{"id":703,"date":"2022-12-05T12:28:47","date_gmt":"2022-12-05T12:28:47","guid":{"rendered":"https:\/\/www.shimico.com\/blog\/?p=703"},"modified":"2025-05-05T12:44:30","modified_gmt":"2025-05-05T12:44:30","slug":"sodium-carbonate","status":"publish","type":"post","link":"https:\/\/www.shimico.com\/blog\/news\/scientific-articles\/sodium-carbonate\/","title":{"rendered":"Sodium carbonate| Soda ash; features and applications"},"content":{"rendered":"

Sodium carbonate<\/strong><\/a>, Na2Co3, (=also known as washing soda<\/strong>, soda ash,<\/strong> and soda crystals) is a mineral compound that has different hydrated structures. All forms of this compound include white, odorless, water-soluble salts that produce moderately alkaline solutions in water. Historically, this substance was extracted from the ashes of plants grown in sodium-rich soils.<\/p>\n

A Look at the History of sodium carbonate<\/strong><\/h2>\n

Humans have known and used soda ash for thousands of years. The ancient Egyptians extracted this compound from a mineral called Natron<\/a>, which was found at the bottom of dry lakes. Natron is a combination of soda ash and baking soda. Egyptians used its soda in embalming corpses<\/a>. This combination kept the bodies of the dead dry and prevented them from decaying. This technique was so effective that some mummified bodies over 3000 years old are still in the same condition as when they died. Over the centuries, sodium carbonate was also produced from the combustion of organic matter, especially seaweed. In this production method, this common compound is soda ash.<\/p>\n

Burning dead plants does not produce very large amounts of sodium carbonate, so chemists of the time looked for synthetic methods to produce this important compound. The first breakthrough in this quest came in 1791 when the French chemist Nicolas LeBlanc (1806-1742) devised a method for producing sodium carbonate that became an industry standard for nearly a century.<\/p>\n

In 1900, almost all sodium carbonate produced in the world was made by the Solvay process. In the following, we explain these processes.<\/p>\n

Soda ash production methods<\/strong><\/h2>\n

\u00a0<\/strong>Production of sodium carbonate from the mine<\/strong><\/h3>\n

Trona, also known as trisodium hydrogen bicarbonate dihydrate, is mined in several regions of the United States and supplies nearly all of the region’s soda ash consumption. Large natural deposits discovered in 1938, such as those near Green River, Wyoming, made mining more economical than industrial production in North America. There are significant reserves of trona in Turkey. Two million tons of soda ash have been extracted from deposits near Ankara. Also, from some lakes such as Lake Magadi in Kenya, this compound is extracted by dredging operations. Hot springs produce lake salt continuously, provided the rate of dredging does not exceed the rate at which the spring draws water, a perfectly stable source of sodium carbonate.<\/p>\n

Production of soda ash from plants and algae (Barilla and kelp)<\/strong><\/h3>\n

Several “halophyte” (salt-tolerant) plant species and seaweed species can be processed to produce the crude form of sodium carbonate; These sources were mostly consumed in Europe and other places until the early 19th century. Plants or seaweed were dried and burned. Then the ashes were washed with water to form an alkaline solution. This solution was boiled dry to produce the final product, which was called “soda ash”. “Barilla” is a trade term for the crude form of potash obtained from seaweed, or kelp.<\/p>\n

LeBlanc process for the production of sodium carbonate<\/strong><\/h3>\n

In 1792, French chemist Nicolas LeBlanc patented a process for producing sodium carbonate from salt, sulfuric acid, limestone, and coal. In the first step, sodium chloride is treated with sulfuric acid in the Mannheim process. This reaction leads to the production of sodium sulfate (salt cake) and hydrogen chloride:<\/p>\n

2NaCl + H2SO4 \u2192 Na2SO4 + 2HCl<\/strong><\/p>\n

Salt cake and crushed limestone (=calcium carbonate) are reduced under heating with coal. This conversion consists of two parts. The first is the carbothermic reaction in which coal, the carbon source, reduces sulfate to sulfide:<\/p>\n

Na2SO4 + 2C \u2192 Na2S + 2CO2<\/strong><\/p>\n

The second stage of the reaction is the production of sodium carbonate and calcium sulfide:<\/p>\n

Na2S + CaCO3 \u2192 Na2CO3 + CaS<\/strong><\/p>\n

This mixture is called black ash. Soda ash is extracted from black ash with water. From the evaporation of this extract, solid sodium carbonate is obtained.<\/p>\n

The hydrochloric acid produced by the Leblanc process was a major source of air pollution, and the calcium sulfide byproduct also caused waste disposal problems. However, this basic method of producing sodium carbonate remained in place until the late 1880s.<\/p>\n

Production of sodium carbonate in the Solvay process<\/strong><\/h3>\n

\"sodium<\/p>\n

In 1861, Belgian chemist Ernest Solvay devised a method for producing sodium carbonate by first reacting sodium chloride, ammonia, water, and carbon dioxide to produce sodium bicarbonate<\/a> and ammonium chloride:<\/p>\n

NaCl + NH3 + CO2 + H2O \u2192 NaHCO3 + NH4Cl<\/strong><\/p>\n

Then the resulting sodium bicarbonate was converted into sodium carbonate by heating and water and carbon dioxide were released:<\/p>\n

2NaHCO3 \u2192 Na2CO3 + H2O + CO2<\/strong><\/p>\n

Ammonia was produced from the by-product of ammonium chloride and by treating it with lime (calcium oxide) remaining from the production of carbon dioxide:<\/p>\n

2NH4Cl + CaO \u2192 2NH3 + CaCl2 + H2O<\/strong><\/p>\n

The Solvay process recovers ammonia. Only salt water and limestone are used in this process and calcium chloride<\/a> is the only waste product. This process is considerably more cost-effective than the Leblanc process, which produces two waste products, calcium sulfide, and hydrogen chloride.<\/p>\n

The Solvay process quickly dominated sodium carbonate production worldwide. By 1900, 90% of this material was produced by the Solvay process, and the last Leblanc process plant closed in the early 1920s.<\/p>\n

Production of sodium carbonate in the Hou process<\/strong><\/h3>\n

This process was developed by the Chinese chemist Hou Debang in the 1930s. Carbon dioxide, the primary byproduct, was pumped through a saturated solution of sodium chloride and ammonia to produce sodium bicarbonate by these reactions:<\/p>\n

CH4 + 2H2O \u2192 CO2 + 4H2<\/strong><\/p>\n

3H2 + N2 \u2192 2NH3<\/strong><\/p>\n

NH3 + CO2 + H2O \u2192 NH4HCO3<\/strong><\/p>\n

NH4HCO3 + NaCl \u2192 NH4Cl + NaHCO3<\/strong><\/p>\n

baking soda Because of its low solubility is collected as a precipitate and then heated to about 80 \u00b0C (176 \u00b0F) or 95 \u00b0C (203 \u00b0F) to obtain pure sodium carbonate, similar to the last step of the Solvay process.<\/p>\n

More sodium chloride is added to the remaining ammonium and sodium chloride solution. Also, more ammonia is pumped into this solution at 30-40 degrees Celsius. Next, the temperature of the solution drops below 10 degrees Celsius. The solubility of ammonium chloride is higher at 30\u00b0C than sodium chloride and lower at 10\u00b0C. Due to this temperature-dependent solubility difference and common ion effect, ammonium chloride precipitates in sodium chloride solution.<\/p>\n

Hou’s process is more economical because it does not require more ammonia and, on the other hand, the ammonium chloride byproduct can be sold as fertilizer.<\/p>\n

Properties and applications of sodium carbonate<\/strong><\/h2>\n

The physical and chemical properties and characteristics of this powdery solid composition make it widely used in various industries. In full, we discuss these features in the table in the next section.<\/p>\n

Physical and chemical characteristics of soda ash<\/strong><\/h3>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Sodium carbonate<\/strong><\/td>\n<\/tr>\n
compound names<\/strong><\/td>\n<\/tr>\n
nomenclature<\/strong>
\nSodium carbonate<\/strong><\/td>\n<\/tr>\n
Name suggested by <\/strong>IUPAC<\/strong>
\nDisodium carbonate<\/strong><\/td>\n<\/tr>\n
Other common names<\/strong>
\nSoda ash<\/strong>
\nwashing soda<\/strong>
\nSoda crystal<\/strong>
\nSodium trioxocarbonate<\/strong><\/td>\n<\/tr>\n
indicator species<\/strong><\/td>\n<\/tr>\n
CAS Number<\/strong><\/td>\n497-19-8\u00a0(without water)<\/strong>
\n5968-11-6\u00a0(single water)<\/strong>
\n6132-02-1\u00a0(ten water)<\/strong><\/td>\n<\/tr>\n
EC Number<\/strong><\/td>\n207-838-8<\/strong><\/td>\n<\/tr>\n
E number<\/strong><\/td>\nE500(i)<\/strong><\/td>\n<\/tr>\n
PubChem\u00a0CID<\/strong><\/td>\n10340<\/strong><\/td>\n<\/tr>\n
RTECS number<\/strong><\/td>\nVZ4050000<\/strong><\/td>\n<\/tr>\n
properties and characteristics<\/strong><\/td>\n<\/tr>\n
Chemical formula<\/strong><\/td>\nNa2<\/sub>CO3<\/sub><\/strong><\/td>\n<\/tr>\n
Molar mass<\/strong><\/td>\n105.9888\u00a0g\/mol (without water)
\n286.1416\u00a0g\/mol (ten water)<\/strong><\/td>\n<\/tr>\n
Appearance<\/strong><\/td>\nWhite solid with moisture absorption properties<\/strong><\/td>\n<\/tr>\n
Smell<\/strong><\/td>\nOdorless<\/strong><\/td>\n<\/tr>\n
Density<\/strong><\/td>\n2.54\u00a0g\/cm3<\/sup>\u00a0(25\u00a0\u00b0C, without water)<\/strong>
\n1.92\u00a0g\/cm3<\/sup>\u00a0(856\u00a0\u00b0C)<\/strong>
\n2.25\u00a0g\/cm3<\/sup>\u00a0(single water)<\/strong>
\n1.51\u00a0g\/cm3<\/sup>\u00a0(seven waters)<\/strong>
\n1.46\u00a0g\/cm3<\/sup>\u00a0(ten water)<\/strong><\/td>\n<\/tr>\n
Melting point<\/strong><\/td>\n851\u00a0\u00b0C (1,564\u00a0\u00b0F; 1,124\u00a0K) (single water)
\n100\u00a0\u00b0C (212\u00a0\u00b0F; 373\u00a0K)
\ndecomposes (single water)
\n33.5\u00a0\u00b0C (92.3\u00a0\u00b0F; 306.6\u00a0K)
\ndecomposes (seven waters)
\n34\u00a0\u00b0C (93\u00a0\u00b0F; 307\u00a0K)
\n(ten water)<\/strong><\/td>\n<\/tr>\n
Solubility in water<\/strong><\/td>\nwithout water, g\/100\u202fmL:<\/strong>
\n7 (0\u00a0\u00b0C)<\/strong>
\n16.4 (15\u00a0\u00b0C)<\/strong>
\n34.07 (27.8\u00a0\u00b0C)<\/strong>
\n48.69 (34.8\u00a0\u00b0C)<\/strong>
\n48.1 (41.9\u00a0\u00b0C)<\/strong>
\n45.62 (60\u00a0\u00b0C)<\/strong>
\n43.6 (100\u00a0\u00b0C)<\/strong><\/td>\n<\/tr>\n
Solubility in other solvents<\/strong><\/td>\nSoluble in alkalis and glycerol<\/strong>
\nRelatively soluble in alcohol<\/strong>
\ninsoluble in carbon disulfide; acetone; Alkyl acetate; alcohol; benzonitrile; Liquid ammonia<\/strong><\/td>\n<\/tr>\n
Solubility in glycerin<\/strong><\/td>\n98.3\u00a0g\/100\u202fg (155\u00a0\u00b0C)<\/strong><\/td>\n<\/tr>\n
Solubility in ethanediol<\/strong><\/td>\n3.46\u00a0g\/100\u202fg (20\u00a0\u00b0C)<\/strong><\/td>\n<\/tr>\n
Solubility in dimethylformaldehyde\u00a0<\/strong><\/td>\n0.5 g\/kg<\/strong><\/td>\n<\/tr>\n
Acidity (pK<\/em>a<\/sub>)<\/strong><\/td>\n10.33<\/strong><\/td>\n<\/tr>\n
Viscosity<\/strong><\/td>\n3.4 cP (887\u00a0\u00b0C)<\/strong><\/td>\n<\/tr>\n
Thermochemistry<\/strong><\/td>\n<\/tr>\n
Heat capacity (C<\/em>)<\/strong><\/td>\n112.3\u00a0J\/mol\u00b7K<\/strong><\/td>\n<\/tr>\n
Molar standard entropy\u00a0(S<\/em>\u29b5<\/sup>298<\/sub>)<\/strong><\/td>\n135\u00a0J\/mol\u00b7K<\/strong><\/td>\n<\/tr>\n
Standard enthalpy of formation\u00a0(\u0394f<\/sub>H<\/em>\u29b5<\/sup>298<\/sub>)<\/strong><\/td>\n\u22121130.7\u00a0kJ\/mol<\/strong><\/td>\n<\/tr>\n
Gibbs free energy (\u0394f<\/sub>G<\/em>\u29b5<\/sup>)<\/strong><\/td>\n\u22121044.4\u00a0kJ\/mol<\/strong><\/td>\n<\/tr>\n
Related compounds<\/strong><\/td>\n<\/tr>\n
corresponding anions<\/strong><\/td>\nSodium bicarbonate<\/strong><\/td>\n<\/tr>\n
corresponding cations<\/strong><\/td>\nLithium carbonate
\nPotassium carbonate
\nRubidium carbonate
\nCaesium carbonate<\/strong><\/td>\n<\/tr>\n
Other related compounds<\/strong><\/td>\nSodium sesquicarbonate
\nSodium percarbonate<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

read more: Caustic soda flakes and the methods of production<\/a><\/p>\n

Uses of soda ash<\/strong><\/h2>\n

Glass manufacturing industry<\/strong><\/h3>\n

The sodium carbonate acts as a flux for the silica (2SiO, with a melting point of 1713 \u00b0C) and raises the melting point of the mixture to a level that can be achieved without the need for special materials. This “soda mix” dissolves slowly in water, so some calcium carbonate is added to the molten mixture to make the glass insoluble. Bottle and window glasses are made by melting such mixtures of sodium carbonate, calcium carbonate and silica sand and silicon dioxide.<\/p>\n

As a water softener<\/strong><\/h3>\n

Hard water contains dissolved compounds, usually calcium or magnesium compounds. Sodium carbonate is used to remove temporary and permanent hardness of water.<\/p>\n

Since this substance is soluble in water and magnesium carbonate and calcium carbonate are insoluble, it is used to soften water by removing 2+ Mg and 2+ Ca. These ions form insoluble solid deposits after treatment with carbonate ions. Water becomes soft because it does not contain dissolved calcium ions and magnesium ions.<\/p>\n

Food additives and cooking<\/strong><\/h3>\n

Sodium carbonate has a variety of uses in cooking, mainly because it is stronger than baking soda but weaker than metal hydroxide alkalia (which may refer to sodium hydroxide or potassium hydroxide). Alkaline affects the production of gluten in the cooked dough. A solution of alkaline salts is used to taste Japanese noodles.<\/p>\n

Bakers similarly use its soda ash as a replacement for freshwater to create special texture in cakes and improve the cake browning.<\/p>\n

It is used in the production of syrup powder. The feeling of coolness and tingling of the mouth, due to the heat reaction between sodium carbonate and poor acid, is usually citric acid that releases carbon dioxide gas, and occurs when the syrup is moistened by saliva.<\/p>\n

It is also used in the food industry as a food additive (code E500) as an acidity regulator, anticoagulant, volume agent and stabilizer.<\/p>\n

Other soda ash uses:<\/strong><\/h3>\n