Raw materials Flashcards
What raw materials are used in soda lime glass?
~ sand (SiO2), limestone (CaCO3), and soda ash (Na2CO3)
What’s the rxn for the solvay process?
~ 2NaCl + CaCO3 –> Na2CO3 + CaCl2
What is a substitution for limestone?
~ dolomite (Ca, Mg)CO3
What is a substitution for soda ash?
~ feldspar (granite, quartz, mica)
~ feldspar is liberated by crushing and separating by froth floatation (quartz is also generated and used as source of silica)
What is borax used for?
~ source of soda and boria
~ in e-glass, which intolerant of alkali, boric acid (borax + HCl) is used
What is iron in terms of raw materials?
~ BA, makes glass green
~ optical glasses can’t have more than 0.015% Fe2O3 impurity
How can iron introduced from crushing and grinding machinery be removed?
~ magnets
How can iron present in the original rock be removed?
~ with hot concentrated sulfuric acid (expensive)
~ used only when lots of freedom from iron oxide is required