How can concentrated sodium hydroxide solution be used for recrystallization to obtain anhydrous sodium hydroxide?
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I’ve been thinking about a problem recently: when sodium reacts with water to produce hydrogen and sodium hydroxide, if the concentration of the sodium hydroxide solution is over 50%, how can the water in it be evaporated to obtain solid anhydrous sodium hydroxide again? I hope experts can give me some advice. Thank you!
What grade of sodium hydroxide requires sodium metal to be used in its production? Sodium hydroxide crystals can be found through information and manuals related to the chlor-alkali industry. It seems that some crystallization processes occur in two steps: in the first step, evaporation and concentration take place followed by cooling, after which the crystals precipitate and are then separated mechanically. The second step is to dry the separated crystals; I need to check the specific details as I’m not an expert in this area
The idea is to use the reaction between sodium and water to produce hydrogen, thereby obtaining sodium hydroxide with high purity and concentration, which can then be recrystallized
The senior’s idea is good; currently, the price of pure sodium ranges from 17,750 to 25,750 yuan per ton, and it is difficult to store and transport； In the chlor-alkali industry, the prices of ion-exchange membrane caustic soda and hydrogen are very low; it is not cost-effective to produce hydrogen and caustic solution by reacting sodium with water – it simply doesn’t make economic sense.
This post was last edited by Qingchengjun on 2019-6-25 at 11:37. He plans to use sodium-water reactors for new energy vehicles; based on a cost of 16 yuan per kilogram for metallic sodium, the cost per kilometer for such vehicles would be 2.88 yuan. The prices ranging from 17,750 to 25,750 yuan per ton make this approach completely unfeasible from an economic perspective
Yeah, the cost is too high – sodium-water reactors? It’s too extravagant; if it’s for experimentation, there’s no need to worry about costs. Focus on achieving success in the experiment first, and then consider reducing costs.
The success of the experiment didn’t help reduce costs at all. Clearly, 23 kg of sodium are needed to produce 1 kg of hydrogen, and the heat released by 1 kg of hydrogen is equivalent to that of more than 3 kg of gasoline; in other words, the value of 4 liters of such hydrogen drops from 400 yuan to just over 30 yuan
This post was last edited by mmliuqing on 2019-6-26 at 15:16. It is not possible to recycle using other materials directly, and other harmful substances are generated during the recycling process. Using sodium hydroxide results in high initial costs, but afterward recycling can be done using the available materials themselves; however, there are costs associated with energy consumption and labor
This post was last edited by mmliuqing on 2019-6-26 at 15:17. If buying ready-made sodium metal isn’t an option, then another approach must be found. If, as stated in the paper, only 3.45 kWh of electricity is required per kilogram of sodium, then cost considerations become apparent quite easily.
First, figure out how much electricity is required to produce 1 kg of sodium – 3.45 degrees of electricity – and then focus on the vehicle aspect. Besides, 3.45 degrees of electricity cost 2.1 yuan; adding in the cost of raw materials at 1 yuan, as well as expenses for management, equipment depreciation, labor, and safety measures, how low can the price of sodium actually be reduced? In an ideal scenario, 50 kg of sodium can be used to produce 200 kg of product; the costs associated with waste liquid recovery and the production of finished sodium suitable for use in car engines are not simple to determine