Introduction Any substance which has solidified from the liquid state without crystallisation is known as glass. Glass may also be defined as a hard, brittle, transparent material chiefly composed of silica, combined with varying...
Tag - Chemistry
Cement can be classified into two major types: Natural cement Artificial cement Natural Cement The cement produced by calcining and pulversing natural rocks consisting of clay limestone is know as natural cement. It possesses a...
Setting and hardening of cement When the cement is mixed with water it produces a plastic mass called “cement paste”. It is due to hydration and hydrolysis reaction that takes place between various constituents of the...
Portland cement In 1824, Joseph Aspdin (UK) discovered Portland cement. Portland cement is chemically defined as a finely ground mixture of calcium aluminates and silicates of varying compositions, which hydrates on mixing with...
Manufacture of Portland cement The chief raw materials required for the manufacture of Portland cement are: Lime stone Clay Gypsum Calcium oxide and iron oxide are obtained from lime stone, while silica and alumina are obtained...
Introduction Cement is defined as a material with adhesive and cohesive properties which make it capable of bonding mineral fragments (like stones, gravel, sand, etc.) into a compact whole. Cement is a fine gray powder, which has...
Properties of refractories depend mainly on their chemical composition, grain size and method of fabrication. Refractoriness: It is the capacity of the material to withstand the heat without appreciable deformation. It is...
Fire bricks Fire clays are suitable for a variety of applications and so they are the most widely used refractory materials. Fire clays are hydrated aluminium silicates having the general composition , Al2O3 2SiO2 2H2O . Fire...
Manufacture of a refractory consists of the following steps: Crushing: The raw materials in the form of big lumps are crushed to about 25mm size. Grinding: The crushed materials are ground down into 200 mesh size by using...
Abrasives are used in three important forms. (a) As loose powder: It is used to clean the surface of materials prior to coating.(e.g.,) Quartz and Garnet. (b) As abrasive paper or cloth: The abrasives are used for cleaning and...
