BARIUM CARBONATE (BaCO₃)

BARIUM CARBONATE (BaCO₃)

Introduction

Barium Carbonate (BaCO₃), which occurs naturally as the mineral witherite, is an inorganic salt of the alkaline earth metal barium. BaCO₃ is a white, odorless precipitate widely used as a flux and stabilizing agent in ceramics and glass, as well as an important additive for preventing defects in brick and tile production.

1. Classification and Composition

• Chemical formula: BaCO₃
• Molar mass: 197.34 g/mol
• Chemical behavior: Upon heating, BaCO₃ decomposes to form barium oxide (BaO) and releases carbon dioxide (CO₂):

BaCO₃ (heat) → BaO + CO₂

2. Technical Properties

3. Key Applications in Industry and Ceramics

● Ceramics & Glazes

• Fluxing and crystallization agent:
  BaO (formed from BaCO₃ during firing) acts as a flux that lowers the melting temperature of glazes. It is used to create special glaze effects such as crystalline and matte glazes, while enhancing glaze strength and gloss.
• Color stabilization:
  Used in combination with coloring oxides (e.g., CoO) to produce unique and more stable color shades.

● Brick, Tile, and Structural Clay Products

• Prevention of Efflorescence:
  One of the most important applications in construction materials. BaCO₃ is added to clay bodies to react with and precipitate soluble salts (such as CaSO₄ and MgSO₄) into insoluble barium sulfate (BaSO₄).
  This prevents soluble salts from migrating to the surface and causing efflorescence, chalking, or yellowish stains after firing.

● Glass Manufacturing

• BaO source for glass:
  BaO increases the refractive index (optical and crystal glass), improves hardness, and enhances mechanical strength.

● Environmental Treatment

• Used in wastewater treatment to remove sulfate ions and heavy metals by precipitation.