Raw materials used in the Solvay process and the products
2NaCl(aq) + CaCO3 (s) Na2CO3(s) + CaCl2(aq)
The raw materials used in the solvay process, include
1. Sodium Chloride, NaCl (In the form of concentrated brine) – comes from seawater
2. Calcium Carbonate, CaCO3 (In the form of limestone)
The products include
1. Sodium Carbonate Na2CO3– which is what the process is designed to manufacture
2. Calcium Chloride CaCl2– A waste product
Additionally Ammonia is used (NH3) in the reaction to create a more efficient method of production.
The uses of sodium carbonate
• Glass Making – Most of the Sodium Carbonate is used to make glass. It, along with Calcium Carbonate and sand
• Water treatment – It is used to soften water by precipitating out the heavy ions, and is used in washing powders and builders present in detergents
• Soap and detergent production – At the moment, it is a cheaper alternative to sodium hydroxide for the production of soap
• Paper Making – It is a raw material for making sodium hydrogen sulfite, a substance used extensively in paper mills
• As a common base – for a variety of purposes instead of sodium hydroxide as it is cheaper
Formation of Sodium Carbonate
The Sodium Carbonate formed in the previous
section is filtered and heated to form Sodium
2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
The CO2, is fed back into the previous step, but is insufficient for the reaction to continue, and so more is added, by heating limestone.
The Na2CO3 is extracted and sold.
There are four main environmental issues that are associated with the Solvay process are:
1. Disposal of Calcium Chloride – Unfortunately, Calcium Chloride has next to no practical use. The only use is for de-icing roads as it lowers the melting point of ice, providing safer roads. However, far more of it is produced than is actually required, especially in Australia, where this problem is almost non-existent. To dispose of the excess...