Ceramic – Glass
Raw materials for Glass Manufacturing:
Solvay’s Process – Lime Calcination :
Lime calcination process produces raw burnt lime and approximate content of CaO in this raw calcined lime is about 75 to 90 percent. However this raw lime cannot be used as such in the Solvay’s process. This is because it is highly difficult to maintain a constant feed rate of CaO in the input lime as it varies highly across the feed. So the lime has to e converted into milk of lime for usage to ensure that the CaO content in the feed is constant. By hydration of CaO into milk of lime a better control of the alkali addition can be achieved during the ammonia recovery step.
Hydration of the raw burnt lime is carried out in slakers where raw burnt lime and water flows are fully controlled to ensure that the alkali content of milk of lime produced is as constant as possible. This reaction is a highly exothermic. A part of the heat generated vaporizes some water which is released from the slaker vent. During the hydration, fine inert materials contained in limestone (sulfates, silica, clay, silico-alumina compounds, unburned limestone and others) can mainly be found in milk of lime. Larger particles are separated by screening, then washed and recycled or released out of the process. The unburned pieces of limestone are recycled.
To be Contd….
