Hardened ashless filters (ash content approx. 0.002%), especially recommended for vacuum and pressure filtration, and for the use of acidic and alkaline solutions.

• Made of super-refined cotton linters and cellulose
• Acid-washed and free of minerals and metallic ions, ideal for the detection of metallic ions
• Very high wet strength; easy to scrap off or wash off precipitates
• Hardened by small quantities of nitrogen-containing resin, which does not introduce significant impurities into the filtrate
• High resistance to aggressive chemical components, like sulphuric and nitric acids (up to 40 % at 50 ° Celsius) and alkalis (up to 10 % at 20 ° Celsius)
• For analytical applications, routine quantitative and /or gravimetric procedures

These filters are available as filter circles with the following sizes (in mm):

110 – 125 – 150 – 185.

Other sizes, sheets and special cuts are available on request.