Uses of Sodium Carbonate Element

To know about the uses of sodium carbonate we have to study its origination and its properties. 

Sodium Carbonate

Sodium carbonate can be found in nature or is made from sodium chloride (common salt). It can be used for a variety of purposes, including the production of glass.

Uses of Sodium Carbonate 

There are two types of sodium carbonate (soda ash) used: heavy and light sodium carbonate. The light form is first obtained, and then some of it is changed to the heavy form. The sodium chloride content of light sodium carbonate is less than 0.5 percent. Heavy sodium carbonate is made by hydrating light sodium carbonate to form a monohydrate (Na2CO310.H2O) and then dehydrating it to produce a product with larger crystals and a higher density.

The two grades are used in various ways.

1.Heavy sodium carbonate is mostly used as a solid, particularly in the manufacture of glass, where it is used as a flux in the melting of silica (sand).

2.Light sodium carbonate has typically been used in applications where the chemical is required in solution. 

A pie chart depicting the numerous applications of both light and heavy sodium carbonate.

Figure 1: Heavy and mild sodium carbonate applications.

Overall, nearly half of all sodium carbonate produced is used to build glass, 18 percent to make other chemicals, and 10% to make soaps and detergents. 

Manufacturer of Sodium carbonate 

Sodium carbonate is obtained from two main sources:

a) sodium carbonate and hydrogencarbonate ores (through the ammonia soda (Solvay) process) 

b) sodium carbonate and hydrogencarbonate ores   (trona and nahcolite)

(a) Calcium carbonate with sodium chloride

The reaction between calcium carbonate and sodium chloride can be summarised as follows:

CaCO2+ 2NaCl = CaCl2+Na2CO3

Calcium carbonate, on the other hand, is too insoluble to react with a salt solution. Instead, the product is obtained by a seven-step process.

The ammonia-soda method, often known as the Solvay process, is named after a Belgian industrial chemist who invented it in 186I.

As seen in the picture and description below, the many stages of the Solvay process are interconnected.

The Solvay technique for producing sodium carbonate from calcium carbonate and sodium chloride is depicted in this diagram.

Figure 2: The Solvay process at various phases.

(1) Brine ammoniation Ammonia gas is absorbed in concentrated brine to produce a solution that contains sodium chloride and ammonia. There are ions such as Na+(aq), Cl-(aq), NH4+(aq), OH-(aq), and NH3 (aq).

(2) Calcium oxide and carbon dioxide formation

A limestone/coke mixture is used to feed the kilns (13:1 by mass). In a counter-current of pre-heated air, the coke burns: 

C+O2=CO2

The kiln’s temperature rises as the heat of burning rises, and the limestone decomposes: 

CaCO3=CaO +CO2

The gas is cleared of lime particles and transported to the carbonating (Solvay) towers, holding around 40% carbon dioxide. Calcium oxide, the leftover, is employed in ammonia recovery (see step 7 below). 

(3) The Solvay Tower  .

This is the most important step in the procedure. The ammoniated brine from step 1 is pumped down the Solvay Tower, while carbon dioxide from stages 2 through 5 is pumped up. The Solvay Tower is a tall structure with mushroom-shaped baffles that slow and break up the liquid flow, allowing the carbon dioxide to be absorbed efficiently by the solution. Liquid carbon dioxide interacts with dissolved ammonia to generate ammonium hydrogen carbonate:

NH3+CO2+H2O= NH4CO3

The ions Na+(aq), Cl-(aq), NH4+(aq), and HCO3-are now present in the solution (aq). The least soluble of the four compounds generated by varied combinations of these ions is sodium hydrogen carbonate (NaHCO3). It condenses as a solid in the cooled lower portion of the tower. The whole procedure is as follows:

NaCl+NH3+H2O+CO2=NaHCO3+NH4Cl  

A suspension of solid sodium hydrogen carbonate in an ammonium chloride solution is discharged from the tower’s base.

(4) Solid sodium hydrocarbonate separation

The solid sodium hydrogencarbonate is separated from the ammonium chloride solution by filtering the suspension, which is then used in stage two (7).

(5) Sodium carbonate formation

In rotating ovens, sodium hydrogen carbonate is heated to 450 K, when it decomposes into sodium carbonate, water, and carbon dioxide:

2NaHCO3=Na2CO3+H2O+CO2

The carbon dioxide is returned to the Solvay Tower, where it will be used in the next stage (3). Anhydrous sodium carbonate, the process’s end product, is obtained as a fine white powder known as light sodium carbonate. 

(6) Calcium hydroxide formation

The regeneration of ammonia from ammonium chloride is the subject of the final two phases, (6) and (7). (made in step 3). The milk of lime is made by squeezing the quicklime from step 2 with extra water:

CaO+CO2=Ca(OH)2

Conclusion 

We conclude that Detergents, soaps, and paper are all made with it. Water glass (sodium silicate), borax, sodium phosphate, and a variety of other salt compounds are all made with it. It is utilised as a water softener – carbonate precipitates hard water, which contains magnesium and calcium ions.