Ammonium bicarbonate and sodium bicarbonate

This is somewhat similar to the Hou's alkali production process. It is a very mature route of the alkali production process. The principle is based on the principle of ion reaction. The ion reaction will proceed in the direction of decreasing ion concentration. NaHCO3 is first prepared by taking advantage of the small solubility of NaHCO3 in solution. Then use the unstable decomposition of sodium bicarbonate to obtain soda ash. To make sodium bicarbonate, a large amount of sodium ions and bicarbonate ions are needed, so ammonia gas is introduced into saturated brine to form a saturated ammonia salt solution, and carbon dioxide is introduced into it. There are a large number of sodium ions, ammonium ions, chloride ions and bicarbonate ions in the solution. Among them, NaHCO3 has the smallest solubility, so it precipitates out. The remaining products can be used as fertilizer or recycled after treatment. Its chemical equation can be summarized as the following three-step reaction. (1)NH3+H2O+CO2=NH4HCO3 (First introduce ammonia, then carbon dioxide) (2)NH4HCO3+NaCl=NH4Cl+NaHCO3↓ (NaHCO3 has the smallest solubility, so it precipitates. ) (3) 2NaHCO3 = Na2CO3 + CO2 + H2O (NaHCO3 has poor thermal stability and easily decomposes when heated) And by taking advantage of the solubility of NH3CL, NACL can be added to the solution in (2) at low temperature, and NH4Cl will precipitate to obtain fertilizer, which improves the utilization of NACL. Hou Debang, the inventor, announced this technology to the world, which greatly developed our country's soda ash industry and contributed to the progress of the world's alkali production industry. However, many of us seem to have forgotten this set of processes. . . The salty wastewater can be used in this process after concentration, or it can be used as a liquid prepared with saturated brine, and then used for the production of soda ash and ammonium chloride.

After reading the posts on the second floor, I gained a lot of knowledge. Only then can I truly understand Hou’s alkali production process.

The explanation on the 2nd floor is very detailed, I like it. However, if it is used for sewage treatment, other corresponding measures must be taken. This post was last edited by river9901 on 2008-2-26 00:36 ]

Thank you for your incisive explanation on the second floor, which made me suddenly enlightened. Fully understand this meaning

Brother on the 4th floor, I don’t know what other measures you mentioned, can you give me some advice?

I learned a lot from the opinions on the second floor, thank you! What I want to ask is that the above method is based on a solution with a higher concentration. If the concentration is lower, whether it is necessary to cool down or concentrate the original solution.

Can electrodialysis be used in conjunction with the above processes to treat such salty wastewater or waste hydrochloric acid, especially hydrochloric acid solutions with relatively dilute concentrations?

The latest process is: triethylamine is added to sodium chloride to pass through carbon dioxide to obtain sodium bicarbonate precipitation, and triethylamine hydrochloride is added to calcium hydroxide to generate calcium chloride and triethylamine (reuse).

Does anyone know? The biggest advantage is that no cooling is required. Ammonia gas can also be used to regenerate organic amines to save energy.

This process is not suitable for treating salty wastewater. Because the concentration of waste brine is low, adding ammonium bicarbonate not only fails to remove the salt, but on the contrary, nothing comes out, and more ammonium bicarbonate is added.

In theory it is possible, but in practice there may be many problems. Also consider other components of the wastewater, such as organic matter, other metal ions. And pH. Salt concentration. The main thing is cost. Our company has about 14% brine, but there is no concentration device in the process. Maybe when foreigners are designing, they think that the cost of concentration will be very high. Hope there are successful experiences to share.

It’s strange, why don’t foreigners add wastewater treatment? It’s easy to concentrate from 14% to 30%.

How do you drain the salt water?

Concentrate to 300g/L to produce baking soda and amine chloride.