What Is Lead Oxide?
Lead oxide is a yellow to reddish-yellow, odorless, powdery, inorganic compound. Composed of lead and oxygen, it has the chemical formula PbO, a molecular weight of 223.20, and CAS No. 1317-36-8. Other names include lead monoxide and lead (II) oxide. Its melting/freezing point is 888°C, and its boiling or first distillation point and boiling range are 1,470°C. It is almost insoluble in water and ethanol but soluble in nitric acid, acetic acid, and aqueous sodium hydroxide.
Structure of Lead Oxide
Lead oxide has two types of structures:
- α-type: red, tetragonal, and stable at room temperature (Mitsudasou or litharge).
- β-type: yellow, orthorhombic, and stable at temperatures above 300℃ (Kintsudasou or massicot).
The transition temperature to the β-type is 587°C, depending on the oxygen partial pressure.
Uses of Lead Oxide
1. Radiation Shielding Agent
Used in radiation protective clothing and shielding agents due to its radiation shielding properties, especially in medical fields where X-rays are used.
2. Pigments
Historically used as a pigment since ancient Roman times, lead oxide serves as an inorganic pigment, a raw material for paints, and a varnish for glass and ceramics.
3. Other Uses
Utilized as a raw material for vinyl chloride stabilizers, solid lubricants, synthetic rubber vulcanization accelerators, and electrode plates for lead-acid batteries.
Other Information on Lead Oxide
1. Production Methods
- Heating Metallic Lead: Lead can be oxidized to lead oxide at around 600°C, melted to lead oxide at around 1000°C, or sprayed with melted lead at 900°C or higher.
- Alkali Treatment: Lead nitrate mixed with ammonium carbonate or ammonium chloride in aqueous solution precipitates lead carbonate.
- Ore Refining: Produced as an intermediate product in the refining of lead ores into metallic lead.
2. Legal Information
Lead oxide is classified and regulated under various laws and regulations related to fire safety, poisonous and deleterious substances, safety and health, working environment evaluation, pollution control, and export.
3. Handling and Storage Precautions
Precautions include keeping containers tightly closed, storing in a cool, dark place, avoiding contact with incompatible materials, using only outdoors or in well-ventilated areas, and wearing protective gear when handling.
- Keep containers tightly closed and store in a cool, dark place.
- Store away from strong oxidizers, hydrogen peroxide, aluminum powder, and other incompatible materials.
- Use only outdoors or in well-ventilated areas.
- Take precautions to prevent dust dispersion.
- Wear protective gloves and glasses when using.
- After use, remove gloves appropriately to avoid skin contact with the product.
- Wash hands thoroughly after handling.
- In case of skin contact, wash with soap and plenty of water.
- In case of eye contact, rinse cautiously with water for several minutes.