Potash
The potassium is never the question. The chloride is.
Muriate and sulphate of potash in standard, granular, coarse and soluble grades. Two products delivering the same nutrient, separated by an anion that some crops do not mind at all and others will not tolerate — and by a price gap that follows from exactly that.
The desk
One nutrient, two salts, and the difference is agronomic rather than commercial.
Potassium chloride — muriate of potash, MOP — is about 95 % of the potash in world trade, at roughly 60–62 % K₂O. It is the cheapest potassium per unit and, for most field crops on most soils, entirely appropriate.
Potassium sulphate — sulphate of potash, SOP — runs around 50 % K₂O with roughly 18 % sulphur, and costs materially more because it is made rather than simply mined and beneficiated. What you are paying for is the absence of chloride, plus a second nutrient.
That premium is justified in specific places and nowhere else. Tobacco, potatoes, grapes, citrus, avocados, berries, most vegetables and much of the greenhouse and fertigation world are chloride-sensitive, either because chloride damages the crop directly or because it degrades quality attributes the buyer is paying for — starch in potatoes, burn characteristics in tobacco. Add salinity-affected soils and irrigation water already carrying chloride, and the case is straightforward. On cereals, oilseeds, maize, sugar beet and palm, it usually is not, and paying an SOP premium there is buying something the crop cannot use.
So the first question on a potash enquiry is the crop and the water, not the tonnage. It is a short conversation and it has saved buyers more money than any negotiation on the price.
Grades
The same salt, sized for four different jobs.
Potash grades are a particle-size classification, not a purity one. Getting it wrong does not degrade the nutrient; it makes the product unusable in the application it was bought for.
| Grade | Character | Where it goes |
|---|---|---|
| Standard MOP | Fine crystalline, the form as produced. | Direct application where equipment suits it, and as feedstock for compound fertiliser manufacture. Too fine to blend well with granular materials — see segregation. |
| Granular MOP | Compacted and crushed to a granular size range, harder and free-flowing. | The blending grade and the direct-application grade for modern spreaders. Commands a premium over standard for exactly that reason. |
| Coarse / soluble MOP | Coarser again, or a high-purity soluble grade with low insolubles. | Coarse for specific blending requirements; soluble grade for fertigation and liquid formulation, where undissolved residue blocks emitters. |
| SOP — standard and granular | Potassium sulphate, white, in powder and granular forms. | Chloride-sensitive crops, fertigation, foliar formulation and speciality blends. Soluble-grade SOP is a distinct product with tighter insolubles. |
| SOP-M / langbeinite | Potassium magnesium sulphate, a mined double salt. | Where magnesium and sulphur are wanted alongside potassium without chloride. Lower K₂O, three nutrients. |
| Colour | Red-pink from iron oxide in the ore, or white where refined further. | Agronomically irrelevant, occasionally a market preference, and sometimes a specification line because a buyer's customers expect one or the other. Worth stating so nobody discovers it at discharge. |
Specification
Six lines, and two of them are about water.
Potash analysis is stable and rarely disputed. What is disputed is the physical condition of the cargo at discharge, and that traces back to moisture almost every time.
| Parameter | Typical trade basis | What it governs |
|---|---|---|
| K₂O | MOP 60–62 % minimum; SOP 50 % minimum | The nutrient, conventionally expressed as the oxide equivalent rather than as elemental potassium. Both conventions exist in different markets, so state which. |
| Moisture | Commonly 0.5 % maximum, tighter on granular | The caking parameter, and the one that decides whether the cargo arrives free-flowing. Potash is hygroscopic and a wet cargo sets hard. |
| Sodium chloride | Stated maximum | The main diluent carried through from the ore. It displaces nutrient and adds salinity, and it is the practical difference between a 60 % and a 62 % product. |
| Water-insoluble matter | Low, and much lower on soluble grades | Irrelevant for broadcast application and decisive for fertigation, where insolubles block filters and emitters. A soluble grade is defined by this line. |
| Particle size distribution | Full sieve analysis with a fines ceiling | Defines the grade, decides spreading behaviour, and governs whether the product will segregate in a blend. |
| Anticaking treatment | Named, with the agent identified | Standard on bulk shipments. Amine-based coatings are common and they need to be compatible with the end use — a coated product may not suit dissolution. |
Carriage
An easy cargo that goes wrong in exactly one way.
Potassium chloride travels under a Group C schedule of the IMSBC Code — it neither liquefies nor presents a chemical hazard, and muriate of potash is listed against that schedule by name. There is no dangerous-goods regime and no moisture limit imposed for safety. Which leaves one failure mode, and it is commercial.
- Caking
- A hygroscopic salt in a humid hold, subject to ship's sweat and to compaction under its own weight, arrives crusted or set. Breaking out a caked cargo is slow, expensive and damaging to the granule, and the dispute afterwards turns on records that either exist or do not.
- What actually prevents it
- Loading within the moisture ceiling, effective anticaking treatment applied at the plant rather than assumed, an agreed ventilation regime recorded by the vessel, and clean dry holds. In that order of importance.
- Hold cleanliness and previous cargo
- Declared and certified. Potash discolours readily from residues and, on a white SOP or a soluble grade, visible contamination is a rejection rather than a discount.
- Salt is corrosive
- Chloride plus moisture attacks steel. Hold condition on redelivery is a charterparty term on this cargo and belongs in the fixture.
- Packed cargo
- Big bags and small bags need a moisture barrier and honest stacking limits. A bag specification that omits the liner is not a bag specification.
Pricing
A concentrated market that settles in large blocks.
Potash comes from a small number of geological basins and a correspondingly small number of producers. That structure shapes how it prices, and it is worth understanding before signing anything long.
- Benchmark settlements
- A large share of world volume has historically been set by periodic negotiated settlements with the biggest importing markets, with the rest of the world pricing in relation to those. The practical effect is that potash can sit still for months and then step, rather than drifting continuously. Comparing a spot assessment with a settlement price is a standard way to reach a wrong conclusion.
- Regional assessments
- CFR Brazil, CFR South East Asia, FOB Vancouver, FOB Baltic and NOLA barge among others. Name the assessment and the publication, not the region.
- Grade differentials
- Granular over standard, soluble grade over both, and SOP at a substantial premium to MOP. These differentials move independently of the flat price, so a formula written on MOP standard does not track a granular requirement.
- Freight is a large share of the delivered cost
- Potash is low value per tonne relative to its bulk. On many routes freight is a bigger swing factor than the FOB price, which is why the delivery basis needs settling before the number is discussed.
- What to fix
- The assessment, the publication, the pricing period, the grade, the basis, and whether moisture is deducted. And, on a long contract, what happens if the benchmark mechanism itself changes.
Scope
Where our obligation ends.
- What we supply
- MOP in standard, granular, coarse and soluble grades, SOP in standard, granular and soluble grades, and SOP-M, in cargo lots, containers, big bags and small bags, FOB or CFR.
- What we do not do
- We do not mine, compact or granulate, we do not operate terminals or blending plants, and we hold no equity in production.
- Agronomic advice
- We will tell you which product suits a chloride-sensitive crop and which does not, because that is a product question. We are not agronomists and we do not write fertiliser programmes.
- Grade substitution
- We will not ship standard against a granular order, or a non-soluble grade against a fertigation requirement, because the analysis matches. Grade is a specification, not a preference.
- Origin
- Potash production is geographically concentrated, and a concentrated supply base is where origin claims most need checking. Counterparty, origin and sanctions status are screened per consignment; where they cannot be cleared we decline at enquiry and do not refer the cargo onward — see Compliance.
How to specify
Six lines and we can price it.
Tell us the crop and we can usually answer the first line for you.
MOP or SOP
Or tell us the crop, the soil salinity and the irrigation water, and we will say which the agronomy calls for.
Grade
Standard, granular, coarse or soluble — with the size range and fines ceiling, not just the grade name.
Analysis floors and ceilings
K₂O minimum, moisture maximum, sodium chloride maximum, insolubles for soluble grades, and chloride maximum on SOP.
Blend or direct
If it is going into a blend, say so — the size guide number and uniformity index have to match the other components.
Packing and basis
Bulk, big bags or small bags with the liner specified; FOB, CFR or delivered; vessel size and discharge rate.
Pricing mechanism
Which assessment, which publication, the pricing period, and the grade the formula is written on.
Inspection
The analysis is routine. The condition record is not.
Independent inspection by an agency appointed for the cargo — SGS, Bureau Veritas or Intertek — instructed jointly, with sampling under supervision. On potash the laboratory result almost always confirms the specification; the money is in what the cargo looked like when it was loaded.
- Sampling
- Mechanical or stopped-belt increment sampling to the applicable procedure, with increment number and mass, division and preparation recorded, and sealed retained samples held for the claim period.
- Analysis
- K₂O, moisture, sodium chloride, water-insoluble matter, and on SOP the chloride content as a guaranteed maximum. Reported on a stated basis with moisture shown separately.
- Sizing
- Full sieve analysis with the fines fraction reported, and, for blend-destined material, the size guide number and uniformity index so the blender can match components rather than discover the mismatch in the field.
- Anticaking
- Agent identified and application confirmed. "Treated" without a named agent and a dosage is not a specification, and it is the line most often left vague on a cargo that later cakes.
- Condition and ventilation
- Holds inspected, cleaned and certified before loading with the previous cargo declared; cargo photographed at load and at discharge; ventilation regime agreed and the vessel's record obtained. This set of documents is what a caking claim stands or falls on.
- Documentation per cargo
- Certificate of analysis, moisture and size certificates, anticaking statement, hold cleanliness certificate with previous cargo declaration, draught survey reports, certificate of origin, the IMSBC cargo declaration, bill of lading and the inspection report with photographs.
Straight answer
What we will tell you before you ask.
- That most crops do not need SOP
- The premium buys the absence of chloride. On cereals, maize, oilseeds and palm that is usually buying something the crop cannot use. Tell us the crop and we will say so plainly, including when it costs us the order.
- That grade is a specification, not a preference
- Standard, granular and soluble are the same salt sized for different jobs. Standard shipped against a granular order meets the analysis and fails the purpose.
- That potash is not covered by CBAM
- Straight potassium fertilisers are outside it, and PK products under CN 3105 60 00 are explicitly carved out. Nitrogen and ammoniated phosphates are not, and that asymmetry now sits inside every European blend economics.
- That caking is decided at loading
- Moisture within spec, anticaking actually applied, dry holds and an agreed ventilation regime. Everything after that is documentation of a decision already made.
- That the supply base is narrow
- A small number of basins and producers, which is exactly the situation where origin claims deserve checking rather than accepting. We screen per consignment and decline where it cannot be cleared.
Enquiries
Every enquiry is answered by the desk that handles it.
Send the product, quantity, delivery basis, destination and timing. We revert with availability, an indication and the documentation that accompanies it. Specifications are released once we know who we are speaking with.