Ceramics: Types, Materials, and Manufacturing Process

Posted on Jan 26, 2025 in Geology

Ceramics: An Overview

Ceramics are artificial stone-like materials created through a manufacturing process using natural rock raw materials. The primary raw material is clay.

Raw Materials

  • Plastic: Clay
  • Non-plastic: Materials added to reduce plasticity, lower cooking temperature, and increase porosity.

Manufacturing Steps

  1. Conveying Systems
  2. Preparation of the paste
  3. Molding
  4. Drying
  5. Cooking

Types of Ceramics by Application

Bricks

  • Perforated
  • Hollow (single, double, Rasilla)
  • Solid

Tiles

  • Curve or Arabic (longitudinal and transverse placement)
  • Flat roof or Mediterranean (rectangular lace placement)
  • Curviplana or mixed (combination of curve and flat)

Nature and Classification of Ceramic Materials

Ceramic materials have diverse applications in industry and everyday life. Their complexity requires a specific classification:

  • Porous Products: Earthy fracture, coarse, dull, and adhere to the tongue. Examples include bricks, roofing tiles, and pottery blocks.
  • Semi-compact Products: Fine-grained, poorly permeable, and non-absorbent of moisture, such as stoneware.
  • Compact Products: Fine china and porcelain, microcrystalline structure, translucent, and waterproof.
  • Vitrified Products: Cryptocrystalline fracture in a glassy state, transparent, glossy, and waterproof. Glass is a prime example.

Raw Materials in Detail

The core materials are clay and water. Degreasers are added to improve quality, and fluxes are added to enhance vitrification.

Clay

Clay is a fragmented rock derived from the disintegration of feldspar-rich rocks. Its essential mineral is kaolin (Sio2 Al2O3 2H2O), often accompanied by secondary minerals like silica, limestone, and limonite. This variety leads to differences in plasticity and color. The silica-alumina ratio, water content, and structure distinguish different clays.

Water

Water used in mixing must be free of soluble salts to prevent efflorescence.

Manufacturing Process

Both traditional and mechanized processes involve similar fundamental steps:

Preparation of Clays

This involves removing stones, lime lumps, and soluble salts, followed by separating the clay into small pieces and crushing.

Homogenization

Essential for quality, this step mixes ingredients thoroughly with the correct amount of water.

Molding

This shapes the product. Imperfections can lead to cracks during cooking.

Drying

A delicate process that must be gradual to prevent cracking.

Cooking

This removes water and gives the product mechanical strength.

Storage

Used to manage production stocks and regulate marketing.