GB/T 18856.7-2008Test methods for coal water mixture - Part 7: Determination for pH value (English PDF)

Foreword

GB/T 18856 Test Methods for Coal Water Mixture consists of the following 7 parts.

--- Part 1: Sampling;

--- Part 2: Determination of Mass Percentage of Solid;

--- Part 3: Sieving Test;

--- Part 4: Determination of Apparent Viscosity;

--- Part 5: Determination of Stability;

--- Part 6: Determination of Density;

--- Part 7: Determination of pH Value.

This Standard replaced GB/T 18856-2002 Test Methods for Quality of Coal Water Mixture.

Compared with GB/T 18856-2002, this Standard has the major changes as follows.

--- Delete Part 6: Determination of Calorific of Coal Water Mixture;

--- Delete Part 7: Proximate Analysis of Coal Water Mixture;

--- Delete Part 8: Determination of Total Sulfur in Coal Water Mixture;

--- Delete Part 10: Determination for Fusibility of Ash of Coal Water Mixture;

--- Delete Part 11: Determination of Carbon and Hydrogen in Coal Water Mixture;

--- Delete Part 12: Determination of Nitrogen in Coal Water Mixture;

--- Delete Part 13: Determination for the Ash of Coal Water Mixture.

The deleted contents have been integrated into the relevant standards for the determination of coal and coal ash.

This Part is Part 7 of GB/T 18856. This revision reserved all contents of GB/T 18856.14-2002, only made the format revision.

This Part replaced GB/T 18856.14-2002 Test Methods for Quality of Coal Water Mixture - Part 14: Determination for pH Value of Coal Water Mixture.

1 Scope

This Part of GB/T 18856 specifies the method overview, reagents, apparatuses, test procedures, result expression, and precision for determining the pH value of coal water mixture.

This Part is applicable to various types of coal water mixture.

2 Normative References

The provisions in following documents become the provisions of this Part through reference in this Part of GB/T 18856. For dated references, the subsequent amendments (excluding corrigendum) or revisions do not apply to this Standard, however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.

GB/T 6682 Water for analytical laboratory use - Specification and test methods

3 Method Overview

The glass electrode and calomel electrode of the pH meter are immersed in the coal water mixture, creating a potential difference between the two electrodes, thereby providing the pH value of the coal water mixture.

4 Reagents

5 Apparatuses

5.1 pH measuring device, capable of measuring to 0.01 unit. It shall be calibrated by standard pH value buffer solutions at the specified test temperature.

5.3 Mercury thermometer. 0°C~50°C, with graduation of 0.2°C

5.2 Wide-mouth plastic bottle or 50 mL beaker

6 Test Procedures

7 Result Expression

Take the arithmetic mean of two repeated pH measurements, rounded-off to one digit after the decimal point; report the result; and indicate the test temperature.

8 Precision of the Method

The repeatability limit for the pH determination of coal water mixture is 0.2. […]