Some Notes of Using Filter Paper
When there are not descriptions on the boxes of using either qualitative filter paper or quantitative filter paper to filter the sediment, it should be noticed that firstly we take natural filtration and use the filter paper and the ability to entrap solid particles to separate the solid from the liquid.
Secondly, as the mechanical strength and toughness of the filter paper are both small, we should try to minimize the use of suction filtration. If the filtration rate must be accelerated, in order to avoid filtration failures and according to the extraction force, we can stack up two or three layers of filter papers in the funnel when using an air pump to do filtration.
When using vacuum filtration, we can lay a densified filter cloth in the funnel in advance, and then put the filter paper on it to do filtration. Furthermore, it is better not to filter hot concentrated sulfuric acid and nitric acid solution with the filter paper.
When performing the mineral wet ultra-fine grinding experiment, as the bore diameter of qualitative filter paper is not regular and relatively large, we can use quantitative filter paper with small-bore diameter to separate and dry samples of some micrometers.