What is soda ash and what are its uses and properties?
What is Hou's alkali production method, and what are its principles and steps?
What are the problems with Hou's alkali production method and how to solve them?
What is ethanol and what are its characteristics and advantages?
How to wash soda ash with ethanol, what conditions and factors need to be paid attention to?
What is the effect of washing soda ash with ethanol, and what are its benefits and significance?
Let me introduce these in detail:
Soda ash is a white solid powder with the chemical formula Na_(2)CO_(3), which means it is composed of sodium (Na) and carbonate (CO_(3)). Soda ash is an alkaline substance that reacts with acidic substances to produce salt and water. Soda ash can dissolve in water to form an alkaline solution. Soda ash has many uses, such as soap, glass, detergents, dyes, paper, ceramics, etc. Soda ash is also an important industrial raw material. It can be used to make sodium compounds, such as sodium bicarbonate (baking soda), sodium hydroxide (caustic soda), sodium peroxide (bleach), etc.
Hou's soda production method is a method that uses the reaction of lime (CaO) and sodium chloride (NaCl, also known as table salt) to make soda ash. Its principle is that lime and salt react in water to produce calcium hydroxide (Ca(OH)(2)) and calcium chloride (CaCl(2)). Calcium hydroxide is a strong base that can react with carbon dioxide (CO_(2)) in the air to produce calcium carbonate (CaCO_(3)) and water. Calcium carbonate is a white precipitate that is insoluble in water. It can be filtered and dried to obtain soda ash. The steps of Hou's method of making alkali are to first add lime and salt to water in a certain proportion, stir evenly, and allow them to fully react. The reaction solution is then filtered to remove unreacted lime and salt to obtain a transparent solution containing calcium chloride. Then put this solution in a ventilated place and let it contact the carbon dioxide in the air to form calcium carbonate precipitation. Finally, the precipitate is filtered and dried to obtain soda ash.
A problem with Hou's soda production method is that during the reaction, some salt will not react completely but will be mixed with soda ash, which will affect the purity and yield of soda ash. This is because both table salt and soda ash are white solid powders. Their particle sizes and shapes are very similar, so it is difficult to distinguish and separate them with the naked eye or ordinary filtration methods. Moreover, the salt will also adhere to the surface of the soda ash during the filtering and drying process, forming a layer of coating, which makes it more difficult to remove. If soda ash contains salt impurities, its properties and uses will be affected. For example, its solubility, alkalinity, reactivity, etc. will decrease, and its weight will also increase, leading to errors in calculating yield.
In order to solve this problem, we can use a liquid called ethanol to wash the soda ash and wash away the salt mixed in it. Ethanol is a colorless and transparent liquid. Its chemical formula is C_(2)H_(5)OH, which means it is composed of carbon (C), hydrogen (H) and oxygen (O). Ethanol is an organic solvent that can dissolve some organic substances, such as grease, esters, ethers, aldehydes, ketones, etc. Ethanol can also dissolve some inorganic substances, such as salt, iodine, sulfur, etc. However, ethanol cannot dissolve soda ash. This is because soda ash is an alkaline substance, and ethanol is a neutral or slightly acidic substance. There is not enough affinity between them to form a solution. This characteristic of ethanol allows it to effectively separate soda ash and salt, because it can dissolve the salt without affecting the soda ash.
How to wash soda ash with ethanol, what conditions and factors need to be paid attention to? We have done many experiments and found the most suitable washing conditions, which is to use ethanol with a concentration of 90%, soak the soda ash in ethanol at a ratio of 3:1 for 3 minutes, and then filter and dry it, so that the soda ash can be washed The impurities of table salt are reduced to very low levels. We also found that used ethanol can be recycled and reused, which saves costs and is more environmentally friendly.
The effects of these conditions and factors are as follows:
Concentration of ethanol: The higher the concentration of ethanol, the stronger its dissolving power, which means it can dissolve more salt without dissolving soda ash. If the concentration of ethanol is too low, such as less than 50%, then it will dissolve some soda ash, resulting in the loss of soda ash. We found through experiments that the optimal concentration of ethanol is 90%, which can dissolve salt and retain soda ash.
Amount of ethanol: The more ethanol, the more soda ash it can come into contact with, thus dissolving more salt. However, the amount of ethanol cannot be too much, otherwise it will cause waste and pollution. We found through experiments that the optimal amount of ethanol is in a ratio of 3 to 1, that is, for every 1 gram of soda ash, 3 ml of ethanol is used for washing.
