Magnesium carbonate powder MgCO3  CAS#: 546-93-0

Magnesium carbonate powder is an important inorganic compound with multiple properties and wide applications

Magnesium carbonate powder
Chemical formula: MgCO₃
Physical properties:
Appearance: Usually white, odorless fine powder.
Density: About 2.96 g/cm³.
Solubility: It is difficult to dissolve in water, which is the basis of many of its applications (such as sports anti-skid). But it can be dissolved in dilute acids (such as hydrochloric acid, acetic acid) to produce carbon dioxide bubbles.
Thermal stability: It will decompose when heated to a certain temperature (about 350°C), lose carbon dioxide, and generate magnesium oxide and carbon dioxide.
Chemical properties:
It is a weak base that can react with acid to produce corresponding magnesium salts, water and carbon dioxide.
It exists in nature in the form of minerals such as magnesite.

Anhydrous magnesium carbonate: The chemical formula is MgCO₃.
Basic magnesium carbonate: The more common commercial form, the chemical formula is usually expressed as xMgCO₃·yMg(OH)₂·zH₂O (for example 3MgCO₃·Mg(OH)₂·3H₂O or 4MgCO₃·Mg(OH)₂·4H₂O). It is composed of magnesium carbonate and magnesium hydroxide hydrate, with similar properties, but lighter specific gravity and larger volume. Many "sports magnesium powders" are actually basic magnesium carbonate.

Main applications of magnesium carbonate powder
Magnesium carbonate powder finds its place in many fields due to its hygroscopicity, insolubility, stability, whiteness, relative inertness, low density (basic form) and the characteristics of magnesium element:
1. Sports field (most well-known application):
Gymnastics/weightlifting/rock climbing/track and field anti-slip powder: This is its most famous application.
Sweat absorption: It can quickly absorb sweat from the hands and keep them dry.
Increase friction: Dry powder can significantly increase the friction between the palm and the equipment (horizontal bar, barbell, rock point, etc.) or between the equipment (such as barbell bar and lock), prevent slipping, improve grip and safety. Commonly called "magnesium powder".
Other sports: Also used in bowling (sweat absorption and anti-slip), billiards (wiping the cue tip), strength training, etc.
2. Industrial field:
Rubber industry:
Filler: Added as a filler to rubber products (such as tires, soles, hoses, seals), it can reduce costs.
Improve performance: It can improve the wear resistance, hardness, tensile strength of rubber, and help disperse other fillers (such as carbon black).
Release agent: During the rubber processing process, it is sprinkled on the surface of the mold or semi-finished product to prevent adhesion.
Plastic industry:
Filler: Used as a filler for thermoplastics (such as PVC, PP) and thermosetting plastics (such as phenolic resins) to reduce costs and improve hardness, dimensional stability and heat resistance.
Flame retardant/smoke suppressant: decomposes to absorb heat and release non-combustible carbon dioxide and water vapor during combustion, diluting oxygen and combustible gases. At the same time, the magnesium oxide coating layer generated can insulate heat and oxygen, play a role in flame retardancy and smoke reduction (often used in conjunction with other flame retardants).
Paints and varnishes:
Body pigment/filler: Provide whiteness, increase volume, improve rheology, and reduce costs. It can improve the wear resistance and durability of the coating.
Rheological additive: Improve the suspension and thixotropy of the coating and prevent sedimentation.
Papermaking industry:
Filler: Added to pulp to improve the opacity, whiteness, smoothness and printability of paper while reducing costs.
Coating pigment: Used for paper coating to improve surface properties and printing effects.
Ceramics and glass:
Raw material/flux: As a raw material for introducing magnesium oxide in ceramic glaze and glass manufacturing, it can reduce the melting temperature, improve glaze properties and the chemical stability of glass.
Flame retardant: As mentioned above, it is used in polymers, textiles, building materials and other fields as an environmentally friendly inorganic flame retardant (often requiring high addition amounts) by utilizing its characteristics of decomposition absorption of heat and release of inert gases.
Other industries: used as raw materials for the production of other magnesium compounds (such as magnesium oxide, magnesium sulfate), wastewater treatment (pH adjustment, precipitation of phosphates), flue gas desulfurization, etc.
3. Food and pharmaceutical fields:
Food additives:
Anticaking agent: added to powdered foods (such as salt, powdered sugar, milk powder, spices) to prevent particles from agglomerating and maintain fluidity. The number is usually E504(i).
Alkalinity regulator/desiccant: used in certain specific food processing.
Nutritional supplements: as a source of magnesium (but the absorption rate is not as good as organic magnesium).
Pharmaceuticals:
Pharmaceutical excipients: used as diluents or fillers for tablets.
4. Cosmetics and Personal Care:
Moisture absorbent/thickener: used in products such as talcum powder, foot powder, and facial powder to absorb excess oil and sweat from the skin, provide a refreshing, dry and smooth skin feel, and help set makeup.
Tooth powder ingredients: as a mild abrasive.
5. Other applications:
Animal feed additives: as a supplementary source of magnesium.
Agriculture: used to improve acidic soil (provide magnesium and alkalinity), or as a fertilizer component.
Fireproof materials: used to make fireproof boards, fireproof coatings, etc.
Desiccant: using its hygroscopicity, it is used in occasions where humidity needs to be controlled (but not as commonly used as silica gel).

Safety and precautions
General safety: Magnesium carbonate is generally considered to be of low toxicity and is used in limited quantities in food and medicine.
Dust inhalation: The most important industrial hazard is dust inhalation. Long-term inhalation of high concentrations of magnesium carbonate dust may cause respiratory irritation and, in extreme cases, may cause pneumoconiosis (although its hazard is much lower than silica or asbestos). Therefore, when handling powders industrially, proper ventilation and respiratory protection must be taken.
Eye contact: Powder may cause irritation if it enters the eyes.
Skin contact: Generally harmless, but prolonged or high-volume contact may cause dry skin.

Magnesium carbonate powder, especially in its basic form, is a versatile inorganic material. It has a wide range of applications, from "anti-slip artifacts" on sports fields to reinforcing fillers for rubber and plastics to anti-caking agents in food. Its core value lies in its unique combination of physical and chemical properties: hygroscopicity, poor solubility, stability, whiteness, low density (basic form), and potential as a magnesium source. When using it, especially when handling the powder state in an industrial environment, you need to pay attention to dust protection.