This page covers how a compacted ammonium chloride granule behaves once it leaves the warehouse — in a spreader, in a blend and in soil. The compaction process itself, and the mechanical properties it produces, are described on the compacted ammonium chloride page in the main fertilizer products section.
Substance identity
| Chemical name | Ammonium chloride |
| Synonyms | Sal ammoniac, muriate of ammonia |
| Formula | NH₄Cl |
| CAS | 12125-02-9 |
| Molar mass | 53.49 g/mol |
| Appearance | White to off-white angular granules with fractured faces |
Specification
| Parameter | Value | Basis |
|---|---|---|
| Nitrogen (N) | ≥ 25.0–25.4 % | Typical commercial range |
| NH₄Cl content | ≥ 94–96 % | Typical commercial range |
| Moisture | ≤ 0.5–1.0 % | Typical commercial range |
| Particle size | 2–4 mm typical cut | Typical commercial range |
| Bulk density | Approximately 0.9–1.05 t/m³ | Typical, approximate |
| Dust / fines after handling | Worth specifying as a maximum measured at delivery, not at production | To be agreed |
Properties
Chemistry is that of the salt and is unchanged by compaction. What changes is rate. A 3 mm granule presents far less surface per unit mass than a 0.3 mm crystal, so it dissolves more slowly in soil moisture, takes up atmospheric water more slowly, and resists caking better. Solubility remains high in absolute terms — approximately 37 g per 100 g water at 20 °C — so “slower” here means hours to days in moist soil rather than any meaningful controlled-release behaviour. Do not treat a compacted granule as a slow-release product; it is a rapid-release product in a more convenient physical package.
Applications
Spreading. Granule mass and density determine how far a spinner throws a particle. Denser, more uniform granules throw further and more consistently than light or variable ones, which directly sets achievable working width and the coefficient of variation of the spread pattern. Because the granules are angular rather than spherical, their flight is somewhat less consistent than that of a rounded prilled or drum-granulated product, and spreader settings should be calibrated with the actual product rather than transferred from another fertilizer.
Blending. Segregation in a blend is driven by differences in particle size and density between components, and every transfer — auger, conveyor, coning into a heap, hopper fill, spreader throw — is an opportunity for it. Matching the ammonium chloride granule to its blend partners is what prevents a correctly formulated blend from being applied incorrectly in the field.
In soil. The granule dissolves from the outside inward, so nitrogen is initially concentrated at the granule site. That local concentration is the reason to keep granules away from germinating seed, since the salinity at a dissolving granule is far higher than the field-average calculation implies.
Handling and storage
Store dry and sealed, and treat every transfer as a source of attrition. Fines generated in handling are doubly unwelcome: they restore the dust exposure that granulation removed, and they concentrate at the bottom of a heap or bag, where they cake first and hardest. Limit drop heights. Where a granule has been through a long logistics chain, verify size distribution before blending rather than relying on the production certificate. Keep away from alkaline materials, and from copper alloys and unprotected steel in humid conditions.
Notes
The useful specification for a granular fertilizer is measured at the point of use, not the point of manufacture. A granule strength or dust figure taken at the plant says little about the material arriving at a farm several transfers later.