Question

Question : Common soda-lime-silica glass is made by melting together Na2CO3, CaCO3, and SiO2. The carbonates break down, liberating CO2 gas bubbles. For 1 kg of container glass (16 wt% Na2O, 11 wt% CaO, 73 wt% SiO2), what is the raw material batch formula (i.e., weight percent of Na2CO3, CaCO3, and SiO2)? Note Na = 22.99 amu, Ca = 40.08 amu, C = 12.01 amu.

Answer 1

Wt% of SiO2 in glass = 73%

Mass of glass = 1000 kg / 0.73 = 1369.86 kg

Mass of Na2O = 0.15 x 1369.86 = 205.48 kg

Mass of CaO = 1369.86 x 0.10 = 136.98 kg

Part a:

The mass of Na₂CO₃ = mass of Na2O * molecular weight of Na2CO3 / molecular weight of Na2O

= 205.48 * (105.99 g/mol / 61.98 g/mol)

= 351.38 kg

Part b:

Mass of CaCO3 = mass of CaO x molecular weight of CaCO3 / molecular weight of CaO

=  136.98 kg x (100.09 g/mol / 56.08 g/mol)

= 244.47 kg

Mass of SiO2 = 1000 kg

Total mass = 351.38 + 244.47 + 1000

= 1595.85 kg

Wt% of CaCO3 = 244.47 *100/ 1595.85

= 15.32%

  

answered by: anonymous