TAPPI T 613 cm-10

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T 613 cm-10

OFFICIAL STANDARD – 1933

REAFFIRMED – 1977

CLASSICAL METHOD – 1983

REAFFIRMED – 2000

REVISED – 2010

The information and data contained in this document were prepared

by a technical committee of the Association. The committee and the

Association assume no liability or responsibility in connection with

the use of such information or data, including but not limited to any

liability under patent, copyright, or trade secret laws. The user is

responsible for determining that this document is the most recent

edition published.

Approved by the Standard Specific Interest Group for this Test Method

TAPPI

CAUTION:

This method may require the use, disposal, or both, of chemicals which may present serious health hazards to humans. Procedures for the handling

of such substances are set forth on Material Safety Data Sheets which must be developed by all manufacturers and importers of potentially

hazardous chemicals and maintained by all distributors of potentially hazardous chemicals. Prior to the use of this test method, the user should

determine whether any of the chemicals to be used or disposed of are potentially hazardous and, if so, must follow strictly the procedures specified

by both the manufacturer, as well as local, state, and federal authorities for safe use and disposal of these chemicals.

Analysis of caustic soda

1. Scope

1.1 This method describes a procedure for the analysis of caustic soda (sodium hydroxide). The following

determinations comprise the usual complete analysis: alkalinity (total), carbonate, chloride, iron, and sulfate.

1.2 Most of the caustic soda used by the pulp and paper industry is a water solution of approximately 50% or

73% NaOH; it is also available in solid, flake, or ground (powder) form. Commercially, it is quoted on a 76% sodium

oxide (Na2O) basis, approximately equivalent to 98% NaOH.

2. Summary

2.1 Alkalinity. Total alkalinity is determined by titrating with hydrochloric acid using methyl orange-xylene

cyanole mixed indicator.

2.2 Carbonate. Carbon dioxide is evolved by acid decomposition of the carbonate in the specimen and is

absorbed on sodium-hydrate-asbestos. The increase in weight is a measure of the carbonate present. The lower limit is

0.001 g of CO2.

2.3 Chloride. The specimen is diluted, acidified, and treated with a small excess of standard AgNO3 solution.

The precipitated AgCl is removed by filtration and the excess silver nitrate is titrated with standard ammonium

thiocyanate solution using ferric ammonium sulfate indicator (Volhard method). The lower level of determination is

0.0001 g as chloride.

2.4 Iron.

2.4.1 Iron is reduced to the ferrous condition where it forms an orange-red complex with 1,10-phenanthroline

(orthophenanthroline) in an acetate-buffered solution at pH 5. Intensity of the color so formed is measured at 510 nm in a

photometer calibrated with standard iron solutions. The color develops within 15 min, is very stable, and follows Beer's

law. The lower limit of determination is 0.1 ppm as Fe.

2.4.2 Impurities normally found in caustic soda do not cause any interference. Copper, if present to the extent

of 0.5 mg/100 mL of final solution, changes the hue of the solution but interferes only slightly when excess reagent is

present. Zinc, cadmium, and nickel form complexes and consume reagent but do not interfere when sufficient reagent is

present.

2.5 Sulfate. Sulfate is determined gravimetrically by precipitation as barium sulfate (BaSO4) which is filtered

off, washed, ignited, and weighed. The lower limit of determination is 0.002 g as S04.

T 613 cm-10 Analysis of caustic soda / 2

3. Apparatus

3.1 General. Apparatus needed is described in the following sections in some detail. For sampling, use items

in 3.2 and 3.3; for total alkalinity, items in 3.6; for sodium carbonate, items in 3.5; for chloride, items in 3.6; for iron,

items in 3.4 and 3.6; for sulfate, items in 3.6.

3.2 Sample containers

3.2.1 Container must be of a size to hold the equivalent of at least 200 g NaOH for determinations in duplicate.

3.2.2 The choice of material for the containers is important for liquids taken or held at elevated temperatures.

Glass is suitable for 50% NaOH unless silica is to be determined. Glass breakage may be encountered with 73%.

Polyethylene or polypropylene may be used with 50% NaOH, polypropylene with 73%. If possible, 73% NaOH should

be held in liquid state until tests are complete. However, it may be "cast" into plastic, nickel, or silver containers or

molds. The molds are later removed and the samples crushed to prepare the specimens.

3.3 Sampling device. A simple “dipper” or “tap” sample taken from a bulk liquid container is inadequate.

One satisfactory device has three or five closed containers mounted on a single rod, and when the device is lowered into

a tank and stoppers are pulled, samples are taken simultaneously at different levels, which are then combined. “Drip”

samples, taken during unloading, may be used if it is not necessary to analyze the caustic before unloading.

3.4 Colorimeter. Colorimeter or spectrophotometer with a 5-cm light path and capable of photometric

measurement at 510 nm.

3.5 Carbonate apparatus. Analytical train for gravimetric determination of carbonate, consisting of the

following principal parts (Fig. 1): separatory funnel (C), 100-mL capacity; flask (F), 250-mL extraction; condenser (G),

20-cm modified Liebig; drying tubes (H and J), Schwartz, glass-stoppered, 10-cm; Bubbler bottle (Q), 100-mL capacity;

siphon-vacuum bottle, approx. 4000-mL capacity.

3.6 Other apparatus: weighing bottle with stopper to hold the equivalent of 20 g of NaOH; seven volumetric

flasks, one 1000-mL, one 500-mL, five 100-mL; four burets (two 25-mL and two 50-mL); three pipets, 0.5-, 10- and

50-mL; two graduated cylinders, 10- and 50-mL; two Erlenmeyer flasks, wide-mouth, 250-mL; two beakers, 250-mL;

small glass funnel; platinum crucible (or porcelain).

Fig. 1. Carbonate apparatus.

4. Reagents

4.1 General

4.1.1 Reagents needed for the several determinations of this method are as follows: for total alkalinity, use

items 4.2, 4.6, 4.16, and 4.17; for the carbonate train, use items 4.6 and 4.18 through 4.23; for chloride, use items 4.2,

4.5, 4.6, 4.7, 4.14, and 4.15; for iron, use items 4.2, 4.4, 4.6, 4.8, 4.9, 4.10, 4.12, and 4.13; for sulfate, use items 4.2, 4.3,

4.5, 4.6, 4.16, and 4.17.

4.2 Hydrochloric acid, concentrated, 1N HCl (see TAPPI T 610 “Preparation of Indicators and Analytical

Reagents, and Standardization of Volumetric Solutions”). Record the temperature when standardizing for special

accuracy.

3 / Analysis of caustic soda T 613 cm-10

4.3 Barium chloride. Dissolve 120 g of BaCl2 in 1000 mL water.

4.4 Pure iron wire, standard solution (1 mL = 0.010 mg Fe). Dissolve 0.1000 g of iron wire, reagent grade,

for standardizing, in 10 mL of 1:1 HCl and 1 mL of saturated bromine water. Boil off excess bromine. Add 200 mL of

1:1 HCl and dilute to 1000 mL in a volumetric flask. Dilute 100 mL of this solution to 1000 mL.

4.5 Silver nitrate, 0.1N AgNO3 (see T 610), also dilute solution (5 g AgNO3 in 100 mL water).

4.6 Water, distilled, CO2-free (freshly boiled and cooled).

4.7 Ammonium thiocyanate, 0.1N NH4CNS solution (see T 610).

4.8 Ammonium hydroxide, 1:1, mix equal volumes concentrated NH4OH and water.

4.9 Ammonium acetate-acetic acid solution. Dissolve 100 g of ammonium acetate (CH3 COONH4) in about

600 mL of water, filter, add 200 mL of glacial acetic acid to the filtrate, and dilute to 1000 mL.

4.10 Congo red indicator paper.

4.11 Ferric ammonium sulfate indicator, saturated solution of ferric ammonium sulfate in water

(approximately 40%).

4.12 1,10-Phenanthroline solution (3 g per 1000mL). Dissolve 3 g of 1,10-phenanthroline monohydrate in 500

mL of water, add 1 mL of concentrated hydrochloric acid (HCl), mix, filter, and dilute to 1000 mL.

4.13 Hydroxylamine hydrochloride. Dissolve 100 g of NH2OH • HCl in water and dilute to 1000 mL.

4.14 Nitric acid, concentrated HNO3.

4.15 Volhard indicator, saturated solution of ferric ammonium sulfate [NH4Fe(SO4)2 • 12H2O] in 100 mL

water and acidified with a few drops of HNO3.

4.16 Modified methyl orange. Dissolve 0.1 g of methyl orange and 0.14 g of xylene cyanole dye in 1000 mL of

water and filter if necessary.

4.17 Phenolphthalein (see T 610).

4.18 Barium perchlorate (or magnesium perchlorate), anhydrous, granular.

4.19 Perchloric acid (1:2). Mix one volume of 60% HC1O4 with two volumes of water and boil for 10 min in

a large Erlenmeyer flask. Cool and bottle.

4.20 Silver arsenite in sulfuric acid. Dissolve 2 g of pulverized As203 in the least amount of 10% KOH that

will effect solution. Dilute to 250 mL and add dilute H2SO4 (1:9) until neutral to litmus. Add 5% AgNO3 as long as a

yellow precipitate forms, keeping the solution neutral by adding drops of the 10% KOH when necessary. Stir until

coagulated, allow to settle, and wash by decantation. Dissolve the precipitate in an excess of H2SO4 (1:9), dilute to 150

mL and filter out any precipitated AgCl.

4.21 Sodium hydrate, asbestos absorbent, 12- to 20-mesh.

4.22 Zinc metal, mossy, clean.

4.23 Sulfuric acid, concentrated (H2SO4).

5. Sampling

5.1 General

5.1.1 The nature of NaOH is such as to require special care for sampling and preparing specimens for analysis.

If trace constituents also are to be determined, additional precautions, such as may be suggested by most major

producers, may be desirable. Both aqueous and anhydrous NaOH rapidly absorb moisture and carbon dioxide (and other

acid gases) from the atmosphere. The aqueous solutions may be corrosive to sampling devices and may become

contaminated.

5.1.2 Caustic soda liquors are usually shipped in insulated tank cars at elevated temperatures and the following

minimum temperatures should be maintained for proper sampling:

50% NaOH liquor = 29°C (85°F)

70-73% NaOH liquor = 85°C (185°F)

Partial freezing results in a separation of liquor and solids and causes sampling problems. Each lot is required to be

completely liquid and well mixed before sampling.

5.2 Liquids. With the sampling device, take samples from at least the upper, middle, and lower thirds of the

tank, avoiding the surface.

5.3 Solids (anhydrous)

5.3.1 Remove the top (75–100 mm) of material in a drum of flake, ground, or powdered caustic soda and then

take a sample from the uncovered middle and immediately enclose and, if necessary, seal it in a container with tape or

wax. 5.3.2 When molten solid caustic is packaged in metal drums and cooled to a solid before sealing, any

impurities present tend to concentrate near the bottom. Open the metal drum at its vertical seam and with an auger (19

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摘要：

TAPPI T 613 cm-10 是国际权威的纸浆行业标准测试方法，专门用于测定纸浆在铜乙二胺（CED）溶液中的特性粘度。该标准通过测量纸浆纤维在特定溶剂中的流动时间，评估纤维素的聚合度及其降解程度，对纸浆生产工艺控制、产品质量评估及研究开发具有关键意义。遵循TAPPI T 613规范可确保实验室数据的一致性和可重复性，帮助造纸企业优化打浆、漂白等流程，并预测纸张的强度与耐久性。本版本（cm-10）更新了实验条件与计算细节，适用于各类化学浆及溶解浆的粘度分析。

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