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This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces the GB/T 3185-1992 Zinc Oxide (Indirect Method) in whole. The following technical deviations have been made with respect to the GB/T 3185-1992 (the previous edition).
— Application field of the product is deleted from the Scope (Clause 1 of Edition 1992);
— Addition of normative references "GB/T 602, GB/T 3186, GB/T 8170, GB/T 19587-2004 and GB/T 5211.18" (see Clause 2; Clause 2 of Edition 1992);
— Normative references GB 1715 and GB 9285 are deleted (Clause 2 of Edition 1992);
— The clause number of "Molecular Formula and Relative Molecular Mass" is modified (see Clause 3; Clause 1 of Edition 1992);
— The clause "Product Classification" is deleted (Clause 3 of Edition 1992);
— The classification mode of products is modified from functional classification to performance classification (see Clause 4; Clause 4 of Edition 1992);
— The technical requirements of products are modified, and the technical indexes have been specified in accordance with the new product type (see Clause 4; Clause 4 of Edition 1992);
— Items and indexes for the content and specific surface area of cadmium (Cd) and iron (Fe) are added (see Clause 4);
— The item name of loss on ignition is modified from "loss on ignition" to "calcination loss" (see Clause 4 and 6.6; Clause 4 and 5.7 of Edition 1992);
— The clause "Sampling" is added (see Clause 5);
— The test methods for determination of lead oxide (Pb), manganese oxide (Mn) and copper oxide (Cu) content by redox process are deleted (5.3.1, 5.4.1 and 5.5.1 of Edition 1992);
— The requirement of relative deviation for parallel determination of HCl insolubles and calcination loss items are added (see 6.5.4 and 6.6.3; 5.6.4 and 5.7.3 of Edition 1992);
— The test methods for the content and specific surface area of cadmium (Cd), iron (Fe) are added (see 6.13, 6.14 and 6.15);
— The valid storage period of products is modified from "six months" to "12 months" (see Clause 8; Clause 7 of Edition 1992).
This standard was proposed by China Petroleum and Chemical Industry Federation.
This standard was prepared by SAC/TC 5 (National Technical Committee 5 on Paints and Pigments of Standardization Administration of China).
The previous editions of this standard are as follows:
— GB/T 3185-1982, GB/T 3185-1992.
Zinc Oxide (Indirect Method)
1 Scope
This standard specifies the requirements, sampling, test methods, inspection rules, marking, packaging, transportation and storage of zinc oxide (indirect method).
This standard is applicable to zinc oxide prepared by indirect method.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 601 Chemical Reagent — Preparations of Reference Titration Solutions
GB/T 602 Chemical Reagent — Preparations of Standard Solutions for Impurity
GB/T 603 Chemical Reagent — Preparations of Reagent Solutions for Use in Test Methods
GB/T 1864-2012 General Methods of Test for Pigments and Extenders — Comparison of Colour of Pigments
GB/T 3186 Paints, Varnishes and Raw Materials for Paints and Varnishes — Sampling
GB/T 5211.2-2003 Determination of Water-soluble Matter of Pigments — Hot Extraction Method
GB/T 5211.3-1985 Determination of Matter Volatile of Pigments at 105 Centigrade
GB/T 5211.15-2014 General Methods of Test for Pigments and Extenders ― Part 15: Determination of Oil Absorption Value
GB/T 5211.16-2007 Comparison of Lightening Power of White Pigments
GB/T 5211.18-2015 General Methods of Test for Pigments and Extenders ― Part 18: Determination of Residue on Sieve — Water Method (Manual Procedure)
GB/T 6682 Water for Analytical Laboratory Use — Specification and Test Methods
GB/T 8170-2008 Rules of Rounding off for Numerical Values & Expression and Judgement of Limiting Values
GB/T 9723-2007 Chemical Reagent — General Rule for Flame Atomic Absorption Spectrometric Analysis
GB/T 19587-2004 Determination of the Specific Surface Area of Solids by Gas Adsorption Using the BET Method
3 Molecular Formula and Relative Molecular Mass
Molecular formula: ZnO
Relative molecular mass: 81.38 (as per IUPAC 2010 standard atomic weights)
4 Requirements
The products shall meet those specified in Table 1.
Table 1 Requirements
Item Index
Type I Type II Type III
Appearance White powder
Zinc oxide content (dried products), w/% ≥ 99.70 99.70 99.50
Metal content (calculated in Zn), w/% ≤ None None 0.008
HCl insolubles, w/% ≤ 0.006 0.008 0.03
Calcination loss, w/% ≤ 0.20 0.20 0.25
Sieve residues (45 μm test sieve), w/% ≤ 0.10 0.15 0.20
Water solubles, w/% ≤ 0.10 0.10 0.15
105℃ volatile matter, w/% ≤ 0.3 0.4 0.5
Plumbum (Pb) content, w/% ≤ 0.008 0 0.05 0.10
Copper (Cu) content, w/% ≤ 0.000 2 0.000 4 0.000 7
Manganese (Mn) content, w/% ≤ 0.000 1 0.000 1 0.000 3
Cadmium (Cd) content, w/% ≤ 0.002 0 0.005 0 0.010
Iron (Fe) content, w/% ≤ 0.005 0 0.010
Special surface area (m2/g) Agreed
Oil absorption a/(g/100 g) Agreed
Colour a Agreed
Lightening powera Agreed
a For zinc oxide (indirect method) products used for pigment only.
5 Sampling
Product sampling shall be conducted according to the requirements of GB/T 3186 or the agreed method. The sampling quantity shall be determined as required by inspection.
6 Test Methods
Caution: Some of the reagents used in the test method are corrosive and must be handled with care! If necessary, conduct the test in a fume cupboard. If it is splashed on the skin, rinse it immediately with water. If it is serious, seek medical care immediately.
6.1 General requirements
Unless otherwise specified, the reagents and water used in this standard refer to analytical reagents and Grade 3 water specified in GB/T 6682-2008; standard titration solution, impurity standard solution, preparations and products used in the test are prepared according to the requirements of GB/T 601, GB/T 602 and GB/T 603.
6.2 Appearance
Under natural light, the sample is placed on a watch glass with white substrate or a white porcelain board for visual observation.
Foreword II
1 Scope
2 Normative References
3 Molecular Formula and Relative Molecular Mass
4 Requirements
5 Sampling
6 Test Methods
7 Inspection Rules
8 Marking, Packaging, Transportation and Storage
