We unleash your business potential by maximize the business innovation.
Send EmailMagnesium Carbonate, Magnesium Hydroxide Carbonate, Magnesite, Magnesium Carbonate Hydrate, Hydromagnesite, E504, 546-93-0, 12125‑28‑9
MAGNESIUM CARBONATE (E504)
1. PRODUCT DEFINITION AND CHEMICAL IDENTITY
| Parameter | Description |
|---|---|
| Chemical Name | Magnesium Carbonate |
| Common Names | Magnesite, Magnesium carbonate, Hydromagnesite (basic form) |
| Food Additive Code | E504 (also INS 504) |
| CAS Number | 546-93-0 (anhydrous); 12125-28-9 (basic / hydromagnesite) |
| Molecular Formula (anhydrous) | MgCO₃ |
| Molecular Weight | 84.31 g/mol |
| Appearance | White, odourless, light and free-flowing powder |
| Taste | Earthy, slightly alkaline |
Note: Commercial magnesium carbonate products are rarely pure anhydrous MgCO₃. They are often found as basic carbonates (hydromagnesite, [Mg₅(CO₃)₄(OH)₂·4H₂O]) or in hydrated forms (dihydrate, trihydrate, tetrahydrate). These different forms directly influence the product's density, fluidity, and application area. The two primary commercial grades are "Light" and "Heavy" magnesium carbonate.
2. PHYSICAL AND CHEMICAL PROPERTIES
| Property | Value / Description |
|---|---|
| Physical form | White, light, free-flowing powder (light form) or white granules (heavy form) |
| Melting point | ~990 °C (decomposes, releasing CO₂ and forming MgO) |
| Density (anhydrous) | 3.05 g/cm³ |
| Bulk density (Light) | ~0.15 g/mL (very low, airy structure) |
| Bulk density (Heavy) | ~0.25 g/mL (higher, granular structure) |
| Solubility in water | Insoluble |
| Solubility in dilute acids | Soluble with effervescence (releasing CO₂ gas). This is the basis for its antacid function. |
| Hygroscopy | Very low; however, the light form, with its high surface area, can absorb moisture and odours. |
| Stability | Stable in air. Decomposes on strong heating to magnesium oxide (MgO) and carbon dioxide (CO₂). |
3. FUNCTIONAL PROPERTIES AND MODE OF ACTION
-
Antacid (Neutralizing Agent): Reacts readily with gastric hydrochloric acid (HCl) to form soluble magnesium chloride, effectively neutralizing excess stomach acid. This provides fast, symptomatic relief from heartburn, indigestion, and acid reflux.
-
Desiccant and Anti-Caking Agent (E504): Effectively absorbs moisture and prevents clumping in powdered foodstuffs like table salt, sugar, baking powder, spices, and powdered drink mixes, ensuring free-flowing properties.
-
Odour and Moisture Absorbent: Due to its high surface area, the light form is excellent at absorbing perspiration, moisture, and odours. This makes it a key component in talcum powders, foot powders, deodorants, sports chalk, and soaps.
-
Magnesium Source (Dietary Supplement): Used in tablets and powders to address magnesium deficiency. Its absorption is contingent upon its reaction with stomach acid.
-
Flame Retardant and Smoke Suppressant: Upon heating, it decomposes to release non-flammable gases (water vapour and CO₂), which dilute combustible gases and form a protective char layer. It also helps suppress smoke formation in plastics and rubber compounds.
-
Filler and Process Aid: Acts as an inert filler in tablets (providing bulk), plastics, rubber, paints, and paper, improving mechanical properties and reducing manufacturing costs.
4. PRODUCT TYPES: LIGHT AND HEAVY FORMS
| Property | Light Magnesium Carbonate | Heavy Magnesium Carbonate |
|---|---|---|
| Bulk Density | Very low, airy structure (~0.15 g/mL) | Higher, granular structure (~0.25 g/mL) |
| Surface Area | Very high | Lower |
| Flowability | Less free-flowing, fluffy powder | More free-flowing, granular |
| Primary Applications | Tablet filler, anti-caking in powders, sports chalk, odour/moisture absorber | Direct tablet compression, antacid formulations, flowability aid in dense mixtures |
5. SECTORAL APPLICATIONS AND USAGE RATES
| Sector | Application | Typical Usage / Notes |
|---|---|---|
| Pharmaceuticals & Nutraceuticals | Antacid tablets/suspensions; magnesium dietary supplement; inert filler, disintegrant, and glidant in tablet manufacturing | Varies by formulation; antacid: 250-500 mg per dose; supplement: 100-400 mg elemental magnesium |
| Food Industry (E504) | Anti-caking agent in salt, sugar, baking powder, spice mixes; carrier for flavours and colours; acidity regulator; colour retention aid | 0.1 – 2% (as anti-caking agent); generally used quantum satis |
| Sports & Fitness | Sports chalk (climbing, gymnastics, weightlifting, yoga, crossfit) to absorb sweat and enhance grip | Applied directly to hands in powder form |
| Cosmetics & Personal Care | Odour and moisture absorber in talcum powders, foot powders, deodorants, soaps, and baby powders; lubricant providing a smooth skin feel; perfume fixative | 1 – 10% |
| Plastics & Rubber | Flame retardant synergist and smoke suppressant; inert filler to reduce cost and improve mechanical properties | 5 – 30% |
| Refractory Materials | Calcined to produce magnesium oxide (MgO) for furnace bricks, crucibles, and high-temperature insulation | Raw material input |
| Agriculture | Soil conditioner to neutralize acidic soils and provide magnesium nutrient | Application rate based on soil pH and magnesium deficiency level |
| Other Uses | Taxidermy (degreasing and whitening skulls); fire extinguishing powders; textile and upholstery for flame resistance | Specialized use |
6. ALTERNATIVE NAMES AND SYNONYMS
| Category | Names |
|---|---|
| Chemical & Mineral Names | Magnesium Carbonate, Magnesite, Hydromagnesite, Carbonic Acid Magnesium Salt, Magnesium Hydroxide Carbonate |
| Physical Form Terms | Light Magnesium Carbonate, Heavy Magnesium Carbonate, Basic Magnesium Carbonate, Anhydrous Magnesium Carbonate, Magnesium Carbonate Hydrate |
| Quality & Standard Terms | Food Grade, Technical Grade, USP (United States Pharmacopeia), Ph. Eur. (European Pharmacopoeia), BP (British Pharmacopoeia), JP (Japanese Pharmacopoeia), FCC (Food Chemicals Codex) |
| Functional Search Terms | Antacid, Dietary Supplement, Anti-caking Agent, Flame Retardant, Smoke Suppressant, Filler, Chalk, Climbing Chalk, Lifting Chalk |
7. ALTERNATIVES AND COMPARISON
| Alternative | Comparison with Magnesium Carbonate |
|---|---|
| Calcium Carbonate (CaCO₃) | Also a potent antacid and common filler. Provides calcium instead of magnesium. Magnesium carbonate has a stronger laxative effect when overused. |
| Sodium Bicarbonate (NaHCO₃) | Fast-acting antacid but can cause rebound acidity and gas. Magnesium carbonate is longer-lasting and less disruptive. |
| Magnesium Hydroxide (Mg(OH)₂) | Stronger antacid, commonly used as a laxative. Magnesium carbonate is milder. |
| Talc (Magnesium Silicate) | Used as a body powder and filler. Magnesium carbonate is more absorbent for moisture and odour. |
| Aluminum Hydroxide | Commonly used antacid; can cause constipation. Magnesium carbonate is often combined with it to balance side effects. |
8. SAFETY, STORAGE, AND REGULATORY INFORMATION
-
GHS Classification: Not classified as a hazardous substance or mixture. Dust may cause mechanical irritation to the eyes and respiratory tract.
-
Food Additive (E504): Approved for use as a food additive by the European Union, Turkey, and many other countries. It is considered safe (GRAS).
-
Pharmaceutical Compliance: Grades meeting USP, Ph. Eur., BP, and JP standards are available for use as an active ingredient or excipient in medicinal products.
-
Storage:
-
Store in a cool, dry, and well-ventilated area in tightly sealed containers.
-
Keep away from strong acids, oxidizing agents, and sources of moisture.
-
Due to its odour-absorbing properties, it must be kept away from strongly smelling substances.
-
-
Personal Protective Equipment (PPE): For handling large quantities where dust is generated, use a dust mask and safety goggles.
9. FREQUENTLY ASKED QUESTIONS
Q1: What is the difference between light and heavy magnesium carbonate?
The difference lies in their bulk density and physical form. Light magnesium carbonate has a very low bulk density (~0.15 g/mL) and a fluffy, airy powder structure, making it ideal as an anti-caking agent and odour absorber. Heavy magnesium carbonate has a higher bulk density (~0.25 g/mL), is more granular, and is preferred for direct tablet compression and antacid suspensions.
Q2: How does it work as an antacid?
Magnesium carbonate reacts with the hydrochloric acid (HCl) in the stomach to form magnesium chloride, carbon dioxide (CO₂), and water. This reaction rapidly neutralizes excess acid, providing relief from heartburn and indigestion.
Q3: Is magnesium carbonate the same as chalk used on blackboards?
No. Blackboard chalk is typically made of calcium sulfate (gypsum) or calcium carbonate. Sports chalk for climbing and gymnastics is composed of magnesium carbonate because of its superior ability to absorb sweat and provide a dry grip.
Q4: Does it dissolve in water?
No, it is practically insoluble in water. However, it dissolves readily in dilute acids with effervescence (bubbling), which is a key characteristic.
10. QUICK REFERENCE TABLE
| Property | Value / Description |
|---|---|
| CAS | 546-93-0 (anhydrous) |
| Formula | MgCO₃ |
| Molecular Weight | 84.31 g/mol |
| Appearance | White, odourless, light powder or granules |
| Food Additive Code | E504 |
| Melting Point | Decomposes at ~990 °C |
| Main Functions | Antacid, anti-caking agent, moisture/odour absorber, filler, Mg supplement |
| Key Feature | Effervescent dissolution in dilute acids |
