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YS/T 575.21-2020Methods for chemical analysis of bauxite - Part 21: Determination of organic carbon content (English PDF)

铝土矿石化学分析方法第21部分：有机碳含量的测定

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Issued by

Ministry of Industry and Information Technology of PRC

Level / Type

National · Recommended

Issue date

December 9, 2020

Implementation date

April 1, 2021

Scope

YS/T 575.21-2020 is the English-translated version of 铝土矿石化学分析方法第21部分：有机碳含量的测定.

YS/T 575.21-2020 — This part specifies the method for determining the organic carbon content in bauxite by titration and infrared absorption. This part is applicable to the determination of organic carbon content in bauxite.

Determination range. 0.010%~1.00%. The infrared absorption method is used as the arbitration test method.

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Document preview — YS/T 575.21-2020

National Standard of the People's Republic of China

ICS: 71.100.10
Classification: H 30

Issued by: Ministry of Industry and Information Technology of PRC

Foreword...3
1 Scope...6
2 Titration...6
3 Infrared absorption method...11
4 Test report...14

Foreword

YS/T 575 Methods for chemical analysis of bauxite is divided into 29 parts.

-- Part 1.Determination of aluminium oxide content - EDTA titrimetric method;

-- Part 2.Determination of silicon dioxide content - Gravimetric-molybdenum blue

photometric method;

-- Part 3.Determination of silicon dioxide content - Molybdenum blue photometric

method;

-- Part 4.Determination of iron oxide content - Dichromate titrimetric method;

-- Part 5.Determination of iron oxide content - Orthophenanthroline photometric

method;

-- Part 6.Determination of titanium dioxide content - Diantipyrylmethane

photometric method

-- Part 7.Determination of calcium oxide content - Flame atomic absorption

spectrophotometric method;

-- Part 8.Determination of magnesium oxide content - Flame atomic absorption

spectrophotometric method;

-- Part 9.Determination of potassium oxide and sodium oxide content - Flame

atomic absorption spectrophotometric method;

-- Part 10.Determination of manganese oxide content - Flame atomic absorption

spectrophotometric method;

-- Part 11.Determination of chromium oxide content - Flame atomic absorption

spectrophotometric method;

-- Part 12.Methods for chemical analysis of bauxite - Part 12.Determination of

vanadium pentoxide content - N-benzoy-N-phenythyroxy lamine photometric

method;

-- Part 13.Determination of zinc content - Flame atomic absorption

spectrophotometric method;

-- Part 14.Determination of rare earth oxide content;

-- Part 15.Determination of gallium oxide content - Rhodamine B-extraction

photometric method;

-- Part 16.Determination of phosphorus pentoxide content - Molybdenum blue

spectrophotometric method;

-- Part 17.Determination of sulfur content - Direct combustion-iodometric method;

-- Part 18.Determination of total carbon content - Non-aqueous titrimetric method

after combustion;

-- Part 19.Determination of loss on ignition - Gravimetric method;

-- Part 20.Preparation of pre-dried sample;

-- Part 21.Determination of organic carbon content;

-- Part 22.Determination of hydroscopic moisture - Gravimetric method;

-- Part 23.Determination of element contents - X-ray fluorescence spectrometry

method;

-- Part 24.Determination of carbon content and sulfur content - Infrared absorption

method;

-- Part 25.Determination of sulfur content - Coulometric titration method;

-- Part 26.Determination of sulphate content - Barium sulphate gravimetric method;

-- Part 27.Determination of element contents - Inductively coupled plasma atomic

emission spectrometric method;

-- Part 28.Determination of lithium oxide content - Flame atomic absorption

spectrophotometric method;

-- Part 29.Determination of available alumina and reactive silica.

This part is Part 21 of YS/T 575.

This part was drafted according to the rules given in GB/T 1.1-2009.

This part replaces YS/T 575.21-2007 Methods for chemical analysis of bauxite - Part

21 Determination of organic carbon content - Titrimetric method. Compared with

YS/T 575.21-2007, in addition to editorial modifications, the main technical changes

of this part are as follows.

-- The requirements for reagent purity and test water are added (see 2.2);

-- The description of the preparation of sodium oxalate standard solution is

modified (see 2.2.4; see 3.4 of the 2007 edition);

-- The test steps are modified (see 2.5; see Chapter 6 of the 2007 edition);

-- The calculation formula is modified (see 2.6; see Chapter 7 of the 2007 edition);

-- The repeatability limit is modified (see 2.7.1; see 8.1 of the 2007 edition);

-- The infrared absorption method is added (see Chapter 3).

This part was proposed by and is under the jurisdiction of the National Technical

Committee on Nonferrous Metals of Standardization Administration of China (SAC/TC

243).

Drafting organizations of this part. CHALCO Shandong Co., Ltd., CHINALCO

Zhengzhou Nonferrous Metals Research Institute Co., Ltd., and China Aluminum

Mining Co., Ltd.

Main drafters of this part. Tian Rui, Cao Jianjun, Shao Jing, Zhou Bo, Shi Lei, Xue

Ning, Ai Zhen, Nian Lina, Wang Xiaoyan and Liu Wei.

The previous versions of the standards replaced by this part are as follows.

-- GB/T 3257.23-1999, YS/T 575.21-2006, YS/T 575.21-2007.

Methods for chemical analysis of bauxite - Part 21.

Determination of organic carbon content

1 Scope

This part specifies the method for determining the organic carbon content in bauxite by

titration and infrared absorption.

This part is applicable to the determination of organic carbon content in bauxite.

Determination range. 0.010%~1.00%.

The infrared absorption method is used as the arbitration test method.

2 Titration

2.1 Method summary

The sample is boiled with phosphoric acid to decompose carbonate, and organic carbon

is oxidized to carbon dioxide with potassium persulfate by using silver sulfate as a

catalyst; thymolphthalein is used as an indicator, and ethanol-ethanolamine-potassium

hydroxide standard titration solution is used for titration to calculate the mass fraction

of organic carbon.

2.2 Reagents

Unless otherwise stated, only reagents confirmed to be of analytical grade and

laboratory grade II water are used in the analyses.

2.2.1 Silver sulfate.

2.2.2 Phosphoric acid (1+1).

2.2.6 Ethanol-ethanolamine-potassium hydroxide standard titration solution.

2.3 Measurement device

The schematic diagram of the measurement device is shown in Figure 1.

2.5 Analysis steps

2.5.1 Test portion

Weigh the specimen according to Table 1, accurate to 0.0001 g.

2.5.2 Parallel experiments

Perform two experiments in parallel and take the average value.

2.5.3 Blank test

Carry out a blank test along with the specimen test.

2.5.4 Determination

2.5.4.4 Transfer 20 mL of saturated potassium persulfate solution (2.2.3) to the

separatory funnel, heat the three-necked flask until the solution boils for 20 minutes,

and add all of the saturated potassium persulfate solution (2.2.3) to the three-necked

flask in several times (2 mL~3 mL each time) within the time. After stopping the heating,

continue to introduce the air for 20 minutes. The following operations are the same as

those in 2.5.4.3, and record the volume of the consumed ethanol-ethanolamine-

potassium hydroxide standard titration solution (2.2.6).

Mass fraction wTOC Mass of specimen m

2.6 Calculation of analysis results

The organic carbon content is expressed as the mass fraction of organic carbon wTOC,

calculated according to formula (2).

2.7 Precision

2.7.1 Repeatability

The measured values obtained from two independent test results under repeatability

conditions are within the average value range given below; the absolute difference

between the two test results does not exceed the repeatability limit (r), and the

probability of exceeding the repeatability limit (r) does not exceed 5%. The

repeatability limit (r) is obtained by linear interpolation or extrapolation method

according to the data in Table 2.

3 Infrared absorption method

3.1 Method summary

The carbon in the specimen is divided into organic carbon and inorganic carbon. Under

the high temperature and catalyst, the carbon is fully burned and converted into CO2.

Inorganic carbon reacts with acid at a certain temperature and converts into CO2, while

organic carbon does not react.

3.2 Reagents

Unless otherwise stated, only reagents of confirmed guaranteed grade and laboratory

grade II water are used in the analyses.

3.3 Instruments and equipment

3.4 Specimens

Grind the specimen to pass through a standard sieve with an aperture of 75 µm, dry it

in an oven at 110 °C±5 °C for 2 hours, place it in a desiccator, and cool it to room

temperature for later use.

3.5 Analysis steps

3.5.1 Test portion

Weigh two specimens (3.4), each with a mass of 0.40 g, accurate to 0.0001 g. The mass

of the test portion used for total carbon determination is recorded as m0, and the mass

of the test portion used for inorganic carbon determination is recorded as m'0.

3.5.5 Drawing of working curve

3.5.5.1 Weigh 0, 12.51 mg, 25.02 mg, 37.53 mg, and 50.04 mg of glucose (3.2.1) and

place them in a set of sample boats (3.3.2). Proceed as in 3.5.4.3.

3.5.5.2 Weigh 0, 22.08 mg, 44.16 mg, 66.24 mg, and 88.32 mg of sodium carbonate

(3.2.2) and place them in a set of sample boats (3.3.2). Weigh 0, 17.50 mg, 35.00 mg,

52.50 mg, and 70.01 mg of sodium bicarbonate (3.2.3) and place them in the sample

boats containing sodium carbonate, respectively. Proceed as in 3.5.4.4.

3.5.5.3 Draw a working curve with carbon content as the abscissa and peak area as the

ordinate.

3.6 Calculation of analysis results

The organic carbon content is expressed as the mass fraction of organic carbon wTOC

and calculated according to formula (3).

3.7 Precision

3.7.1 Repeatability

The measured values obtained from two independent test results under repeatability

conditions are within the average value range given below; the absolute difference

between the two test results does not exceed the repeatability limit (r), and the

probability of exceeding the repeatability limit (r) does not exceed 5%. The

repeatability limit (r) is obtained by linear interpolation or extrapolation method

according to the data in Table 4.

4 Test report

The test report shall at least include the following contents.

......

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 14 pages — is available in the English PDF.

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