Magnesium oxide, with the chemical formula MgO, is an inorganic compound that appears as a white to off-white powder. It is also known as magnesia and occurs naturally as the mineral periclase, although the commercial product is usually produced by calcining magnesite (magnesium carbonate) or magnesium hydroxide. MgO is valued for its high melting point (around 2,800°C), its alkaline (basic) character, and its ability to neutralize acids. These properties make it a workhorse material across refractories, environmental treatment, animal nutrition, agriculture, and construction. As a source factory, Weifang Hailei Fine Chemical Co., Ltd supplies magnesium oxide in several grades matched to these different industries.
Commercial magnesium oxide is most commonly made by the calcination of magnesite (MgCO₃). When magnesite ore is heated, it decomposes and releases carbon dioxide, leaving behind magnesium oxide — the reaction can be written as MgCO₃ → MgO + CO₂. The calcination temperature is the key process variable: lower temperatures produce a porous, chemically reactive "light-burned" or "caustic calcined" material, while much higher temperatures produce a dense, stable "dead-burned" material. Alternative routes calcine magnesium hydroxide obtained from seawater or brine. The temperature, residence time, and raw-material purity together determine the final grade, activity, and impurity profile of the product.
These terms describe the same oxide prepared at different temperatures, which changes its physical and chemical behavior. Light-burned (also called caustic calcined magnesia, CCM) is calcined at roughly 700–1,000°C, giving a porous, low-density powder with high reactivity and a larger surface area. Dead-burned magnesia (DBM) is calcined at much higher temperatures, typically around 1,500–2,000°C or more, producing dense, hard, low-reactivity grains that resist hydration and high heat — ideal for refractories. In general industry terminology, "caustic calcined" emphasizes the reactive, acid-neutralizing character, while "light-burned" describes the same family of lower-temperature products. A fourth category, fused magnesia, is melted in an electric arc furnace for premium refractories, but Hailei's product line centers on dead-burned, desulfurization-grade, and light-burned powders.
Weifang Hailei Fine Chemical Co., Ltd supplies magnesium oxide in three main grades: dead-burned powder, desulfurization-grade powder, and light-burned powder. Dead-burned powder is intended primarily for refractory and high-temperature applications where low reactivity and stability are required. Desulfurization-grade powder is optimized for flue-gas desulfurization (FGD), where a reactive magnesium oxide slurry neutralizes sulfur oxides. Light-burned powder serves the more reactive, lower-temperature uses such as feed additives, magnesium fertilizers, and construction materials. Buyers are encouraged to specify their application so the correct grade can be matched to their process.
Specifications for magnesium oxide are usually expressed through three key parameters: MgO content, reactivity or activity (commonly measured by citric acid activity or iodine adsorption), and loss on ignition (LOI). In general industry terms, light-burned and desulfurization-grade products typically have a high MgO content on a calcined basis, a moderate to high activity suitable for fast acid neutralization, and a measurable LOI reflecting residual carbonate or hydroxide; dead-burned products have a lower LOI, minimal reactivity, and high bulk density. The exact figures vary by grade and production batch, so exact MgO, activity, and LOI values should be confirmed against the certificate of analysis (COA) for each order. Hailei provides a COA with each shipment and can supply samples for pre-purchase verification.
Dead-burned and other high-density magnesia grades are a backbone of the refractory industry because MgO melts at roughly 2,800°C and remains chemically stable at very high temperatures. Refractory bricks and castables made with magnesium oxide line steelmaking furnaces, cement kilns, and non-ferrous metal furnaces, protecting the vessel from molten metal and slag. Dead-burned magnesia's low reactivity and resistance to hydration are essential, because a material that readily reacted with moisture or slag would degrade the lining. The purity, grain size, and bulk density of the magnesia directly influence the service life of the refractory.
In flue-gas desulfurization, magnesium oxide is mixed with water to form a magnesium hydroxide slurry that absorbs sulfur dioxide (SO₂) from power-plant or industrial boiler exhaust gases. The SO₂ reacts to form magnesium sulfite and, with oxidation, magnesium sulfate, removing the pollutant before the gas is released. Magnesium-based FGD is valued for its high desulfurization efficiency, smaller equipment footprint, and useful by-products compared with some limestone processes. A reactive, desulfurization-grade magnesia is preferred because its higher activity allows faster and more complete absorption of SO₂. Weifang Hailei's desulfurization-grade powder is supplied specifically for this application.
Magnesium is an essential macro-mineral for livestock and poultry, needed for bone formation, enzyme function, and nervous-system regulation. Magnesium oxide is a common feed additive because it delivers a concentrated, bioavailable source of magnesium with good palatability and low cost per unit of magnesium. It is frequently included in ruminant rations, especially for cattle, to help prevent grass tetany (magnesium deficiency) and to buffer rumen pH. Feed-grade magnesium oxide must meet strict limits on heavy metals and other impurities, so buyers typically request a grade with appropriate purity and safety documentation. The light-burned grade is generally used in this sector because of its suitable particle size and reactivity.
Magnesium is the central atom of chlorophyll, so it is critical for photosynthesis and for healthy plant growth; crops growing in magnesium-deficient, acidic soils show reduced yield and quality. Magnesium oxide is used to manufacture magnesium fertilizers and soil conditioners because it is a slow-release, alkaline source of magnesium that also helps raise soil pH. It is applied either directly to soils or blended into compound fertilizers, particularly for crops such as oil palm, rubber, citrus, and various cash crops. Choosing a reactive grade allows the magnesium to become available to plants more quickly after application. Hailei supplies light-burned magnesium oxide suitable for fertilizer and soil-amendment applications.
In construction, magnesium oxide appears in two main forms: as a component of magnesium oxychloride and magnesium oxysulfate cements, and as an additive in boards and fire-resistant panels. Reactive (light-burned) magnesia reacts with magnesium chloride or magnesium sulfate solutions to form strong, fast-setting cements used in flooring, decorative panels, and fireproof building boards. Magnesium oxide boards are valued for fire resistance, moisture tolerance, and light weight. The grade chosen depends on whether the buyer needs reactive magnesia for cement chemistry or a filler-grade material for panels.
Beyond refractories, FGD, feed, agriculture, and construction, magnesium oxide serves a broad range of industries. It is used in water and wastewater treatment as an alkali for pH adjustment and for heavy-metal removal, in pulp and paper processes, in textile and dyeing as a buffering agent, and in glass and ceramic formulations. It also appears in the production of magnesium salts, in mining and metallurgy for leaching and neutralization, and in detergent and cleaning-product formulations. This versatility is why suppliers like Weifang Hailei, which also produces calcium chloride, magnesium chloride, and industrial salt, serve buyers across many industrial segments.
Grade selection starts with the function the material must perform: high-temperature stability points to dead-burned magnesia, fast acid neutralization points to desulfurization-grade or light-burned magnesia, and nutritional or agricultural use points to a reactive, low-impurity light-burned grade. Next, confirm the key specification parameters — MgO content, activity, LOI, particle size, and impurity limits — against your own process requirements or formulation. Where possible, test a sample in your own process before committing to a full container, because the same nominal grade can behave differently depending on raw material and calcination conditions. Supplying your end-use, target specification, and any regional regulatory requirements up front lets the manufacturer recommend the most cost-effective match.
Magnesium oxide is commonly tested for MgO content, calcium oxide (CaO) and other impurities (such as SiO₂, Fe₂O₃, and Al₂O₃), loss on ignition, reactivity or activity, particle size distribution, bulk density, and — for feed and agricultural grades — heavy-metal content. The applicable standards depend on the country and application; general references include national standards for industrial, feed-grade, and refractory magnesia, as well as customer-specific specifications. Buyers should agree in advance which test methods will govern acceptance, since activity (citric acid, iodine adsorption) and LOI methods can differ between laboratories. Weifang Hailei provides a certificate of analysis per batch and supports third-party inspection when required.
Magnesium oxide is typically packed in multi-layer kraft paper bags or polypropylene woven bags with an inner polyethylene liner, most commonly 25 kg or 50 kg per bag, or in 500–1,000 kg jumbo bags (FIBC) for bulk users. The packaging is chosen to protect the product from moisture, since magnesium oxide is hygroscopic and can absorb water and carbon dioxide from the air. Custom packaging, including private-label printing, palletization, and shrink-wrapping, is generally available on request. Buyers should specify their preferred bag weight, pallet configuration, and any labeling requirements when placing an order.
Magnesium oxide should be stored in a cool, dry, well-ventilated warehouse, away from moisture, rain, and direct contact with the ground. Because the material slowly absorbs water and CO₂ from humid air — especially the reactive light-burned grades — bags should remain sealed and be stacked on pallets off the floor. Storage areas should also be kept away from strong acids, since MgO is a basic oxide that will react with acids. First-in, first-out inventory rotation is recommended to preserve activity and free-flowing properties over time.
Weifang Hailei is a source factory in Weifang, Shandong — one of China's major inorganic-salt production bases — and typically serves buyers with full-container quantities. The minimum order quantity and lead time depend on the grade, the volume, the packaging, and the destination, so they are confirmed at quotation stage rather than fixed universally. In general industry practice, full 20-foot or 40-foot container orders are standard, and lead time includes production scheduling plus ocean freight transit. Buyers should request a quotation with the target quantity and delivery port to receive a firm MOQ and delivery schedule.
The price of magnesium oxide is driven primarily by raw-material and energy costs, since calcination of magnesite is energy-intensive and magnesite prices fluctuate. The grade and specification also matter: dead-burned and higher-purity products generally command a premium over standard light-burned material. Packaging, order volume, payment terms, and freight to the destination port add to the landed cost, and exchange rates and seasonal energy policies can cause short-term variation. Because exact pricing depends on these variables, buyers receive a current quotation tied to a specific grade, quantity, and Incoterm.
A reliable magnesium oxide supplier should be able to explain its raw-material source, calcination process, and quality-control system, and to provide a certificate of analysis, samples, and references. Buyers should confirm the supplier can consistently meet the agreed specification batch after batch and can support the required documentation for export or regulated uses such as feed. Factory-direct sourcing from a manufacturer like Weifang Hailei — a source factory located in a major inorganic-salt production region — often improves price stability and traceability compared with trading intermediaries. Verifying production capacity, response time, and third-party inspection options completes the evaluation.
Magnesium oxide is a non-flammable, non-explosive solid that is typically shipped as packaged cargo in standard dry containers, either palletized bagged goods or jumbo bags. Because the product is hygroscopic, containers should be clean, dry, and free of leaks to prevent moisture damage during ocean transit. The material is generally not classified as dangerous goods under most international transport regulations, which simplifies shipping documentation and reduces freight costs. Buyers can work with the supplier on Incoterms (such as FOB or CIF) and on securing the route that best balances cost and transit time.
Magnesium oxide is a low-hazard material, but as a fine alkaline powder it can irritate the eyes, skin, and respiratory tract if dust is inhaled in quantity. Workers should use basic personal protective equipment — dust masks, safety glasses, and gloves — and handle the material in ventilated areas. In case of eye contact, flush with plenty of water and seek medical advice if irritation persists. The main handling hazard is not flammability but the dusty, slightly alkaline nature of the powder, plus the fact that it reacts with acids, so it should be kept separate from strong acids during storage.
Yes — most reputable suppliers, including Weifang Hailei, provide samples and a certificate of analysis so buyers can verify quality before committing to a bulk order. A representative sample allows you to test MgO content, activity, particle size, and impurities against your own specification and, where relevant, regulatory requirements. Buyers should request the COA for the specific lot or batch they will receive and agree on the test methods in advance. For larger or long-term contracts, third-party inspection (such as pre-shipment inspection by an independent agency) can be arranged.
International B2B suppliers typically support common payment methods such as T/T (telegraphic transfer) and letter of credit (L/C), with the specific terms agreed at contract stage. Standard export documents include the commercial invoice, packing list, bill of lading, certificate of analysis, certificate of origin, and any documents required by the destination country. For regulated uses such as feed, additional health or quality certificates may be needed, and the supplier should confirm which documents it can provide. Weifang Hailei's export team advises buyers on the documentation needed for customs clearance in their market.