IX-900 Ion Exchange — Softening and Demineralisation

IX-900Ion Exchange — Softening and Demineralisation

The resin swaps one ion for another: hardness off the water, sodium onto it. When the resin runs out of sodium to give, you wash it back on with brine. Everything about the design is that trade.

Cutaway — Ion Exchange — Softening and Demineralisation

WaterHardness ionsSoftenedBrine

How it works

The exchange — Each resin bead carries fixed negative sites loaded with sodium. Calcium and magnesium have a stronger affinity, so they displace the sodium and stay behind. The water leaves soft, with a little more sodium than it arrived with.
The service run — An exchange zone forms at the top and travels down, exactly like the carbon bed. Above it the resin is exhausted, below it still in sodium form. The run ends when that zone reaches the underdrain and hardness appears in the outlet.
Co-current regeneration — Brine enters at the top, following the service flow, and leaves at the bottom. Simple, and no hold-down needed — but the regenerant reaching the outlet end is already loaded with the calcium it stripped higher up. So the bottom of the bed, where the treated water leaves, is the least completely regenerated part. That is where leakage comes from.
Leakage and salt — Under-dose the regeneration and calcium is left on the resin at the bottom of the bed — exactly where the treated water leaves. That shows up as hardness leakage during the next run. Pull the salt dose down and watch leakage climb.
What governs it — Resin volume and feed hardness set the run length; salt dose sets leakage and running cost; service velocity decides whether the exchange has time to happen at all. Salt and water quality are the same dial, turned in opposite directions.

Design parameters

The panel opposite runs the same correlations as the IX-900 design sheet, so the animation and the calculator cannot disagree. Every parameter below is live — drag one and the picture responds.

Parameter	Unit	Default	Range
Regeneration configuration
Arrangement		Co-current regen	3 options
Counter-current regeneration passes fresh brine over the outlet end of the bed last, so the resin the treated water leaves through is the most completely regenerated. Same salt, far less leakage.
Duty
Flow	m³/h	25	2 – 200
Feed hardness	mg/L CaCO₃	250	30 – 1,000
Resin volume	L	1,200	100 – 6,000
Operating capacity	g CaCO₃/L	45	15 – 90
Salt dose	g NaCl/L resin	120	60 – 250
Vessel diameter	m	1	0.3 – 2.5

Open the full IX-900 design sheet for the other five inputs, all twenty-six results with their envelopes, the five equations printed beside the numbers they produce, and a calculation record you can export and put in a design file.

Live parameters

Six of the eleven inputs the IX-900 design sheet takes.

Regeneration configuration

Arrangement

Counter-current regeneration passes fresh brine over the outlet end of the bed last, so the resin the treated water leaves through is the most completely regenerated. Same salt, far less leakage.

Duty

Flow 25 m³/h

Feed hardness 250 mg/L CaCO₃

Resin volume 1200 L

Operating capacity 45 g CaCO₃/L

Salt dose 120 g NaCl/L resin

Vessel diameter 1 m

You have an estimate. The design sheet is the justification.

This page sizes the unit on six variables and tells you whether the headline numbers land in range. That is enough to sketch with, and it stays free. What it will not do is survive a design review: it does not show you the equation behind any number, it checks the obvious limits rather than all of them, and there is nothing to file.

The IX-900 design sheet runs the same physics on eleven inputs, reports twenty-six results against their envelopes, prints the five governing equations beside the numbers they produce, and exports the lot as a calculation record for the design file.