Uses Of Plaster Of Paris

Uses Of Plaster Of Paris

          

               It is used

             •      For making plaster walls

             •      For casts of statury, coins etc

 •      In surgery. Its bandages are used to keep the fractured bone in place after setting.

Portland cement is obtained by heating a mixture of clay and lime stone. The resulting mass called clinker is cooled and crushed to fine powder. During crushing about 2% gypsum is also added. It prevents the cement from hardening quickly and decreases the setting time of cement.

1. Ordinary mortar, also called lime mortar, is prepared by mixing freshly slaked lime with sand and water to form a thick paste. 

Mortar is made by mixing slaked lime (one volume), sand (three or four volumes) and water to make thick paste. This material is hardened or sets when placed between stones and bricks. Thus it binds the blocks firmly together. 

The reactions for this process are

                                                CaO + H₂O                         Ca(OH)₂

                                                Ca(OH)₂ + CO₂                                    CaCO₃ + H₂O

                                                Ca(OH)₂ + SiO₂                                   CaSiO₃ + H₂O

2. When lime is heated with coke at about 2800⁰C in an electric furnace, calcium carbide is produced. 

                                            CaO + 3C                        CaC₂ + CO