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Sodium Bicarbonate, A Downstream Product of Limestone2023-08-04 17:02:59

About Sodium Bicarbonate

Sodium bicarbonate, commonly referred to as baking soda, is an inorganic compound with the chemical formula NaHCO₃. It comprises small white crystals that exhibit lower solubility in water compared to sodium carbonate. Sodium bicarbonate is produced as an acid salt following the neutralization of a strong base and a weak acid, and it acquires weak alkaline properties upon dissolution in water.
Sodium bicarbonate is a white, crystalline powder with an opaque monoclinic crystal system. It is odorless and has a salty taste. While it is soluble in water, it does not dissolve in ethanol. Its solubility in water is 7.8g (18℃) and 16.0g (60℃). The compound remains stable at room temperature but decomposes easily when exposed to heat, rapidly losing carbon dioxide above 50°C and completely at 270°C. In dry air, sodium bicarbonate remains unchanged while slowly decomposing in humid air.
Sodium bicarbonate reacts with both acids and bases to form the corresponding salts, water, and carbon dioxide when reacting with acids; while reacting with bases forms the corresponding carbonates and water. Additionally, it can react with certain salts such as double hydrolysis with aluminum chloride and aluminum chlorate to produce aluminum hydroxide along with sodium salts and carbon dioxide.


How is Sodium Bicarbonate Made From Limestone

Soda ash is produced through the combination of sodium chloride, limestone (which is calcined to produce quicklime and carbon dioxide), and ammonia gas. Initially, ammonia gas is introduced into saturated salt water to form ammonia brine, which is then mixed with carbon dioxide to precipitate sodium bicarbonate and ammonium chloride solution with low solubility. The chemical reaction principle can be expressed as follows: NaCl + NH3 + H2O + CO2 = NaHCO3↓ + NH4Cl. The tiny crystals of NaHCO3 obtained by filtration and washing are heated and calcined in order to produce soda ash products according to the following equation: 2NaHCO3 = Na2CO3 + H2O + CO2↑. The released carbon dioxide gas can be recovered and recycled. Finally, the filtrate containing ammonium chloride is mixed with lime milk [Ca(OH)2] before being heated, allowing for the recovery and recycling of any released ammonia gas.

Application of Sodium Bicarbonate


Pharmaceuticals Industry

Sodium bicarbonate can serve as a pharmaceutical raw material for the treatment of hyperacidity, metabolic acidosis, and urine alkalization to prevent uric acid kidney stones. Additionally, it can mitigate renal toxicity caused by sulfonamides, prevent hemoglobin deposition in renal tubules during acute hemolysis, and alleviate symptoms associated with excessive gastric acid secretion. Intravenous infusion exhibits non-specific therapeutic effects against barbiturate, salicylic acid, and methanol poisoning.

Food Processing

In the field of food processing, sodium bicarbonate is extensively utilized as a leavening agent in the production of biscuits, bread, and other similar products. However, excessive usage can lead to an excessively alkaline taste and an undesirable yellow-brown color due to the presence of sodium carbonate residue. Sodium bicarbonate also finds application as a carbon dioxide generator in soft drinks. It can be combined with alum to form alkaline baking powder or with soda ash to create civil stone alkali. Additionally, it serves as a preservative for butter and acts as a color protection agent during the processing of fruits and vegetables. The addition of approximately 0.1% to 0.2% sodium bicarbonate while washing fruits and vegetables helps maintain their green color stability. When employed as a treatment agent for fruits and vegetables, it elevates their pH value, enhances protein water retention, softens food tissue cells, and dissolves astringent components effectively. Furthermore, at usage levels ranging from 0.001% to 0.002%, it efficiently eliminates the odor associated with sheep milk.

Industrial Use

Sodium bicarbonate finds application in the production of acid-base and foam fire extinguishers, as well as rubber and sponge manufacturing in the rubber industry. It also serves as a flux for casting ingots in metallurgy, a molding aid for casting steel sand in machinery, and a fixing agent, acid-alkali buffer, and post-treatment agent for fabric dyeing and finishing in printing and dyeing industries. Additionally, adding baking soda to dyeing prevents colored flowers from appearing on yarns and can be used as a wool detergent.

Limestone Grinding Mill Recommendation

The fields in which sodium bicarbonate is applied typically necessitate a high degree of fineness for the final product, such as pharmaceuticals, food products, and other areas closely intertwined with human life. Consequently, it is imperative that the powder be finely ground.
HGM Ultrafine Grinding Mill
Capacity:0.2-45 t/h
Feed Size:≤20 mm
Powder Fineness:325-3000 mesh

Mill Adavantages
  1. Enhanced Efficiency With equivalent final size and motor power, the superfine powder grinding mill boasts double the capacity of a jet mill, mixing grinder, or ball mill, while reducing energy consumption by 30%.
  1. Prolonged Lifespan of Spare Parts The ring and roller are forged from specialized materials with high utilization rates. Under identical grinding material and desired special size conditions, spare parts have a lifespan of approximately one year - two to three times longer than an impact mill or turbo mill. Moreover, when grinding calcite carbonate, their longevity can reach 2-5 years. The lifespan of spare parts varies depending on material hardness.
  1. Superior Safety and Reliability Due to the absence of rolling bearings or screws in the grinding cavity, issues caused by bolt shedding or rapid wear of bearings and seal components are eliminated.
  1. Exceptional Fineness and Adjustable Precision The ultimate fineness of ground materials can be flexibly adjusted within the range of 150 meshes to 3000 mesh (74-5 micron).
  1. Advanced Intelligent Speed Control Device Pulse bag filters and mufflers effectively mitigate dust pollution and noise.

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