CPAM for GCC-Filled Fine Paper: Set Retention and Formation Purchase Gates

Ground calcium carbonate source, particle distribution, dispersion condition and addition route belong in the supplier brief. Include fibre blend, fines, target sheet ash, basis weight, broke and the existing wet-end chemistry. A general request for filler-retention PAM leaves too much of the fine-paper duty undefined.

Use samples representing the current grade and credible variation. Do not assume a previous approval transfers after a filler-source change merely because both minerals are called GCC. Record which source and loading range the qualification actually covered before establishing routine supply.

Compare coded candidates at a confirmed active basis with the incumbent and appropriate blank. Keep the addition point, dilution and process shear realistic. Measure stock and white-water solids and ash over comparable intervals; unsynchronized samples can create an apparent retention improvement during a changing loop.

Separate total retention from ash retention rather than using one as a proxy for the other. Preserve the calculation basis and raw measurements. Where another additive or filler setting changes, label a distinct condition instead of assigning the whole response to the new CPAM.

Pair retention with drainage, formation and the mill's required optical, print or strength properties. A larger aggregate can retain mineral while reducing uniformity. The acceptance gate should reflect the actual grade requirement, not automatically reward the highest ash retention point in a laboratory screen.

Confirm the shortlisted condition on the machine after the white-water system responds. Record press behavior, breaks and off-grade observations where relevant. Do not assume a lower white-water turbidity alone establishes improved paper production or permission to increase filler loading.

Send filler identity, furnish, sequence, test method, target balance and preparation capacity with the RFQ. Ask for a small candidate set and documents tied to the proposed commercial codes. Keep potential increases in ash or production as separate trial objectives, not guaranteed savings used to justify an initial order.

Link the approved sample and first-delivery checks to the demonstrated filler window. Define re-screen triggers for particle source, dispersion, broke or chemistry changes. Commercial comparison should preserve the grade quality that made the paper acceptable in the first place.

Keep the related operating qualification with the purchase record. Further checks include PAM for PCC and High-Ash Paper: Qualify the Filler Program Before Ordering and Retention PAM for High-Speed Paper Machines: Request Post-Shear Bid Evidence.

Request coded material through the papermaking PAM sample and quotation brief. Include paper grade, furnish, additive sequence, preparation limits, acceptance method, quantity and destination. Separate demonstrated results from conditions still awaiting a trial.