precious metals recovery brochure

8/14/2019 Precious Metals Recovery Brochure

1/32

Precious MetalExtraction Solutions


2/32

ExtractionPrecious M


3/32

FLSmidth draws from the Metallurgical, Instrumentation,

Mechanical and Mining Engineering, Structural Design,

Project Management and Maintenance disciplines.

Today, FLSmidth strives to provide competitive quality

process engineering and equipment to the same industries

first envisioned in 1990. FLSmidth has installed equipment

and completed engineering services in eight countries onfour continents around the world. FLSmidth leads the

world in gold electrolysis and mercury vacuum distillation

and is a world leader in indirect fired rotary kilns and

packaged carbon strip systems.

ADR Plant for Power Generation, Distribution &

Supplies, and Material Delivery Systemstal

3


4/32

(Above) Typical 4 Cell Single Train Installation

(Left) 150 cu ft E/W Cell Installation showing ease of

Access w/ Lid Open Note security locks on front

Electrowinning Cells


5/32

(Top) 50 cu. Ft. Cell w/Support Frame

(Bottom) Typical 4-cell two train installation

Key Features

Cells are sludging design using FLSmidths patented

high efficiency basketless cathodes.

Cathodes are 304 SS punched plate, wrapped in

knitted stainless steel mesh.

Anodes are 304 SS punched plates. Speciality materials

and designs are available where adverse solution

chemistry requires them.

Sludge is harvested in-cell by direct washing from the

cathodes. Cathodes and anodes remain in the cell for

harvesting. Cells operate closed under a slight vacuum for

excellent Industrial Hygiene (important where Ag or Hg

is present) No external hoods or other ventilation

systems are required for the cell area.

Low maintenance and labour costs.

Typical wash time 2 -3 hours once per week

Cells lids open full width for access to electrodes. No

heavy lifting required hence no overhead crane.

Tanks are robust - 304 stainless steel with

polypropylene liners submerged and bolted inside cell

for insulation.

Minimal fire risk - cell is closed in operation and most

plastic is submerged in electrolyte

Compact design resulting in small installation footprint

= lower construction costs.

Cell design provides for all security, ventilation, and

cathode washing activities to take place within the

lidded cell, avoiding costs for cranage for lifting loaded

cathodes from the cell, cathode washing tanks, and

ventilation hoods.

Basketless Cathodes

FLSmidth offers a new electrowinning cell basketless

cathode designed to decrease operator service time and

decrease gold inventory in the cells while providing

continued high cell efficiencies characteristic of Summit

Valley cells. Gold sludge servicing is performed in the cell by

washing precious metal sludge from the cathodes with a

pressure sprayer. Sludge is pumped from the cell bottom

via. the sludge outlet flange to a sludge filter. Since the

cathodes are serviced in the cell, less cathode handling is

required during servicing. Less cathode handling decreases

operator exposure to toxic metals when present in

electrowinning solutions, i.e. mercury, arsenic, cadmium.

The new electrodes eliminate the need for cathode baskets.


6/32

(Above) 5 Metric ton fuel oil fired carbon reactivation kiln

(Right) 12 Metric ton fuel oil fired carbon reactivation kiln

CarbonRegeneration Kilns


7/32

(Top) Summit Valley patented kiln seal

(Bottom) Control panel mounted on kiln skid. The

complete skid is pre-wired in the shop.

7

FLSmidth Kilns Feature:

Sizes: 1 12 tonnes per day.

Heating: Electric, LPG, or Fuel Oil systems

Packages included feed hopper, dewatering feed

screw, local control panel and quench tank

Complete unit skid mounted for installation on flat

concrete floor

Fired and tested before shipment.

Effective low maintenance trunnion seals provide with

12-18 months life (Patented)

Carbon burn is minimal Temperature range 600 - 750 C

Long life 253 MA alloy tube

Design uses entrained moisture in carbon to generate

steam for regeneration.

FLSmidth designs and manufactures indirect heated carbon

regeneration kilns and calciners from 1/2 ton per day and

larger. Our kilns and calciners can be fuel gas, oil, or

electric, and are skid mounted, pre-wired and pre-piped.

We also design and fabricate the structural steel required

for elevated installation.

FLSmidths patented (US Patent 5,551,870) bellows kiln seal

has proven effective in eliminating air ingress and process

gas egress. We have retrofitted clients kilns, from other

manufacturers, to use this seal.

Temperatures for carbon regeneration and time at tempera-

ture are important factors in regeneration of carbon. Drying

prior to regeneration is counter-productive. (ref.: Activated

Carbon for Precious Metals Recovery; William Faulker et

al, Calgon Carbon Corp.; presented at the 110th Annual

Meeting of the Society of Mining Engineers; Denver, CO;

1987). The steam generated from the feeding of wet

carbon is found to be critical to obtaining good carbon

activity during regeneration. Kilns with pre-dryers have

been found to produce inferior results to kilns without

pre-dryers.

Under normal conditions, alloy RA252MA is the material of

choice for carbon regeneration kiln tubes. This alloy offers

good corrosion resistance and structural properties at the

operating temperatures required for carbon regeneration.


8/32

Summit Valley Mercury Retorts

Mercury Retorts


9/32

(Top) Interior of 30 cubic foot capacity

retorts shown during loading.

(Bottom) Mercury Retort - Fluorescent

Tube Recycling Plant

9

FLSmidth manufactures mercury retorts and vacuum

distillation ovens ranging from 0.5 cubic foot to 40 cubic

feet material capacity. Both gas and electric models are

available. Gas fired retorts are of classic retort design with

the retort being externally heated. Electrically heated retorts

can be built as classic externally heated retorts, or internally

heated vacuum distillation ovens. In general, the internally

heated electric vacuum distillation ovens are the most

economical design. However, the internally electric heated

models do have some limitations when the retort feed

materials contain elemental sulfur or sulfide minerals thatoxidize to produce sulfuric acid gas, which can attack the

heating element material.

Mercury condensing and handling systems are included

with all retort systems. Custom condensing and mercury

handling systems can be provided to meet specific custom-

er requirements. Most retort systems designed and manu-

factured by FLSmidth have been tailored in some manner to

meet specific customer requirements. FLSmidth can also

supply closed loop refrigerated water systems for installa-

tions where adequate cooling water is not already available

for the mercury condensers. FLSmidth designs to meet all

North American and international mercury emissions

standards.

Our latest generation of 30 and 40 cubic foot internally

electric heated retorts have no equal for processing high

volume, high mercury materials such as Merrill-Crowe

precipitates. These retorts have cycle times of approximately

24 hours and can produce a product that contains less than

0.01% mercury. By placing heating elements between the

pans, all material is thoroughly heated, assuring proper

mercury removal. Large volume, externally heated retorts

may not achieve thorough material heating. One Summit

Valley installation operates eight 30 cubic foot retorts,

capable of treating up to 24,000 lb. per day of Merrill-

Crowe precipitate containing 20% mercury. At full produc-

tion rates, 4,800 lb. per day of mercury is recovered.

While FLSmidths largest retort market is for precious metals

extraction and refining, We manufacture retorts for

fluorescent lamp powder recycling and hazardous waste

processing. Additionally, FLSmidth has the expertise to

tackle unusual retorting problems such as selenium and

cadmium in the feed material.


10/32

(Above) Clarification Filter Installation 700 m3/hr plant

(Right) 750 m/hr Merill Crowe Plant Zinc Feeder/Precip

Pump area

0

Merrill Crowe Plants


11/32

(Top) 3.4 cu m/hr Skid Mounted Plant.

(Bottom) Deaeration Tower 700 m3/hr plant

1

Features

Plant capacities range from skid mounted 3.4 m3/hr

modular plants to full size 2100 m3/hr noting that due

to de-aeration tower transportation and fabrication

limits plants larger than 700 m3/hr generally consist of

two or three modules e.g. the 2100 m3/hr plant cited

above consisted of three 700 m3/hr parallel streams

The range of supply for plants includes clarification

filters, de-aeration tower(s), vacuum pump(s), zinc dust

feeder , lead nitrate feeders and zinc cone, precipitate

filter feed pumps, filter pre-coat and body feedsystems, and precipitate filters followed by refinery and

smelting facilities to produce gold bullion.

Application is principally to treat high silver bearing

gold ores(>5:1 Ag/Au ratio)

Plants incorporate Summit Valleys proprietary zinc

dust/lead nitrate feeder and mixing cone system

FLSmidth offers individual plant components, and

partial or complete plant equipment packages,

together with total plant design G.A.s, P.&I.Ds,

foundation and concrete design, pipe and steel

fabrication drawings (detail by fabricators), and even

buildings and furniture etc for the plant and

supporting facilities as required


12/32

FLSmidth has considerable experience in the design and

supply of integrated packages for these areas and is able to

provide the following services in support of these packages:

Complete Flow sheet development, P&IDs, Piping and

Electrical requirements and Plant area layout GAs Equipment specification, sizing, and supply

Detailed Concrete, Structural steelwork, Piping,

Electrical, and Building designs

Local Fabrication and Procurement of piping structural

steel

2

Integrated Gold Roomand Plant Packages

In some cases these will be stand-alone plants and, in

others cases, integrated sections designed to fit in with

existing designs and facilities in the clients related plant

areas. To the extent possible FLSmidth uses existing designs

and packages from other projects to expedite the design,construction and procurement in these packages to reduce

not only engineering and design costs but also to shorten

times for the plant schedules. In these areas FLSmidth

typically works very closely with the client and their EPCM

engineers.


13/32

13

Merrill Crowe Plant Packages

Typically these will include the

following major components

1. Clarification filters

2. De-aeration Tower and vacuum

pump(s)

3. Zinc feeder and Lead Nitrate

addition systems

4. Precipitation Filter feed pumps

5. Precipitate Filters

6. Pre-coat and body feed tank(s)and pumping systems for the

clarification and precipitate filters

7. Precipitate smelting and gold

refining systems including flux

mixing, drying ovens, smelting

furnace, molds, slag pots,

ventilation and merury removal

systems as required

8. Engineering and design for

concrete, piping, structural steel,

tankage, instrumentation,

electrical, ventilation and building

enclosure.

Carbon Adsorption Plant

Packages

FLSmidth has considerable experience

in the design of Carbon Adsorption

Plants in capacities ranging from

primary gold recovery to scavenging

and clean up of heap leach mine sites

after operations have been

completed. Effectively they are

applicable wherever gold and silver

are to be recovered from lower grade

clear solutions.

Typically these will include:

1. Countercurrent Carbon contact/

adsorption tanks and/or

multistage columns.

2. Carbon elution column systems

with supporting screens, strip

solution heating and heat

exchanger packages.

3. Electro-winning cells and

rectifiers.

4. Sludge filters, drying ovens, and

smelting equipment.

5. Carbon regeneration kiln

6. Carbon acid wash system


complete layout, concrete,

piping, structural steel, tankage,

instrumentation, electrical,

ventilation and building enclosure

as required.

Carbon Elution and

Electrowinning Packages

FLSmidth holds patents for two

significant developments in this area

namely the development of the

Basketless Cathode (sludging) cell and

the innovative split Zadra carbon

elution process.

Typically this package will include:

1. Carbon screen

2. Elution column (s)

3. Strip solution heating skid

4. Heat exchanger skid

5. Stainless steel basketless cathode

(sludging) electro-winning cells

and rectifiers

6. Sludge pump and filter system

7. Supporting ventilation systems

8. Supporting tanks and pipework.

9. Structural steel, piping, electrics

and instrumentation as required


14/32

4

Mercury Removal and

Recovery Plants

FLSmidth designs and supplies

vacuum retort mercury recovery

systems. The incoming material is

dried, pulverised and loaded into

trays for insertion into the vacuum

retort. The mercury volatilizes and issubsequently cooled and condensed

with chilled water and recovered as

liquid mercury into flasks. The

remaining gas is scrubbed in a

sulphidised carbon tower where

mercury levels are reduced to EPA

levels. The vacuum system ensured

that there is no leakage of mercury

into the atmosphere from the retort.

These retorts are used for treating

gold sludges afrom electrowinning

circuits and also for cleaning upindustrial wastes e.g. fluorescent

tubes

The carbon scrubbing system is also

used for cleaning up off gas from

heated tanks and also for treating kiln

off gas as required.

Typically this package will include a

material preparation section where

the incoming material to be treated

will be crushed and pulverised, and

loaded into trays for insertion into the

retort. Upon completion of the cycle

these trays are removed and the

cleaned material passed on theremaining process steps.


1. Material preparation (crushing/

pulverization) for industrial

wastes but not required for E.W

sludge

2. Suitable trays to hold the

material for insertion into the

retort

3. An electric heated retort oven

4. A two stage mercurycondensation section

5. Sulphidised final gas scrubbing

column

6. Supporting bins and material

handling systems for the spent

material

7. Mercury flasks to hold the

product for subsequent sale

Complete Gold Electrowinning

and Refining Packages

FLSmidth will design and supply

complete integrated area packages

for the stripping of the carbon, the

electro-winning and recovery the gold

from the strip solutions, filtration,

drying and smelting of the resultantsludge from the E/W process, the

regeneration of the carbon in a

horizontal kiln and the acid washing

of the reactivated carbon before

returning it to the leach circuits.

Typically this package would include:

1. Initial Carbon screen

2. Elution column(s)

3. Heating system skid

4. Heat exchanger skid (sometimes

combined)5. Stainless steel basketless cathode


and rectifiers

6. Sludge filter feed pump and plate

and frame filter

7. Drying oven

8. Flux mixing system (if required)


15/32

1

9. Smelting furnace

10. Bullion Molds

11. Slag pots

12. Bullion Safe

13. Stripped carbon dewatering

screen, and holding tank

14. Carbon Feed bin and kiln feed

screw system w/final dewateringscreen

15. Horizontal carbon regeneration

kiln

16. Carbon Quench tank

17. Acid Wash column


19. Supporting tanks and pipe work.

20. Miscellaneous required

equipment e.g. safety showers,

security systems etc

21. Structural steel, piping, electrics,

instrumentation security systemsdesign as required

22. Area building design if required.

23. Design drawings and layouts

required for concrete, structural

steel, P&IDs, electrical, piping

Integrated Package and Plant

Benefits

1. Integrated systems are designed

for all components to workeffectively together with high

efficiency.

2. Summit Valley equipment has

OEM agreements with most

external suppliers and prices

accordingly.

3. Designs are based on existing

engineering drawings and

layouts from previous projects

reducing engineering costs.

4. Layouts consider operator and

maintenance requirements for

efficient operation as well as

appropriate vehicular and

maintenance equipment access.

5. Integrated plant package reduces

commissioning time and

expenses during start up time.

6. All equipment provided has been

tried and tested in other

installations ensuring reliability

and suitability for the purposes.

7. Summit Valley equipment is

designed to provide process

efficiency, minimise labour and

maintenance manpower

requirements and can be installed

in compact layouts.

8. Proprietary Summit Valley designs

for the elution/electro-winning

circuit can provide energy savings

of 25% over conventional

design.

9. FLSmidth will work with the

major engineering firms to

incorporate our designs and

equipment effectively into theoverall plant design.

10. Large engineering firms we have

done packages with include:

Fluor Corp.

Aker Kvaerner (Aker Solutions)

SNC Lavalin

Ausenco

11. Benefits for the client include:

Lower engineering,

procurement and process

design costs

Access to FLSmidth knowledgeand experience with recovery

of metals from cyanide

solutions in a broad range of

processes and conditions.

Efficient and faster engineering

and procurement processes.

Designs are optimised for the

specific solution tenors and

chemistry at the site.

Efficient and compact layouts.

Reliable and easily maintained

equipment with good

performance history in other

installations we have done


16/32

www.flsmidth.comCopyright 2012 FLSmidth A/S. ALL RIGHTS RESERVED. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations or

warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time.

FLSmidth Summit Valley

FLSmidth Salt Lake City, Inc.

7158 S. FLSmidth Dr.

Midvale, UT 84047-5559

USA

Tel: +1 801 871 7000

Fax: +1 801 871 7001

Email: [email protected]


17/32

www.flsmidth.comCopyright 2012 FLSmidth A/S. ALL RIGHTS RESERVED. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations or

warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time.

Minerals Processing

Technology Center

FLSmidth Salt Lake City, Inc.

7158 S. FLSmidth Dr.

Midvale, UT 84047-5559

USA

Tel: +1 801 871 7000

Fax: +1 801 871 7001

Email: [email protected]


18/32

Precious Metal

Extraction Solutions


19/32

ExtractionPrecious M


20/32

1

9. Smelting furnace

10. Bullion Molds

11. Slag pots

12. Bullion Safe

13. Stripped carbon dewatering

screen, and holding tank

14. Carbon Feed bin and kiln feed

screw system w/final dewateringscreen

15. Horizontal carbon regeneration

kiln

16. Carbon Quench tank

17. Acid Wash column


19. Supporting tanks and pipe work.

20. Miscellaneous required

equipment e.g. safety showers,

security systems etc

21. Structural steel, piping, electrics,

instrumentation security systemsdesign as required

22. Area building design if required.

23. Design drawings and layouts

required for concrete, structural

steel, P&IDs, electrical, piping

Integrated Package and Plant

Benefits

1. Integrated systems are designed

for all components to workeffectively together with high

efficiency.

2. Summit Valley equipment has

OEM agreements with most

external suppliers and prices

accordingly.

3. Designs are based on existing

engineering drawings and

layouts from previous projects

reducing engineering costs.

4. Layouts consider operator and

maintenance requirements for

efficient operation as well as

appropriate vehicular and

maintenance equipment access.

5. Integrated plant package reduces

commissioning time and

expenses during start up time.

6. All equipment provided has been

tried and tested in other

installations ensuring reliability

and suitability for the purposes.

7. Summit Valley equipment is

designed to provide process

efficiency, minimise labour and

maintenance manpower

requirements and can be installed

in compact layouts.

8. Proprietary Summit Valley designs

for the elution/electro-winning

circuit can provide energy savings

of 25% over conventional

design.

9. FLSmidth will work with the

major engineering firms to

incorporate our designs and

equipment effectively into theoverall plant design.

10. Large engineering firms we have

done packages with include:

Fluor Corp.

Aker Kvaerner (Aker Solutions)

SNC Lavalin

Ausenco

11. Benefits for the client include:

Lower engineering,

procurement and process

design costs

Access to FLSmidth knowledgeand experience with recovery

of metals from cyanide

solutions in a broad range of

processes and conditions.

Efficient and faster engineering

and procurement processes.

Designs are optimised for the

specific solution tenors and

chemistry at the site.

Efficient and compact layouts.

Reliable and easily maintained

equipment with good

performance history in other

installations we have done


21/32

4

Mercury Removal and

Recovery Plants

FLSmidth designs and supplies

vacuum retort mercury recovery

systems. The incoming material is

dried, pulverised and loaded into

trays for insertion into the vacuum

retort. The mercury volatilizes and issubsequently cooled and condensed

with chilled water and recovered as

liquid mercury into flasks. The

remaining gas is scrubbed in a

sulphidised carbon tower where

mercury levels are reduced to EPA

levels. The vacuum system ensured

that there is no leakage of mercury

into the atmosphere from the retort.

These retorts are used for treating

gold sludges afrom electrowinning

circuits and also for cleaning upindustrial wastes e.g. fluorescent

tubes

The carbon scrubbing system is also

used for cleaning up off gas from

heated tanks and also for treating kiln

off gas as required.

Typically this package will include a

material preparation section where

the incoming material to be treated

will be crushed and pulverised, and

loaded into trays for insertion into the

retort. Upon completion of the cycle

these trays are removed and the

cleaned material passed on theremaining process steps.


1. Material preparation (crushing/

pulverization) for industrial

wastes but not required for E.W

sludge

2. Suitable trays to hold the

material for insertion into the

retort

3. An electric heated retort oven

4. A two stage mercurycondensation section

5. Sulphidised final gas scrubbing

column

6. Supporting bins and material

handling systems for the spent

material

7. Mercury flasks to hold the

product for subsequent sale

Complete Gold Electrowinning

and Refining Packages

FLSmidth will design and supply

complete integrated area packages

for the stripping of the carbon, the

electro-winning and recovery the gold

from the strip solutions, filtration,

drying and smelting of the resultantsludge from the E/W process, the

regeneration of the carbon in a

horizontal kiln and the acid washing

of the reactivated carbon before

returning it to the leach circuits.

Typically this package would include:

1. Initial Carbon screen

2. Elution column(s)

3. Heating system skid

4. Heat exchanger skid (sometimes

combined)5. Stainless steel basketless cathode


and rectifiers

6. Sludge filter feed pump and plate

and frame filter

7. Drying oven

8. Flux mixing system (if required)


22/32

FLSmidth draws from the Metallurgical, Instrumentation,

Mechanical and Mining Engineering, Structural Design,

Project Management and Maintenance disciplines.

Today, FLSmidth strives to provide competitive quality

process engineering and equipment to the same industries

first envisioned in 1990. FLSmidth has installed equipment

and completed engineering services in eight countries onfour continents around the world. FLSmidth leads the

world in gold electrolysis and mercury vacuum distillation

and is a world leader in indirect fired rotary kilns and

packaged carbon strip systems.

ADR Plant for Power Generation, Distribution &

Supplies, and Material Delivery Systems

tal

3


23/32

(Above) Typical 4 Cell Single Train Installation

(Left) 150 cu ft E/W Cell Installation showing ease of

Access w/ Lid Open Note security locks on front

Electrowinning Cells


24/32

13

Merrill Crowe Plant Packages

Typically these will include the

following major components

1. Clarification filters

2. De-aeration Tower and vacuum

pump(s)

3. Zinc feeder and Lead Nitrate

addition systems

4. Precipitation Filter feed pumps

5. Precipitate Filters

6. Pre-coat and body feed tank(s)and pumping systems for the

clarification and precipitate filters

7. Precipitate smelting and gold

refining systems including flux

mixing, drying ovens, smelting

furnace, molds, slag pots,

ventilation and merury removal

systems as required


concrete, piping, structural steel,

tankage, instrumentation,

electrical, ventilation and building

enclosure.

Carbon Adsorption Plant

Packages

FLSmidth has considerable experience

in the design of Carbon Adsorption

Plants in capacities ranging from

primary gold recovery to scavenging

and clean up of heap leach mine sites

after operations have been

completed. Effectively they are

applicable wherever gold and silver

are to be recovered from lower grade

clear solutions.

Typically these will include:

1. Countercurrent Carbon contact/

adsorption tanks and/or

multistage columns.

2. Carbon elution column systems

with supporting screens, strip

solution heating and heat

exchanger packages.

3. Electro-winning cells and

rectifiers.

4. Sludge filters, drying ovens, and

smelting equipment.

5. Carbon regeneration kiln

6. Carbon acid wash system


complete layout, concrete,

piping, structural steel, tankage,

instrumentation, electrical,

ventilation and building enclosure

as required.

Carbon Elution and

Electrowinning Packages

FLSmidth holds patents for two

significant developments in this area

namely the development of the

Basketless Cathode (sludging) cell and

the innovative split Zadra carbon

elution process.


1. Carbon screen

2. Elution column (s)

3. Strip solution heating skid

4. Heat exchanger skid

5. Stainless steel basketless cathode


and rectifiers

6. Sludge pump and filter system


8. Supporting tanks and pipework.

9. Structural steel, piping, electrics

and instrumentation as required


25/32

FLSmidth has considerable experience in the design and

supply of integrated packages for these areas and is able to

provide the following services in support of these packages:

Complete Flow sheet development, P&IDs, Piping and

Electrical requirements and Plant area layout GAs Equipment specification, sizing, and supply

Detailed Concrete, Structural steelwork, Piping,

Electrical, and Building designs

Local Fabrication and Procurement of piping structural

steel

2

Integrated Gold Roomand Plant Packages

In some cases these will be stand-alone plants and, in

others cases, integrated sections designed to fit in with

existing designs and facilities in the clients related plant

areas. To the extent possible FLSmidth uses existing designs

and packages from other projects to expedite the design,construction and procurement in these packages to reduce

not only engineering and design costs but also to shorten

times for the plant schedules. In these areas FLSmidth

typically works very closely with the client and their EPCM

engineers.


26/32

(Top) 50 cu. Ft. Cell w/Support Frame

(Bottom) Typical 4-cell two train installation

Key Features

Cells are sludging design using FLSmidths patented

high efficiency basketless cathodes.

Cathodes are 304 SS punched plate, wrapped in

knitted stainless steel mesh.

Anodes are 304 SS punched plates. Speciality materials

and designs are available where adverse solution

chemistry requires them.

Sludge is harvested in-cell by direct washing from the

cathodes. Cathodes and anodes remain in the cell for

harvesting. Cells operate closed under a slight vacuum for

excellent Industrial Hygiene (important where Ag or Hg

is present) No external hoods or other ventilation

systems are required for the cell area.

Low maintenance and labour costs.

Typical wash time 2 -3 hours once per week

Cells lids open full width for access to electrodes. No

heavy lifting required hence no overhead crane.

Tanks are robust - 304 stainless steel with

polypropylene liners submerged and bolted inside cell

for insulation.

Minimal fire risk - cell is closed in operation and most

plastic is submerged in electrolyte

Compact design resulting in small installation footprint

= lower construction costs.

Cell design provides for all security, ventilation, and

cathode washing activities to take place within the

lidded cell, avoiding costs for cranage for lifting loaded

cathodes from the cell, cathode washing tanks, and

ventilation hoods.

Basketless Cathodes

FLSmidth offers a new electrowinning cell basketless

cathode designed to decrease operator service time and

decrease gold inventory in the cells while providing

continued high cell efficiencies characteristic of Summit

Valley cells. Gold sludge servicing is performed in the cell by

washing precious metal sludge from the cathodes with a

pressure sprayer. Sludge is pumped from the cell bottom

via. the sludge outlet flange to a sludge filter. Since the

cathodes are serviced in the cell, less cathode handling is

required during servicing. Less cathode handling decreases

operator exposure to toxic metals when present in

electrowinning solutions, i.e. mercury, arsenic, cadmium.

The new electrodes eliminate the need for cathode baskets.


27/32

(Above) 5 Metric ton fuel oil fired carbon reactivation kiln

(Right) 12 Metric ton fuel oil fired carbon reactivation kiln

CarbonRegeneration Kilns


28/32

(Top) 3.4 cu m/hr Skid Mounted Plant.

(Bottom) Deaeration Tower 700 m3/hr plant

1

Features

Plant capacities range from skid mounted 3.4 m3/hr

modular plants to full size 2100 m3/hr noting that due

to de-aeration tower transportation and fabrication

limits plants larger than 700 m3/hr generally consist of

two or three modules e.g. the 2100 m3/hr plant cited

above consisted of three 700 m3/hr parallel streams

The range of supply for plants includes clarification

filters, de-aeration tower(s), vacuum pump(s), zinc dust

feeder , lead nitrate feeders and zinc cone, precipitate

filter feed pumps, filter pre-coat and body feedsystems, and precipitate filters followed by refinery and

smelting facilities to produce gold bullion.

Application is principally to treat high silver bearing

gold ores(>5:1 Ag/Au ratio)

Plants incorporate Summit Valleys proprietary zinc

dust/lead nitrate feeder and mixing cone system

FLSmidth offers individual plant components, and

partial or complete plant equipment packages,

together with total plant design G.A.s, P.&I.Ds,

foundation and concrete design, pipe and steel

fabrication drawings (detail by fabricators), and even

buildings and furniture etc for the plant and

supporting facilities as required


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(Above) Clarification Filter Installation 700 m3/hr plant

(Right) 750 m/hr Merill Crowe Plant Zinc Feeder/Precip

Pump area

0

Merrill Crowe Plants


30/32

(Top) Summit Valley patented kiln seal

(Bottom) Control panel mounted on kiln skid. The

complete skid is pre-wired in the shop.

7

FLSmidth Kilns Feature:

Sizes: 1 12 tonnes per day.

Heating: Electric, LPG, or Fuel Oil systems

Packages included feed hopper, dewatering feed

screw, local control panel and quench tank

Complete unit skid mounted for installation on flat

concrete floor

Fired and tested before shipment.

Effective low maintenance trunnion seals provide with

12-18 months life (Patented)

Carbon burn is minimal Temperature range 600 - 750 C

Long life 253 MA alloy tube

Design uses entrained moisture in carbon to generate

steam for regeneration.

FLSmidth designs and manufactures indirect heated carbon

regeneration kilns and calciners from 1/2 ton per day and

larger. Our kilns and calciners can be fuel gas, oil, or

electric, and are skid mounted, pre-wired and pre-piped.

We also design and fabricate the structural steel required

for elevated installation.

FLSmidths patented (US Patent 5,551,870) bellows kiln seal

has proven effective in eliminating air ingress and process

gas egress. We have retrofitted clients kilns, from other

manufacturers, to use this seal.

Temperatures for carbon regeneration and time at tempera-

ture are important factors in regeneration of carbon. Drying

prior to regeneration is counter-productive. (ref.: Activated

Carbon for Precious Metals Recovery; William Faulker et

al, Calgon Carbon Corp.; presented at the 110th Annual

Meeting of the Society of Mining Engineers; Denver, CO;

1987). The steam generated from the feeding of wet

carbon is found to be critical to obtaining good carbon

activity during regeneration. Kilns with pre-dryers have

been found to produce inferior results to kilns without

pre-dryers.

Under normal conditions, alloy RA252MA is the material of

choice for carbon regeneration kiln tubes. This alloy offers

good corrosion resistance and structural properties at the

operating temperatures required for carbon regeneration.


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Summit Valley Mercury Retorts

Mercury Retorts


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(Top) Interior of 30 cubic foot capacity

retorts shown during loading.

(Bottom) Mercury Retort - Fluorescent

Tube Recycling Plant

9

FLSmidth manufactures mercury retorts and vacuum

distillation ovens ranging from 0.5 cubic foot to 40 cubic

feet material capacity. Both gas and electric models are

available. Gas fired retorts are of classic retort design with

the retort being externally heated. Electrically heated retorts

can be built as classic externally heated retorts, or internally

heated vacuum distillation ovens. In general, the internally

heated electric vacuum distillation ovens are the most

economical design. However, the internally electric heated

models do have some limitations when the retort feed

materials contain elemental sulfur or sulfide minerals thatoxidize to produce sulfuric acid gas, which can attack the

heating element material.

Mercury condensing and handling systems are included

with all retort systems. Custom condensing and mercury

handling systems can be provided to meet specific custom-

er requirements. Most retort systems designed and manu-

factured by FLSmidth have been tailored in some manner to

meet specific customer requirements. FLSmidth can also

supply closed loop refrigerated water systems for installa-

tions where adequate cooling water is not already available

for the mercury condensers. FLSmidth designs to meet all

North American and international mercury emissions

standards.

Our latest generation of 30 and 40 cubic foot internally

electric heated retorts have no equal for processing high

volume, high mercury materials such as Merrill-Crowe

precipitates. These retorts have cycle times of approximately

24 hours and can produce a product that contains less than

0.01% mercury. By placing heating elements between the

pans, all material is thoroughly heated, assuring proper

mercury removal. Large volume, externally heated retorts

may not achieve thorough material heating. One Summit

Valley installation operates eight 30 cubic foot retorts,

capable of treating up to 24,000 lb. per day of Merrill-

Crowe precipitate containing 20% mercury. At full produc-

tion rates, 4,800 lb. per day of mercury is recovered.

While FLSmidths largest retort market is for precious metals

extraction and refining, We manufacture retorts for

fluorescent lamp powder recycling and hazardous waste

processing. Additionally, FLSmidth has the expertise to

precious metals recovery brochure

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