LEWATIT® NM 91

Summary

Product identification

• Product Name: Lewatit® NM 91
• Type: Gel type, high capacity, high purity mixed ion exchange resin
• Composition: 55% gel, strong acid cation resin and 45% gel, Type 1 strong base anion resin
• Functional Groups: Quaternary ammonium (anion), Sulfonic acid (cation)
• Matrix: Styrenic
• Structure: Gel
• Appearance: Dark brown / Yellow translucent beads
• Delivery Form: H⁺/OH⁻

Application

Lewatit® NM 91 is specifically designed for water demineralization applications with high alkalinity or high FMA ratios, where complete removal of silica and CO₂ is not required. It is designed for non-regenerable applications and can also be used for:

• Demineralization of service water and wastewater
• Water recovery in small units and once-through cartridges (DI water)
• EDM recycling
• Alkaline feed demineralization
• Laboratories and photo laboratories
• Household appliances (e.g., steam irons, air humidifiers)
• Small industrial plants (e.g., refilling of starter batteries or coolant circuits)
• Water for watering

Operating limits

• Stability pH range: 0-14
• Operating pH range during exhaustion: 0-14
• Maximum operating temperature: 60 °C
• Maximum pressure loss during operation: 200 kPa
• Bed depth for single column: min. 600 mm

Feed water

• Designed for applications with high alkalinity or high FMA ratios.
• Complete removal of silica and CO₂ is not required.

Product water

• Mixed bed test (column capacity) endpoint: min. 0.02 MΩ·cm
• Mixed bed test (polishing quality) NaCl exhaustion: min. 10 MΩ·cm

Electrical

• Mixed bed test (column capacity) endpoint: min. 0.02 MΩ·cm
• Mixed bed test (polishing quality) NaCl exhaustion: min. 10 MΩ·cm

Mechanical / hydraulic

• Uniformity coefficient: max. 1.9
• Range of size for >90 vol% of all beads: 0.3-1.25 mm
• Bulk density for shipment (+/- 5%): 740 g/L
• Density (approx.): 1.2 g/mL
• Water retention (delivery form, approx. weight %): 50-60 %
• Volume change (during exhaustion, max. approx. %): -15 %
• Specific pressure loss (15°C): 1.5 kPa·h/m²
• Specific flow rate (max.): 50 BV/h

Storage

• Recommended storage temperature: Above freezing point of water, under roof, dry conditions, without direct sunlight.
• Storage time (after delivery): max. 2 years. Packaging stability is limited to 24 months.
• Storage temperature range: -20 - +40 °C
• Frozen resin: Thaw out gradually at ambient temperature. Do not mechanically handle.

Disclaimer: Extraction may miss figures, footnotes, or revisions; contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror