Preparation Of NaCl Crystal And Research Of NaCl Crystal Growing Process

As a very important component of Organic lives, sodium chloride can adjust the biological equilibrium and maintain the life functioning normally. Crystal materials of sodium chloride become the focus of medical research. Latest research shows that aerosol preparing by NaCl crystal materials can be used to treat asthma, the effect is rapid and has no toxicity, it can also reduce burden of patients. Dentifrice preparing by NaCl crystal materials has cleaning and antimicrobial effect. It also can be used to prevent dental caries, whiten teeth, stop bleeding and being anti-inflammatory, deodorant, desensitization durgs to protect oral health. But preparing small,uniform size distribution,high dispersive,intact crystal structure and less secondary dissolved NaCl crystal material is very difficult in the current production process. NaCl crystal material prepared by traditional process cannot be used in the medical research such as asthma treatment and stomatological care.This paper prepared NaCl crystal material by lamellar liquid crystal,salting-out crystallization and anti-solvent method. The influence factors of NaCl crystal preparation were researched in this paper.Nucleation and growing process of NaCl crystal was analysed. Surface topography of NaCl crystal was also investigated in this paper.The results show that the crystal structure is integrated and angular. The crystals don’t redissolve and dissolve each other. The particle size is distributed from 300 nm to 400 nm and the crystals are dispersed. The crystal has high purity and no impurities, the crystallinity of NaCl is 99.75%. NaCl crystal culturing in lamellar liquid crystal is relatively independent and different in size. The crystal particle size is distributed from 300 nm to 400 nm after culturing for 12 h. In this period the nucleation is based on outbreaking growth and nucleation rate is faster than crystal growth rate. The crystal particle size is distributed from 800nm-1000 nm after culturing for 18 h. The crystal growing process is relatively independent and secondary nucleation dosen’t exist while culturing. Defect which is in different size and shape exists on NaCl crystal surface while growing in culture solution. The crystal particle size is 0.7cm×0.5cm×0.3cm after culturing for 144 h. Finally crystal grows into cuboid shape and stacks together, this situation is correspond with the structure of lamellar liquid crystal.The concentration of alcohol in NaCl-C₂H₅OH-H₂ O system has no influence to NaCl crystal structure and measurement while preparing NaCl by salting-out crystallization method. The crystal particle size is distributed from 1μm to 10 μm and water molecule which restricted between crystals can form hydrogen bond to make crystals agglomerate.The precipitated NaCl crystal structure is integrated and angular while dripping saturated NaCl solution into ethanol solution in anti-solvent method. Redissolving and dissoving each other can be prevented in this way. The crystal particle size is distributed from 40 nm to 60 nm. The result shows that acid environment is conducive to crystal growth and refining. Chloride ion is used to shorten NaCl crystal nucleation induction period. PEG-1000 is used to control crystal particle size, change surface morphology and avoid crystals agglomerating. Ultrasonic field is used to assist in controlling crystal particle size and dispersivity.