All About Silver Button Batteries.

All about silver button batteries.
Not all button batteries contain silver,actually there are three principal types of button
batteries:Lithium,Manganase dioxide (MnO2) and Silver oxide (Ag2O) ,used all of them
for watches,hearing aids,digital thermometers,cameras,computers,calculators,keyless car
devices,Ipods and so for.Once that they have finished their useful life you can get them in
watch repairing sotres,jeweleries,computer reparing stores and recover all value metals that
they contain.
Since spent batteries are not completely discharged they can short circuit and blow up if
you storage them in an inaproppriate way.To avoid this risk put them in a layer over a
plastic bag and continue making layers of batteries with plastic bags until you storage all of
them.This is the safe way you can storage and transport spent batteries.
Lithium batteries are easily recognized because they are very flat,just like a coin,and
behind of these batteries are the letters “CR” followed by a serial of numbers,besides,they
have the legend “LITHIUM 3V”.These batteries do not contain silver,but you can recover
the lithium.(See U.S. Patent 549103,U.S. Patent 6120927,U.S. Patent 5888463,U.S. Patent
20030180604 and U.S. Patent 20070292746).
MnO2 and Ag2O button batteries at first look seem like the same but MnO2 batteries do
not contain any silver,so our first task is to recognize Ag2O batteries.The trick is to take a
look behind each button cell.All silver oxide batteries have a manufacturer´s name,a
number between 301 to 399 or the letters “SR” and a number between 43SW to
1130W,with a little practice you will be an expert.Here is the list of button batteries that
contain silver:

MANUFACTURER

NUMBER CODE

RENATA
EVEREADY
VARTA
DURACELL
ETA
GP BATTERIES
PAKKO

From 301 to 399
From 301 to 399
From V301 to V399
From D301 to D399
From 301 to 399
From GB301 to GP399
From 301 to 399

SONY
PANASONIC
SEIZAIKEN
SWISEBAUCHERS
MAWELL
MALAM

From SR43SW to SR1130W
From SR43SW to SR1130W
From SR43SW to SR1130W
From SR43SW to SR1130W
From SR43SW to SR1130W
From SR43SW to SR1130W

For best understanding you can consulte the manual standars from manufacturers on their
web sites,I will provide you a quick cross reference (from GP Batteries):

Silver Oxide
Button
Dimensión
Nominal
Model Voltage
Capacity Diameter Height
GP
(V)
IEC
(mAh)
(mm)
(mm)

Material Safety Data Sheet
Referencias
JIS EVEREADY VARTA DURACELL

SONY

GP301

1.55

120

11.6

4.2

SR43 SR43

301

V301

D301

SR43SW

GP303

1.55

165

11.6

5.6

SR44 SR44

303

V303

D303

SR44SW

GP315

1.55

21

7.9

1.65 SR67 SR67

315

-

D315

SR716SW

GP317

1.55

11.5

5.8

1.65 SR62 SR62

317

V317

D317

SR516SW

GP319

1.55

20

5.8

2.7

SR64 SR64

319

-

D319

SR527SW

GP321

1.55

16

6.8

1.65 SR65 SR65

321

V321

D321

SR616SW

GP329

1.55

37

7.9

3.1

-

-

329

-

D329

SR731SW

GP337

1.55

7.5

4.8

1.65

-

-

337

-

-

SR416SW

GP348

1.55

12

4.8

2.15

-

-

-

-

-

SR421SW

GP357

1.55

165

11.6

5.4

SR44 SR44

357

V357

D357

SR44W

GP362

1.55

24

7.9

2.1

SR58 SR58

362

V362

D362

SR721SW

GP364

1.55

23

6.8

2.15 SR60 SR60

364

V364

D364

SR621SW

GP366

1.55

33

11.6

1.65

366

-

-

SR1116SW

GP370

1.55

44

9.5

2.1

SR69 SR69

370

V370

D370

SR920W

GP371

1.55

44

9.5

2.1

SR69 SR69

371

V371

D371

SR920SW

GP373

1.55

26

9.5

1.65 SR68 SR68

373

V373

-

SR916SW

GPS76E

1.55

130

11.6

5.4

SR44 SR44

-

V76PX

MS76

SR44W

GP377

1.55

25

6.8

2.6

SR66 SR66

377

V377

D377

SR626SW

GP379

1.55

14

5.8

2.15 SR63 SR63

379

V379

D379

SR521SW

GP381

1.55

40

11.6

2.1

SR55 SR55

381

V381

-

SR1120SW

GP384

1.55

42

7.9

3.6

SR41 SR41

384

V384

D384

SR41SW

GP386

1.55

120

11.6

4.2

SR43 SR43

386

V386

D386

SR43W

GP389

1.55

70

11.6

3.1

SR54 SR54

389

V389

D389

SR1130W

GP390

1.55

70

11.6

3.1

SR54 SR54

390

V390

D390

SR1130SW

-

-

GP391

1.55

40

11.6

2.1

SR55 SR55

391

V391

D391

SR1120W

GP392

1.55

42

7.9

3.6

SR41 SR41

392

V392

D392

SR41W

GP393

1.55

70

7.9

5.4

SR48 SR48

393

V393

D393

SR48W

GP394

1.55

60

9.5

3.6

394

V394

D394

SR936SW

GP395

1.55

55

9.5

2.7

SR57 SR57

395

V395

D395

SR927SW

GP396

1.55

30

7.9

2.65 SR59 SR59

396

V396

D396

SR726W

GP397

1.55

30

7.9

2.65 SR59 SR59

397

V397

D397

SR726SW

GP399

1.55

55

9.5

2.7

399

V399

D399

SR927W

-

-

SR57 SR57

High Voltage
Dimensión
Capacidad
Voltaje
Modelo GP
Nominal Diámetro Altura
(V)
IEC
(mAh)
(mm)
(mm)
GP476

6.0

165

13.0

Material Safety Data Sheet
Referencias
JIS

25.2 4SR44 4SR44

EVEREADY VARTA DURACELL
-

V28PX

PX28

As a rule of thumb,biggest batteries are MnO2,smallest batteries are Ag2O
If the manufacturer is not in this list probably the battery is MnO2 type,besides these
batteries have the letters “LR”,or say “ALKALINE BATTERY” and a number between
301 to 399.Usually MnO2 batteries do not have manufacturer´s name and are made in
China..
Remember.your health is first,use gloves,mask and the procedures to handle corrosive/toxic
substances.
If you are in doubt,take the battery,make six cuts on the edge each 60 grades as showed:

push down with a screwdriver in the middle of each cut just to make a daisywheel:
Take off the front part and inside you will see a black/grey pellet,which suppose to be a
mixture of Ag2O/Ag:

Put this pellet in a glass vessel,add nitric acid and if it dissolves (and makes positive the
silver test adding common salt and forms white clumbs) then it is a silver oxide battery,if it
does not dissolve then it is a MnO2 battery.
From my own experience the composition of 1 kilogram of mixed spent button
batteries(Li,MnO2 and Ag2O) is:

Manganese dioxide type
350 gr.

Lithium type
150 gr.

Silver oxide type
500 gr.

Once that you have selected the two types of button cells then it is time to recover the
value metals.
MnO2 batteries have little value,but there is a process for recovering the MnO2,Fe,Ni and
Zn,see U.S.Patent 4992149.
Ag2O batteries contain a Ag2O/Ag mixture pellet indise,so let us go for it.There is a
process for recovering without fumes generation,see U.S. Patent 5221325.I tried this
process but I did not get the silver yield expected,probably I did something wrong but you
can try it and get better results than I.
I prefer the nitric acid method,consists on making a cut on the edge of the battery using a
simple pair of pliers,if you have a metal mill you can crush them.Our goal is just to let the
acid get inside the battery.

Put 250 gr. of cut/crushed batteries in a one plastic galon container,add exactly one litre of
nitric acid,instantly you will see the brown fumes of NO2,so you have to use a scrubber to
absorb these fumes in a NaOH solution or do it outside.
It is very important to keep the proportion of 1litre of nitric acid/250 gr. of batteries,less
acid will not dissolve the Ag2O/Ag mixture,too much acid will dissolve all the battery
generating a lot of NO2 fumes.
In half an hour you will see there is not more NO2 brown fumes,this means that all silver
compounds are dissolved.Carefully filter and pour off the liquid into another container and
wash the metallic remainder with tap watter for three times adding the washes to the liquid
container.The metallic remainder is Fe and Ni that you can sell it to metal scrapers.

The liquid of the container is a mixture of nitrates(AgNO3,ZnNO3 and HgNO3) but we
have got to recover the mercury first because it is extraordinary toxic for environment and
humans.Add common salt to the liquid and you will get a white precipitate of white clumps
of AgCl and HgCl,stirr well,let settle down,wash with tap water,let settle down again and
pour off the washes.
To the white precipitate add NH4OH until all the white clumps dissolve,you will see at the
bottom there is a black precipitate of Hg(NH2)Cl,filter the liquid,wash the filter and keep
the black powder of Hg(NH2)Cl in a secure and hermetic container to recover the Hg.
To the filtrated liquid add HCl to reprecipitate the AgCl forming the white clumps
again,now free of mercury,so you can process it as the standard way,adding NaOH,wash
and add Karo syrup and you will get 0.999 silver.
From my own experience you can get 300 to 350 gr. pure silver from one kilogram of
spent silver oxide batteries.Stop asking God for a gold mine because you have already
found an urban silver mine.
Comments and questions are welcomed
Manuel