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Production process of carbonic acid

TIME:22-08-26    NUM:0

1. Lubranza


2. Soxhlet method

In 1859, Solvay, a Belgian, used salt, ammonia water and carbon dioxide as raw materials to precipitate sodium bicarbonate from the solution at room temperature, and heated it to decompose it into sodium carbonate. This method is called the Soxhlet method. , this method has been used till now:


3. Hou's alkali method

In 1943, Chinese Hou Debang returned from studying abroad. He improved the Solvay method based on the national conditions of salt shortage in mainland China. He combined the two industries of soda ash and synthetic ammonia to produce sodium carbonate and fertilizer ammonium chloride at the same time, which greatly improved the consumption of salt. utilization.

In the first step, ammonia gas reacts with water and carbon dioxide to form a molecule of ammonium bicarbonate, and in the second step, ammonium bicarbonate reacts with sodium chloride to form sodium bicarbonate precipitation and ammonium chloride. of less solubility. Sodium bicarbonate solid was obtained by filtration.

In the third step, the synthesized sodium bicarbonate can be sold directly from the factory, and the rest of the sodium bicarbonate will be decomposed by heating to generate sodium carbonate, and the generated carbon dioxide can be recycled back to the first step. According to the principle that NH4Cl is more soluble than NaCl, but less soluble than NaCl at low temperature, at 278K ~ 283K (5 ℃ ~ 10 ℃), fine salt powder is added to the mother liquor, so that NH4Cl is crystallized separately for use as nitrogen fertilizer.

The difference between Soxhlet method and Hou's alkali method is that NH3 is recycled in the whole production process of Soxhlet method, while CO2 is recycled in the whole production process of Hou's method, and NH4Cl is directly used as A by-product of soda ash - fertilizer. Therefore, the product of the Soxhlet method is sodium carbonate and the by-product calcium chloride; while the product of the Hou's method is sodium carbonate and the by-product ammonium chloride.

The advantages of this method: retain the advantages of the ammonia-alkali method, eliminate its shortcomings, and increase the utilization rate of salt to 96%; NH4Cl can be used as nitrogen fertilizer; it can be combined with a synthetic ammonia plant to convert the raw material gas CO of synthetic ammonia into CO2, leather Except for the process of making CO2 from CaCO3.