Basic Properties 
Physical Properties: Soda ash is usually a white powder or fine granular crystal, odorless, and easily soluble in water. Its aqueous solution is alkaline. The melting point is 851℃, and the density is 2.532 g/cm³. It has strong hygroscopicity. When exposed to air, it easily absorbs moisture and carbon dioxide, gradually forming sodium bicarbonate. 
Chemical Properties: Sodium carbonate is a salt of a strong base and a weak acid, and it has the general properties of salts.
  
Production Methods 
1.Ammonia-soda process: Using common salt, limestone and ammonia as the main raw materials. First, the common salt is made into a saturated salt solution. After removing the impurities in it, ammonia gas is introduced to make an ammonia-salt solution. Then, carbon dioxide is introduced to generate sodium bicarbonate precipitation. After filtration and calcination, soda ash is obtained. The advantages of this method are high product purity and low cost. However, its disadvantages are low utilization rate of common salt and the generation of a large amount of calcium chloride waste residue. 
2.Combined soda process: Also known as the Hou's soda process, it was invented by the Chinese chemist Hou Debang. This method combines the ammonia-soda process with the synthetic ammonia process. While producing soda ash, ammonium chloride, a kind of nitrogen fertilizer, can also be obtained. Its advantages are high utilization rate of common salt, basically no waste residue discharge, and it is environmentally friendly. 
3.Natural soda process: Using natural soda ore as the raw material, soda ash is obtained through processes such as dissolution, refining and evaporation. This method has a low production cost and little environmental impact, but it is limited by the resources of natural soda ore.

Application Fields 

1.Glass Industry: Soda ash is one of the main raw materials for glass production. During the glass manufacturing process, soda ash is melted at high temperature together with raw materials such as quartz sand and limestone. It lowers the melting point of glass and promotes the formation of glass. Approximately 0.2 tons of soda ash is consumed per ton of glass, and it is widely used in the production of flat glass, bottle glass, optical glass, etc.

2.Chemical Industry: It is a basic chemical raw material and is used to manufacture a variety of chemical products, such as sodium salts, metal carbonates, baking soda (sodium bicarbonate), sodium silicate (water glass), etc. In organic synthesis, it is also commonly used as a neutralizing agent or a catalyst. For example, in some esterification reactions, soda ash can neutralize the acid generated in the reaction, thus promoting the progress of the reaction.

3.Metallurgical Industry: In the metallurgical industry, it is used as a flux, which can lower the melting point of ores and facilitate the extraction of metals from ores. For example, in the ironmaking process, soda ash can react with the gangue (such as silicon dioxide, etc.) in iron ore to form slag, thereby removing impurities and improving the purity of iron. In addition, it can also be used for the surface treatment of metals. For instance, in the surface treatment of aluminum, the soda ash solution can remove the oil stains and the oxide film on the surface of aluminum.

4. Textile Printing and Dyeing Industry: In the textile printing and dyeing industry, soda ash is used for washing wool, which can remove the grease and impurities on the wool. In the treatment of cotton fabrics, it can be used as a scouring agent to remove the natural impurities and residual sizing agents on the cotton fabrics, improving the whiteness and hand feel of the fabrics. During the printing and dyeing process, soda ash can also be used as a fixing agent to adjust the pH value of the dye liquor, increase the fixation rate of the dyes, and make the dyeing more uniform and firm.

5.Food Industry: It can be used as a food additive. For example, in the production of pasta, it can adjust the acidity and alkalinity of the dough, improve the properties of the dough, and make the pasta softer and more delicious. In food processing, it can also be used to remove the pesticide residues on the surface of fruits and vegetables, and as a tenderizer in meat processing to make the meat more tender. In addition, in the food industry, soda ash is also used in the production of seasonings such as monosodium glutamate and soy sauce.

6.Water Treatment: It can adjust the pH value of water to make the acidity and alkalinity of water reach an appropriate range. It helps to remove calcium and magnesium ions in water, reduce the hardness of water, and prevent the formation of scale. Soda ash is widely used in industrial circulating water and boiler water, which can effectively protect equipment and prolong the service life of the equipment.