Currently, there are three kinds of quantitative filter papers in the domestic market. They are fast speed, intermediate speed and low speed, with category labels of white belt, blue belt and red belt respectively on the filter paper boxes.
The shapes of quantitative filter paper are round and square. The specification of round papers is classified by diameter with 9cm, 11cm, 12.5cm, 15cm and 18cm. As for the specification of square papers, there are 60cm x 60cm and 30cm x 30cm.
Normally, the residual ash remains a lot in the qualitative filter paper. It is only for ordinary qualitative analysis, sediment filtration and solution for suspension. It cannot be used for quality analysis. When referring to specification, the qualitative filter paper is almost the same with the quantitative filter paper. However, instead of belts with different colors, the words of fast speed, intermediate speed and low speed are printed on the filter paper boxes.
Furthermore, the quantitative filter paper is mainly used for analysis experiment which needs ashing weighing after filtration. The ash weight is a constant value after each filter paper is ashinged. While the qualitative filter paper is primarily used for ordinary filtration. So, the difference between the two kinds of filter papers mainly focus on the ash weight after ashing.
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