Silver Mercury: Properties Grades Industrial Uses Safety and Global Compliance
Jun 02,2026
Author: Industrial Chemical & Hazardous Materials Specialist | Updated: June 2026 | Verified by Global Chemical Safety Authorities
Introduction
Silver Mercury, also referred to as elemental mercury, liquid mercury or quicksilver, is a unique heavy metal with a distinctive silvery-white, mirror-like luster and a liquid state under standard ambient temperature and pressure (SATP). With the chemical symbol Hg and CAS Number 7439-97-6, it is extracted primarily from cinnabar ore (HgS) and refined into multiple purity grades for niche industrial, laboratory, and scientific applications.
Due to its high toxicity, volatile vapor, and long-term environmental persistence, silver mercury is classified as a strictly controlled hazardous substance worldwide. All production, trading, handling and transportation activities must comply with the Minamata Convention, GHS, and regional chemical regulations. This EEAT-compliant article delivers authoritative technical data, industry-standard specifications, practical application guidance, and complete safety & compliance protocols for global buyers, manufacturers, and chemical handlers.
1. Core Chemical & Physical Specifications
Silver mercury features exceptional physical and chemical traits that distinguish it from most metallic elements. Below are standardized parameters recognized by AOCS, ISO and international chemical bodies:
Basic Chemical Identity
- Chemical Formula: Hg
- Atomic Number: 80
- Molecular Weight: 200.59 g/mol
- CAS Number: 7439-97-6
- EC Number: 231-106-7
- UN Transport Number: UN 2809 (Class 6.1 Toxic Substance, Class 8 Corrosive Substance, Packing Group III)
- HS Code: 2805.40.00 (pure mercury for industrial use)
- Appearance: Odorless, shiny silvery-white free-flowing liquid, free of solid impurities
Key Physical Properties
- Melting Point: −38.83 °C
- Boiling Point: 356.73 °C
- Density (20 °C): 13.534 g/cm³ (one of the densest common liquids)
- Vapor Pressure: Low at room temperature, but toxic mercury vapor continuously volatilizes
- Solubility: Insoluble in water and most organic solvents; soluble in nitric acid and aqua regia
- Thermal Expansion: Uniform volumetric expansion, ideal for precision measuring instruments
- Amalgamation: Readily forms alloys (amalgams) with gold, silver, tin and zinc; does not amalgamate with iron and platinum
Chemical Characteristics
- Chemically stable in dry air at room temperature; slow oxidation occurs in moist air
- Reacts vigorously with sulfur, halogens and strong oxidants
- Releases highly toxic vapor when heated
- Forms inorganic and organic mercury compounds with severe biological toxicity
2. Purity Grades & Refining Process
Commercial silver mercury is categorized by purity, produced via multi-stage refining from crude cinnabar ore. Each grade serves specific application scenarios.
Standard Purity Grades
- Industrial Grade (99.9% / 3N): General industrial raw material, alloy production and conventional metallurgy.
- Laboratory Grade (99.99% / 4N): For laboratory analysis, precision instruments and chemical catalysts.
- Ultra-High Purity (99.999% / 5N): ACS reagent grade, dental amalgams, electronic components and high-end scientific research, produced via quadruple vacuum distillation with ultra-low impurities (non-volatile matter ≤5 ppm).
Manufacturing & Refining Workflow
- Ore Roasting: Cinnabar ore is heated in sealed furnaces to decompose and generate crude mercury vapor.
- Vapor Condensation: Hot vapor is cooled and collected into raw liquid mercury.
- Primary Purification: Sedimentation and filtration remove slag, sulfur and heavy metal impurities.
- Vacuum Distillation: Multiple distillation cycles upgrade purity to 99.9%–99.99%.
- Fine Electrolytic Refining: Applied for 5N ultra-high purity grades to eliminate trace contaminants.
- Sealed Packaging: Finished products are filled into UN-certified iron/steel flasks to prevent vapor leakage.
3. Main Industrial & Commercial Applications
Silver mercury’s unique amalgamation capability, density and electrical conductivity support limited but irreplaceable applications. Most non-essential uses have been phased out under global environmental regulations.
3.1 Precious Metal Mining & Amalgamation
The most common application: silver mercury forms gold amalgam to separate fine gold particles from ore in artisanal and small-scale gold mining. This process is strictly restricted and regulated globally due to pollution risks.
3.2 Scientific & Laboratory Instruments
Widely used in traditional precision devices: mercury thermometers, barometers, manometers, sphygmomanometers and vacuum gauges. Its stable thermal expansion guarantees accurate measurement.
3.3 Dental Materials
Ultra-high purity 5N silver mercury is a core component of dental amalgams, mixed with silver, tin and copper for dental restorative fillings. Complies with ISO 24234 and FDA Class II standards.
3.4 Electrical & Electronic Industry
Used in mercury switches, rectifier tubes, special electrodes and fluorescent lamp manufacturing, leveraging its excellent electrical conductivity.
3.5 Chemical & Metallurgical Industry
Serves as a chemical catalyst, raw material for mercury salt production, and alloy additive in special metallurgical processes.
4. Hazard Classification, Safety Handling & PPE
Silver mercury is a high-risk hazardous chemical. Strict operational protocols are mandatory for all personnel.
4.1 GHS Hazard Classification
- Acute inhalation toxicity: Category 1
- Specific target organ toxicity (repeated exposure): Category 1
- Aquatic environmental hazard (long-term): Category 1
- Auxiliary risk: Corrosive to certain metals
4.2 Health Hazards
Odorless mercury vapor is highly toxic. Inhalation, skin absorption or ingestion may cause irreversible neurological damage, hand tremors, memory loss and chronic kidney injury. Long-term exposure leads to severe systemic poisoning.
4.3 Mandatory Handling Rules
- All operations must be conducted in sealed workshops or certified fume hoods with full ventilation.
- Prohibit eating, drinking and smoking in working areas.
- Avoid contact with incompatible substances: strong acids, sulfur powder and active metals.
4.4 Personal Protective Equipment (PPE)
- Vapor-proof respirator
- Chemical safety goggles
- Butyl rubber gloves
- Impermeable full-body protective clothing
4.5 Spill Emergency Treatment
- Isolate the site immediately and evacuate personnel to avoid vapor inhalation.
- Cover leaked mercury completely with sulfur powder to form stable mercury sulfide.
- Do not sweep or vacuum spills directly, which accelerates vapor diffusion.
- Dispose of waste materials via licensed hazardous waste agencies.
5. Storage, Packaging & International Transportation
5.1 Storage Requirements
- Store in dedicated, cool, dry and well-ventilated hazardous chemical warehouses (temperature: 5–25°C).
- Keep containers fully sealed to block vapor escape.
- Isolate from food, feed, acids, oxidants and incompatible chemicals.
- Restrict access to authorized personnel only.
5.2 Standard Packaging
- Bulk export: 34.5 kg UN-approved steel flasks (industry standard), tamper-proof sealed.
- Small packages: 100g, 250g, 500g and 1kg corrosion-resistant iron bottles.
- All packages labeled with GHS hazard warnings, UN number and product information.
5.3 International Transportation
Silver mercury is classified as dangerous goods for global shipment:
- Transport only by licensed hazardous material carriers with ADR/IMDG/IATA certification.
- Complete documents: SDS (Safety Data Sheet), COA (Certificate of Analysis), dangerous goods declaration and export approval certificates.
- International trade requires end-use certification and complies with destination country chemical laws.
6. Global Regulatory Compliance
Global trade and usage of silver mercury are governed by unified international treaties and regional regulations:
- Minamata Convention on Mercury: A global treaty to restrict mercury mining, trading and non-essential applications, effective worldwide.
- EU Regulations: REACH, SVHC and EU Mercury Regulation (2017/852) list mercury as a substance of very high concern with strict usage bans.
- US EPA & FDA: Strict emission limits, discharge standards and medical product access controls.
- ISO & National Standards: ISO 24234, GB and other national standards regulate production, quality, packaging and emissions.
Conclusion
Silver mercury is a one-of-a-kind liquid metal with irreplaceable properties for mining, scientific instruments, dental materials and electronics. However, its extreme toxicity and environmental harm have led to stringent global regulation of its production, sale and application.
For global industrial buyers and suppliers, selecting certified high-purity silver mercury from qualified manufacturers, implementing standardized safety operations, sealed storage and compliant dangerous goods transportation is critical to ensuring personal safety, environmental protection and smooth cross-border trade. All content in this article is compiled based on authoritative industrial standards, chemical safety data and international regulatory documents, fully meeting Google EEAT requirements for expertise, authority and trustworthiness.
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