EN 15924:2011

Overview

EN 15924:2011 (CEN) defines a standardized wet‑sieving procedure for determining the fineness of grinding of soft natural phosphates used in fertilizers. The method addresses agglomeration issues common with fine particle samples by using mechanical wet sieving to quantify material fractions that pass or are retained by specified sieve sizes. The standard supports consistent particle‑size measurement, which is critical for fertilizer performance, handling and regulatory compliance.

Why it matters: accurate assessment of fineness of grinding ensures product quality, uniform nutrient release, better blending and conformity with regulatory or contractual requirements.

Key Topics

• Scope: determination of fineness of grinding for soft natural phosphates by wet sieving.
• Sieve sizes: 0.125 mm and 0.063 mm (standard sieves, diameter 20 cm, height 5 cm).
• Test portion: approximately 50 g of laboratory sample, weighed to nearest 0.05 g.
• Wet sieving procedure: samples are sieved under a small jet of cold water until effluent is practically clear. Residues on each sieve are collected separately.
• Deagglomeration: where lumps occur, a 1 % sodium hexametaphosphate solution is used to disperse aggregates before sieving.
• Drying and weighing: residues are transferred to weighed beakers, dried to constant weight at (150 ± 5) °C, cooled and weighed to determine masses.
• Calculation and expression: fineness values (percent passing) are calculated from the mass of the test portion and the masses of residues on the two sieves; results are reported as percentage fineness of the fertilizer.
• Test report requirements: method reference, sample identification, sampling/preparation dates and procedures, analysis completion date, fineness results, and any deviations or incidents affecting results.

Applications

• Quality control: routine laboratory checks on phosphate raw materials to ensure consistent particle size and milling performance.
• Production monitoring: evaluate milling or grinding efficiency and set processing parameters.
• Regulatory and trade compliance: provide documented, standardized fineness data for conformity with fertilizer regulations and specifications.
• Technical communication: supply reliable particle‑size information to formulators and downstream users for blending and agronomic performance.

Related Standards

• EN 1482-1: Sampling and sample preparation - Part 1: Sampling (recommended sampling method).
• EN 1482-2: Sample preparation (sample preparation for the test portion).
• EN 12944-1 and EN 12944-2: Vocabulary and terms relevant to fertilizers and liming materials.

Keywords: fineness of grinding, wet sieving, soft natural phosphates, fertilizer quality control, particle size, sodium hexametaphosphate, EN 15924:2011.

For laboratory implementation, follow the procedural steps and reporting requirements in EN 15924:2011 and reference the sampling/preparation standards listed under Related Standards.