Find the size of the crystalline particles of the material
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What methods can be used to make crystal particles larger? For example, is there anyone who knows how to control temperature, stirring speed, etc.
I don’t know what kind of product is crystallized. In addition to paying attention to the process and process conditions, adding a crystal modifier appropriately will improve the particle size and density.
To obtain larger crystals, you can also use the method of slowly lowering the temperature and slowing down the crystallization rate. Atoms must move to arrange themselves into a crystal structure, and movement takes time.
Our approach is to precisely control the time and temperature required for the crystallization precipitation point, and then control the crystallization process at the appropriate temperature, including rate, stirring speed, cooling gradient... Usually the crystallization produced under such circumstances is more in line with theory...
It would be better for the poster to be more detailed and analyze the specific issues in detail.
Controlling crystallization mainly starts from the following two aspects:: 1. Initial nucleation requires controlling the initial nucleation amount according to the output and particle size. ； 2. Control the supersaturation of crystallization according to material components and environmental factors. The poster would like to clarify the following questions to make it easier to explain.: 1. Whether the crystallization is continuous crystallization ； 2. Whether the crystallization is evaporation crystallization, cooling crystallization or other ； 3. Process parameters such as material composition and temperature.
Ours is a glyphosate product that crystallizes after cooling. Crystallization should be continuous crystallization. Now I just want to make the particles bigger.
If you want to make the crystals larger, you can reduce the stirring speed to facilitate the rapid attachment of the crystals.； Lower the temperature appropriately ； Extend crystallization time ； At the same time, it is recommended to appropriately add some finished product particles to quickly provide crystallization nuclei for rapid crystallization.
For continuous crystallization, the residence time can be increased, the stirring speed can be appropriately reduced, or the stirrer material can be replaced.
Enhancing the cooling effect can improve the mass transfer driving force, and the particle size should also be increased under the same residence time. However, the temperature difference should not be too large, otherwise it will cause crystal shape or other defects (including nucleation problems).
To make the crystal particles larger, we mainly focus on the following aspects:: ⑴Control the stirring speed. If necessary, you can stop stirring and let it stand for crystallization. ； ⑵Control the cooling rate and cool down slowly so that the crystal form grows slowly and at the same time, the occurrence of impurity encapsulation can be reduced. ； ⑶Putting a small amount of finished particles as crystal nuclei can speed up the crystallization process. ； ⑷Prolonging the crystallization time will result in better growth of crystalline particles.
1. Add seed crystals at the early stage of crystallization to prevent the formation of a large number of fine crystals in a supersaturated state, but instead precipitate on the surface of the seed crystals. 2. After the crystals are formed and left to stand for aging, the small particles will dissolve and the large particles will continue to grow.
Thank you for your brainstorming. We will experiment with many of the above factors to gradually grow our crystal particles. At the same time, we will also consider that good crystallization should also increase the content of the product. This is what we hope for.