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The testing method of impurity composition in high-purity graphite block

  Graphite has good resistance to high temperature, electrical conductivity, thermal conductivity, lubricity, and chemical stability, widely used in metallurgical, mechanical, environmental, chemical, fire resistance, electronics, medical, military and aerospace fields, is becoming more and more important in the national economy, is essential to modern industry and high and new advanced technology development the important non-metallic materials, and trace impurities have a great effect on the performance of graphite products. The higher the carbon content of graphite, the better the performance of the functional materials will be.

  Because there are very few impurities in high purity graphite, and the general analytical method of instrumental analysis can not be detected accurately, this method needs to be improved.

  The analysis of trace impurities in high purity graphite, usually will sample pre ashing and wet digestion to remove carbon and acid with the dissolution of the ash, and determination of the impurity content of the solution. Ashing method do not need to dissolve with pure acid ash, so as to avoid the risk of introducing the measured elements, so with the more.

  The detection of high purity graphite ash is very difficult, because the enrichment ash need high temperature burning, and in high temperature ash branch bond in the sample boat is difficult to be separated, which leads to unable to accurately determine the impurity composition and content.

  Existing methods using platinum crucible discord acid reacts the characteristic, using platinum crucible burning high purity graphite enrichment ash, then in the crucible directly by heating and acid dissolution of sample processing, determination of solution components can be calculated in graphite content of impurities.

  But this method has a certain limitation, because of the high pure graphite containing large amounts of carbon, can make the platinum crucible brittle brittle under high temperature conditions, easy to cause the rupture of the platinum crucible, the detection cost is high, difficult to widely used. Because the conventional method can not detect the impurity composition of high pure graphite, we need to improve the detection method.