GE P&W Spiral Wound Membranes - Duracid Series - Manual

Fact Sheet
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FSsmDuracid_EN.docx Sep-13
Duracid Series
Industrial Acid Stable Nanofiltration Elements
Description and Use
The Duracid NF membrane element is engineered
to operate continuously under extreme acid condi-
tions where pH is at or below zero.
The family of Duracid proprietary thin-film nanofil-
tration membrane elements is characterized by an
approximate molecular weight cut-off of 150-200
Dalton for unchanged organic molecules. Divalent
and multivalent ions are preferentially rejected by
the membrane while monovalent ions and mineral
acids commonly have full transmission through the
membrane (transmission can vary depending upon
feed concentration and composition). Since mineral
acids and monovalent ions have high passage
through the membrane, these substances have a
minor contribution to the osmotic pressure.
Among other applications, Duracid NF Elements are
used for acid purification and metals concentration
in low pH streams.
They feature patented feed spacers, polysulfone
parts and a fiberglass outer wrap. All materials of
construction are low pH tolerant.
Features and Benefits
 Extreme low pH stability
 100% wet testing Quality Assurance
 Durable construction
 High temperature compatibility
Markets
 Metal Surface Treatment / Coating / Galvanic
 Heap Leaching Process in Mining
 Phosphate-based Chemical Production
 Spent Acid Recovery
Application Data
Table 1: Membrane Metal Rejection
Metal Ion
Feed
Concentration
Rejection in 5%
H
2
SO
4 1
Rejection in 5%
H
3
PO
41
Fe 2+ 2000ppm >90% >85%
Al 3+
2000ppm >90%
>85%
Cu 2+ 2000ppm >90% >85%
Cd 2+ 100ppm >90% >85%
Ni + 2000ppm >90% >85%
1 Based on flat sheet test conducted at 25°C (77°F) under 400 psig operating
pressure in a dead-end filtration mode. A single acid feed solution was dosed with
a mixture of all metals listed in Table 1 for each type.
Table 2: Typical Process Streams
Acid
Concentration
HCl 5-37%
H
2
SO
4
5-20%
H
3
PO
4
5-20%