Potash (Muriate of Potash)

Key data

Deadweight cargo
Stowage factor0.78–0.95 m³/t (typical 0.86)27.5–33.5 ft³/t (typical 30.4)
FormBulk
IMSBC groupC Cargoes that neither liquefy nor carry a chemical hazard.
Angle of repose~30-35

ft³/t values are per metric tonne (1 m³/t ≈ 35.31 ft³/t). Stowage factors are indicative — see note below.

Description

Muriate of potash, or potassium chloride, is the dominant potassium fertiliser, mined and shipped in large parcels as standard or granular grades. As a dense mineral it is a deadweight cargo at around 0.86 m3/t, reaching the marks before the holds fill. It is inert chemically as a fertiliser, but its chloride content makes it unfriendly to the ship's steelwork.

Stowage & loading

Holds are presented clean and dry, and the free-flowing material is loaded by grab or conveyor and trimmed level. Because the cargo and its residues are corrosive to steel when damp, attention is paid to protecting the tank top and structure and to keeping moisture out, and loading is managed to avoid wetting in rain.

Hazards & handling

Potash is hygroscopic and cakes if it takes up moisture, downgrading the cargo and complicating discharge. The more distinctive concern is corrosion: chloride is aggressive to steel, particularly in the presence of moisture, so prolonged contact and unwashed residues can damage the structure and coatings. Dust and staining are housekeeping matters; it is not a safety-of-ship hazard.

Carriage & discharge

Ventilation is managed to keep humidity out, and the holds are monitored for water ingress. Discharge is by grab, with caked material broken out as needed. Thorough washing-down on completion is important precisely because chloride residue left in place will continue to attack the steel, so cleaning is a structural-protection step, not just housekeeping.

Key hazards

  • Chloride corrosion of steel structure and coatings, especially when damp
  • Hygroscopic caking on exposure to moisture
  • Dust and staining during handling

Loading precautions

  • Load into clean, dry holds and protect the tank top and structure from prolonged contact
  • Exclude moisture during loading and the voyage to limit caking and corrosion
  • Plan a thorough wash-down on completion to remove corrosive residue

Stowage factors are indicative and vary with grade, origin, moisture and packing. Always verify against the shipper's cargo declaration and the applicable IMSBC Code schedule before fixing or loading. This is general information, not professional or safety advice.

Scroll to Top