Magnesium Chloride Grades: Food, Industrial and USP Specs

Buyers most often ask which magnesium chloride grades are suitable for their process: food-grade flakes and USP-grade powder are used where the compound contacts food or pharmaceutical formulations, while technical and de-icing grades serve industrial, water-treatment and infrastructure applications where trace-metal purity requirements are lower. The correct grade choice depends on hydrate form, assay purity, and the impurity limits your end application tolerates.

Magnesium chloride (MgCl2) is an inorganic salt supplied commercially as the hexahydrate (MgCl2·6H2O, CAS 7791-18-6) or, less commonly, the anhydrous form (CAS 7786-30-3). It occurs naturally in seawater and underground brine deposits, and most commercial supply is derived from brine evaporation or as a by-product of potash processing. The hexahydrate is a white to colorless crystalline solid, highly soluble in water, and deliquescent — it readily absorbs atmospheric moisture, which shapes both its handling requirements and its usefulness as a drying or dust-suppression agent.

Magnesium chloride grades and the standards behind them

Grade selection is the first specification decision a buyer makes. Food-grade material is commonly referenced against Food Chemical Codex (FCC) monographs and is used where the salt becomes part of a food product, such as a coagulant. USP/EP-referenced grades apply where magnesium chloride is used as an excipient or mineral source in pharmaceutical or nutraceutical formulations, carrying tighter heavy-metal and assay controls. Technical and industrial grades, including de-icing and dust-control qualities, are formulated for cost efficiency rather than trace-purity, and typically carry no pharmacopeial reference.

Physical forms and packaging

Magnesium chloride is traded as dry flakes, pellets, granular powder, and as a liquid brine solution at various concentrations. Dry forms are commonly packed in 25kg multi-wall paper or PP/PE bags, with bulk options in 500-1,000kg jumbo bags for industrial-volume buyers. Liquid brine grades are shipped in drums, IBC totes, or bulk tanker depending on volume, since the deliquescent nature of the dry salt makes moisture-tight packaging and storage a practical necessity rather than an option.

Applications across industries

In food manufacturing, magnesium chloride functions as a coagulant in soy protein processing (traditionally known as nigari) and as a firming or processing aid in select food applications. In water treatment, it serves as a magnesium source and conditioning agent. Industrial uses include dust suppression and de-icing on unpaved and paved surfaces, drilling fluid formulation in oil and gas operations, textile finishing, and as a component of magnesium oxychloride cement used in flooring and construction panels. In nutraceutical and mineral-supplement formulation, magnesium chloride functions as a magnesium source for finished-product formulators; DIC supplies the raw material only and makes no claims regarding finished-product health effects.

Formulation and handling notes

Magnesium chloride is highly soluble in water and dissociates readily, giving aqueous solutions a near-neutral to mildly acidic pH. It is hygroscopic and deliquescent, meaning dry product will absorb moisture from ambient air and can cake or liquefy if storage humidity is not controlled. Aqueous solutions and moist product are mildly corrosive to carbon steel and some other metals, so storage tanks, fittings, and packaging lines in contact with concentrated solutions are typically specified in corrosion-resistant materials such as certain plastics, fiberglass, or appropriately rated stainless steel. Dry product should be stored in sealed, moisture-barrier packaging, off the floor, in a cool, dry warehouse away from strong oxidizers.

QA documentation buyers should request

For every lot, buyers should request a Certificate of Analysis (COA) confirming assay (as MgCl2 or MgCl2·6H2O), moisture content, heavy-metal limits (particularly for food- and pharma-grade lots), and insoluble matter. A current specification sheet detailing grade classification, hydrate form, and applicable standard reference (FCC, USP/EP, or technical) should accompany the first shipment and any specification change. Lot traceability documentation, including production or repackaging batch numbers, supports recall readiness and is standard practice for regulated end-uses such as food and pharmaceutical manufacturing.

Sourcing considerations

Magnesium chloride supply is inherently tied to brine and seawater-derived sources, so assay and impurity profiles can vary by origin and extraction method — buyers running sensitive formulations should request origin and process information alongside the COA rather than assuming interchangeability between suppliers. Hydrate content also affects effective magnesium loading per kilogram, which matters when converting between flake, granular, and liquid brine forms in a formulation.