Potassium sulfate (K2SO4), also called sulfate of potash (SOP), is a water-soluble, chlorine-free inorganic salt that supplies both potassium and sulfur. In agriculture it is a premium potassium fertilizer, while in industry it serves as a process chemical for glassmaking, textile dyeing, detergents and other manufacturing. It appears as a white or off-white crystalline powder or granular solid with a neutral-to-slightly-acidic reaction in water. Weifang Hailei Fine Chemical Co., Ltd supplies potassium sulfate as a source factory (源头厂家) from Weifang, Shandong, China — one of the country's major inorganic-salt production bases — to global B2B buyers.
Fertilizer potassium is conventionally expressed as K2O (potassium oxide equivalent) rather than as the element itself. Pure potassium sulfate contains roughly 54% K2O by theoretical assay, so a commercial agriculture grade standardized at 50% K2O is a high-strength, concentrated potash source. The K2O figure tells a buyer exactly how much usable potassium each tonne delivers, which drives both the agronomic value and the price. For procurement, confirming the guaranteed K2O minimum on the certificate of analysis is the single most important specification check.
Unlike potassium chloride (MOP), potassium sulfate contains essentially no chloride, which is why it is called a low-chloride potash source. Many high-value crops are sensitive to chloride and suffer leaf burn, lower yield or poorer quality when excess chloride builds up in the soil. Because K2SO4 delivers potassium without that chloride load, it protects crop quality and allows repeated application in chloride-sensitive cropping systems. This low-chloride profile is the core reason SOP commands a premium over MOP in fertilizer markets.
Weifang Hailei supplies potassium sulfate in three main specifications: an agriculture grade standardized at 50% K2O, a low-chloride industrial grade, and a water-soluble fertilizer grade designed for fertigation and foliar use. The agriculture grade is aimed at field and plantation crops, the industrial grade serves process uses where chloride must be controlled, and the water-soluble grade is refined for rapid, residue-free dissolution. The exact chloride, moisture, water-insoluble and particle-size limits for each grade are confirmed on the supplier's certificate of analysis.
Commercial potassium sulfate is typically made either from natural potassium minerals or by chemical conversion of potassium chloride. The most common synthetic route is the Mannheim process, in which potassium chloride reacts with sulfuric acid in a high-temperature furnace to yield K2SO4 and hydrochloric acid as a by-product. Other routes include the reaction of potassium chloride with sulfate salts or the processing of minerals such as langbeinite. Each route affects purity, particle form and cost, so understanding the production method helps buyers anticipate quality and price behaviour.
Chloride-sensitive crops — such as tobacco, potato, grapes, many fruits, vegetables and some ornamentals — respond badly to excess chloride, which can reduce yield, burn leaf margins and degrade taste or storage quality. Potassium sulfate supplies the same potassium nutrition as MOP but without the chloride stress, making it the agronomist's preferred potash source for these crops. It also contributes sulfur, which supports protein synthesis and oil formation in oilseed and legume crops. For premium horticulture and export-oriented produce, SOP is often a requirement rather than an option.
Potassium sulfate is widely used on chloride-sensitive field crops, including tobacco, potato, tea, sugarcane and grapes, as well as greenhouse vegetables, fruit trees and flowers. It is also favoured for fertigation systems and soilless growing media, where controlled nutrition and low salt stress are essential. Industrial crop processors and seed growers use it where product quality, sugar content or storage life must be protected. Because it adds sulfur as well as potassium, it fits oilseeds, legumes and high-protein forage where sulfur demand is high.
Beyond agriculture, potassium sulfate is used in glassmaking, where potassium improves the workability and clarity of certain glass compositions. It is used in textile and dyeing processes, in detergent formulation, and in some mineral-processing and specialty chemical applications. The low-chloride industrial grade is intended for these process uses where chloride contamination must be avoided. Buyers should specify the intended process so the supplier can match the right purity and particle specification.
Choose the agriculture grade for bulk field, plantation or blended-fertilizer use where 50% K2O is the key requirement and normal granulation or powder form is acceptable. Choose the low-chloride industrial grade when K2SO4 is a process input and chloride, heavy-metal or insoluble-matter limits matter to your process. Choose the water-soluble fertilizer grade for fertigation, drip irrigation, foliar spraying or stock solutions, where fast and complete dissolution and minimal residue are essential. Sharing your end use and application method with the supplier lets them recommend the best fit and avoid over- or under-specifying.
The key specification is the guaranteed K2O content, followed by chloride content, sulfur content, moisture, water-insoluble matter and particle-size distribution. Buyers commonly request a certificate of analysis (COA) covering these items, and many align acceptance with the relevant national or international potash standards for their market. Because limits vary by grade and by destination, the supplier should state the exact guaranteed values and test methods up front. A third-party pre-shipment inspection is a standard way to confirm the shipped lot matches the COA.
Potassium sulfate is normally supplied in 25 kg or 50 kg woven bags, often with an inner polyethylene liner to protect against moisture, or in jumbo bags of around 1000–1250 kg for bulk handling. Palletization, shrink-wrapping and custom bag marking can usually be arranged on request. Buyers should confirm the packaging type, net weight tolerance and marking requirements (including any language or hazardous-symbol needs) at the quotation stage so the goods arrive ready for their market.
Store potassium sulfate in a cool, dry, well-ventilated area away from moisture, direct sunlight and incompatible materials. Although it is hygroscopic to a limited degree, caking can still occur if bags are exposed to humidity, so keep packs sealed until use and stack them on pallets clear of the floor. Maintain first-in-first-out rotation and keep the product away from acids and strong reducing agents. Proper storage preserves free-flowing quality and extends the product's usable life.
For containerized export, the practical MOQ is usually one 20-foot container, roughly 20–28 tonnes depending on packaging and bag size; larger jumbo-bag or bulk orders are also common. Lead time depends on current production scheduling, the specific grade and the season, so it is normally confirmed at the time of quotation rather than as a fixed figure. Buyers should plan for production plus inland transport and vessel booking, and confirm the shipping window with the sales team early in the procurement cycle.
Potassium sulfate pricing is driven mainly by the cost of the potassium feedstock (typically potassium chloride) and sulfuric acid, along with energy costs for the conversion process. International potash market conditions, freight rates, exchange rates and seasonal fertilizer demand also move prices. Packaging, grade refinement, order size and destination-specific requirements add further cost layers. For budgeting, buyers should request a current FOB or CIF quotation for their specific grade and port rather than relying on published list prices.
Look for a manufacturer with an actual production base rather than only a trading operation, and confirm that it can state grade specifications, supply a certificate of analysis and support pre-shipment inspection. Check whether the supplier can handle your packaging, documentation and Incoterm requirements, and whether it has experience exporting to your region. A source factory such as Weifang Hailei, located in a major inorganic-salt production area, can offer more direct pricing and consistency than intermediaries. Request a sample, verify a COA, and if possible arrange a factory audit or third-party inspection before a large order.
Potassium sulfate is a stable, non-flammable solid that ships safely in standard dry containers or as bulk cargo, normally by sea for international B2B orders. It should be kept dry during transit, with bags protected from rain and condensation in the container. The exporter arranges the appropriate commercial invoice, packing list, bill of lading and certificate of analysis, plus any destination-required documents. Buyers should confirm the Incoterm (FOB, CIF, etc.) and the named port or place so responsibility and cost for freight and insurance are clear.
Potassium sulfate is generally considered a low-hazard material, but standard dust-control and hygiene measures still apply. Workers should avoid breathing dust and use suitable dust masks or ventilation when handling large quantities, and rinse eyes or skin with water in case of contact. It is not flammable and does not require special dangerous-goods classification in most cases, but the material safety data sheet (MSDS/SDS) should always accompany the shipment. Keep the product away from strong acids and follow local occupational-safety rules.
Both supply potassium, but potassium chloride (MOP) carries a high chloride load while potassium sulfate is essentially chloride-free and also contributes sulfur. MOP is cheaper per unit of potassium and suits chloride-tolerant crops, whereas SOP is preferred for chloride-sensitive crops and higher-value produce. Potassium sulfate also generally has a lower salt index, making it gentler on roots and safer at higher application rates. The choice is therefore agronomic and quality-driven as much as price-driven.
Potassium nitrate supplies nitrogen along with potassium and is chloride-free, making it common in hydroponics and foliar programs, but it is more expensive and its nitrogen must fit the crop program. Potassium sulfate supplies sulfur instead of nitrogen and is the standard chloride-free choice for field and soil-based fertility. Mono-potassium phosphate (MKP) adds phosphorus and is used where phosphate is needed. Buyers choose among them by matching the secondary nutrient (S, N or P) and the crop stage to the fertilizer program.
Yes — potassium sulfate is water-soluble, though its solubility is moderate compared with chloride or nitrate salts, and it dissolves more readily in warm water. The dedicated water-soluble fertilizer grade is refined for rapid, low-residue dissolution and is suitable for drip irrigation, fertigation, foliar spraying and stock solutions. For fertigation, users should prepare the solution at the recommended concentration and avoid mixing with calcium-containing products that could form precipitates. Matching the grade to the irrigation method prevents nozzle clogging and dosing errors.
For an international purchase, request at minimum the commercial invoice, packing list, bill of lading and a certificate of analysis (COA) covering K2O, chloride, sulfur, moisture and water-insoluble matter. Also ask for the material safety data sheet (SDS), a certificate of origin, and any documents your destination country requires for fertilizer or chemical import, such as a phytosanitary or quality certificate. Confirming the full document set before shipment avoids customs delays and costly demurrage at the destination port.
Contact the sales team through the company website (haileichemicals.com for international buyers or haileichemical.com for Chinese-language buyers) and specify the grade, K2O and chloride requirements, packaging preference, target quantity and destination port. The team will confirm the applicable specification, packaging and available shipping window, and can arrange samples and a certificate of analysis for evaluation. Providing your end use and application method up front helps the factory recommend the most cost-effective grade for your market.