This standard specifies the ignition loss of talc product, the content and acidity/alkalinity of silicon dioxide, total iron, aluminum oxide, titanium dioxide, calcium oxide, magnesium oxide, potassium oxide, sodium oxide, hydrochloric acid insoluble substance, acid-soluble iron, acid-soluble calcium, manganese, copper, acid-soluble substance and hydrotrope as well as the analysis methods for chemical constituents like ferric salt, arsenic, heavy metal and lead.
This standard is applicable to the constituent analysis of talc lump and talc powder.
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 normative document (including any amendments) applies.
GB/T 8170 Rules of Rounding Off for Numerical Values & Expression and Judgment of Limiting Values
GB/T 15341 Talc Lumps
GB/T 15342 Talc Powder
3 General Provisions
3.1 Except for moisture determination, the specimen shall be dried for 2h under 105~110℃, and then cooled to room temperature in dryer before being weighed.
3.2 Unless otherwise specified, the weighing of specimen shall be accurate to 0.1mg. The constant mass in this method refers to that the difference between 2 weighing is not greater than 0.3mg.
3.3 Unless otherwise specified, only the water recognized as distilled or deionized water or water with equivalent purity is adopted for analysis in this method. All solutions, unless otherwise indicated, refer to water solutions.
3.4 The concentration of solution is the molar concentration or the mass of solute contained in 1L solution (g/L). (1+1), (1+2), (m+n) refer to the ratio of solute volume to water volume.
3.5 Unless otherwise specified, only the reagent recognized as analytical reagent or guaranteed reagent is adopted for analysis, while only the reagent recognized as reference reagent or spectral pure/high-purity reagent is adopted for calibration. Unless otherwise specified, only the acid and ammonia water recognized as concentrated acid or stronger ammonia water are adopted for analysis.
3.6 Except for determination of ignition loss, blank test shall be carried out simultaneously for other determinations, and the determined results shall be calibrated.
3.7 Unless otherwise specified, the value of analysis result (%) shall be rounded off to two decimal places according to GB/T 8170.
4 Specimen
4.1 Sampling
4.1.1 Sampling of talc lump specimen is carried out according to GB/T 15341.
4.1.2 Sampling of talc lump specimen is carried out according to GB/T 15342.
4.2 Specimen Preparation
Pulverize the sample delivered to the laboratory to make it pass through the 1μm sieve; the mass of sample shall not be less than 1kg; reduce the mass to 1000g with quartering or divider; then grind the sample until it completely passes through the 180μm sieve, and reduce the mass to 100g with quartering or divider; regrind the sample until it completely passes through the 75μm sieve, and reduce the mass to 50g with quartering or divider; gather and remove the scrap iron brought by crushed sample with magnet; sufficiently mix it for standby.
