GB/T 24998-2010Paper and board -- Determination of alkali reserve (English PDF)

Foreword

This revised standard adopts the International Standard ISO 10716:1994 "Paper and board - Determination of alkali reserve." this standard and ISO 10716:1994 The main differences are as follows.

--- Modify the scope of the reason for discomfort paper (see Chapter 1);

--- Normative references increased by GB/T 462, GB/T 601, GB/T 6682, ISO 10716 references cited in ISO 186 the corresponding national standard GB/T 450, delete the ISO 287 (see Chapter 2);

--- Modified principle, remove the word "dissociation" (see Chapter 4);

--- Increased preparation methods Reagents and reagent requirements (see Chapter 5);

--- Modify the size of the sample preparation (see Chapter 7);

--- Increased "cool to room temperature" requirement (see Chapter 8);

--- Modified formula (see Chapter 9);

--- Increased quality assurance and control chapter (see Chapter 11).

The standard proposed by China National Light Industry Council.

This standard by the National Standardization Technical Committee of the paper industry.

This standard was drafted. SZCIQ Industrial Testing Center, China Pulp and Paper Research Institute, Shenzhen test Quarantine Science Research Institute, the national paper quality supervision and inspection center.

1 Scope

This standard specifies the method for determination of the base paper and paperboard in reserves.

This standard applies to the paper in order to improve acid resistance, and add paper and cardboard basic pigment or other alkaline substances in the production process.

This standard does not apply to laminated paper, the printed paper or through other processed paper, because these reprocessed paper, base paper may have Interfere with the determination of the existence of reserves.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 450 and take samples to an aspect of paper and paperboard samples, positive and negative determination (GB/T 450-2008, ISO 186.

2002, MOD)

GB/T 462 paper, board and pulp - Determination of water sample (GB/T 462-2008, ISO 287. 1985, ISO 638.

1978, MOD)

Preparation of GB/T 601 chemical reagent standard titration solution GB/T 6682 analytical laboratory use specifications and test methods (GB/T 6682-2008, ISO 3696. 1987, MOD)

3 Terms and definitions

The following terms and definitions apply to this standard.

Alkali reserves alkalireserve Paper and paperboard in the amount of the basic compound of a class, such as calcium carbonate, such compounds and due to natural aging or exposed to atmospheric pollution Acid generated, according to the standard method for determining a base value of reserves.

Principle 4

Sample first soaked in water, boiled for a period of time, while a certain amount of hydrochloric acid solution was added, and the hydrochloride in solution alkalinity Quality completion of the reaction with sodium hydroxide standard solution titration of unreacted hydrochloric acid, thereby calculating the reserve base.

5 Reagents

Unless otherwise indicated in the analysis using only recognized as analytical reagents.

5.1 Water, GB/T 6682, three, or fresh distilled water.

5.2 hydrochloric acid (HCl), rho = 1.40g/mL, mass fraction of 36% to 38%.

5.3 Sodium hydroxide (NaOH), AR.

5.4 hydrochloric acid standard solution, c (HCl) = 0.1mol/L, according to GB/T 601 formulation and concentration of hydrochloric acid calibration solution.

5.5 standard sodium hydroxide solution, c (NaOH) = 0.1mol/L, according to GB/T 601 formulation and calibration concentration of sodium hydroxide solution.

5.6 Methyl red indicator, weighed 0.2g methyl red dissolved in 100mL ethanol and stored in a brown reagent bottle.

6 Instruments

6.1 electronic balance, a sense of the amount of 0.001g.