GB/T 18856.7-2008 English PDF
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GB/T 18856.7: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 18856.7-2008 | 130 | Add to Cart | Auto, 9 seconds. | Test methods for coal water mixture -- Part 7: Determination for pH value | Valid |
| GB/T 18856.7-2002 | 239 | Add to Cart | 2 days | Test methods for quality of coal water mixture -- Part 7: Proximate analysis of coal water mixture | Obsolete |
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GB/T 18856.7-2008: Test methods for coal water mixture -- Part 7: Determination for pH value
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT18856.7-2008GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 75.160 D 21 Replacing GB/T 18856.14-2002 Test Methods for Coal Water Mixture – Part 7. Determination of pH Value Issued on: JULY 29, 2008 Implemented on: APRIL 1, 2009 Issued by. General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China
Table of Contents
Foreword... 3 1 Scope... 5 2 Normative References... 5 3 Method Overview... 5 4 Reagents... 5 5 Apparatuses... 7 6 Test Procedures... 7 7 Result Expression... 7 8 Precision of the Method... 7 9 Test Report... 8Foreword
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. This Part was proposed by China National Coal Association. This Part shall be under the jurisdiction of National Technical Committee on Coal of Test Methods for Coal Water Mixture – Part 7. Determination of pH Value1 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 methods3 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
4.1 Water The water used in this Part shall be Grade II water as specified in GB/T 6682.It shall be freshly boiled and cooled to room temperature before use. 4.2 Buffer solution with standard pH 4.2.1 Neutral phosphate solution. pH around 7 Weigh 3.40 g of potassium dihydrogen phosphate (GB/T 6853) and 3.55 g of disodium5 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. 5.2 Wide-mouth plastic bottle or 50 mL beaker. 5.3 Mercury thermometer. 0℃~50℃, with graduation of 0.2℃.6 Test Procedures
6.1 pH meter calibration Select two buffer solutions with standard pH values, which are close to or cover the pH values of the coal water mixture being tested. Immerse the test electrode of the pH meter into one of the standard solutions and adjust the indicating part until the displayed pH value matches that of the standard buffer solution. Then immerse the test electrode into the other standard buffer solution. If the pH value displayed by the pH meter matches the standard value, the pH meter shall be used for normal test. If the pH value displayed by the pH meter does not match the standard value, the pH meter shall be further adjusted to match the standard value; or check whether the standard value of the standard buffer solution used to calibrate the instrument has changed. If it has changed, the standard solution shall be prepared again; and the pH meter shall be recalibrated according to the instructions. 6.2 Determination of pH value Pour the well-stirred coal water mixture specimen into a plastic bottle or a 50 mL beaker; and insert a clean electrode into the specimen. After shaking, measure the pH value. Take the stable reading as the pH value of the coal water mixture, rounded-off to one digit after the decimal point. Record the room temperature simultaneously.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. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
