Mixed Bed Resin MX900: Insider Notes on Bulk DI Polishing

If you’re sourcing mixed bed di resin bulk for lab polishers, power makeup, or microelectronics, MX900 keeps popping up in buyer shortlists. I’ve toured facilities from Hebei to Hamburg; the teams that look past brochure gloss and into test data usually end up with fewer headaches—and better resistivity, obviously.

Industry snapshot

Demand for ultrapure water is soaring in semiconductors, EV batteries, bioprocessing, and analytical labs. The trend is away from on-site regeneration and toward mixed bed di resin bulk cartridges/swappable totes—less downtime, cleaner compliance stories. Many customers say their biggest fear is sodium or silica leakage post-corrosion events; MX900 was built for that niche pain point.

What MX900 actually is

MX900 is a pre-mixed, high-purity blend of strong acid cation (H+) and strong base anion type I (OH−), optimized to scrub trace sodium and other metal cations often shed by alloy corrosion in pipes and heat exchangers. Origin: NO.2 East Jianshe Road, High-Tech Industrial Development South Zone, Wei County, Xingtai, Hebei Province, China. To be honest, the consistency lot-to-lot has been the pleasant surprise.

Product specifications (MX900)

Resin chemistry	SAC (H+) + SBA Type I (OH−), gel-type beads
Mix ratio (vol.)	≈ 40–60% cation to 60–40% anion (optimized for Na+ traces)
Moisture content	40–60% (real-world use may vary)
Particle size / UC	0.6–0.8 mm; UC ≤ 1.6
Output resistivity	Up to 18.2 MΩ·cm at 25°C with proper pretreatment
Silica leakage	≤ 10 ppb typical; as low as 2–5 ppb in trials
Operating temp	5–60°C; pH service 2–12
Flow rate	10–40 BV/h recommended

Process flow and QC (how it’s made and tested)

Materials: premium gel SAC/SBA beads, pre-washed to low TOC; sieve-graded; fines removed. Methods: counter-current conditioning, H+/OH− polishing, inert mixing to prevent segregation, nitrogen blanket packaging. Testing: ASTM D2187 for capacity/physicals; particle size via wet-sieve; rinse to conductivity plateau; optional leachables check for NSF/ANSI 61 alignment. Service life: often 20–80 BV per run depending on CO2/SiO2 load and upstream RO/EDI. Industries: microelectronics UPW polish, pharma PW loop final polish, power plant condensate, analytical labs, metal finishing rinses.

Applications and why teams pick it

• Final polish to 18.2 MΩ·cm after RO/EDI; protects analyzers from cation blips.
• Corrosion-prone loops where sodium spikes sneak through—MX900 catches them.
• Portable exchange tanks: stable blend that resists bed stratification in transit.

Feedback is blunt: “less babysitting.” In fact, several lab managers said the mixed bed di resin bulk cartridge swap frequency dropped once CO2 was stripped upstream.

Vendor comparison (quick take)

Vendor / Model	Typical resistivity	Na+ leakage	Certs (indicative)	Lead time
Lijiresin MX900	Up to 18.2 MΩ·cm	Very low (ppb range)	ISO 9001; NSF/ANSI 61-ready	≈ 2–4 weeks
Purolite MB400	18.2 MΩ·cm with pretreatment	Low	ISO 9001; NSF/ANSI 61	Stock-dependent
Lanxess Lewatit Ultrapure MB	18.2 MΩ·cm	Low	ISO 9001	3–6 weeks
ResinTech MBD-30	18.2 MΩ·cm	Low	NSF/ANSI 61	Varies

Note: values are indicative; field performance depends on pretreatment, CO2, organics, and flow.

Case study: semiconductor pilot (surprisingly smooth)

Southeast Asia wafer fab, 2 m³/h polish skid after RO+EDI. MX900 tote ran 62 BV before breakthrough. Resistivity held 17.8–18.2 MΩ·cm; Na+

Customization and logistics

• Blend tuning for low-alkalinity feeds or high-silica waters.
• Color-change indicator option for service end-point (lab carts).
• Bulk pack: 25 L bags, 1 ft³ boxes, 200–500 L totes/supersacks; nitrogen-purged.
• Documentation: lot CoA, conductivity rinse curves, leachables summary.

Compliance and standards

Manufactured under ISO 9001 QMS; tested per ASTM D2187; materials aligned with NSF/ANSI 61 for potable-contact components. For microelectronics, systems aiming at ASTM D5127 and SEMI F63 purity targets reported clean pass with mixed bed di resin bulk MX900 when upstream pretreatment was dialed in.

References:

1) ASTM D2187 – Standard Test Methods for Physical and Chemical Properties of Ion-Exchange Resins.

2) NSF/ANSI 61 – Drinking Water System Components–Health Effects.

3) ASTM D5127 – Standard Guide for Electronic-Grade Water.

4) SEMI F63 – Guide for Ultrapure Water Used in Semiconductor Processing.

5) ISO 9001 – Quality Management Systems Requirements.