Transcript Metal Recovery system - Oil Water Separator

Rinse water Recovery System-METAPure
for recovery and reuse of electroplating rinse water.
Pure Tech India,
A-5, Trec step, Thuvakudi, Trichy -620 015
Telephone:00 91-431 320 6753; Telefax: 00 91-431 250 1100
E-Mail: [email protected]; website: www.puretechindia.com
Electroplating processes and various chemicals
used:
S. No
Plating process
Major chemicals used
1
Cadmium plating
Cadmium Oxide, Sodium Cyanide,
Sodium Hydroxide
2
Zinc plating
Zinc Oxide, Sodium Cyanide, Sodium Hydroxide
3
Copper plating
Copper Cyanide, Sodium Cyanide, Sodium
Hydroxide
4
Nickel plating
Nickel Sulphate, Nickel Chloride, Boric Acid
5
Chromium plating
High speed self regulating salt (Chromium sulphate,
Chromic Acid)
Important Contributors in a Electroplating Effluent Generation:
Component
Function
Effluent Contribution/Remarks
Plating Bath
Main component primarily
responsible for plating.
Contains bath chemicals.
Bath is not drained at all except for some
unavoidable circumstances generally not seen.
Plating Rinse
Removes excess coating
material.
Major contributor of effluent. Contains primarily bath
chemicals with some environmental contaminants.
Acid Bath and
Rinse
To clean materials of rust.
Bath and rinse becomes unusable after a particular
period of operation. Main contaminants include rust
material with some dust particles.
Alkali Bath
and Rinse
To clean materials of rust
preventive solutions, oil and
grease for better plating
efficiency.
Bath and rinse becomes unusable after a particular
period of operation. Main contaminants include oil
and grease, rust preventive solution.
Floor
Washings
Spillovers from plating, rinse,
acid and alkali tanks.
All effluents listed above in small quantities with
water used for floor washing.
Treatment processes available:
• Chemical treatment using
– Sulphuric Acid (pH reduction for chromium conversion)
– Sodium Bisulphite (used for converting hexavalent to trivalent
Chromium)
– Sodium Hypo (Cyanide Oxidation)
– Lime/ Caustic (neutralization)
– Polyelectrolyte (flocculation)
– Clarification (solid- liquid separation) and
– Solid sludge separation.
• Membrane based physical/physiochemical processes.
Conventional Treatment:
Electroplating Effluent
Oxidation/ Reduction/ Neutralization *
Neutralization
Precipitation
Flocculation (Polyelectrolyte)
Waste water discharge
Clarification
Sludge Storage
* : NOTE
Cyanide waste: Oxidation
Dewatering
Chromium Waste: Reduction
Acid/Alkali Waste: Neutralization
Disposal
Membrane Systems
An Overview
Filtration: Types and Comparison
Normal Filtration
Cross- flow Filtration
•
Normal Filtration: Water with contaminants pass in direction perpendicular to
filter media. The contaminants will choke the pores of the filter media.
•
Cross- flow Filtration: Water with contaminants pass in direction parallel to the
filter media. The Outlet from this filtration will have two streams coming out. The
concentrate stream will carry along with it the contaminants. The filtered water
will come out of a separate outlet. The frequency of filter media getting choked is
very low when compared to normal filtration.
Cross- flow Membrane Processes:
MF
SS
UF
Macromolecules
NF
Sugar, DV Salts, DA
RO
MV Salts, UA
Water
KEY:
SS
DV Salts
DA
MV Salts
UA
- Suspended solids
- Divalent salts
- Dissociated acids
- Monovalent salts
- Undissociated acids
Reject portion
Permeate portion
MF – Micro filtration
UF - Ultra filtration
NF – Nano Filtration
RO – Reverse Osmosis
Specific advantages of membrane based
treatment systems:
• Compact and less space occupying.
• Marginal chemical consumption (needed in case of pH
correction).
• Skid mounted systems.
• Very low sludge generation.
• Very low electricity consumption.
• Requires little/ no civil construction.
• Separated water is ideally suitable for high quality rinse and
bath top up.
Reverse Osmosis:
Finest form of filtration
Osmosis - Reverse Osmosis Illustration:
Pressure P
Concentrate
Dilute
Concentrate
Dilute
Semi- Permeable Membrane
Semi- Permeable membrane is one which will allow only water molecules to pass and not salts.
In the Left diagram, under normal circumstances, water molecules from dilute solution side will permeate
towards concentrate side to form an equilibrium.This is Osmosis and the pressure present is Osmostic
pressure.
In the right diagram, when a pressure P is applied in excess to the normal pressure , water alone is
squeezed into the dilute solution side from the concentrate solution side. This is Reverse- Osmosis.
Typical Reverse Osmosis Membranes:
Reverse Osmosis Process flow diagram:
RO membrane structure:
Separated components applications:
•
•
Permeate flow (usable/product water flow)
–
Rinse
–
Bath top up
Concentrate flow (Reject flow):–
Bath (if the concentrate contains only salts used in the
electroplating bath with permissible contaminants)
Reverse Osmosis Membranes Rejection Rates:
Solute
Symbol
Molecular weight
Rejection (%)
Sodium Fluoride
NaF
42
99
Sodium Cyanide
NaCN (pH 11)
49
97
Sodium Chloride
NaCl
58
99
Silica
SiO2 (50 ppm)
60
98
Sodium Bi- Carbonate
NaHCo3
84
99
Sodium Nitrate
NaNo3
85
97
Magnesium Chloride
MgCl2
95
99
Calcium Chloride
CaCl2
111
99
Magnesium Sulphate
MgSo4
120
>99
Nickel Sulphate
NiSo4
155
>99
Copper Sulphate
CuSo4
160
>99
Membrane based Rinse water
recovery systems
Major contaminants and their removal:
S .No
1.
Contaminant
pH Correction
Removal Process
• Acid/ Alkali addition
• Stainless Steel Filter Strainer
• Stainless Steel Bag Filter
2.
Suspended Solids
3.
Microscopic oil particles
• Activated Carbon Filter
4.
Coating Materials
• IONICS unit using Reverse Osmosis
membranes
Process Flow Diagram
Effluent from
electroplating
process
Filtration
System
Prep Tank
Pump
Acid/ Alkali
addition
Permeate tank
to process
RO based IONICS
Unit
Reject back
to bath/ treatment
High pressure
pump
Low flow membrane systems:
High flow membrane systems:
A Typical application in electroplating process:
Flow of parts
Stage 1
Stage 2
High Pressure
Rinse
Stage 3
Spray-Dip-Spray
Chemical
Cleaner
Stage 4
Phosphate Dip
City Water Rinse
Flow of parts
Stage 5
Spray-Dip-Spray
City Water Rinse
Stage 6
Chromate Dip
Stage 7
Spray Rinse
Stage 8
Spray-Dip-Spray
Water Rinse
RO
TO WASTE
TREATMENT
Stage 9
Spray Water
Rinse
DI
water
RO Process in Nickel Plating
evaporation
RINSE # 1
PLATE
parts
RINSE # 2
parts
feed
RO
permeate
concentrate
95%
recovery
Make-up
(Pure water)
Benefits:
• 70% of rinse water can be recovered and reused for Bath Top up
and as Rinse water.
• Pollution Problem solved
• The cost of treatment is got back to by way of water which can be
reused for rinsing process.
Customers:
• Silver Crown Electroplaters: 100 and 200 LPH
• Divya Engineering : 10 LPH
• Sundaram Fasteners Limited, Chennai: 200 LPH
Other Electroplating Process related Products:
• Desorber: Oil water separator for Degreasing Baths.
• OleoSepa: Desorber, Ultrafiltration System for complete oil removal
and reuse of Degreasing solutions.
• Bag Filtration System: For filtering suspended solids upto 1
microns for your plating baths. Filter media can be offered in
Stainless Steel, Polypropylene and HDPE wire cloths. Complete
unit can be fabricated in the above materials.
• RO Plant: For removing Total Dissolved Solids in water used for
bath and rinse for better efficiency of plating.
Thank You
For Queries, Please contact:
E- Mail: [email protected]
(Photographs shown are taken from our supplied equipments and
there are feature additions taking place in each new equipment
manufactured)