GB/T 3286.11-2022Methods for chemical analysis of limestone and dolomite—Part 11: Determination of calcium oxide, magnesium oxide, silicon dioxide, aluminium oxide and iron oxide content—Wavelength dispersive X-ray fluorescence spectrometry (Fused cast bead method) (English PDF)

1 Scope

This document specifies the determination of calcium oxide, magnesium oxide, silicon dioxide, aluminium oxide and iron oxide content in limestone and dolomite by wavelength dispersive X-ray fluorescence spectrometry.

This document applies to the determination of calcium oxide, magnesium oxide, silicon dioxide, aluminium oxide and iron oxide content in limestone and dolomite. The determination range is shown in Table 1.

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 2007.2 General rules for the sampling and sample preparation of minerals in bulk - Sample preparation by manual method

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

GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values

GB/T 15000.3 Directives for the work of reference materials - Part 3: Reference materials - Characterization and assessment of homogeneity and stability

GB/T 16597 Analytical methods of metallurgical products - General rule for X-ray fluorescence spectrometric methods

JJG 810 Wavelength dispersive X-ray fluorescence spectrometers

YB/T 082 Specification for certified reference materials for metallurgical product analysis

3 Terms and definitions

There are no terms or definitions to be defined in this document.

4 Principle

The sample is ignited at high temperature and melted with borate to prepare fused cast beads. The sample on the surface layer is irradiated by primary X-rays to produce characteristic X-ray fluorescence. After spectroscopy by the crystal, the detector measures the X-ray fluorescence intensity at the 2theta angle corresponding to the selected characteristic wavelength.

5 Reagents and materials

Unless otherwise stated, only approved analytical reagents are used in the analysis, and the water for test shall be distilled water of Grade 3 or above specified in GB/T 6682 or water with a purity equivalent to it.

5.1 Ammonium iodide. solid, analytical reagent.

5.2 Lithium borate mixed flux (lithium tetraborate. lithium metaborate = 67.33). solid; it shall be in an anhydrous dry state, otherwise it needs to be burned at 500 °C ± 10 °C for 4 hours, cooled to room temperature, and then placed in a desiccator for later use.

5.4 Argon methane gas (90 % Ar - 10 % CH4). selected according to the instrument.

6 Instruments and equipment

7 Sampling and sample preparation

7.1 Sampling and sample preparation shall be carried out according to the provisions of

GB/T 2007.2.All samples shall pass through the 0.125 mm sieve.

7.2 Limestone and dolomite samples shall be dried in an oven at 105 °C ± 5 °C for 2 hours before analysis, and then placed in a desiccator to cool to room temperature. The retention time of the dried sample shall not exceed 8 hours, otherwise it shall be dried again.

8 Preparation of fused cast bead

9 Preparation of instruments

10 Analysis steps