When sourcing specialty fertilizers or industrial potassium compounds, you’ve likely seen “0-0-50” on product labels, certificates of analysis, or supplier specification sheets. For procurement managers and formulators, these three numbers carry critical information about nutrient content and product suitability. 0-0-50 potassium sulfate is the standard commercial designation for a premium sulfate of potash (SOP) that delivers 50% potassium oxide (K2O) with zero nitrogen and zero phosphorus—a pure, chloride-free potassium source demanded by high-value crop growers, glass manufacturers, and pharmaceutical producers worldwide. This guide breaks down everything a professional buyer needs to know about the 0-0-50 grade, from chemical fundamentals and quality benchmarks to cost-performance comparisons and China sourcing best practices.
Premium 0-0-50 potassium sulfate from Weifang Hailei Fine Chemical meets or exceeds 50% K2O minimum purity, making it a trusted choice for chloride-sensitive applications. Let’s examine the full meaning behind that critical NPK ratio.
The NPK system used on fertilizer labels expresses the guaranteed minimum percentages of total nitrogen (N), available phosphate (P2O5), and soluble potash (K2O)—in that exact order. So a 0-0-50 potassium sulfate product guarantees 0% nitrogen, 0% phosphate, and 50% potassium oxide by weight. This is a straight potash fertilizer: it supplies only potassium, with no other primary macronutrients.
In the case of potassium sulfate (K2SO4), the K2O content is a convention rather than a direct measurement—pure K2SO4 contains about 54% K2O theoretically, while a commercial 0-0-50 potassium sulfate typically contains around 92–95% K2SO4 purity to achieve the guaranteed 50% K2O. The remaining mass is made up of moisture, trace chloride, and minor sulfate residues. Understanding this relationship helps buyers evaluate the true value: a product with 52% K2O might command a premium over a standard 50% grade, but only if the application demands that extra concentration.
Historically, the fertilizer industry adopted the oxide form for phosphorus and potassium to ensure consistency across different chemical formulations. For potassium, K2O is the standard reference. The conversion factor from K to K2O is 1.205, and from K2O to K2SO4, it’s approximately 1.85. When you buy a 0-0-50 potassium sulfate product, you are effectively purchasing 41.5% elemental potassium (K) by weight, because 50% K2O Ă— 0.83 = 41.5% K. This elemental potassium is what plants actually absorb, so advanced buyers often calculate their needs in K rather than K2O to avoid over- or under-application.
The “0-0” prefix is not a deficiency; it’s a design feature. Many high-value crops—fruits, vegetables, tobacco, potatoes, and turf—require potassium boost applications late in the growth cycle, when nitrogen would delay maturity or reduce quality. Applying a 0-0-50 potassium sulfate fertilizer allows precise potassium nutrition without unwanted green growth or phosphorus runoff. This is especially critical in chloride-sensitive plants like berries, citrus, grapes, and ornamental flowers, where potassium chloride (MOP) can cause leaf burn and soil salinity buildup.
For industrial users, the absence of nitrogen and phosphorus simplifies formulation. Glass manufacturers using potassium sulfate as a fluxing agent need a clean potassium source without other cations that would alter the glass color or melting behavior. Similarly, in aluminum recycling, potassium sulfate acts as a salt flux to separate impurities; nitrogen or phosphorus compounds would interfere with metal quality. The 0-0-50 grade ensures a single-function additive that regulatory and quality control teams can trust.
Many buyers initially compare 0-0-50 potassium sulfate with the more common 0-0-60 muriate of potash (MOP). While MOP offers a slightly higher K2O content (60%) and a lower price per unit of K2O, it contains roughly 47% chloride—a dealbreaker for crops and processes sensitive to chlorine. The chloride index of SOP is less than 1%, typically below 0.5% in premium grades. This low chloride content dramatically reduces soil salinity risk and prevents corrosion in industrial furnaces or pharmaceutical processing equipment.
When evaluating total cost of ownership, the per-kg K2O price only tells part of the story. Crop yield and quality penalties from chloride toxicity, additional irrigation to leach salts, or damage to glass furnace refractories can far outweigh the upfront savings of MOP. For these reasons, procurement teams in the specialty fertilizer, pharmaceutical, and glass sectors overwhelmingly select 0-0-50 potassium sulfate despite the higher unit cost. Hailei Chemical’s low-chloride SOP delivers the purity and performance specification that demanding applications require.
In technical procurement, the molecular weight of potassium sulfate is more than a classroom number. At 174.259 grams per mole, K2SO4 provides a stoichiometric basis for calculating exact formulation requirements in pharmaceutical compounding, laboratory reagents, and industrial chemical reactions. For example, a batch recipe that calls for 100 kg of potassium sulfate can be precisely weighed without moisture corrections if the assay and water content are known, but understanding the molar mass allows direct conversion to moles when scaling reactions.
Pure potassium sulfate is a white, crystalline solid with a density of 2.66 g/cm³, melting point 1069°C, and water solubility of 111 g/L at 20°C. In the 0-0-50 fertilizer grade, the product remains highly soluble but may come in granular or powder forms depending on application method. Particle size distribution (e.g., 90% passing 2–4 mm for granular) directly impacts spreading uniformity in agricultural use and dissolution rate in industrial tanks. A proper specification sheet for 0-0-50 potassium sulfate should list not only K2O content by weight but also bulk density, moisture, chloride content, and sieve analysis—critical technical parameters that distinguish a reliable industrial-grade product from a commodity fertilizer.
During online research, buyers occasionally encounter the search term what is potassium sulfide and may confuse it with potassium sulfate. It’s important to clearly distinguish them. Potassium sulfide (K2S) is an inorganic compound with a molecular weight of 110.26 g/mol, most often encountered as a reagent in analytical chemistry or as a depilatory agent in leather processing. It is highly alkaline, hygroscopic, and releases toxic hydrogen sulfide gas upon contact with acids. Potassium sulfide has no relation to the fertilizer-grade 0-0-50 potassium sulfate discussed here.
For procurement managers, mixing up potassium sulfide with potassium sulfate could lead to hazardous sourcing errors. Always verify the CAS number: potassium sulfate is CAS 7778-80-5, while potassium sulfide is CAS 1312-73-8. A reputable supplier’s certificate of analysis and safety data sheet will clearly state the correct chemical identity. When sourcing 0-0-50 potassium sulfate for fertilizer or industrial use, confirm that the material is indeed dipotassium sulfate, not any sulfur-containing variant with different properties.
Another compound that sometimes appears in supplier catalogues alongside SOP is aluminium potassium sulfate (also known as potassium alum), with the formula KAl(SO4)2·12H2O. Its molecular weight is 474.39 g/mol, and it finds common uses in water purification, dyeing, and as a food additive (E522). While aluminium potassium sulfate is a double salt containing potassium, it cannot replace pure potassium sulfate in fertilizer or glass manufacturing because the aluminium content would be detrimental.
Similarly, the raw mineral from which some potassium sulfate is derived—kainite or langbeinite—may contain magnesium and other ions, but refined SOP used in the 0-0-50 grade is essentially free of aluminium. Buyers seeking a clean potassium source for pharmaceutical excipient production or aluminum recycling must insist on a specification that limits aluminium content to trace levels (typically <10 ppm). Hailei Chemical’s high-purity potassium sulfate is manufactured via the Mannheim process, a synthesis route that yields a product with negligible heavy metals and aluminium contamination, ensuring compliance with pharmacopoeia standards.
Procurement professionals cannot rely solely on the NPK label. A rigorous certificate of analysis (COA) should include the following parameters for a 0-0-50 potassium sulfate fertilizer:
For pharmaceutical-grade or laboratory-grade potassium sulfate, additional specifications like heavy metals (Pb ≤ 10 ppm, As ≤ 3 ppm), loss on drying, and assay (99.0–100.5% K2SO4) apply. Importers must also confirm compliance with local fertilizer regulations (e.g., EC Fertilizer Regulation 2003/2003 in Europe) and ensure proper labeling of the K2O source as “water-soluble potassium oxide.”
China is the world’s largest exporter of potassium sulfate, with manufacturing concentrated in Shandong, Sichuan, and Xinjiang provinces. However, not all Chinese suppliers deliver consistent 0-0-50 quality. When evaluating potential partners, procurement departments should examine the production technology. The Mannheim process, which reacts potassium chloride with sulfuric acid in high-temperature furnaces, yields a high-purity product with low chloride. Alternatively, the sulfate double-salt method (from langbeinite) can result in variable potassium content and higher magnesium. Request a detailed manufacturing flow chart and third-party test reports from an ISO 17025 accredited lab.
Logistics and documentation are equally critical. As a granular chemical, SOP requires moisture-proof packaging—typically 25 kg PP/PE bags or 1000 kg super sacks—and protection from precipitation during sea freight. Ensure the supplier provides a full set of shipping documents: commercial invoice, packing list, certificate of origin, fumigation certificate for wooden pallets, and a valid REACH pre-registration or K-REACH if shipping to the EU or Korea. Weifang Hailei Fine Chemical Co., Ltd. holds necessary export qualifications and has a proven track record of delivering consistent 0-0-50 potassium sulfate to buyers in over 30 countries. Explore our product specification sheet to see how our SOP compares with your current supply.
B2B buyers often stumble when they assume all SOP is equal. A product labeled only “potassium sulfate” might be a 0-0-48 grade (with lower K2O) or may contain fillers that reduce solubility. Always ask for a complete nutrient analysis, not just the NPK numbers. Another pitfall is ignoring the particle hardness and caking tendency. In humid climates, low-quality SOP can harden into rock-like lumps inside supersacks, causing costly handling delays. Specification of anti-caking agent and bag seal integrity can prevent this.
Price fluctuations in MOP and sulfuric acid markets directly affect SOP pricing. Buyers who negotiate quarterly pricing formulas linked to MOP benchmarks can gain better cost predictability. However, long-term contracts with a reliable supplier like Hailei Chemical often include price stabilization clauses and priority allocation during supply crunches—a strategic advantage when formulating high-margin specialty fertilizers or pharmaceutical products.
The seemingly simple label “0-0-50 potassium sulfate” encodes a wealth of chemical, agronomic, and industrial information that smart procurement managers turn into competitive advantage. From understanding the K2O convention and chloride limits to distinguishing it from potassium sulfide and aluminium potassium sulfate, the details matter. A true 50% K2O SOP with minimal chloride enables chloride-free fertilization, brighter glass, higher aluminum yields, and purer pharmaceutical excipients. Next time you review a supplier’s COA, you’ll know exactly which parameters separate premium-grade material from an expensive compromise.
Ready to secure a stable, high-quality supply of 0-0-50 potassium sulfate? Contact Weifang Hailei Fine Chemical today to request samples, receive a tailored quotation, or discuss custom packaging and logistics. Get your quote now and experience the Hailei difference in chloride-free potash excellence.
For procurement managers, agronomists, and chemical buyers, the price of potassium sulfate fertilizer is one of the most closely watched market metrics. Also known as sulfate of potash (SOP), this premium chlorine-free potassium source commands a higher price than muriate of potash (MOP), but its benefits for high-value crops, glass production, and pharmaceutical applications make it irreplaceable in many supply chains. Understanding how that price is built—from raw material extraction to dock delivery—empowers you to negotiate smarter, avoid hidden costs, and form lasting supplier relationships.
At Hailei Chemical, we’ve exported potassium sulfate fertilizer to over 30 countries, consistently delivering product with a minimum 50% K2O content and strict impurity controls. In this guide, we break down every component that shapes the per-metric-ton cost, provide a practical framework for evaluating quotes, and connect pricing dynamics to real-world usage so you can make data-driven purchasing decisions.
The per-unit price you see on a quote is the culmination of production, logistics, seasonal demand, and quality choices. By isolating each element, you can spot opportunities to optimize costs without compromising on performance.
Potassium sulfate is manufactured through two primary methods: the Mannheim process (reacting potassium chloride with sulfuric acid) and natural brine extraction from salt lakes or minerals such as langbeinite. Natural routes often have lower energy requirements but are limited by geographic availability, while Mannheim facilities are common in China, Europe, and the United States but are sensitive to energy and sulfur prices.
Imported SOP from China, which includes Hailei Chemical’s output, often benefits from efficient Mannheim production at scale, delivering a competitive price per metric ton while still meeting international purity standards.
Standard agricultural grade SOP typically contains 50% K2O by weight, but premium water-soluble or pharmaceutical grades may go higher, increasing production costs. Impurities such as chloride, sodium, or heavy metals must be kept low, especially for fertigation, hydroponics, or pharmaceutical excipient use. Meeting this requires additional purification steps, which adds to the final price of potassium sulfate fertilizer.
Always verify that the quoted grade matches the intended application. A lower-priced product with 48% K2O and elevated chloride may end up costing more per unit of effective nutrient delivered—or even damage sensitive crops like tobacco, citrus, or berries.
The particle size and form influence both unit price and handling logistics:
When comparing quotes, make sure the physical form is identical. A granular price may appear higher, but its handling efficiency and lower dust loss can outweigh the powder discount.
For international buyers, the landed cost often rivals the ex-works price. Key packaging decisions—25-kg bags, 50-kg bags, 1,000-kg supersacks, or bulk vessel—influence both unit cost and freight rates. Additionally, the chosen Incoterms (FOB, CIF, CFR) determine where risk and cost transfer.
Proximity to a major Chinese export port (Qingdao, Tianjin) helps Hailei Chemical offer competitive sea freight rates to Asia, Africa, Latin America, and Europe.
Agricultural demand peaks before planting seasons in the Northern and Southern Hemispheres, causing quarterly price fluctuations. Unexpected events—a gas supply disruption in Europe, export restrictions in major producer countries, or changes in anti-dumping duties—can abruptly alter global supply. Staying in regular contact with your supplier and monitoring these cycles allows you to place orders during demand troughs and lock in favorable pricing.
When multiple suppliers submit quotes, a simple price-per-ton comparison can be misleading. Use this structured evaluation framework to reveal the true value behind each offer.
Convert each offer to a price per unit of K2O. If Supplier A quotes USD 500/ton for 50% K2O and Supplier B quotes USD 480/ton for 48% K2O, the effective K2O price is USD 10.00/unit and USD 10.00/unit—identical. Supplier B’s lower nominal price provides no economic advantage once purity is considered.
Request a detailed certificate of analysis. Chloride content should be below 1.5% for fertilizer-grade SOP, and even lower for chloride-sensitive crops. Pharmaceutical and food-grade applications demand near-zero chlorides and heavy metals. A cheaper product with a higher chloride load can reduce crop yield and create liability—an invisible cost that far outweighs the initial price difference.
If your end use is fertigation, a standard 50% K2O powder may need additional processing to dissolve completely, clogging irrigation lines. Quoting a purpose-formulated water-soluble grade avoids hidden equipment maintenance costs. Factor in the in-field performance, not just the invoice price.
Add inland trucking, customs clearance, port handling, and documentation fees to the quoted FOB or CIF price. A supplier that offers pre-arranged container shipping and experienced logistics support (like direct container loading at the factory) can reduce demurrage risks and smooth your supply chain.
A low price from an unverified source often masks inconsistency in grade, short weight, or delayed shipments. Validate the exporter’s track record, manufacturing capabilities, and quality certifications (ISO, SGS inspections). Long-term partnerships with a trusted producer like Hailei Chemical deliver more predictable pricing and on-spec product lot after lot.
One frequent question we hear is, “how is potassium supplied?” The answer lies in the form and channel of delivery. Potassium sulfate reaches the global market as both a pure compound for fertilizer and as an intermediate for industrial processes. The supply chain structure itself influences cost.
SOP is produced by dedicated chemical plants and then distributed via three main channels:
The physical form—crystalline solid, granular, or powder—affects how potassium is supplied and, consequently, the price. Water-soluble grades require extra processing and quality control, which is reflected in a premium over standard agricultural SOP.
It’s also worth distinguishing potassium sulfate from chemically similar but functionally different compounds. Anhydrous potassium aluminum sulfate (often called burnt alum) and hydrated aluminium potassium sulfate formula KAl(SO4)2·12H2O (potassium alum) are used in water treatment, food additives, and cosmetics. While they share the potassium cation, their aluminum content and different sulfate chemistry render them unsuitable for fertilizer or glass-making applications. Buyers searching for potassium salts should carefully verify the chemical identity, as confusing SOP with alum can lead to costly procurement mistakes.
For horticulture and fertigation managers, the question “how much potassium sulfate per gallon” is directly tied to budgeting. Because SOP is a premium potassium source, even small improvements in application efficiency cascade into significant monetary savings over a season.
The exact dosage depends on the crop’s potassium demand, growth stage, and water quality. As a general reference:
Calculating the cost per application is straightforward: multiply the SOP price per pound by the pounds used per acre or per gallon of spray mix. By buying a high-solubility SOP from a supplier that guarantees lot-to-lot consistency, you can avoid over-application and reduce waste, turning the price of potassium sulfate fertilizer into a manageable operational cost rather than a guess.
The versatility of potassium sulfate means its price is influenced by demand from multiple sectors. While fertilizer dominates SOP consumption, industrial users in glass manufacturing, aluminum recycling, and gypsum board production specify their own quality thresholds. Pharma-grade SOP for effervescent tablets or saline laxatives requires even tighter controls.
When you source SOP from a manufacturer that supplies both agricultural and industrial grades, like Hailei Chemical, you benefit from cross-sector quality discipline. Our premium sulfate of potash meets GB/T 20406-2017 for fertilizer and can also be tailored to USP requirements for pharmaceutical buyers. This dual expertise allows us to produce high-purity material that works across applications, reducing the need for multiple suppliers and simplifying your supply chain.
Regardless of where the price per ton falls, the true cost of inadequate quality can dwarf any initial savings. Prioritize these specifications when reviewing offers:
Insist on pre-shipment inspection (SGS, Intertek, or similar) and full traceability from production batch to container. This transparency protects you from quality arbitrage and ensures the price you pay reflects genuine product value.
Procurement leaders who treat the price of potassium sulfate fertilizer as a long-term investment rather than a spot transaction gain a competitive edge. Hailei Chemical’s integrated manufacturing, in-house logistics team, and commitment to consistent quality provide the foundation for that stability.
We offer:
Understanding how prices are formed is the first step; securing a partner who delivers value beyond the invoice is the next. Review our detailed product specifications and request a personalized quote today.
Contact our export team to discuss your potassium sulfate requirements, projected volumes, and delivery timelines. Let’s turn your procurement goals into a reliable, cost-efficient supply stream.