Manufacturing method of sodium bisulfite
I. Introduction
Sodium bisulfite (NaHSO3) is an important inorganic salt, which is widely used in the fields of chemical industry, medicine, food and so on. It has the properties of reducing, antiseptic and antioxidant, and can be used as a food additive, bleaching agent, preservative and so on. Therefore, it is of great practical significance to study the manufacturing method of sodium bisulfite. In this paper, we will introduce a method to prepare sodium bisulfite by chemical reaction with sodium hydroxide and sulfur dioxide as raw materials.
II. Raw materials and equipment
1. Raw materials: sodium hydroxide (NaOH), sulfur dioxide (SO2)
2. Equipment: reaction kettle, stirrer, thermometer, pH meter, condenser, vacuum pump
III. Manufacturing method
1. Sodium hydroxide is prepared into a certain concentration of the solution, and put into the reaction kettle.
2. Pass in the sulfur dioxide gas, and at the same time turn on the stirrer, so that the gas is in full contact with the sodium hydroxide solution.
3. The reaction temperature is controlled and the pH is maintained within the desired range by adjusting the rate of sulfur dioxide admittance.
4. During the reaction, crystals of sodium bisulfite are precipitated from the resulting sodium bisulfite. When the crystals reach a certain amount, the sulfur dioxide feed is stopped, ending the reaction.
5. The reaction solution is filtered to separate the sodium bisulfite crystals from the mother liquor.
6. Wash and dry the sodium bisulfite crystals to obtain the final sodium bisulfite product.
4. Precautions
1. Control the reaction temperature and pH so as not to affect the product quality and yield.
2. Stirring speed should be moderate to ensure that the gas is in full contact with the solution, and at the same time avoid crystal fragmentation.
3. Keep the equipment airtight during the reaction to prevent sulfur dioxide leakage.
4. Operators are required to wear protective gear to avoid exposure to hazardous substances.
5. Conclusion
The method of preparing sodium bisulfite by chemical reaction with sodium hydroxide and sulfur dioxide as raw materials is feasible. In the actual production process, good control of the reaction conditions can obtain high-quality products. At the same time, the method is easy to operate, low cost, and has a good industrialization prospect. Through the introduction of this paper, it is hoped that it can provide certain reference and reference for the manufacture of sodium bisulfite.
