The chemical composition analysis of silicon brick mainly includes the following steps and detection items:

I. Sample collection and preparation

Sample collection: randomly select representative samples from silicon bricks to ensure that the samples can reflect the overall chemical composition.

Sample preparation: the collected samples are crushed to a suitable particle size (usually less than 0.2mm), and ground and screened to ensure the uniformity of the samples.

II. Detection of SiO₂ content

Methods: X-ray fluorescence spectrometry (XRF) or chemical titration were used. XRF method determines the content of SiO₂ in the sample by measuring the intensity of X-rays, which is rapid and accurate.

Standard requirements: SiO₂ content is usually required to be ≥93%, and high-purity silicon brick is required to be ≥95%.

III. Analysis of Impurity Elements

Testing items: focus on testing impurity elements such as Al₂O₃, Fe₂O₃, CaO and MgO.

Methods: Chemical analysis or X-ray fluorescence spectrometry (XRF) was used. XRF method is suitable for simultaneous detection of multiple elements with high accuracy.

Standard requirements: the total amount of impurities should be controlled within 3%-5%.

IV. Detection of free silica content

Methods: Using chemical dissolution method, the samples were treated with specific chemical reagents, and the free SiO₂ was separated and quantitatively analyzed.

Significance: Excessive free SiO₂ may lead to volume stability problems and affect the service life of silicon bricks.

V. Analysis of other chemical components

Content of cristobalite and tridymite: The crystalline phase composition of silicon brick was evaluated by quantitative analysis of X-ray diffraction (XRD).

Alkali metal oxides (such as Na₂O and KO): These components may affect the fire resistance of silicon bricks by chemical titration or XRF method.

VI. Data processing and reporting

Data processing: statistical analysis of the test data to ensure the accuracy and reliability of the results.

Report generation: issue a detailed chemical composition analysis report, including SiO content, impurity element content, free SiO content, etc., and compare with the standard requirements to evaluate whether the sample is qualified.

Through the above steps, the chemical composition of silicon brick can be comprehensively and accurately analyzed, thus providing scientific basis for quality control and performance evaluation of silicon brick.