How To Use Filter Paper?
According to the different degrees of tightness, qualitative filter paper, and quantitative filter paper can be divided into three kinds: fast, medium, and slow. Because qualitative filter paper contains more ash, filter paper uses in precipitation or residue filtration without burning weighing.
Quantitative filter paper is used in precipitation weight analysis. Because the quantitative filter paper has been treated with hydrochloric acid and hydrofluoric acid, the ash content after burning is negligible, so it is also called ashless filter paper.
The following are the specific methods for choosing filter paper:
1. The effective area is large, that is, the filter paper uses a large area, and the dust holding capacity is large, the resistance is small, and the service life is long. Of course, the cost will increase accordingly.
2. The finer the fiber diameter, the better the interception effect and the correspondingly higher filtration efficiency.
3. If the content of binder in the filter material is high, the tensile strength of the paper is high, the filtering efficiency is high, the linting phenomenon is less, the background dust of the filter material is small, the resistance is good, but the resistance increases accordingly.
Generally speaking, the filter paper of amorphous precipitation (such as Fe (OH) 3 and Al (OH) 3) can be chosen loosely so as to avoid too slow filtration speed. For fine-grained precipitation such as CaC2O4 and BaSO4, close slow-speed filter paper should be selected to prevent precipitation leakage.
Medium-sized crystalline precipitation, such as K2SiF6 and SiO2, can be selected as medium-speed filter paper disc. The size of the filter paper should be selected according to the amount of sediment. In the analysis of cement and raw materials, the circular filter paper with a diameter of 9-11 cm should be selected.