Properties And Traditional Preparation Methods Of Sodium Hydrosulfide：
Sodium hydrosulfide is a colorless needle shaped crystal that is easily deliquescent and soluble in water and alcohol. The aqueous solution is strongly alkaline. Sodium hydrosulfide is a new type of chemical raw material after sodium sulfide. It not only has the basic characteristics and functions of sodium sulfide, but also has a higher concentration of HS ions in water compared to sodium sulfide. Therefore, it has superior performance in fields such as light industry and chemical industry.
At present, the traditional production method of sodium sulfide in China mostly involves introducing hydrogen sulfide gas into sodium sulfide or sodium hydroxide solution for production. The absorption of hydrogen sulfide gas needs to be carried out in a packed tower. For safety reasons, the absorption process needs to be carried out under negative pressure, and the reaction involves multiple equipment. The method of evaporating and concentrating sodium sulfide under negative pressure can be applied in industrial production to reduce production costs.
Preparation Method Of Sodium Hydrosulfide：
Using industrial product barium sulfide (60%) to prepare a barium sulfide solution with a content of 18%, add the corresponding industrial sodium sulfide in a 1:1 ratio to the above solution, and prepare a mixed solution of the same concentration. The reaction is carried out in a closed container equipped with a drip funnel, a magnetic stirrer, and a round bottom flask. The prepared mixed solution is added to the flask, and the magnetic stirrer is started to slowly add sulfuric acid with a concentration of 25% at room temperature, After the sulfuric acid is added dropwise, continue stirring for a period of time to allow the reaction to proceed fully. Let it stand, take the upper yellow green solution, filter it three times to remove impurities, and then transfer the reaction solution to a vacuum distillation device for evaporation and concentration. Under a certain negative pressure, it can obtain sodium hydrosulfide that meets the requirements of the leather industry, which to some extent reduces production costs. Under vacuum pressure of 0.4 MPa, vacuum distillation can obtain sheet-like crystals, Convenient product packaging and transportation.
Reaction time control is very important. If the reaction time is too short, it cannot meet the product quality requirements. If the reaction time is too long, it will increase industrial production capacity consumption and reduce production efficiency. The best reaction time is 120 minutes. When the reaction time is too short, sodium sulfide does not fully react, resulting in high sodium sulfide content and low sodium sulfide content. When the reaction time is too long, sodium sulfide will decompose slightly, not only reducing efficiency, It also wastes production costs.
