How to Determine if Color-Changing Silica Gel is Fully Regenerated

The main criteria for judging if the color-changing silica gel is properly regenerated are: full colour recovery, dry and loose granules without clumping, and early sealing after cooling to avoid secondary moisture absorption.

 

1. Colour Recovery: The simplest evaluation measure

Blue Silica Gel: Should transform entirely from pink/red to deep blue, the colour should be consistent without any greyish white, dark red or local black.

Orange Silica Gel – Should return entirely to brilliant orange from dark green/green and must be free of turbidity or mottled appearance;

Key Note: Incomplete colour return after Heating means Ageing, Contamination or Not enough Regeneration Temperature.

Take the granules into natural light to make the colour change even, and to avoid incorrect judgement due to local incomplete dehydration.

 

2. Physical State: Dryness and Structure

Full Regeneration Performance of Indicators

Touch: Dry, Non-Sticky, Dampness Free

Particle State: Loose, free rolling, no clumping or softening

Integrity: Hard particles, no signs of powdering or splitting

Clumping, greasiness or powdering means that it is contaminated or structurally damaged and cannot be completely regenerated.

 

3. Functional Verification Test for Real Moisture Absorption Capacity

(1) Humidity Test, Closed

Operation Place the cooled silica gel in a sealed food storage box with a moist towel and let it stand for 24 hours;

Judgement:

Slow colour change uniformly –> Regeneration successful, regular function;

No colour shift or quick complete colour change → Clogging or failure of micropores, incomplete regeneration.

(2) Moisture Retention Capacty Test

Method: Put in a closed box with camera, medicine etc. for one week;

Decision: 1.

No colour change => Moisture-proof ability still exists, regeneration is effective;

Change of colour in a short time → Adsorption capacity is not enough, needs regeneration or replacement.