Suck the patent from the shelf

Crystallization is the densest form of matter molecules. The closer the size and shape of the molecule are, the easier it is to adsorb on the surface of the crystal and become a part of the crystal. Crystals are generally solid (there are other forms such as liquid crystal), that is, impurities will be removed when crystals crystallize. When we refine high-purity silicon wafers, we use repeated crystallization. Ice is the crystallization of water. In the remaining water, impurities (pigment and sugar) remain in the liquid part. Pigment and sugar have different solubility in solid phase and liquid phase. The initial system is located at 1 in the figure. After the temperature rises, it enters the solid-liquid mixing zone and is divided into liquid phase and solid phase. The composition is represented by the intersection of temperature isotherm, liquidus and solidus (2 and 3) respectively. The part you gargle into your mouth is 3. Then the process continues, 1 moves to the left, and 2 and 3 move up. Then I suck most impurities (sugar and pigment) into my mouth. Ps: The right half of this phase diagram does not necessarily reflect the real trend of sucrose-water, but it is enough to look at the left half. One more thing: this conclusion can be used for effective purification, which is called regional melting. The reason is the same, and the process is similar. The solubility of sugar and pigment in water decreases with the decrease of temperature, and solute begins to precipitate when the solution reaches saturation. When water forms ice, the ice is loose and porous because of the existence of air and precipitated sugar and pigment, and sugar and pigment can move freely in these gaps under the action of force when sucking. From a professional point of view, iced drinks are like crystals with a second phase. If there is a second phase, there must be grain boundaries. According to the principle of thermodynamics, the grain boundary energy is high, and the second phase impurities gather in the most stable place on the grain boundary, but it is also the place where the phase change (melting) is most likely to occur, so the pigments and sugars as the second phase are absorbed first.