The ashless papers are manufactured with a very pure cotton cellulose base. They are purified with acid to reduce the amount of mineral material such as silicon, aluminium or magnesium oxides as far as possible. The residues of the paper after calcination are reduced to negligible quantities and do not affect the results of the qualitative analysis.
Grade 6601: Slow filtration speed, suitable for the retention of fine precipitates. For critical gravimetric quantitative analysis. Recommended for precipitates such as barium sulphate, lead, zinc sulphate, nickel, calcium fluoride and calcium hydroxide.
Grade 6600: Average filtration speed. For standard gravimetric quantitative analysis. Recommended for general use. This is the intermediate filter in terms of speed and retention requirements.
Grade 6602: Fast filtration speed, suitable for the retention of voluminous precipitates. Large pore diameter, which only allows filtering of easily retained precipitates. Recommended for quantitative analysis of precipitates such as iron hydroxide and a range of metallic sulphides.
Grade 6603: Very fast filtration speed, suitable for the retention of particularly voluminous large-grain and gelatinous precipitates. Paper for quantitative analysis, recommended for precipitates such as iron hydroxide or aluminium.