GB/T 42944-2023Paper, board and paper products - Determination of effective-recyclable components (English PDF)

Foreword

This document was issued on 6 August 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 March 2024.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 42944-2023 covers the laboratory determination of how much of a paper, board or paper product actually comes back as usable fibre — the effective-recyclable component — and applies across the whole range of paper, board and paper products as well as paper-based items. Disintegration behaviour and the related terms are defined, the apparatus is listed, and specimen processing is set out in detail: samples are never touched with bare hands but handled in clean powder-free gloves, and an absolutely dry portion of roughly 480 g is weighed as m0 and cut down before the test begins. The test procedure starts at repulping — the specimen is poured into the low-consistency hydraulic pulper and disintegrated for five minutes, after which the whole stock is drained into a barrel — and the results calculation and the test report close the document. Packaging that reads as paper is not all paper once it reaches a mill, and the fraction that survives repulping as fibre is what a recycler is paying for and what a recyclability claim stands on. Of use to paper mills buying recovered fibre, packaging converters, and testing houses assessing recyclability.

This document describes the method for determination of effective-recyclable

components in paper, board and paper products.

This document applies to all kinds of paper, board and paper products; as well as paper-

based composite materials such as aluminum-foil paper and coated paper.

2 Normative references

The contents of the following documents, through normative references in this text,

constitute indispensable provisions of this document. Among them, for dated references,

only the edition corresponding to that date applies to this document. For undated

references, the latest edition (including all amendments) applies to this document.

GB/T 450 Paper and board - Sampling for testing and identification of machine and

cross direction, wire side and felt side

GB/T 5399 Pulps - Determination of stock concentration

GB/T 21557-2008 Waste paper - Estimation of stickies

GB/T 22877 Paper, board and pulps - Determination of residue (ash) on ignition at

525 Celsius

3 Terms and definitions

The following terms and definitions apply to this document.

3.1

Disintegration behavior

The process in which the specimen is dissociated and dispersed into a fiber suspension.

3.2

Coarse reject

2 - Barrel lid;

3 - Rotor;

4 - Motor;

5 - Discharge valve;

6 - Stand.

Figure 1 -- Structural diagram of low-consistency hydraulic pulper

4.2 Coarse-screening equipment

The coarse-screening equipment used in the test is a pulp screen equipped with a sieve

plate with a sieve hole diameter of 10 mm. The volume is not less than 12 L. It shall

have a vibration or stirring function. For a vibrating pulp screen, the vibration frequency

of the vibrating membrane is (700+/-10) times/min. For a stirring pulp screen, the

distance between the edge of stirring blade and the upper surface of sieve plate is 10

mm~20 mm; the blade speed is 200 r/min.

4.3 Stickies screen

For laboratory stickies screen, the average slit width of sieve plate shall be

(0.100+/-0.005)mm. The difference between each slit width and the average slit width

shall not be greater than 0.015 mm.

4.4 Fine-screening equipment

The fine-screening equipment used in the test is a vibrating pulp screen equipped with

a hole sieve plate with a sieve hole diameter of 0.7 mm AND a slotted sieve plate with

a sieve gap of 0.10 mm. The vibration frequency of the vibrating membrane is (700+/-10)

times/min. The amplitude is (3.2+/-0.1)mm. The water flow velocity is (8.6+/-0.2)L/min.

4.5 Other apparatus

Other apparatus is detailed in the corresponding method standards, respectively.