Ahlstrom manufactures a series of extremely high purity, acid washed filter papers designed for use in analytical and gravimetric analysis. The quantitative grades are manufactured from top quality cotton linters using ultra-pure, reverse-osmosis water and are further treated with dilute acid to remove any remaining organic and inorganic impurities. All quantitative grades are manufactured in a strictly controlled environment that ensures high uniformity and high purity from filter to filter.
- Quantitative analysis
- Low ash content 0.007% (Acid-wash treated)
- High wet-strength
- Consistent performance
- Custom cut
- Bulk packaging
Hardened Ashless Grades (Ash 0.006%)
These specially treated hardened ashless grades are available for critical quantitative analytical techniques requiring increased wet-strength and handling capacity. These high purity filter papers have a tough, smooth surface free of loose fibers and are ideal for collecting wet precipitates. Each grade offers a convenient combination of particle retention and flow rate and are generally used because of their high chemical resistance to strong acid and alkali.
Ahlstrom 95: 1.5µm – Slow Speed
This is an extremely fine retention filter for critical gravimetric analysis and metal determination of very fine particles such as barium and lead sulfates, stannic and nickel sulfide, calcium oxalate and calcium fluoride.
Mining Laboratory Applications:
ASTM E278-01 Determination of Phosphorus in Iron Ores
This test has two filtration stages. The first stage can use a qualitative filter, such as grade 631. The second stage requires a hardened, ashless, fine filter. Grade 95 is recommended.
ASTM E314-10 Determination of Manganese in Iron Ore
The precipitate from this procedure is very fine and is ashed for a quantitative analysis. The procedure also requires a strong filter when wet. Grade 95 is a perfect selection for this procedure.
STM4500-SO4 2-.C Total Sulfate in Water: Gravimetric Method
The gravimetric method with ignition of residue calls for an acid-washed, ashless, hard-finish paper retentive enough for find precipitate. These requirements are met by Grade 95.
Construction Laboratory Applications:
ASTM D5891-02 Fluid Loss of Clay Component of Geosynthetic Clay Liners
The clay slurry is filtered through a fine hardened filter. The amount of time to extract a certain volume of water from the sample is determined. Grade 95 is used for this test.