What is Soda Ash?
Soda Ash, sodium carbonate, is an alkali chemical refined from the mineral trona or from naturally occurring sodium carbonate-bearing brines. Synthetic soda ash is sodium carbonate that has been manufactured from one of several chemical processes.
Annual production of sodium carbonate
China is the world’s largest producer of sodium carbonate, accounting for 46% of world production and U.S. 23%.)
World 52 million tonnes
China 25 million tonnes
U.S. 12 million tonnes
Europe 11 million tonnes
Russia 0.71 million tonnes
Manufacture of sodium carbonate
There are two main sources of sodium carbonate:
a) from salt and calcium carbonate (via the ammonia soda (Solvay) process)
b) from sodium carbonate and hydrogen carbonate ores (trona and nahcolite)
(a) From sodium chloride and calcium carbonate
The overall reaction can be regarded as between calcium carbonate and sodium chloride:
(b) From trona and nahcolite ores
The Solvay process is not used in the US. Instead, the industry uses two ores and this accounts for about 30% of the world’s production. One is trona, found in vast amounts in Wyoming. Trona has the formula:
The ore is mined as a solid and heated to drive off carbon dioxide, to yield sodium carbonate:
The other ore is nahcolite which is sodium hydrogencarbonate. On heating it forms sodium carbonate.
What is the difference between Dense and Light Soda Ash?
In general, light and dense forms are not chemically different from each other and their only difference is in their densities. In addition to higher density, the dense form also has larger particles and is mostly used in the glass industry, while the light form has a lower density and is used in the food industry, water purification, etc.
What is the use of soda?
1. Glass Manufacture – Soda ash is the chief source of the alkali constituent of glass and the Magadi Soda Ash is increasingly used in the glass manufacturing industry. Sodium carbonate introduces sodium oxide or soda (Na2O) into the glass formulation. The soda acts as a fluxing agent, breaking the Si-O bonds of silica, thus reducing the viscosity of the melt and lowering the temperature required to form the glass.
2. Manufacture of sodium silicate and other sodium compounds – One of the common uses of Magadi Soda Ash is in the production of Sodium Silicate. Soda Ash and silica sand are fused in a furnace at high temperatures, with the ratio of Na2O to SiO2 depending on the relative amounts of each used.
3. Soda Ash is also used to produce sodium chromate, which is usually further processed to yield sodium dichromate or chromic acid. Chromium compounds are used in a number of applications, including pigments, preservatives (example wood and leather) catalysts, and chrome plating.
4. Formulation of detergents, soap and rayon – The largest single use of Soda Ash within the cleaning products category is in the formulation of household laundry detergent powders where it is added to build, buffer and dilute the detergent mixture. Soda Ash is incorporated in powdered soaps, detergents, and various specialty cleaning products for household, industrial, and commercial applications. It is added to emulsify oil stains, reduce re-deposition of dirt in wash cycles, provide alkalinity for cleaning and soften laundry water.
5. Soda Crystals Manufacture – The manufacture of soda crystals from Magadi ash can readily be carried out. Soda crystals, which have the composition Na2CO3-10H2O, are made by cooling down hot, saturated, solutions of soda ash.
6. Water Softening – Water never occurs in a pure state in nature but always contains impurities in suspension or solution. Thus by adding the appropriate amounts of lime and soda ash, the calcium and magnesium in hard water is almost entirely removed. For cheap and efficient water softening, the use of lime and Magadi Soda Ash, together with a small quantity of sodium aluminate, is recommended.
7. Pulp and paper industry – Magadi Soda Ash is used by the pulp and paper industry primarily in the preparation of pulping liquors. The neutral sulfite semi chemical pulping process consumes the majority of the soda ash used. This process uses a weak solution of sodium sulfite prepared from sulfur dioxide and sodium carbonate. It can also be used to produce pulping liquors for other chemical pulping processes.
8. Steel and metallurgical industries – used in mining and smelting of various metals and minerals, especially in alumina productions. However, only 5.8% of sodium carbonate produced is consumed by this sector globally.
9. Caustic Liquor Manufacture – Certain industries such as the soap and mercerizing industries use solutions of caustic soda in large quantities to causticize soda ash with lime.
10. Used in the textile, dyeing and bleaching industries, souring wool and cotton
Packaging And Storage
Soda ash packaging is done in polymer bags of various sizes from 1kg to 50kg metric ton depending on customer requirements.
Soda ash should be stored under cover in a cool, dry place and bags containing the substance should not be loaded a height of more than 15 bags.