Course Code: CHM-DSC-353
Paper Name: Industrial Chemistry
Ceramics are inorganic, non-metallic solids prepared by the action of heat and subsequent cooling. They are characterized by their hardness, high melting points, and low electrical conductivity.
Refractories are materials that can withstand very high temperatures without melting or deforming. They are used to line furnaces, kilns, and reactors.
Glass is a transparent or translucent amorphous solid, technically a supercooled liquid of silicates.
The manufacture involves four main steps: Melting of raw materials → Shaping/Forming → Annealing (slow cooling) → Finishing.
| Type | Composition | Uses |
|---|---|---|
| Soda-lime Glass | Na2O, CaO, SiO2 | Window panes, bottles (common glass). |
| Borosilicate Glass | B2O3, SiO2 | Laboratory glassware (Pyrex), high thermal resistance. |
| Lead Glass | PbO, SiO2 | High refractive index; used for lenses and decorative crystal. |
The most common form is Portland Cement, a complex mixture of silicates and aluminates of calcium.
The raw materials are crushed, mixed (Wet or Dry process), and heated in a rotary kiln to form Clinkers.
The chemical process that occurs when water is added to cement is called hydration.
Q: Why is glass called a supercooled liquid?
A: Because it possesses the structural characteristics of a liquid (disordered arrangement) but is rigid at room temperature due to its high viscosity.
Q: What are cement clinkers?
A: These are small, dark gray, stone-like pellets formed by heating the raw materials in the kiln. They are ground with gypsum to make the final cement powder.
Q: What gives color to glass?
A: The addition of transition metal oxides (e.g., FeO for green, CoO for blue, MnO2 for violet).