A bleaching aid is not a bottle of bleach. It is the chemistry that keeps hydrogen peroxide alive, lifts pulp whiteness in a silicate bath, or adds optical brightener after residual color is gone. This guide maps Esteem bleaching aids so mill chemists specify AGA, SB, and OB by job—not as a single “whiteness chemical.”
What Bleaching Aids Actually Do
Mechanical and recycled pulps still carry lignin chromophores and metals. Alkaline H2O2 is the workhorse brightness step, but metals decompose peroxide. Silicate helps in many Indian mills and also deposits. Optical brightener only works on a reasonably clean sheet. Esteem’s paper chemicals bleach-aid table therefore mixes three jobs: bath auxiliary, peroxide stabilizer, and OBA—plus a mill slimcide that belongs to hygiene, not bleach.
Esteem Grades by Bleach Job
| Grade | Role | When to start here |
|---|---|---|
| VENPAPER AGA | Nonionic bleaching aid with silicates | Peroxide/silicate baths that need a higher pulp whiteness index |
| VENPAPER SB | Non-silicate alkaline peroxide stabilizer | Mills fighting silicate scale or wanting silicate-free bleach |
| VENPAPER OB | Optical brightener for paper | Writing/printing grades after mechanical brightness is in range |
| GRANDA-S-80 | Slimcide (bacteria, algae, fungi) | Circuit hygiene; not a substitute for peroxide or OBA |
Peroxide Stabilizers and Metal Control
If residual peroxide at the end of the tower is near zero and brightness is flat, metals are eating the bleach. Options: improve process-water quality, add a chelating agent (HEDTA is useful for Fe3+ at modest pH), and/or a dedicated stabilizer such as VENPAPER SB. Do not stack three chelants “just in case”—you will perturb sizing, retention, and effluent COD.
Recycled furnish also carries ink. Bleach after deinking, not instead of it.
Optical Brightener After Real Brightness
OBA is a visual increment, not a substitute for lignin and ink removal. Specify shade (blue vs violet), furnish (mechanical pulp quenches OBA), and whether the mill already uses OBA in the size press. Trial VENPAPER OB on handsheets with a UV cabinet, not only a brightness meter in office light.
Silicate Bath vs Silicate-Free Stabilizer
VENPAPER AGA is published as a nonionic bleaching aid used in the pulp bleaching bath along with silicates to improve the pulp whiteness index. That is a silicate-bath auxiliary, not a replacement for hydrogen peroxide and not an OBA. Sodium silicate is cheap and common in Indian mills; it also scales, deposits on wires, and complicates effluent. If the mill wants brightness without that scale, the published non-silicate stabilizer is VENPAPER SB for alkaline hydrogen peroxide bleaching.
Do not convert AGA to SB by “whiteness chemical” language on a purchase order. AGA sits with silicate. SB sits when the mill is fighting silicate scale or specifying silicate-free bleach. Residual peroxide at the end of the tower is the lab check: if peroxide is gone and brightness is flat, metals are eating the bleach. Pair SB (or a named chelant) with mill water analysis—Fe, Mn, Cu—not a guess dose. Do not stack three chelants “just in case”; that perturbs sizing, retention, and effluent COD.
Slimcide Is Not Brightness
GRANDA-S-80 is listed on the bleaching-aids page as a mill slimcide: an antimicrobial for slime-forming bacteria, algae, and fungi in pulp and paper mill systems. Slime stains and deposits can look like a bleach failure. They are a circuit-hygiene failure. Keep GRANDA-S-80 on its own program. Do not raise peroxide or OBA to hide a dirty chest.
Sequence on recycled furnish: detach ink first (deinking), then stabilize peroxide (AGA with silicate, or SB without), then optical brightener if the grade needs perceived whiteness. Mechanical pulp quenches OBA; trial VENPAPER OB on handsheets in a UV cabinet, not only a brightness meter in office light. Writing and printing grades after mechanical brightness is in range are the OBA job. Newsprint that still shows specks is still a deinking job.
Textile peroxide bleaching uses related stabilizer logic on a different hub. These four rows are pulp and paper. Request AGA vs SB vs OB as distinct trials, and keep the slimcide request separate so Esteem does not ship “one whiteness chemical.”
What a Bleach-Aid Trial Must Record
A useful mill trial is not “add brightness chemical.” Record furnish (virgin kraft, OCC, mixed), peroxide %, alkali, silicate yes/no, residual H2O2 at the tower, ISO brightness before OBA, and metals in process water. If residual peroxide is already gone, VENPAPER AGA will not invent oxidant. If specks remain, VENPAPER OB will not hide ink. If the chest is slimy, GRANDA-S-80 is the hygiene request, not a third bleach aid. Textile peroxide bleaching uses related stabilizer logic on the textile hub; do not order mill AGA against a fabric-bleach brief without saying so.
How to Specify with Esteem
- Name furnish, bleach chemical (% H2O2, alkali, silicate yes/no), and target ISO brightness.
- Share metals (Fe, Mn) and whether silicate scale is a known problem.
- State OBA yes/no and end-use (newsprint vs writing vs board).
- Keep slimcide as a separate circuit program.
- Request AGA vs SB vs OB as distinct trials from the bleaching aids table.
Related mill guides: sizing, sheet-making aids, textile chemicals for fabric bleach logic.
Contact Esteem for mill samples, or custom synthesis for a non-catalogue stabilizer window.