Potassium hydroxide is a kind of strong alkali, which is often used as chemical raw materials. However, if the main content of the main products fails to meet the requirements, it will also affect the subsequent use effect. How to solve it when the main content of the products is low? Let's take a look.
The main content refers to the mass fraction of KOH in the finished product, which is one of the main parameters to determine the product quality. Generally, the content is required to be greater than 90%. In this process, the key is to control the temperature of alkali liquor. 1.148% of the alkali liquor concentration needs to reach or exceed 48% after being evaporated by the first effect evaporator and the second effect evaporator, so as to prepare for the quality qualification of the subsequent processes.
This process mainly uses the heat generated by steam condensation to evaporate the water in the alkali liquor, so as to improve the concentration. Therefore, it is necessary to ensure that the pressure and temperature of the steam meet the corresponding requirements: the boiling point of the alkali liquor can be reduced in the vacuum state. Therefore, in order to save energy and improve efficiency, the vacuum degree in the evaporator should be kept as high as possible. The vacuum degree of alkali liquor in the two-effect evaporator is 0.085 ~ 0.094mpa, and the temperature is between 75 ~ 85 ℃.
1. Increase the pressure and temperature of high-pressure steam
The rising film evaporator takes high-pressure steam as the heating medium, which can continue to improve the concentration of alkali liquor. The temperature of potassium hydroxide alkali liquor is generally between 190 ~ 210 ℃.
2. Hydrogen combustion furnace and molten salt system
Molten salt HTS is used as the heating medium in the concentration and production process, and hydrogen combustion furnace is used to provide heat source for heating BTS. The heat provided by the combustion furnace shall be stable, so as to ensure the stability of molten salt temperature and flow, generate sufficient stable heat to heat the alkali liquor, and make the alkali liquor temperature after passing through the concentrator meet the standard requirements, generally between 380-400 ℃.
3. Keep the system closed
In order to avoid the decrease of alkali liquor temperature and deliquescence and reduce the k0h content, the alkali liquor needs to be kept in a closed state as far as possible during the flow from the concentrator to the flake alkali machine to avoid contact with air.
The four methods described above are the solutions to the low main content of potassium hydroxide. After treatment by the above methods, the purity of the product can be effectively improved.