Ahlstrom’s qualitative grades of filter paper are, by definition, recommended for use in analytical methods, which determine or identify particulate constituents of a mixture irrespective of the amount present. Qualitative filter papers are often used in routine separation work that still requires high purity and consistent performance.
Ahlstrom offers a complete range of low ash filter papers for general laboratory work that provides you with the correct combination of particle retention, filtration speed, loading capacity and wet-strength. All our qualitative grades consist of > 95% super refined a-cellulose and linter fibers.
- Qualitative analysis
- Low ash content 0.06%
- Untreated
- Consistent performance
- Wet-strengthened grades available
- Custom cut
- Bulk packaging
Standard Grades (Non Wet-Strengthened)
Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. We do not recommend these grades for use in vacuum work or when wet handling is required.
Ahlstrom 613: 6µm – Medium Speed
This is a strong filter paper with a medium flow rate and retention. Ahlstrom 613 is commonly used in student laboratories. This strong general-purpose filter is also useful in Buchner funnels for barium carbonate, lead chromate and beryllium hydroxides.
Construction Laboratory Applications:
ASTM C204-11 Fineness of Hydraulic Cement by Air Permeability Apparatus
The Blaine Freeness Apparatus is used to measure the relative freeness or fineness of hydraulic cement. Grade 613 is used to protect the porous disc in the test equipment from test sample intrusion.
ASTM D1561-92 Preparation of Bituminous Mixture Test Specimens by Means of California Kneading Compactor
A mechanical compactor consolidates test specimens to replicate the equipment being used for the compaction of asphalt concrete pavement. Grade 613 or Grade 615 is installed between the asphalt mixture and the mold to prevent sticking
during the compaction process.
ASTM D2844-07 Resistance R-Value and Expansion Pressure of Compacted Soils
This information is gathered to predict the R-value and Expansion pressure of soil that would be subjected to road traffic. The test is done with a stabilometer and expansion pressure device. This test needs absorptive pads between the sample and the
mold to prevent sticking. The method calls for a creped filter, Grade 615 and a smooth filter, Grade 613.