Hardened Quantitative Ashless Filter Paper, 373 Grade, 55mm - 320mm

Hardened Ashless Filter Papers are chemically strengthened for high wet strength and durability in demanding filtration tasks. With an ash content below 0.01%, these acid-hardened papers are ideal for quantitative gravimetric analysis involving strong acids or alkalis. Their tough, smooth surface prevents fibre shedding and enables easy recovery of precipitates without contamination. Suitable for use in Buchner funnels or pressure filtration setups, these papers are available in slow, medium, and fast grades to suit various particle sizes and flow requirements.

Grade 373: is a fast-filtering, high-strength ashless paper designed for the separation of coarse particles and gelatinous precipitates. With a nominal pore size of 12–15 µm and a filtration speed of 10 seconds (DIN 53137), it is ideal for high-throughput vacuum or suction filtration in Buchner or Hirsch funnels. Grade 373 maintains its structure under pressure and wet conditions, supporting consistent flow and low fibre release. Commonly used for hydroxide and sulfide precipitates, it is also suitable for applications in steel analysis, air and foodstuffs testing, and the determination of chloride and phosphorus in cement, coal, and coke.

Application: Used for coarse and voluminous precipitates, iron, cobalt and chromium hydroxides as well as bismuth sulphides, analysis of acid solutions

Key Features

Fast Filtration Speed: Designed for quick separation of large or gelatinous precipitates.​

Large Pore Size (12–15 µm): Suitable for high-volume, coarse particle filtration.​

Wet Strength and Durability: Resilient in suction and vacuum filtration, compatible with Buchner and Hirsch funnels.​

Low Ash Content: ≤0.06%, ensuring reliable residue measurement after combustion.​

Smooth, Acid-Hardened Surface: Prevents fibre release during filtration and allows for easy precipitate removal.

• Gravimetric analysis of coarse hydroxides: iron, aluminium, chromium, zirconium
• Filtration of copper, cobalt, and sulfide precipitates
• Silicon determination in steel and pig iron testing
• Air quality and foodstuffs particulate analysis
• Analysis of chloride and phosphorus in cement, coal, and coke
• Fast filtration workflows requiring high flow rates with reliable retention

HS Code / Commodity Code: 4823209000