Soda soda, also known as soda, or sodium carbonate, is a very important chemical raw material. There are two preparation methods. One is the ammonia soda process developed by Solvi company in Belgium, also known as Soxhlet soda process, and the other is the combined soda process developed by Mr. Hou in China, also known as Hou soda process. The principle of these two technologies is the same, and the raw materials used are similar.
At first, nicolas leblanc method was used to prepare soda ash, and sodium carbonate was produced from salt, sulfuric acid, coal and limestone. The purity of sodium carbonate produced was not high. Soxhlet method and Hoff method are the main methods to prepare soda ash in modern times. The raw materials used are salt (sodium chloride), limestone (calcined to produce quicklime and carbon dioxide), ammonia and water.
Second, how is soda ash produced?
There are many production methods of soda ash, which are introduced as follows:
1, laboratory method
Sodium carbonate prepared in the laboratory is made of sodium hydroxide and carbon dioxide, and the reaction equation is:
2 Sodium hydroxide+carbon dioxide = sodium carbonate +H2O.
2. Nicholas LeBron's Law
(1) salt is converted into sodium sulfate by sulfuric acid: 2NaCl+H2SO4 (concentrated) = = Na2SO4+2 HCl =
(2) sodium sulfate, charcoal and limestone are heated together in a furnace. Sodium sulfate reacts with charcoal in the furnace to generate sodium sulfide and carbon monoxide: Na2SO4+4C== high temperature = ==Na2S+4CO↑ = then sodium sulfide reacts with limestone to generate sodium carbonate and calcium sulfide: Na2S+CaCO3== high temperature ==Na2CO3+CaS. Because the product is mixed with unreacted black carbon, the product is black ash, which is called black ash. Black ash contains 40%~45% sodium carbonate.
(3) leaching black ash with water, and crystallizing sodium carbonate after the solution is concentrated. Calcium sulfide is not easily soluble in water, so it precipitates into slag and is discarded.
3. Suoge Park Jung Su Su style of play
(1) Ammonia reacts with water and carbon dioxide to generate a molecule of ammonium bicarbonate: NH3+H2O+CO2 = NH4CO3.
(2) Ammonium bicarbonate reacts with sodium chloride to produce precipitation of sodium bicarbonate and ammonium chloride because of its low solubility. Filtering to obtain sodium bicarbonate solid: NaCl+NH4CO3 = nahco3 ↓+NH4Cl.
(3) heating and decomposing sodium bicarbonate to generate water, carbon dioxide and sodium carbonate, that is, we want soda ash: 2NaHCO3== high temperature = = Na2CO3+H2O+CO2 =
(4) mixing and heating the by-product ammonium chloride and slaked lime in the second step, and the obtained ammonia gas can be recycled: 2NH4Cl+Ca(OH)2== high temperature = = 2nh3 =+2h2o+CaCl2.
4. Hou Shi soda process
(1) Ammonia reacts with water and carbon dioxide to form a molecule of ammonium bicarbonate.
(2) Step 2, ammonium bicarbonate reacts with sodium chloride to generate sodium bicarbonate precipitate and ammonium chloride. The precipitation of sodium bicarbonate is due to its low solubility. Filtering to obtain sodium bicarbonate solid. (These two steps are the same as the Soxhlet process above).
(3) Part of the synthesized sodium bicarbonate can be sold directly from the factory, and the remaining sodium bicarbonate is decomposed by heating to generate sodium carbonate, and the generated carbon dioxide can be recycled in the first step.
The difference between Soxhlet method and Hou method is that NH3 is recovered in the whole process by Soxhlet method, CO2 is recovered in the whole process by Hou Shi method, and NH4Cl is directly used as a by-product of soda ash-fertilizer. Therefore, the product of Soxhlet method is sodium carbonate and the by-product is calcium chloride; The product of Hou Shi process is sodium carbonate, and the by-product is ammonium chloride.