your operation.
SELECTING THE PROPERUNIT
Gallons per day of silver-richsolution.
Nature of the Solution
(chart at left).Silver Content (grams/litre) inthe Solution.
Time available (daily, in hours)to run ESR.
NATURE OF EFFLUENT
If Effluent is: Then B =
AreaCathodeRequired
Area
1.1 ft=2
40=
CathodeRequired
=Amps10.6
4 x 8=
AmpsRequired 20 x 3.785 x 4.5 10.6 x 4
EXAMPLE #2
8 hours per day.
A radiography group produces 20 gallons of black-and-white fixer at 4.5 g/L; work time is only
=2
1.8 ft= =40
35.5 x 2
amps3.55
2 x 16
100 x 3.785 x 3=
ampsRequired
ft 210.6amps
AmpsRequiredC
4.5
B
4
g/L
D
8hours
A
gal20
(chart)1.1
CathodeArea
Required
2ft1.8
amps35.5
hours16
g/L3
(chart)2
gal100
AreaCathodeRequired
AmpsRequired
DCBA
busy day. Average silver content is approximately 3 g/L with a second-shift operation.
A consumer lab produces 100 gallons of combined Process RA-4, C-41, and E-6 effluent on a
EXAMPLE #1
40
Amps x B
B x D
A x 3.785 x C
2Determine the Cathode Area Required (ft ) =
Determine the Required Amperage (amps) =
1.5
2
3
4
Bleach-Fix alone
C-41, and/or E-6
Bleach-Fix + Low Flow Wash,
C-41 or E-6 Fixer
Black-and-White Fixer
)(
)(
D =
C =
B =
A =
YOU NEED TO KNOW:
Sizing an Electrolytic Silver Recovery (ESR) Unit
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Recovering Silver from Photographic Processing Solutions J-2156
It is very important that you followthe installation/operation manual
that comes with your new unit. Installthe electrolytic unit in a well-ventilated area with enough roomaround it to allow someone to serviceit. The electricity to the unit must besufficient to provide the voltage/current requirements specified for theunit. Follow the current and timerecommendations suggested in themanual for your type of solution ormixtures. Keep a log detailing criticalparameters (voltage, current,electrolysis time, preventive-maintenance service, generalcomments) to allow a process re-creation in the event troubleshootingbecomes necessary. Use the correctiveactions shown in the troubleshootingtable to optimize your process.
The correct initial unit set-up isessential to good long-term
performance, the quality of silverflake produced, and the ease ofremoving that flake from the cathode(sometimes referred to as mining thecathode). Some troubleshootingguides are included in table at theright. Generally, current adjustment isthe best tool. Surface preparation iskey to easy removal of the silver flakefrom the cathode. We recommendmildly polishing the surface with aScotch-Brite or similar pad prior to
beginning electrolysis. In some cases,where good flake is being formed atthe correct deposition rate but is stilldifficult to remove from the cathode, avery thin coating of automotive waxprior to electrolysis will help. Consultyour equipment manufacturer fortheir advice in this area.Developments in electronics andequipment design over the pastdecade have significantly reducedproblems in this area.
GENERAL TIPS FORSTARTING UP ANELECTROLYTIC UNIT
REMOVING SILVER FROMTHE CATHODE
The table below provides a guide totroubleshooting various problems
that can occur with electrolytic silverrecovery equipment.
Proper pH is important foroptimum performance inelectrolytic desilvering; this is
TROUBLESHOOTING ANDTIPS FOR BETTEROPERATION
especially true for iron-containingsolutions. Increasing pH: Reduces the tendency for iron to
interfere with reduction silverelectroplating.
Makes the cathode reaction for
silver plating energetically morefavorable.
Electrolysis Troubleshooting
Problem Probable Cause Corrective Action
Poor platinglow
silver plating or lost
silver
Current too high
Improper plating time
Adjust current or plating
time
Improper cathode surface
preparation
Scour w/Scotch-Brite-like
pad prior to electrolysis
Sulfiding Current too high for silver
concentration
Plating time too long
Agitation too low
Adjust current or plating
time
Recovered silver not
pure
Current too high, resulting in
sulfiding
Current is not appropriate for
the type of solution being
desilvered
Adjust current or plating
time
Match current neededwith
the type of solution being
desilvered
Nodules on the
cathode or sell
shorts out
Accumulated dirt in the bath
plates or becomes occluded
in the silver plate
Make sure used fixer fixer
is adequately filtered prior
to electrolysis
Silver sulfideformation
(silver platingfalls off
or silver collects in
the bottom of the
cell)
Low sulfide in solution To maintain plating effi-ciency from most fixers,
the concentration of
sodium sulfite should be
8 10 g/L when the silver
level is 1 5 g/L
Platingcurrent toohigh orunit
run too long
Adjust current or time
Solution not
desilvered to proper
level
Low pH Adjust pH
Low current or insufficient
time
Adjust current or time
Electrical problems, bad
connection
Check connections,
consult operation manual
Very dark plate Initial silver concentration of
solution is too low
Adjust current
Platingcurrent toohigh orunit
running too long
Adjust current or plating
time
Always exercise care when working with corrosive chemicals
(use proper eye protection, adequate ventilation, gloves, etc.)
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Recovering Silver from Photographic Processing Solutions J-215 7
Generally, the higher the pH, thebetter. In practice pH should not beincreased above 7.8 8.0 due to theevolution of ammonia that takesplace in ammoniumbased fixers andbleach-fixes. You can use a strong
base, such as sodium (orammonium) hydroxide or sodium(or potassium) carbonate, to adjustthe pH upward. The carbonates arethe safest to work with; thehydroxides are usually the leastexpensive. You can also use pHadjustment chemicals sold by manyswimming pool supply houses.Some examples are given in table onthe right.
Always exercise care whenworking with these corrosive
chemicals; use proper eyeprotection, adequate ventilation,gloves, etc.
You can perform the adjustmentsatisfactorily using most brands ofpH measurement strips. Two typesof strips that perform particularlywell are: colorPHast Indicator Strips
pH 0 - 14, by EM Science,Gibbstown, New Jersey.
Baker pHIX, Universal pH Sticks,range 2.0 9.0.
Obviously, a pH meter worksbetter than pH adjustment papers,but requires significant effort tocalibrate. Consult the video, UsingKODAK Control ToolsHow toMeasure pH(CAT No. 129 5914), for
additional information on pHmeasurement and adjustment withmeters.
If your facility plans to reuse thesolution being electrolyticallydesilvered or is experiencingdifficulty with the quality of silverflake formed, you may wish to add
additional sodium sulfite to thebatch prior to electrolysis. A rule-of-thumb is to add the equivalent of1 g/L of additional sulfite for everyg/L of silver to be removed from thesolution. This will help to prevent
the solution from being degradedand the cathode burned. Neveradd sulfite to Process RA-4 Bleach-Fix, since it significantly reduces theelectrolysis efficiency.
Recommendations for Adjusting the pH of Iron-Containing Solutions
Solution mL of Solution per Litre of
Bleach-Fix Overflow*
* Approximate mL required to raise EKTACOLOR RA-4 Bleach-Fix overflow pH to 7.5 8.0. Use a pHmeter or pH strip to determine exact amount required for your facilitys overflow.
28% Ammonium hydroxide 10
10N Sodium hydroxide 13
45% Potassium hydroxide 14
10% Sodium carbonate 200
10% Potassium carbonate 300
EKTACOLOR RA Developer Tank Overflow 900
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Recovering Silver from Photographic Processing Solutions J-2158
A metallic replacement cartridgecontains metallic iron in a form thatphotographic solutions can passthrough in a controlled manner toallow the silver complexes in thesolution to react with the iron. Thesilver is reduced to its metallic formand stays in the cartridge while theiron is oxidized and passes intosolution. There are many forms ofiron that can be used in MRCs.Some include: Steel wool
Iron filings
Steel screen wire
Iron filings on a rigid support
Most photographic solutions canbe desilvered by the proper use of aMRC or MRC system. Someexceptions include: Black-and-white reversal bleach
Fixer preceded directly byferricyanide bleach
Seasoned ferric-ammoniumEDTA bleach
Fixers with a highly alkaline pHCall Kodak Environmental
Services for information on how todesilver these specific cases.
Some of the pros and cons ofMRC use are shown in the followingtable.
METALLICREPLACEMENTCARTRIDGES (MRCs)
Pros and Cons of MRC Desilvering
Pros Cons
If used properly, can be very efficient for
low silver compliance.
MRCs are relatively inexpensive and
work reasonably well with a broad range
of solution types. The metallic replacement process is a
simple technology not requiring a high
degree of sophistication to perform.
It is easy to monitor canister
breakthrough, especially with a
colormetric silver test.
Breakthrough can be estimated by
keeping records of time in service and
volume throughout.
Although capable of good efficiency, a
less than optimum performance is
common.
Spentcanisters aremore costly to refine
than silver recovered by othertechniques.
MRCs are dependent upon contact time
with steel media and therefore require
good control of solution flow rate.
MRCs frequently require a "break-in"
period and work best when used
continually with no breaks in service.
Monitoring required to detect
breakthrough.
MRCs discharge iron to the effluent.
The single biggest factor influencingthe performance of MRCs is theresidenceor dwell time of thesolution in the cartridge. In actualpractice, the cartridges are usuallyused in pairs for performance safety.You can control solution flow eitherby gravity feed through a flow-restricting orifice or by a meteringpump. Almost always, metering
pump systems do a better job.Always follow the flow raterecommendations provided by themanufacturer of your MRC. If youmust, use a longer residence timerather than a shorter one. Althoughthis may dissolve the steel slightlyfaster than necessary and reduce theultimate capacity of the cartridge,too little residence time can lead tohigh silver discharges from thesystem.
CHOOSING THE PROPERUNIT
Each MRC has a fixed amount ofsteel in it. As this is consumed by thedesilvering process the MRC willeventually decrease in its capacity toremove silver from the solutions.MRCs are normally used in pairs(series)*, preferably with a samplingport placed between individualunits. Samples are taken from theport and silver concentrationmeasured by some convenient
technique such as estimating paper,copper strips or a colorimetricmethod. (See KODAK PublicationJ-211,Measuring Silver inPhotographic Processing Facilities,for additional information onmeasuring silver.) When either ofthese tools detect silverthecolorimetric method is much moreaccurate and reproducibleyoushould replace the cartridges.
USEFUL LIFE OF MRCs
* A few customers have used3 MRCs in series
for added insurance.
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Recovering Silver from Photographic Processing Solutions J-215 9
Generally, you remove the firstMRC, move #2 into the #1 position,and place a new unit in the #2position. If strict silver compliance isnecessary, you can replace bothcartridges at the same time.
You can use Metallic ReplacementCartridges as a primary (and only)system or as a secondary or tailingsystem following electrolysis. Acommon misconception is thatcartridges will work much longerbefore replacement when they areused for the tailing operation (i.e.,due to less silver removal). This istrue, but the natural corrosivity tosteel of many photographicprocessing solutions consumes steelwool even when silver is not being
removed. Always monitor thesystem to detect breakthrough, andreplace the cartridges on a regularbasis.
You must monitor (and sometimescontrol) the pH of the solutionpassing through the system. Tooperate most efficiently, the pH ofthe solution needs to be acidic to
encourage the steel wool to dissolve.Most photographic fixers andbleach-fixes have an acceptable pHrange. Ideally, the pH should bebetween 5.5 and 6.5. If the pH isbelow 5.0, the steel wool will becatalyzed to dissolve too rapidly andthe capacity of the cartridge could bereduced significantly. If the pH is
ADJUSTMENT OF pH
basic (above 7), the steel wooldissolution reaction will be slow andoptimum silver removal may nottake place.
You can adjust the pH upward ordownward with acetic acid or pH
adjustment chemicals found atswimming pool supply stores.Again, pH papers are sufficient tomonitor this adjustment.
MRCs work best when they are pre-conditioned by allowing to stand forseveral hours with a mildly acidicsolution such as fixer or bleach-fix inthem. This allows the steel wool to
PRE-CONDITIONING MRCs
begin to etch or becomechemically activated for silverrecovery. At the very least, fill a newMRC with water to begin tochemically prepare the steel surfaceand minimize the potential to
channel or form pathways that donot contact the steel wool once it isplaced in service.
You will obtain the bestperformance and longest life bycontinuous use with approximatelythe same solution composition/mixture. Intermittent or infrequentuse of MRCs allows the steel wool tooxidize or rust. Once this processhas begun, it is very difficult topredict the useful life of thecartridge.
MRC Troubleshooting
Problem Probable Cause Corrective Action
Cartridge becomes
exhausted too quickly
Flow rate too high
MRC too small for
application
Adjust flow rate
Use larger MRC
pH of solution too low Raise the pH
Loss of recovery efficiency
Lower silver yield thanexpected
Highsilver concentration
out of MRC
Solution discharged is
untreated
Solution pH too high
Flow rate too high Cartridge not
"preconditioned"
Solution flow pattern
causes steel wool
erosion to form a
channel; solution is able
to pass untreated. (This
is a possible result of
low volume or
intermittent usage.)
Lower the pH
Adjust flow rate Soak with solution prior
to installing
Pre-condition MRCs
before installation. Use
a mildly acidic solution,
fixer, bleach-fix, or at
the very least, water
Flow has become
plugged allowing MRC
by-pass
Look for obstructions to
flow; may be as simple
as a "crimped tube"
Plugged drain lines Precipitation of iron
hydroxide
Use an acid-type drain
cleaner when changing
MRC
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Recovering Silver from Photographic Processing Solutions J-21510
Chemical precipitation, or theaddition of a chemical to thephotographic processing solution tocause an insoluble silver salt to form,
has not been popular in the pastexcept at large centralized waste-treaters. Over the past several years,Kodak has developed a newprecipitation technology based onTri-sodium 2,4,6-Trimercapto-s-triazine, more commonly called (forobvious reasons) TMT. TMTprecipitation technology wasinitially optimized for use assecondary treatment followingelectrolysis at large photographicprocessing facilities. The advantagesof the technique versus traditionalsecondary treatment with MRCs are: More consistent low silver results
Lower cost over the long-term
Reduced refining cost of theresulting silver sludge
Less labor required
PRECIPITATIONLarge-scale secondary recovery
can be very simple. However, youshould follow certain procedures.You must use the proper TMTdosage for the silver level of themixture under treatment.
Consistently mix the same solutions(day after day) and use acolorimetric silver test to determinethe correct dosing level. Typically,the silver concentration of thesolution mixture before treatmentshould not be below 300 mg/L.Choose the proper electrolysisconditions during primarytreatment. If you use the properTMT dosage level and do not obtainacceptable final silverconcentrations, consult the
following table.
Large-Scale Secondary Precipitation Troubleshooting
Concern Probable Cause Corrective ActionFinal silver concentration
too high
Improper dosing Determine initial silver concentration of
mixture and adjust dose
Try to treat as consistent a mixture of
overflow solutions as possible
Insufficient settling time Optimize using a controlled study
Silver concentration before treatment less
than 300 mg/L
Adjust electrolysis conditions with
primary equipment
Settled sludge volume exceeds stand-pipe
height. (You may see excessive yellow solid
getting to final filter.)
Adjust stand-pipe height
Line purge step has been skipped or
shortened
Lengthen purge line
Improper filter cartridge or improper
installation
Check filter type and installation
Several manufacturers now makecustomized equipment forautomated secondary precipitationtreatment with TMT.
In 1995, Kodak introduced a semi-automatic unit designed to serve as
the primary silver-recovery unit forsmaller Process C-41, Process RA-4,and Process E-6 photographicprocessing facilities. This unit hassignificantly changed the way silveris recovered at many smallphotographic processing facilities.Some of the features of the unitinclude: More consistent low silver results
Less labor (almost fully-automaticoperation)
Lower refining cost of the
resulting silver sludge
Less floor space required
Easy-to-monitor performance
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Recovering Silver from Photographic Processing Solutions J-215 11
The operation of the semi-automatic unit makes silverrecovery as simple as it can get;however, you must keep an eye onseveral very basic items. Like large-scale TMT recovery, proper dosing
level is important with the semi-automatic unit. The Part B flocculantmust be mixed properly and withinmix age to ensure the formation oflarge "scrambled egg-like" particlesthat easily separate from the liquidphase of the treated solution. Toguarantee easy solution flowthrough the unit, you must rinse thesystem according to themaintenance schedule in theoperator's manual and you mustoccasionally clean the particle screen
in the unit's hold tank. Althoughthese items may seem cumbersome,proper routine maintenance on theunit is by far the least time-consuming of any type of functionalsilver-recovery equipment today.
Semi-Continuous Precipitation Troubleshooting
Concern Probable Cause Corrective Action
Final silver concentration
too high
Improper Part A dosing Determine initial silver
concentration of mixture
and adjust Part A dose.
Always treat solutions in
"as replenished" propor-
tions. If you periodically
dumpyour stabilizer tanks,
try to blend this solution
gradually with the other
overflows.
Part B is either not mixed
properly or is very old.
(Another clue is lack of
formation of "large
particles" in the reactor
tubing prior to the filter.)
Refill the Part B reagent
tank with a fresh mix of
Part B.
Short filter life Equipment not forming
large particles (i.e., a lotof"dust" instead of clumps).
Check Part A & Part B
delivery rates. Checkinitialsilver concentration to
verify at least 1 g/L
concentration. Modify
procedure for stabilizer
dump to increase silver
concentration, if
applicable.
Slow flow-through
system
Tubing is beginning to
plug
Rinse system according to
Users Guide
The screen on the pump
suction line in the
collection tank is plugged
Clean screen per Users
Guide
Pumps need calibratingorcheck valves require
cleaning
Check flow rate of eachpump using the calibration
procedure in Appendix C
of the Users Guide;
remove and clean the
check valve.
Semi-automatic unit will
not run, although
plugged in and turned on
Solution level in collection
tank is low
This is part of the normal
operation; youdo not need
to take any corrective
action.
Low level in Part A tank;
not indicated by status
light
Check solution level in
Part A tank and refill, if
necessary. Replace
indicator bulb,if necessary.
Low level in Part B tank;
not indicated by status
light
Check solution level in
Part B tank and refill, if
necessary. Replace
indicator bulb, if
necessary.
High system pressure; not
indicated by status light
Check sludgelevel in filter.
Replace, if full.
Replace indicator light
bulb, if necessary.
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EASTMAN KODAK COMPANY ROCHESTER, NY 14650
Revised 7/99
Recovering Silver from PhotographicProcessing SolutionsKODAK Publication No. J-215
CAT 804 1576
If you have environmental or safety questionsabout Kodak products or services, contact KodakEnvironmental Services at 1-585-477-3194,between 8 a.m. and 5 p.m. (Eastern time) or visitKES on-line at www.kodak.com/go/kes.
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MORE INFORMATIONThe following publications are available from
Kodak Customer Service or from dealers who sell
Kodak products.
J-210 Sources of Silver in Photographic Processing
Facilities
J-211 Measuring Silver in Photographic Processing
Facilities
J-212 The Technology of Silver Recovery for
Photographic Processing Facilities
J-213 Refining Silver Recovered from
Photographic Processing Facilities
J-214 The Regulation of Silver in Photographic
Processing Facilities
J-216 The Fate and Effects of Silver in the
Environment
J-217 Using Code of Management Practice to
Manage Silver in Photographic Processing
Facilities
For more information about Kodak Environmental Services,
visit Kodak on-line at:
www.kodak.com/go/kesMany technical support publications for
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